Thermo-Mechanical Reliability of PCBs

PCB designers know that it is critical to design a board for temperature rise, thermal expansion and external structural loads. The difficulty has always been to capture a board’s structural makeup accurately without having an impractical effect on solve time.

CLICK HERE for a PDF that shows how ANSYS solves this challenge in a unique straightforward and effective manner.  And as always feel free to reach out to us at info@padtinc.com if you have any questions.

ANote_Picture

Fused Deposition Modeling (FDM) Properties: A Micromechanics Perspective

Have you ever looked at the mechanical properties in an FDM material datasheet (one example shown below for Stratasys ULTEM-9085) and wondered why properties were prescribed in the non-traditional manner of XZ and ZX orientation? You may also have wondered, as I did, whatever happened to the XY orientation and why its values were not reported? The short (and unfortunate) answer is you may as well ignore the numbers in the datasheet. The longer answer follows in this blog post.

FDM_01

Mesostructure has a First Order Effect on FDM Properties

In the context of FDM, mesostructure is the term used to describe structural detail at the level of individual filaments. And as we show below, it is the most dominant effect in properties.

Consider this simple experiment we did a few months ago: we re-created the geometry used in the tensile test specimens reported in the datasheets and printed them on our Fortus 400mc 3D printer with ULTEM-9085. While we kept layer thickness identical throughout the experiment (0.010″), we modified the number of contours: from the default 1-contour to 10-contours, in 4 steps shown in the curves below. We used a 0.020″ value for both contour and raster widths. Each of these samples was tested mechanically on an INSTRON 8801 under tension at a displacement rate of 5mm/min.

As the figure below shows, the identical geometry had significantly different load-displacement response – as the number of contours grew, the sample grew stiffer. The calculated modulii were in the range of 180-240 kpsi. These values are lower than those reported in datasheets, but closer to published values in work done by Bagsik et al (211-303 kpsi); datasheets do not specify the meso-structure used to construct the part (number of contours, contour and raster widths etc.). Further, it is possible to modify process parameters to optimize for a certain outcome: for example, as suggested by the graph below, an all-contour design is likely to have the highest stiffness when loaded in tension.

FDM-02

Can we Borrow Ideas from Micromechanics Theory?

The above result is not surprising – the more interesting question is, could we have predicted it? While this is not a composite material, I wondered if I could, in my model, separate the contours that run along the boundary from the raster, and identify each as it’s own “material” with unique properties (Er and Ec). Doing this allows us to apply the Rule of Mixtures and derive an effective property. For the figure below, the effective modulus Eeff becomes:

Eeff = f.Ec + (1-f).Er

where  represents the cross-sectional area fraction of the contours.

FDM-3

With four data points in the curve above, I was able to use two of those data points to solve the above equation simultaneously and derive Er and Ec as follows:

Er = 182596 psi
Ec = 305776 psi

Now the question became: how predictive are these values of experimentally observed stiffness for other combinations of raster and contours? In a preliminary evaluation for two other cases, the results look promising.

FDM-4

So What About the Orientation in Datasheets?

Below is a typical image showing the different orientations data are typically attributed to. From our micromechanics argument above, the orientation is not the correct way to look at this data. The more pertinent question is: what is the mesostructure of the load-bearing cross-section? And the answer to the question I posed at the start, as to why the XY values are not typically reported, is apparent if you look at the image below closely and imagine the XZ and XY samples being tested under tension. You will see that from the perspective of the load-bearing cross-section, XY and XZ effectively have the similar (not the same) mesostructure at the load-bearing cross-sectional area, but with a different distribution of contours and rasters – these are NOT different orientations in the conventional X-Y-Z sense that we as users of 3D printers are familiar with.

fdm-5

Conclusion

The point of this preliminary work is not to propose a new way to model FDM structures using the Rule of Mixtures, but to emphasize the significance of the role of the mesostructure on mechanical properties. FDM mesostructure determines properties, and is not just an annoying second order effect. While property numbers from datasheets may serve as useful insights for qualitative, comparative purposes, the numbers are not extendable beyond the specific process conditions and geometry used in the testing. As such, any attempts to model FDM structure that do not account for the mesostructure are not valid, and unlikely to be accurate. To be fair to the creators of FDM datasheets, it is worth noting that the disclaimers at the bottom of these datasheets typically do inform the user that these numbers “should not be used for design specifications or quality control purposes.”

If you would like to learn more and discuss this, and other ideas in the modeling of FDM, tune in to my webinar on June 28, 2016 at 11am Eastern using the link here, or read more of my posts on this subject below. If you are reading this post after that date, drop us a line at info@padtinc.com and cite this post, or connect with me directly on LinkedIn.

Thanks for reading!

~

Two related posts:

The Additive Manufacturing Software Conundrum

Why are there so many different software solutions in Additive Manufacturing and which ones do I really need?

This was a question I was asked at lunch during the recently concluded RAPID 3D printing conference by a manager at an aerospace company. I gave her my thoughts as I was stuffing down my very average panini, but the question lingered on long after the conference was over – several weeks later, I decided to expand on my response in this blog post.

There are over 25 software solutions available and being used for different aspects of Additive Manufacturing (AM). To answer the question above, I found it best to classify these solutions into four main categories based on their purpose, and allow sub-categories to emerge as appropriate. This classification is shown in Figure 1 below – and each of the 7 sub-categories are discussed in more detail in this post.

Figure 1. Seven sub-categories of software that are applicable to Additive Manufacturing, sorted by the need into four main categories

Basic Requirements

1. Design Modeler

You need this if you intend to create or modify designs

Most designs are created in CAD software such as SOLIDWorks, CATIA and SpaceClaim (now ANSYS SpaceClaim).  These have been in use long before the more recent rise in interest in AM and most companies have access to some CAD software internally already. Wikipedia has a comparison of different CAD software that is a good starting point to get a sense of the wide range of CAD solutions out there.

2. Build Preparation

You need this if you plan on using any AM technology yourself (as opposed to sending your designs outside for manufacturing)

Once you have a CAD file, you need to ensure you get the best print possible with the printer you have available. Most equipment suppliers will provide associated software with their machines that enable this. Stand-alone software packages do exist, such as the one developed by Materialise called Magics, which is a preferred solution for Stereolithography (SLA) and metal powder bed fusion in particular – some of the features of Magics are shown in the video below.

Scanning & File Transfer

3. Geometry Repair

You need this if you deal with low-quality geometries – either from scans or since you work with customers with poor CAD generation capabilities

Geomagic Design X is arguably the industry’s most comprehensive reverse engineering software which combines history-based CAD with 3D scan data processing so you can create feature-based, editable solid models compatible with your existing CAD software. If you are using ANSYS, their SpaceClaim has a powerful repair solution as well, as demonstrated in the video below.

Improving Performance Through Analysis

4. Topology Optimization

You need this if you stand to benefit from designing towards a specific objective like reducing mass, increasing stiffness etc. such as the control-arm shown in Figure 2

Topology optimization applied to the design of an automobile upper control-arm done with GENESIS Topology for ANSYS Mechanical (GTAM) from Vanderplaats Research & Development and ANSYS SpaceClaim
Figure 2. Topology optimization applied to the design of an automobile upper control-arm done with GENESIS Topology for ANSYS Mechanical (GTAM) from Vanderplaats Research & Development and ANSYS SpaceClaim

Of all the ways design freedom can be meaningfully exploited, topology optimization is arguably the most promising. The ability to now bring analysis up-front in the design cycle and design towards a certain objective (such as maximizing stiffness-to-weight) is compelling, particularly for high performance, material usage sensitive applications like aerospace. The most visible commercial solutions in the AM space come from Altair: with their Optistruct solution (for advanced users) and SolidThinking Inspire (which is a more user-friendly solution that uses Altair’s solver). ANSYS and Autodesk 360 Inventor also offer optimization solutions. A complete list, including freeware, can be availed of at this link.

5. Lattice Generation

You need this if you wish to take advantage of cellular/lattice structure properties for applications like such as lightweight structural panels, energy absorption devices, thermal insulation as well as medical applications like porous implants with optimum bone integration and stiffness and scaffolds for tissue engineering.

Broadly speaking, there are 3 different approaches that have been taken to lattice design software:

I will cover the differences between these approaches in detail in a future blog post. A general guideline is that the generative design approach taken by Autodesk’s Within is well suited to medical applications, while Lattice generation through topology optimization seems to be a sensible next step for those that are already performing topology optimization, as is the case with most aerospace companies pursuing AM technology. The infill/conformal approach is limiting in that it does not enable optimization of lattice structures in response to an objective function and typically involves a-priori definition of a lattice density and type which cannot then be modified locally. This is a fast evolving field – between new software and updates to existing ones, there is a new release on an almost quarterly, if not monthly basis – some recent examples are nTopology and the open source IntraLattice.

Below is a short video demo of Autodesk’s Within:

6. Analysis

You need this if you do either topology optimization or lattice design, or need it for part performance simulation

Basic mechanical FE analysis solvers are integrated into most topology optimization and lattice generation software. For topology optimization, the digitally represented part at the end of the optimization typically has jarring surfaces that are smoothed and then need to be reanalyzed to ensure that the design changes have not shifted the part’s performance outside the required window. Beyond topology optimization & lattice design, analysis has a major role to play in simulating performance – this is also true for those seeking to compare performance between traditionally manufactured and 3D printed parts. The key challenge is the availability of valid constitutive and failure material models for AM, which needs to be sourced through independent testing, from the Senvol database or from publications.

Process Development

7. Process Simulation

You need this if you would like to simulate the actual process to allow for improved part and process parameter selection, or to assess how changes in parameters influence part behavior

The real benefit for process simulation has been seen for metal AM. In this space, there are broadly speaking two approaches: simulating at the level of the part, or at the level of the powder.

  • Part Level Simulation: This involves either the use of stand-alone AM-specific solutions like 3DSIM and Pan Computing (acquired by Autodesk in March 2016), or the use of commercially available FE software such as ANSYS & ABAQUS. The focus of these efforts is on intelligent support design, accounting for residual stresses and part distortion, and simulating thermal gradients in the part during the process. ANSYS recently announced a new effort with the University of Pittsburgh in this regard.
  • Powder Level Simulation: R&D efforts in this space are led by Lawrence Livermore National Labs (LLNL) and the focus here is on fundamental understanding to explain observed defects and also to enable process optimization to accelerate new materials and process research

Part level simulation is of great interest for companies seeking to go down a production route with metal AM. In particular there is a need to predict part distortion and correct for it in the design – this distortion can be unacceptable in many geometries – one such example is shown in the Pan Computing (now Autodesk) video below.

A Note on Convergence

Some companies have ownership of more than one aspect of the 7 categories represented above, and are seeking to converge them either through enabling smooth handshakes or truly integrate them into one platform. In fact, Stratasys announced their GrabCAD solution at the RAPID conference, which aims to do some of this (minus the analysis aspects, and only limited to their printers at the moment – all of which are for polymers only). Companies like Autodesk, Dassault Systemes and ANSYS have many elements of the 7 software solutions listed above and while it is not clear what level of convergence they have in mind, all have recognized the potential for a solution that can address the AM design community’s needs. Autodesk for example, has in the past 2 years acquired Within (for lattice generation), netfabb (for build preparation) and Pan Computing (for simulation), to go with their existing design suite.

Conclusion: So what do I need again?

What you need depends primarily on what you are using AM technologies for. I recommend the following approach:

  • Identify which of the 4 main categories apply to you
  • Enumerate existing capabilities: This is a simple task of listing the software you have access to already that have capabilities described in the sub-categories
  • Assess gaps in software relative to meeting requirements
  • Develop an efficient road-map to get there: be aware that some software only make sense (or are available) for certain processes

In the end, one of the things AM enables is design freedom, and to quote the novelist Toni Morrison: Freedom is not having no responsibilities; it is choosing the ones you want.”  AT PADT, we work with design and analysis software as well as AM machines on a daily basis and would love to discuss choosing the appropriate software solutions for your needs in greater detail. Send us a note at info@padtinc.com and cite this blog post, or contact me directly on LinkedIn. .

Thank you for reading!

Simulation Driven Product Development with Free Form Fabrication

am-topo-prezo-titleJoining Two of PADT’s Favorite Things: Simulation and 3D Printing

Recent advances in Additive Manufacturing (3D Printing) have removed barriers to manufacturing certain geometry because of constraints in traditional manufacturing methods. Although you can make almost any shape, how do you figure out what shape to make. Using ANSYS products you can apply topological optimization to come up with a free-form shape that best meets your needs, and that can be made with Additive Manufacturing.

A few months ago we presented some background information on how to drive the design of this type of part using ANSYS tools to a few of our customers.  It was a well received so we cleaned it up a bit (no guarantee there all the typos are gone) and recorded the presentation.  Here it is on YouTube

Let us know what you think and if you have any questions or comments, please contact us.

ANSYS R17 Brings Added Tools to Mechanical Licenses

ansys-r17-splashSome of you have probably already noticed, but ANSYS Mechanical licenses have some changes at version 17. First, the license that for years has been known as ANSYS Mechanical is now known as ANSYS Mechanical Enterprise. Further, ANSYS, Inc. has enabled significantly more functionality with this license at version 17 than was available in prior versions. Note that the license task in the ANSYS license files, ‘ansys’ has not changed.

16.2 and Older (task) 17.0 (task)
ANSYS Mechanical (ansys) ANSYS Mechanical Enterprise (ansys)

The 17.0 ANSYS License Manager unlocks additional capability with this license, in addition to the existing Mechanical structural/thermal abilities. Previously, each of these tools used to be an additional cost. The change includes other “Mechanical-” licenses: e.g. Mech-EMAG, Mech CFD. The new tools enabled with ANSYS Mechanical Enterprise licenses at version 17.0 are:

Fatigue Module Rigid Body Dynamics Explicit STR Composite PrepPost (ACP)
SpaceClaim DesignXplorer ANSYS Customization Suite AQWA

Additionally, at version 17.1 these tools are included as well:

AIM Simplorer Entry

These changes do not apply to the lower level licenses, such as ANSYS Structural and Professional. In fact, these licenses are moving to ‘legacy’ mode at version 17. Two newer products now slot below Mechanical Enterprise. These newer products are ANSYS Mechanical Premium and ANSYS Mechanical Pro. We won’t explain those products here, but your local ANSYS provider can give you more information on these two if needed.

Getting back to the additional capabilities with Mechanical Enterprise, these become available once the ANSYS 17.0 and/or the ANSYS 17.1 license manager is installed. This assumes you have a license file that is current on TECS (enhancements and support). Also, a new license task is needed to enable Simplorer Entry.
Ignoring Simplorer Entry for the moment, once the 17.0/17.1 license manager is installed, the single Mechanical Enterprise license task (ansys) now enables several different tools. Note that:

  • Multiple tool windows can be open at once
    • g. ANSYS Mechanical and SpaceClaim
  • Only one can be “active” at a time
    • If solving, can’t edit geometry in SpaceClaim
  • Capabilities are then available in older versions, where applicable, once the 17.0/17.1 license manager is installed

Here is a very brief summary of these newly available capabilities:

Fatigue Module:

  • Runs in the Mechanical window
  • Can calculate fatigue lives for ‘simple’ products (linear static analysis)
    • Stress-life for
      • Constant amplitude, proportional loading
      • Variable amplitude, proportional loading
      • Constant amplitude, non-proportional loading
    • Strain-life
      • Constant amplitude, proportional loading
    • Activated by inserting the Fatigue Tool in the Mechanical Solution branch
    • Postprocess fatigue lives as contour plots, etc.
    • Requires fatigue life data as material properties

ansys-rbd-1Rigid Body Dynamics:

  • Runs in the Mechanical window
  • ANSYS, Inc.-developed solver using explicit time integration, energy conservation
  • Use when only concerned about motion due to joints and contacts
    • To determine forces and moments
  • Activated via Rigid Dynamics analysis system in the Workbench window

drop-test-of-mobile-phoneExplicit STR:

  • Runs in the Mechanical window
  • Utilizes the Autodyn solver
  • For highly nonlinear, short duration structural transient problems
    • Drop test simulations, e.g.
    • Lagrangian-only
  • Activated via Explicit Dynamics analysis system in the Workbench window

simulation-of-3d-compositesComposite PrepPost (ACP):

  • Tools for preparing composites models and postprocessing composites solutions
  • Define composite layup
    • Fiber Directions and Orientations
    • Draping
    • Optimize composite design
  • Results evaluation
    • Layer stresses
    • Failure criteria
    • Delamination
    • Wrinkling
  • Activated via ACP (Pre) and ACP (Post) component systems in the Workbench window

SpaceClaim-Model1bSpaceClaim:

  • Geometry creation/preparation/repair/defeaturing tool
  • Try it, learn it, love it
  • A direct modeler so no history tree
    • Just create/modify on the fly
    • Import from CAD or create in SpaceClaim
    • Can be an incredible time saver in preparing geometry for simulation
  • Activated by right clicking on the Geometry cell in the Workbench project schematic

DesignXplorer:

  • Design of Experiments/Design Optimization/Robust Design Tool
  • Allows for variation of input parameters
    • Geometric dimensions including from external CAD, license permitting
    • Material property values
    • Loads
    • Mesh quantities such as shell thickness, element size specifications
  • Track or optimize on results parameters
    • Max or min stress
    • Max or min temperature
    • Max or min displacement
    • Mass or volume
  • Create design of experiments
  • Fit response surfaces
  • Perform goals driven optimizations
    • Reduce mass
    • Drive toward a desired temperature
  • Understand sensitivities among parameters
  • Perform a Design for Six Sigma study to determine probabilities
  • Activated by inserting Design Exploration components into the Workbench project schematic

ANSYS Customization Suite:

  • Toolkit for customization of ANSYS Workbench tools
  • Includes tools for several ANSYS products
    • Top level Workbench
    • DesignModeler
    • Mechanical
    • DesignXplorer
  • Based on Python and XML
  • Wizards and documentation included

AQWA:

  • Offshore tool for ship, floating platform simulation
  • Uses hydrodynamic defraction for calculations
  • Model up to 50 structures
  • Include effects of moorings, fenders, articulated connectors
  • Solve in static, frequency, and time domains
  • Transfer motion and pressure info to Mechanical
  • Activated via Hydrodynamic Diffraction analysis system in the Workbench window

AIM:

  • New, common user interface for multiphysics simulations
    • Structural
    • Thermal
    • CFD
    • Electromagnetics
  • Capabilities expanding with each ANSYS release (was new at 16.0)
  • Uses SpaceClaim as geometry tool
  • Single window
  • Easy to follow workflow
  • Activated from the ANSYS 17.0/17.1 Start menu

Simplorer Entry:

  • System level simulation tool
  • Simulate interactions such as between
    • Controllers
    • Actuators
    • Sensors
    • Structural Reduced Order Models
    • Simple circuitry
  • Optimize complex system performance
    • Understand interactions and trade offs
  • Entry level tool, limited to 30 models (Simplorer Advanced enables more)
  • Activated from the ANSYS Electromagnetics tools (separate download)
  • Requires an additional license task from ANSYS, Inc.

Where to get more information:

  • Your local ANSYS provider
  • ANSYS Help System
  • ANSYS Customer Portal

Do you have an Internet of Things Strategy? PADT Can Help

thing-1-250w“It is not just a trend, it is a Tsunami. One day you will wake up and see a giant wave headed your way, and that wave will be the Internet of Things!”

This was the opening line from a presentation given by the VP of sales for a major engineering software company. It got my attention because it wasn’t hype or hyperbole.  He was just pointing out the obvious. Over the past two years the signs have been there. Smart devices will connected to the internet, and older devices will be made smart and then connected. Those that don’t, will no longer be competitive.

It is not all about smart thermostats. Far from it.  I went to IoT world in San Jose last week and saw a lot of people scrambling to find their solution. And a few that found them.  The best example was an older letter stamping machine, you can guess at the manufacturer, that plugged a modular device from Electric Imp in to their controller and boom – they were connected.  Some back end programming and they now had a competitive IoT device.

iot-networ-graphic-1 It is time to define and execute on your IoT strategy

When we visit customers, we will often ask them what their IoT Strategy is.  The answers vary from “we don’t really think our products have an IoT play” to existing products on the market.  The focus in the media is on consumer IoT products, but the bigger push right now is for industrial Internet, where machines used in manufacturing, energy generation, raw material extraction, and processing are smart and connected.

Customers from consumers to other companies will be requiring the benefits of IoT devices as they look to replace older hardware.  That is why every company that makes physical products needs to develop an IoT strategy.

PADT Can Help

We have been helping our customers define and implement their approach to IoT well, since before it was called the Internet of Things.  From assisting semiconductor companies that make MEMS sensors to making smart medical devices we are plugged in to what is needed to make IoT work.

iot-landing-page-padt-1A good place to start is our IoT landing page at:

www.padtinc.com/iot

There you can find some basic information about how PADT is a more comprehensive and technically capable solution then most design houses that claim to have IoT solutions.  We are uniquely qualified to make sure the “Thing” in your IoT strategy is designed and manufactured right.

pbj-phoenix-business-journal-logoWe also published a series of articles in the Phoenix Business Journal that provide some fundamental background information on the Internet of Things and how to deal with the challenges it presents:

ansys-iot-wheelSimulation can play a big role in almost every aspect of making your IoT device development faster and more productive.  PADT uses ANSYS, Inc.’s comprehensive Multiphysics simulation tool set to model everything from the chip to the embedded system software.

We highly recommend this white paper, “Engineering the Internet of Things

We also have a recording of a very popular webinar that we did: “Engineering the Internet of Things Devices with ANSYS Simulation

and this video on how ANSYS can drive your IoT Design:

For detailed examples, check out the ANSYS IoT Landing page to get a feel for why so many companies are driving their design with ANSYS simulation software:  www.ansys.com/iot

PADT-Webinar-Logo

Engineering the Internet of Things Devices with ANSYS Simulation

June 21, 2016 (Tue)
1:00 PM AZ & PDT / 2:00 pm MDT

REGISTER

Make sure you subscribe to PADT’s email list so you don’t miss future Events

Talking is the Best Approach

We hope that you find all of the material above, and the information we will provide in the coming months useful. But they are no substitute for giving us a call or sending us an email and setting up a face-to-face to talk about your IoT strategy and device development needs.  If you are doing the work in-house, we have the hardware and software tools you need to be successful. If you need outside help, you won’t find engineers with more applicable experience.

Give us a call at 1-800-293-PADT or email info@padtinc.com.

shutterstock_321231902

Unexpected Joys at Rapid 2016

While much has been (justifiably) written about HP and XJet releasing new, potentially game-changing products at RAPID 2016, I wanted to write this post about some of the smaller, unexpected joys that I discovered. If I sound overly enthusiastic about the people and companies behind them, it is likely due to the fact that I wrote this on the flight back, staring out at the clouds and reflecting on what had been a wonderful trip: I own no locks, stocks or barrels in any of these companies.

1. Essentium Materials – Carbon Nanotubes and Microwaves to improve FDM mechanical properties
Over the past year, I have studied, written and made presentations about the challenges of developing models for describing Fused Deposition Modeling (FDM) given their complex and part-specific meso-structure. And while I worked on developing analytical and numerical techniques for extracting the best performance from parts in the presence of significant anisotropy, the team at Essentium has developed a process to coat FDM filaments with Carbon nanotubes and extrude them in the presence of microwave radiation. In the limited data they showed for test specimens constructed of unidirectional tool-paths, they demonstrated significant reduction in anisotropy and increase in strength for PLA. What I liked most about their work is how they are developing  this solution on a foundation of understanding the contributions of both the meso-structure and inter-filament strength to overall part performance. Essentium was awarded the “RAPID Innovations award”, first among the 27 exhibitors that competed and are, in my opinion, addressing an important problem that is holding back greater expansion of FDM as a process in the production space.
Website: http://essentiummaterials.com/

2. Hyrel 3D – Maker meets Researcher meets The-Kid-in-All-of-Us
I only heard of Hyrel 3D a few days prior to RAPID, but neglected to verify if they were exhibiting at RAPID and was pleasantly surprised to see them there. Consider the options this 3D printer has that you would be hard pressed to find in several 3D printers combined: variable extrusion head temperatures (room temp to 450 C), sterile head options for biological materials, a 6W laser (yes, a laser), spindle tools, quad head dispensing with individual flow control and UV crosslinking options. Read that again slowly. This is true multiple degree-of-freedom material manipulation. What makes their products even more compelling is the direct involvement of the team and the community they are building up over time, particularly in academia, across the world, and the passion with which they engage their technology and its users.
Website: http://www.hyrel3d.com/

3. Technic-Print: New Chemistry for Improved FDM Support Removal
If you manufacture FDM parts with soluble supports, keep reading. A chemist at Technic Inc. has developed a new solution that is claimed to be 400% faster than the current Sodium-Hydroxide solution we use to dissolve parts. Additionally, the solution is cited as being cleaner on the tank, leaving no residue, has a color indicator that changes the solution’s color from blue to clear. And finally, through an additional agent, the dissolved support material can be reclaimed as a clump and removed from the solution, leaving behind a solution that has a pH less than 9. Since PADT manufactures one of the most popular machines that are used to dissolve these supports that unbeknown to us, were used in the testing and development of the new solution, we had an enriching conversation with the lead chemist behind the solution. I was left wondering about the fundamental chemistry behind color changing, dissolution rates for supports and the reclaiming of support – and how these different features were optimized together to develop a usable end-solution.
Website: http://www.technic.com/techni-print-lp

 

4. Project Pan: Computationally Efficient Metal Powder Bed Fusion Simulation
I presented a literature review at AMUG (another Additive Manufacturing conference) last month, on the simulation of the laser-based powder bed fusion. At the time, I thought I had captured all the key players between the work being done at Lawrence Livermore National Labs by Wayne King’s group, the work of Brent Stucker at 3DSIM and the many academics using mostly commercially available software (mostly ANSYS) to simulate this problem. I learned at RAPID that I had neglected to include a company called “Project Pan” in my review. This team emerged from Prof. Pan Michaleris’s academic work. In 2012, he started a company that was acquired by Autodesk two months ago. In a series of 3 presentations at RAPID, Pan’s team demonstrated their simulation techniques (at a very high level) along with experimental validation work they had done with GE, Honeywell and others through America Makes and other efforts. What was most impressive about their work was both the speed of their computations and the fact that this team actually had complex part experimental validations to back up their simulation work. What most users of the powder bed fusion need is information on temperatures, stresses and distortion – and within time frames of a few hours ideally. It seems to me that Pan and his team took an approach that delivers exactly that information and little else using different numerical methods listed on their site (novel Hex8 elements, an element activation method and intelligent mesh refinement) that were likely developed by Pan over the years in his academic career and found the perfect application, first in welding simulation and then in the powder bed fusion process. With the recent Autodesk acquisition, it will be interesting to see how this rolls out commercially. Details of some of the numerical techniques used in the code can be found at their website, along with a list of related publications.

Website: http://pancomputing.com/

5. FDA Participation: Regulating through education and partnership
On a different note from the above, I was pleasantly surprised by the presence of the FDA, represented by Matthew Di Prima, PhD. He taught part of a workshop I attended on the first day, took the time to talk to everyone who had an interest and also gave a talk of his own in the conference sessions, describing the details of the recently released draft guidance from the FDA on 3D printing in medical applications. It was good to connect the regulatory agency to a person who clearly has the passion, knowledge, intelligence and commitment to make a difference in the Additive Manufacturing medical community. Yes, the barriers to entry in this space are high (ISO certifications, QSR systems, 510(k) & Pre-Market Approvals) but it seems clear that the FDA, at least as represented by Dr. Di Prima, are doing their best to be a transparent and willing partner.
Website: http://www.fda.gov/MedicalDevices/ProductsandMedicalProcedures/3DPrintingofMedicalDevices/default.htm

What really makes a trip to a conference like RAPID worth it are the new ideas, connections and possibilities you come away with that you may not stumble upon during your day job – and on that account, RAPID 2016 did not disappoint. As a line in one of my favorite song’s goes:

“We’ll never know, unless we grow.
There’s too much world outside the door.”
– Fran Healy (Travis, “Turn”).

Just One CUBE With Just One Click! A 1.3x Speedup For ANSYS® Mechanical™

Greetings from the HPC numerical simulation proving grounds of PADT, Inc. in Tempe, Arizona. While bench marking the very latest version of ANSYS® Mechanical™ I learned something very significant and I need to share this information with you right now.As I gazed down on the data outputs from the new solve.out files, I began to notice something. Yes change indeed, something was different, something had changed.

A brief pause for emphasis, in regards in overall ANSYS® productivity and amazing improvements please read this post.

However, pertaining to this blog post, I am focusing on one very important HPC performance metric to me. It is one of the many HPC performance metrics that I have used when creating a balanced HPC server for engineering simulation.. But wait there is more! so please wait just a little bit longer, for very soon I will post even more juicy pieces of data garnered from taken from these new ANSYS® benchmark solver files.

To recap in all of its bullets points & glories:

  • For today and just for today, we are focusing on just one of the performance metrics.
    • The Time Spent Computing The Solution!
  • This 1.3x speedup in solve times was achieved using just one CUBE workstation and with just one click!
    • Open ANSYS®and while you are creating your solve.
    • Select, withjust one click either the INTEL MPI or IBM Platform MPI.
    • Next, run your test repeat as necessary using whichever MPI version that you did not start your test with.

The ANSYS® Mechanical™ Benchmark Description:

  • V15sp-5
    • Sparse solver, symmetric matrix, 6000k DOFs, transient, nonlinear, structural analysis with 1 iteration
    • GPU Accelerator or Co-Processor enabled for: NVIDIA and Intel Phi
    • A large sized job for direct solvers, should run incore on machines with 128 GB or more of memory, good test of processor flop speed if running incore and I/O if running out-of-core

CUBE ANSYS Numerical Simulation Appliance Used:

The ANSYS® Mechanical™ Benchmark Results:


TIME SPENT COMPUTING THE SOLUTION TIME SPENT COMPUTING THE SOLUTION
IBM Platform MPI INTEL MPI
Cores 2016 CUBE w16i-v4 2016 CUBE w16i-v4 This Speedup is…X faster!
2 396.1 380.9 1.04
4 239.7 229.6 1.04
6 210.1 196.7 1.07
8 182.9 168.7 1.08
10 167.2 161.4 1.04
12 167.1 160.7 1.04
14 196.1 151.3 1.30
16 184.7 161.7 1.14

justonecubejustoneclickspeedup

Wow! using these latest 14nm INTEL® XEON®  CPU’s, phew, I have been forever changed! As you can see from the data above, in just one simple click, changing from the IBM Platform MPI to using INTEL MPI and look! the benchmark time spent computing times are faster! A 1.3x Speedup!

Now in this specific benchmark example along with the use of the latest  ANSYS® Mechanical achieving a 1.3x speedup without spending another penny is very wise and not so foolish.

Disclaimer: Please check with your ANSYS Software Sales Representative for the very latest on solver updates and information. Because some of the models and compatibility can very on the . You may need to use the MS-MPI, INTEL-MPI or IBM Platform MPI for your distributed solving. If you are not sure please contact your local ANSYS® Corporate Software Sales or ANSYS® Software Channel Partner that was assigned specifically to you and/or your company.

References:

http://www.ansys.com/Solutions/Solutions-by-Role/IT-Professionals/Platform-Support/Benchmarks-Overview/ANSYS-Mechanical-Benchmarks

PADT and ASU Collaborate on 3D Printed Lattice Research

The ASU Capstone team (left to right): Drew Gibson, Jacob Gerbasi, John Reeher, Matthew Finfrock, Deep Patel and Joseph Van Soest.
ASU student team (left to right): Drew Gibson, Jacob Gerbasi, John Reeher, Matthew Finfrock, Deep Patel and Joseph Van Soest

Over the past two academic semesters (2015/16), I had the opportunity to work closely with six senior-year undergraduate engineering students from the Arizona State University (ASU), as their industry adviser on an eProject (similar to a Capstone or Senior Design project). The area we wanted to explore with the students was in 3D printed lattice structures, and more specifically, address the material modeling aspects of these structures. PADT provided access to our 3D printing equipment and materials, ASU to their mechanical testing and characterization facilities and we both used ANSYS for simulation, as well as a weekly meeting with a whiteboard to discuss our ideas.

While there are several efforts ongoing in developing design and optimization software for lattice structures, there has been little progress in developing a robust, validated material model that accurately describes how these structures behave – this is what our eProject set out to do. The complex internal meso- and microstructure of these structures makes them particularly sensitive to process variables such as build orientation, layer thickness, deposition or fusion width etc., none of which are accounted for in models for lattice structures available today. As a result, the use of published values for bulk materials are not accurately predictive of true lattice structure behavior.

In this work, we combined analytical, experimental and numerical techniques to extract and validate material parameters that describe mechanical response of lattice structures. We demonstrated our approach on regular honeycomb structures of ULTEM-9085 material, made with the Fused Deposition Modeling (FDM) process. Our results showed that we were able to predict low strain responses within 5-10% error, compared to 40-60% error with the use of bulk properties.

This work is to be presented in full at the upcoming RAPID conference on May 18, 2016 (details at this link) and has also been accepted for full length paper submission to the SFF Symposium. We are also submitting a research proposal that builds on this work and extends it into more complex geometries, metals and failure modeling. If you are interested in the findings of this work and/or would like to collaborate, please meet us at RAPID or send us an email (info@padtinc.com).

Our final poster and the Fortus 400mc that we printed all our honeycomb structures with
The final poster summarizing our work rests atop the Stratasys Fortus 400mc that we printed all our honeycomb structures on

Webinars: Overview of Add-On Products that Work with ANSYS Mechanical

PADT-Webinar-LogoWith the introduction of the new ANSYS Mechanical Enterprise, many add-on products that had to be purchased separate, are now included. In these webinars PADT’s engineers will provide an overview of the key applications that users now have easy access to.

Each product will be reviewed by one of PADT’s engineers. The will share the functionality of each tool, discuss some lessons we have learned in using and supporting each tool, and provide a short demonstration. Each session will have time for Questions and Answers.

ANSYS-Footer-RBD-STR-ACT

Sign up for the one you want, or all three. Everyone that registers will receive a link to the recording and to a copy of the slides. So register even if you can not make the specific dates.

Here are the times and links to register:

Overview of ANSYS Rigid Body Dynamics (RBD) and ANSYS Explicit STR
May 19, 2016 (Thu)
11:00 am MST & PDT / 12:00 pm MDT

      REGISTER

Overview of ANSYS SpaceClaim and ANSYS AIM
May 24, 2016 (Tue)
11:00 am MST & PDT / 12:00 pm MDT

    REGISTER

Overview of ANSYS Customization Toolkit (ACT) and ANSYS DesignXplorer (DX)
May 26, 2016 (Thu)
11:00 am MST & PDT / 12:00 pm MDT

     REGISTER

We hope to see you online.  If you have any questions, contact us at support@padtinc.com or call 480.813.4884.

ANSYS_Mechanical_Header

An Eye for the Win! – Signal Integrity with ANSYS

DDRComparisonIn today’s world of high speed communication we are continuously pushing the envelope in data throughput and reliability – There are many challenges that restrict speedy progress: Time – Spinning multiple boards to find and fix problems costs valuable time and money; Cost – additional test procedures can significantly add to this cost; Scalability of Solutions – it’s fundamentally difficult to accurately predict what might happen solely through previous experiences; which is often why multiple spins are required.

ANSYS has the simulation platform that enable signal integrity engineers to predict and improve the performance of high speed communication channels before any board is prototyped – Imagine being able get the design right the first time by testing several design parameters such as different trace routing, power profiles and components.

This sounds like a great proposition but in actuality what do you get from doing that? The answer is a reduced design cost, detailed insight into the design and a reduced time to market. The only way to obtain this “full picture” is to understand the electrical, thermal and mechanical aspects of the design.

EyediagramEye Diagram of Data Signal Obtained in ANSYS

A critical characterization in high speed communication channel design is the Eye diagram. Extensive testing is done to obtain Eye diagrams for various signal nets across a PCB or Package – ANSYS can provide the Eye diagram so that engineers can address potential failures and weaknesses in their design before it is sent out for prototyping. Bathtub curves, effects of jitter and identifying crosstalk are equally important in the design of communication channels and all can be obtained and considered with ANSYS tools.

ANSYS supports IBIS-AMI modeling, SERDES design, TDR measurement and Statistical Eye analysis among much more. With chip, memory and board manufacturers all utilizing ANSYS products it is easy to incorporate and analyze real world product performance of the entire PCB.

TDRTDR Measurement Across Net

ANSYS allows all aspects of the design to be tested and optimized before prototyping. Apart from signal integrity ANSYS tools can also accurately model power integrity concerns such as decoupling capacitor optimization, thermal response and structural issues, as well as cooling solutions for chips, packages, PCBs and full electronic systems. With the ability to analyze and help optimize different design characteristics of a PCB, ANSYS can provide engineers with “the full picture” to help reduce cost and time to market, and to understand the design’s expected real world operation.

VoltageDropBoardWarpageElectronicsCooling

Top: Voltage Drop; Middle: PCB Warpage;
Bottom: Cooling Flow Through Enclosure

The “Eye” is only a phone call away.

Please give us a call at 1-800-293-PADT or reach out to me directly at manoj@padtinc.com for more information.

Phoenix Business Journal: ​What is numerical simulation? And why should I care?

pbj-phoenix-business-journal-logoNumerical simulation has been the bulk of my career for 30 years now. I love simulation. It has had a huge positive impact on product development as well as many other industries.  In “What is numerical simulation? And why should I care?” I evangelize a bit about my professional passion.

Helpful New Meshing Feature in ANSYS Mechanical 17.0 – Nonlinear Mechanical Shape Checking

ansys=new-mesh-r17Meshing for Nonlinear Structural Problems

Overcoming convergence difficulties in nonlinear structural problems can be a challenge. I’ve written a couple of times previously about tools that can help us overcome those difficulties:

I’m pleased to announce a new tool in the ANSYS Mechanical tool belt in version 17.0.
With version 17.0 of ANSYS we get a new meshing option for structural simulations: Nonlinear Mechanical Shape Checking. This option has been added to the previously available Standard Mechanical Shape Checking and Aggressive Mechanical Shape Checking. For a nonlinear solution in which elements can become significantly distorted, if we start with better-shaped elements they can undergo larger deformations without encountering errors in element formulation we may encounter fewer difficulties as the nodes deflect and the elements become distorted. The nonlinear mechanical setting is more restrictive on the element shapes than the other two settings.

We’ve been recommending the aggressive mechanical setting for nonlinear solutions for quite a while. The new nonlinear mechanical setting is looking even better. Anecdotally, I have one highly nonlinear customer model that reached 95% of the applied load before a convergence failure in version 16.2. That was with the aggressive mechanical shape checking. With 17.0, it reached 99% simply by remeshing with the same aggressive setting and solving. That tells you that work has been going on under the hood with the ANSYS meshing and nonlinear technology. By switching to the new nonlinear mechanical shape checking and solving again, the solution now converges for the full 100% of the applied load.
Here are some statistics using just one measure of the ‘goodness’ of our mesh, element quality. You can read about the definition of element quality in the ANSYS Help, but in summary better shaped elements have a quality value close to 1.0, while poorly shaped elements have a value closer to zero. The following stats are for tetrahedral meshes of a simple turbomachinery blade/rotor sector model (this is not a real part, just something made up) comparing two of the options for element shape checking. The table shows that the new nonlinear mechanical setting produces significantly fewer elements with a quality value of 0.5 or less. Keep in mind this is just one way to look at element quality – other methods or a different cutoff might put things in a somewhat different perspective. However, we can conclude that the Nonlinear Mechanical setting is giving us fewer ‘lower quality’ elements in this case.

Shape Checking Setting Total Elements Elements w/Quality <0.5 % of elements w/Quality <0.5
Aggressive Mechanical 31683 1831 5.8
Nonlinear Mechanical 31865 1249 3.9

Here are images of a portion of the two meshes mentioned above. This is the mesh with the Aggressive Mechanical Shape Checking option set:ansys-new-meshing-17-01
The eyeball test on these two meshes confirms fewer elements at the lower quality contour levels.

And this is the mesh with the Nonlinear Mechanical Shape Checking option set:

ansys-new-meshing-17-02

So, if you are running nonlinear structural models, we urge you to test out the new Nonlinear Mechanical mesh setting. Since it is more restrictive on element shapes, you may see longer meshing times or encounter some difficulties in meshing complex geometry. You may see a benefit in easier to converge nonlinear solutions, however. Give it a try!

Driving the Design of Small Modular Nuclear Reactors with Flownex

Flownex-Logo-2015-250wThe development of small modular nuclear reactors, or SMR’s, is a complex task that involves balancing the thermodynamic performance of the entire system. Flownex is the ideal tool for modeling  pressure drop [flow] and heat transfer [temperature] for the connected components of a complete system in steady state and transient, sizing and optimizing pumps or compressors, pipes, valves, tanks, and heat exchangers.

To highlight this power and capability,  PADT and Flownex will be exhibiting at the 2016 SMR conference in Atlanta where we will be available to discuss exciting new Flownex developments in system and subsystem simulations of SMRs.  If you are attending this year’s event, please stop by the Flownex booth and say hello to experts from M-Tech and PADT.

If you are not able to make the conference or if you want to know more now, you can view more information from the new Flownex SMR brochure or this video:

Why is Flownex a Great Tool for SMR Design and Simulation?

These developments offer greatly reduced times for performing typical design tasks required for Small Modular Nuclear Reactor (SMR) projects including sizing of major components, calculating overall plant efficiency, and design for controllability

This task involves typical components like the reactor primary loop, intermediate loops, heat exchangers or steam generators and the power generation cycle. Flownex provides for various reactor fuel geometries, various reactor coolant types and various types of power cycles.

Flownex can also be used for determining plant control philosophy. By using a plant simulation model, users can determine the transient response of sensed parameters to changes in input parameters and based on that, set up appropriate pairings for control loops.

For passive safety system design Flownex can be used to optimize the natural circulation loops.  The program can calculate the dynamic plant-wide temperatures and pressures in response to various accident scenarios, taking into account decay heat generation, multiple natural circulation loops, transient energy storage and rejection to ambient conditions.

flownex-smr-model-1

Learn more at www.padtinc.com/flownex, give us a call at 480.813.4884 or email brian.duncan@padtinc.com.

 

New Tricks for an Old Dog: Eric Learns ANSYS SpaceClaim – Post 3

Adding Complexity and Moving

ANSYS-SpaceClaim-Learning-00-00
This post is the third in a series on learning ANSYS SpaceClaim. After over 31 years of CAD use, it has become difficult for me to learn new tools. In this series I will share my experience as I explore and learn how to use this fantastic tool.
If you have not read the previous post, start here.  A table of contents is here.

After playing with that block it seems like it may be time to try a more complex geometry.  For business banking, I’ve got this key fob that generates a number every thirty seconds that I use for security when I log in.  Might as well sort of model that.

keyfob

So the first thing I do is start up a new model and orient myself on to the sketch plane:

ANSYS-SpaceClaim-Learning-03-01

Then I use the line and arc tools to create the basic shape. Play around a bit. I found that a lot of things I had to constrain in other packages are just assumed when you define the geometry.  A nice thing is that as you create geometry, it locks to the grid and to other geometry. ANSYS-SpaceClaim-Learning-03-02

I dragged around and typed in values for dimensions to get the shape I wanted. As I was doing it I realized I was in metric. I’m old, I don’t do metric. So I went in to File and selected SpaceClaim options from the bottom of the window.  I used the Units screen to set things to Imperial.

ANSYS-SpaceClaim-Learning-03-03

This is the shape I ended up with:

ANSYS-SpaceClaim-Learning-03-04

I took this and pulled it up and added a couple of radii:

ANSYS-SpaceClaim-Learning-03-05

But if I look at the real object, the flat end needs to be round.  In another tool, I’d go back to the sketch, modify that line to be an arc, and regen.  Well in SpaceClaim you don’t have the sketch, it is gone.    Ahhh. Panic. I’ve been doing it that way for 25 some years.  OK. Deep breath, just sketch the geometry I need. Click on the three point arc tool, drag over the surface, then click on the first corner, the second, and a third point to define the arc:

ANSYS-SpaceClaim-Learning-03-06

Then us pull to drag it down, using the Up to icon to lock it to the bottom of the object.

ANSYS-SpaceClaim-Learning-03-07

Then I clicked on the edges and pulled some rounds on there:

ANSYS-SpaceClaim-Learning-03-08

OK, so the next step in SolidEdge would be to do a thin wall.  I don’t see a thin wall right off the top, but shell looks like what I want, under the Create group on the Design tab.  So I spinned my model around, clicked on the bottom surface I want to have open and I have a shell.  A thickness of 0.035″ looks good:

ANSYS-SpaceClaim-Learning-03-09

My next feature will be the cutout for the view window.   What I have not figured out yet is how to lock an object to be symmetrical. Here is why. I sketch my cutout as such, not really paying attention to where it is located.  Now I want to move it so that it is centred on the circle.

ANSYS-SpaceClaim-Learning-03-10

Instead of specifying constraints, you move the rectangle to be centered.  To do that I drag to select the rectangle then click Move. By default it puts the nice Move tool in the middle of the geometry.  If I drag on the X direction (Red) you can see it shows the distance from my start.

ANSYS-SpaceClaim-Learning-03-11

So I have a couple of options, to center it. The easiest is to use Up To and click the X axis for the model and it will snap right there.  The key thing I learned was I had to select the red move arrow or it would also center horizontally where I clicked.

If I want to specify how far away the edge is from the center of the circle, the way I did it is kind of cool.  I selected my rectangle, then clicked move. Then I clicked on the yellow move ball followed by a click on the left line, this snapped the move tool to that line. Next I clicked the little dimension Icon to get a ruller, and a small yellow ball showed up. I clicked on this and dragged it to the center of my circle, now I had a dimension from the circle specified that I could type in.ANSYS-SpaceClaim-Learning-03-13

After playing around a bit, if found a second, maybe more general way to do this.  I clicked on the line I want to position.  One of the icons over on the left of my screen is the Move Dimension Base Point icon. If you click on that you get another one of those small yellow balls you can move. I dragged it over to the center of the circle and clicked. then I can specify the distance as 0.75″

ANSYS-SpaceClaim-Learning-03-14

I’ve got the shape I want, so I pull, using the minus icon to subtract, and I get my cutout:

ANSYS-SpaceClaim-Learning-03-15

If you look closely,you will notice I put rounds on the corners of the cutout as well, I used Pull again.

The last thing I want to do is create the cutout for where the bank logo goes. It is a concentric circle with an arc on the right side.  Saddly, this is the most complex thing I’ve ever sketched in SpaceClaim so I was a bit afraid. It was actually easy.  I made a circle, clicking on the center of the outside arc to make them concentric. The diameter was 1″. Then I made another circle of 2″ centered on the right.  To get the shape I wanted, I used the Trim Away command and clicked on the curves I don’t want. The final image is my cutout.

ANSYS-SpaceClaim-Learning-03-16

Now I can do the same thing, subtract it out, put in some rounds, and whalla:

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Oh, and I used the built in rendering tool to quickly make this image. I’ll have to dedicate a whole posting to that.

But now that I have my part, it is time to play with move in 3D.

Moving in 3D

Tyler, who is one of our in-house SpaceClaim experts (and younger) pointed out that I need to start thinking about editing the 3D geometry instead of being obsessed with controlling my sketches. So here goes.

If I wanted to change the size of the rectangular cutout in a traditional CAD tool, I’d go edit the sketch. There is no sketch to edit! Fear. Unknown. Change.

So the first thing I’ll do is just move it around. Grab one of the faces and see happens.

ANSYS-SpaceClaim-Learning-03-17

It moves back and forth, pretty simple.  The same tools for specifying the start and stop points are available. Now, if I ctrl-click on all four surfaces the whole thing moves. That is pretty cool.

ANSYS-SpaceClaim-Learning-03-18

Note: I’m using the undo all the time to go back to my un-moved geometry.

Another Note:  As you select faces, you have to spin the model around a lot. I use the middle mouse button to do this rather than clicking on the spin Icon and then having to unclick it.

Play with it some more. I was able to put draft by using the arcs on the Move gizmo, and if you pull far enough it adds material.ANSYS-SpaceClaim-Learning-03-19

That is enough for this post. More soon.