ANSYS Breakthrough Energy Innovation Campaign is live!

As the worldwide demand for energy continues to grow every year, energy systems simulation is becoming an indispensable tool for improving the way energy is produced and consumed. At the same time, concerns about climate change are leading to stricter emissions regulations and calls for sustainable design in all future energy systems. Clearly, breakthroughs in energy innovation are needed to meet these formidable challenges.

Join PADT in exploring the impact of breakthrough energy innovation as well as how ANSYS simulation solutions can be used to help combat the challenges that this area presents.

This campaign covers five main topics:

  1. Advanced Electrification
  2. Machine & Fuel Efficiency
  3. Effective Lightweighting
  4. Thermal Optimization
  5. Aerodynamic Design
Information on each topic will be released over the course of the next few months as the webinars take place.
The campaign will consist of a series of webinars explaining the applications of ANSYS simulations software with regards to each topic, along with additional downloadable content.

Sign Up Now to receive updates regarding the campaign, including additional information on each subject, registration forms to each webinar and more.

More information regarding the campaign in general can be found Here.

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Classification of Cellular Solids (and why it matters)

Updated (8/30/2016): Two corrections made following suggestions by Gilbert Peters: the first corrects the use of honeycomb structures in radiator grille applications as being for flow conditioning, the second corrects the use of the Maxwell stability criterion, replacing the space frame example with an octet truss.

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This is my first detailed post in a series on cellular structures for additive manufacturing, following an introductory post I wrote where I classified the research landscape in this area into four elements: design, analysis, manufacturing and implementation.

Within the design element, the first step in implementing cellular structures in Additive Manufacturing (AM) is selecting the appropriate unit cell(s). The unit cell is selected based on the performance desired of it as well as the manufacturability of the cells. In this post, I wish to delve deeper into the different types of cellular structures and why the classification is important. This will set the stage for defining criteria for why certain unit cell designs are preferable over others, which I will attempt in future posts. This post will also explain in greater detail what a “lattice” structure, a term that is often erroneously used to describe all cellular solids, truly is.

1. Honeycomb

1.1 Definition
Honeycombs are prismatic, 2-dimensional cellular designs extruded in the 3rd dimension, like the well-known hexagonal honeycomb shown in Figure 1. All cross-sections through the 3rd dimension are thus identical, making honeycombs somewhat easy to model. Though the hexagonal honeycomb is most well known, the term applies to all designs that have this prismatic property, including square and triangular honeycombs. Honeycombs have a strong anisotropy in the 3rd dimension – in fact, the modulus of regular hexagonal and triangular honeycombs is transversely isotropic – equal in all directions in the plane but very different out-of-plane.

Figure 1. Honeycomb structure showing two-dimensional, prismatic nature (Attr: modified from work done by George William Herbert, Wikipedia)
honeycomb_bmwi3
Figure 2. Honeycomb design in use as part of a BMW i3 crash structure (Attr: adapted from youkeys, Wikipedia)

1.2 Design Implications
The 2D nature of honeycomb structures means that their use is beneficial when the environmental conditions are predictable and the honeycomb design can be oriented in such a way to extract maximum benefit. One such example is the crash structure in Figure 2 as well as a range of sandwich panels. Several automotive radiator grilles are also of a honeycomb design to condition the flow of air. In both cases, the direction of the environmental stimulus is known – in the former, the impact load, in the latter, airflow.

2. Open-Cell Foam

openfoam
Figure 3. Open cell foam unit cell, following Gibson & Ashby (1997)

2.1 Definition
Freeing up the prismatic requirement on the honeycomb brings us to a fully 3-dimensional open-cell foam design as shown in one representation of a unit cell in Figure 3. Typically, open-cell foams are bending-dominated, distinguishing them from stretch-dominated lattices, which are discussed in more detail in a following section on lattices.

2.2 Design Implications
Unlike the honeycomb, open cell foam designs are more useful when the environmental stimulus (stress, flow, heat) is not as predictable and unidirectional. The bending dominated mechanism of deformation make open-cell foams ideal for energy absorption – stretch dominated structures tend to be stiffer. As a result of this, applications that require energy absorption such as mattresses and crumple zones in complex structures. The interconnectivity of open-cell foams also makes them a candidate for applications requiring fluid flow through the structure.

Metal_Foam
Figure 4. SEM image of a metallic open-cell foam (Attr: SecretDisc, Wikipedia)
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Figure 5. FEA simulation of open cell foam unit cell under compression, showing predominant mode of deformation is on account of bending

3. Closed-Cell Foam

closedfoam
Figure 6. Open cell foam unit cell representation [following Gibson and Ashby, 1997]
3.1 Definition
As the name suggests, closed cell foams are open-cell foams with enclosed cells, such as the representation shown in Figure 6. This typically involves a membrane like structure that may be of varying thickness from the strut-like structures, though this is not necessary. Closed-cell foams arise from a lot of natural processes and are commonly found in nature. In man-made entities, they are commonly found in the food industry (bread, chocolate) and in engineering applications where the enclosed cell is filled with some fluid (like air in bubble wrap, foam for bicycle helmets and fragile packaging).

3.2 Design Implications
The primary benefit of closed cell foams is the ability to encapsulate a fluid of different properties for compressive resilience. From a structural standpoint, while the membrane is a load-bearing part of the structure under certain loads, the additional material and manufacturing burden can be hard to justify. Within the AM context, this is a key area of interest for those exploring 3D printing food products in particular but may also have value for biomimetic applications.

Closed_cell_metal_foam_with_large_cell_size
Figure 8. Closed cell Aluminum foam with very large cells [Shinko Wire Company, Attr: Curran2, Wikimedia Commons]

 4. Lattice

4.1 Definition
Lattices are in appearance very similar to open cell foams but differ in that lattice member deformation is stretch-dominated, as opposed to bending*. This is important since for the same material allocation, structures tend to be stiffer in tension and/or compression compared to bending – by contrast, bending dominated structures typically absorb more energy and are more compliant.

So the question is – when does an open cell foam become stretch dominated and therefore, a lattice? Fortunately, there is an app equation for that.

Maxwell’s Stability Criterion
Maxwell’s stability criterion involves the computation of a metric M for a lattice-like structure with b struts and j joints as follows:

In 2D structures: M = b – 2j + 3
In 3D structures:
M = b – 3j + 6

Per Maxwell’s criterion, for our purposes here where the joints are locked (and not pinned), if M < 0, we get a structure that is bending dominated. If M >= 0, the structure is stretch dominated. The former constitutes an open-cell foam, the latter a lattice.

There are several approaches to establishing the appropriateness of a lattice design for a structural applications (connectivity, static and kinematic determinism etc.) and how they are applied to periodic structures and space frames. It is easy for one (including for this author) to confuse these ideas and their applicability. For the purposes of AM, Maxwell’s Stability Criterion for 3D structures is a sufficient condition for static determinancy. Further, for a periodic structure to be truly space-filling (as we need for AM applications), there is no simple rigid polyhedron that fits the bill – we need a combination of polyhedra (such as an octahedron and tetrahedron in the octet truss shown in the video below) to generate true space filling, and rigid structures. The 2001 papers by Deshpande, Ashby and Fleck illustrate these ideas in greater detail and are referenced at the end of this post.

Video: The octet truss is a classic stretch-dominated structure, with b = 36 struts, j = 14 joints and M = 0 [Attr. Lawrence Livermore National Labs]

4.2 Design Implications
Lattices are the most common cellular solid studied in AM – this is primarily on account of their strong structural performance in applications where high stiffness-to-weight ratio is desired (such as aerospace), or where stiffness modulation is important (such as in medical implants). However, it is important to realize that there are other cellular representations that have a range of other benefits that lattice designs cannot provide.

Conclusion: Why this matters

It is a fair question to ask why this matters – is this all just semantics? I would like to argue that the above classification is vital since it represents the first stage of selecting a unit cell for a particular function. Generally speaking, the following guidelines apply:

  • Honeycomb structures for predictable, unidirectional loading or flow
  • Open cell foams where energy absorption and compliance is important
  • Closed cell foams for fluid-filled and hydrostatic applications
  • Lattice structures where stiffness and resistance to bending is critical

Finally, another reason it is important to retain the bigger picture on all cellular solids is it ensures that the discussion of what we can do with AM and cellular solids includes all the possibilities and is not limited to only stiffness driven lattice designs.

Note: This blog post is part of a series on “Additive Manufacturing of Cellular Solids” that I am writing over the coming year, diving deep into the fundamentals of this exciting and fast evolving topic. To ensure you get each post (~2 a month) or to give me feedback for improvement, please connect with me on LinkedIn.

References

[1] Ashby, “Materials Selection in Mechanical Design,” Fourth Edition, 2011
[2] Gibson & Ashby, “Cellular Solids: Structure & Properties,” Second Edition, 1997
[3] Gibson, Ashby & Harley, “Cellular Materials in Nature & Medicine,” First Edition, 2010
[4] Ashby, Evans, Fleck, Gibson, Hutchinson, Wadley, “Metal Foams: A Design Guide,” First Edition, 2000
[5] Deshpande, Ashby, Fleck, “Foam Topology Bending versus Stretching Dominated Architectures,” Acta Materialia 49, 2001
[6] Deshpande, Fleck, Ashby, “Effective properties of the octet-truss lattice material,”  Journal of the Mechanics and Physics of Solids, 49, 2001

Notes

* We defer to reference [1] in distinguishing lattice structures as separate from foams – this is NOT the approach used in [2] and [3] where lattices are treated implicitly as a subset of open-cell foams. The distinction is useful from a structural perspective and as such is retained here.

New Second Edition in Paperback and Kindle: Introduction to the ANSYS Parametric Design Language (APDL)

APDL-Guide-Square-Advert-1After three years on the market and signs that sales were increasing year over year, we decided it was time to go through our popular training book “Introduction to the ANSYS Parametric

Introduction_to_APDL_V2-Kindle-Ipad-1
I’ll be honest, it was cool to see the book in print the first time, but seeing it on my iPad was just as cool.

Design Language (APDL)” and make some updates and reformat it so that it can be published as a Kindle e-book.   The new Second Edition includes two additonal chapters: APDL Math and Using APDL with ANSYS Mechanical.  The fact that we continue to sell more of these useful books is a sign that APDL is still a vibrant and well used language, and that others out there find power in its simplicity and depth.

This book started life as a class that PADT taught for many years. Then over time people asked if they could buy the notes. And then they asked for a real book. The bulk of the content came from Jeff Strain with input from most of our technical staff. Much of the editing and new content was done by Susanna Young and Eric Miller.

Here is the Description from Amazon.com:

The definitive guide to the ANSYS Parametric Design Language (APDL), the command language for the ANSYS Mechanical APDL product from ANSYS, Inc. PADT has converted their popular “Introduction to APDL” class into a guide so that users can teach themselves the APDL language at their own pace. Its 14 chapters include reference information, examples, tips and hints, and eight workshops. Topics covered include:

– Parameters
– User Interfacing
– Program Flow
– Retrieving Database Information
– Arrays, Tables, and Strings
– Importing Data
– Writing Output to Files
– Menu Customization
– APDL Math
– Using APDL in ANSYS Mechanical

At only $75.00 it is an investment that will pay for itself quickly. Even if you are an ANSYS Mechanical user, you can still benefit from knowing APDL, allowing you to add code snippets to your models. We have put some images below and you can also learn more here or go straight to Amazon.com to purchase the paperback or Kindle versions.

Introduction_to_APDL_V2-1_Cover

PADT-Intro-APDL-pg184-185 PADT-Intro-APDL-pg144-145 PADT-Intro-APDL-pg112-113 PADT-Intro-APDL-pg100-101 PADT-Intro-APDL-pg-020-021

Investigation Signal Integrity: How to find problems before they find you – Webinar

In the Age of IoT, electronics continue to get smaller, faster, more power efficient, and are integrated into everything around us. Increasingly, companies are incorporating simulation early in the product development process, when the cost of design changes are at their lowest, to meet the challenges presented by Signal Integrity. For this to be effective, simulation tools need to be easy-to-use, compatible with existing work flows, and accurate, all while delivering meaningful results quickly.

If you or your company are designing or using electronics that are:
Critical to revenue, performance, or safety
Getting smaller, faster, or more efficient
Communicating with Gbps data rates
Using several or new connectors
Using long cables or backplanes
Then you could be a victim of Signal Integrity failure!

Join us September 7th, 2016 at 1 pm Pacific Time for this free webinar to discover how ANSYS is delivering intuitive Signal Integrity analysis solutions that can easily import ECAD geometry to compute SYZ parameters, inter-trace coupling, or impedance variations. Learn how ANSYS can help identify Signal Integrity problems and optimize potential solutions faster and cheaper than prototyping multiple iterations.

This webinar will introduce:

  • What products ANSYS provides for Signal Integrity problems
  • How these products can integrate into existing design workflows
  • And how easy these products are to use, even for novice operators

Followed by a Q&A session!

Click Here to register for this event and be sure to add it to your calendar to receive reminders.

Can’t make it? We suggest you register regardless, as our webinars are recorded and sent out along with a PDF of the presentation to our contacts within 24 hours of the presentation finishing.

Video Tips: Changing Multiple Load Step Settings in ANSYS Mechanical

ANSYS Mechanical allows you to specify settings for load steps one at a time. Most users don’t know that you can change settings for any combination of load steps using the selection of the load step graph. PADT’s Joe Woodward shows you how in this short but informative video.

ANSYS AIM Webinar: Increase Simulation Realism with Multiphysics

Some product designs require a single physics solution, while others require multiple physics simulations. Electronics cooling, wind loading on a solar array and the thermal performance of a heat exchanger are just a few examples of applications that require multiphysics simulation. Setting up and running multiphysics simulations used to be a challenging task involving the transfer of data between multiple physics solvers. With AIM, multiphysics simulations are easy to perform. AIM provides a consistent workflow and intuitive simulation environment for fluids, structures and electromagnetics that lowers the barrier to entry for multiphysics simulations.

 

Join us for this webinar to discover how AIM makes it easier than ever to solve your multiphysics design challenges in a single, easy-to-use environment. Don’t settle for single physics approximation when multiphysics simulations yield more accurate results with AIM.

This webinar will be held on September 1st from 1:00 – 2:00 pm PT 
Click Here to register for this webinar
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ANSYS AIM Webinar: Democratize Simulation for Your Design Engineers

Innovative companies are using simulation early in the product development process to improve and optimize product designs. Companies deploying up-front simulation to their product design teams require simulation software that is easy-to-use, provides accurate simulation results and allows customization to enforce best practices. Such design engineering simulation software allows teams to develop and refine design ideas early in the design cycle when the cost of making design changes is still low.

Join us for this webinar to discover how AIM’s intuitive simulation workflow delivers high levels of automation and allows customization to automate engineering simulation best practice. Learn how AIM’s custom applications enable every engineer in your organization to benefit from simulation insights.
This webinar will be held on August 24th from 1:00 pm – 2:00 pm PT

 

Click Here to register for this webinar

AIM Webinar Title Page2

Introducing Signal Integrity: What is it and how does it impact you? – Webinar

Is your comapny designing or using electronics that are:
  • Critical to revenue, performance, or safety
  • Designed in-house or by 3rd parties
  • Using wireless technology (e.g. Wi-Fi, Bluetooth)
  • Connecting to the cloud or Internet of Things (IoT)
  • Collecting large sets of data
  • Getting smaller, faster, or more efficient
If so then you could potentially be a victim of signal integrity failure!
Join us August 17th, 2016 at 1 pm Pacific Time for a free webinar covering an introduction to Signal Integrity

This is a high-level introduction that will cover:
  • What Signal Integrity is
  • Some of the challenges related to it
  • How to identify those at risk of signal integrity related failure
  • What is being done in response
Followed by a Q&A session afterwards!

Click Here to register for this event and be sure to add it to your calendar to receive reminders.

 

Can’t make it? We suggest you register regardless, as our webinars are recorded and sent out along with a PDF of the presentation to our contacts within 24 hours of the presentation finishing.

Five Basic Windows 10 Computer Skills Every Engineer Should Know

WINDOWS-ANSYS-1
At PADT we provide help to many of our customers who have trouble with their ANSYS simulations. At the top level, though, there are some computer skills for Windows that we consider basics that every engineer should know. If these are skills you already have in your tool belt, fantastic! If not, hopefully this information will help you be more effective in your simulation tasks.
Also, since most of us have been or are currently being updated to Windows 10, I’m providing the instructions for Windows 10. Windows 7 is similar, though.

1. Run as Administrator

This allows us to run programs, a.k.a. “apps” with administrator privilege, even if our login credentials don’t allow this level of usage. This is the case for most users of engineering software. Certain components of ANSYS, including the CAD Configuration Manager and the Client ANSLIC_ADMIN Utility require changes to your computer that non-admin rights won’t allow. By running as administrator, we allow the program to make the needed changes.

To do this, click the Start Menu, then find the program (app) you need to run in the resulting list, such as the Client ANSLIC_ADMIN Utility. Next, right click on that program, select More with the left mouse button, then select Run as Administrator with the left mouse button. If you are prompted to allow changes to your system, click Yes. Here is what it will look like:

ansys-windows-10-f01
2. View File Extensions

When using Windows Explorer, now known as File Explorer in Windows 10, by default you probably won’t see file extensions. Instead, you’ll see the prefix of files, but won’t see the endings of the file names. This will be the case when browsing for files to open or save as well. Sometimes you can rely on the icons associated with a file to know which program it’s associated with or the Type field in the list view, but sometimes there are conflicts. For example, an ANSYS Mechanical APDL macro file will have the extension .mac. You can probably guess that there is at least one other major company that can have software that uses that extension. By viewing the file extensions, even if the icons are wrong, we can more easily identify the files we need. Here is how it’s done:
Click Start, then File Explorer:

ansys-windows-10-f02

The default view using “Details” in File Explorer will look something like this (file names don’t include extensions):

ansys-windows-10-f03

To view the extensions, we click on the View menu in File Explorer, then Options, then Change Folder and Search Options.

ansys-windows-10-f04

The way I set this option for all folder on my computer is to then click on the View tab in the resulting small window, then uncheck the box for Hide extensions for known file types, then click Apply to Folders, then click OK.

ansys-windows-10-f05

Now the list view (using Details under the View menu) in File Explorer looks like this, with each file showing its extension in the list:

ansys-windows-10-f06

3. Define and Edit Environment Variables

Environment Variables are values that are used by certain programs to define settings. For example, an environment variable can be used to specify the license server for certain programs. It’s good to know how to define and edit these if needed. To do this, we bring up the control panel. In Windows 10, click on the Start button, then Settings:

ansys-windows-10-f07

A quick way to get there is to type “environment” in the search window in the resulting Settings window:

ansys-windows-10-f08

The search should find Edit the System Environment Variables. Click on that:

ansys-windows-10-f09

In the resulting System Properties window, click on the Environment Variables button in the Advanced tab:

ansys-windows-10-f10

A new window will open with a list of currently defined User variables (just for your login) and System variables (for anyone who is logged in), like this:

ansys-windows-10-f11

You can click on an environment variable to edit it using the Edit… button, or you can click on the New… button to create a new one. One ANSYS-related environment variable that occasionally needs to be set is ANSYSLMD_LICENSE_FILE. This is only needed if the default license server specifications aren’t working for some reason. You won’t need to set this under normal circumstances. Just in case, here is how to define it, using the New… button under System variables. We type in the Variable Name, in this case ANSYSLMD_LICENSE_FILE and then the Variable Value, which in this example is 1055@myserver.

ansys-windows-10-f12
When done defining and editing environment variables, we click on the OK button to complete the action and get out of that environment variable-related windows.

4. Check Usage of Your Computer Resources

As simulation experts, we are often pushing the limits of our computer resources. It’s good to know how to check those. First is disk space. An easy way to check disk space is to bring up File Explorer again. Click on This PC on the left side. This will give you a snapshot of the available space on each hard drive that is accessible on this computer:

ansys-windows-10-f13

Next, we may want to check CPU or memory utilization. Perhaps we want to make sure that our solution is running on multiple cores as we have requested.
To do this, hold down the Alt, Control, and Delete keys on the keyboard, all at the same time. Then click on Task Manager in the resulting window (it will look for a second like your computer is going to restart – it won’t actually do that).
In the resulting Task Manager window, click on More details:

ansys-windows-10-f14

In the resulting window, we can click on the Performance tab and view, for example, the current memory utilization, or we can click on Open Resource Monitor and get even more details, including utilization on each CPU:

ansys-windows-10-f15
5. Search for Large Files

It’s very common in the simulation world to end up filling up your disk drives. Therefore, it’s good to be able to find large files so we can delete them if they are no longer needed. For a simple way to do this, we’ll start with File Explorer again. This time, we’ll click in the search window at upper right, but won’t actually type in anything. We just want the search tools menu to appear:

ansys-windows-10-f16

Next, click on Search under Search Tools, followed by Size, then Gigantic (I will argue that 128 MB isn’t all that gigantic in the simulation world, but Microsoft hasn’t caught up with us yet):

ansys-windows-10-f17

Windows will now perform a search for files larger than 128 GB. If any of these are no longer needed, you can right click and delete them. Just make sure you don’t delete any files that are truly needed!

That completes our discussion on 5 computer skills every engineer should know. In conclusion, these basic skills should help you be more productive over time as you perform your simulation tasks.

ANSYS AIM Webinar: Simulation For Product Design Engineers

Product design engineers are increasingly under pressure to complete product designs faster so innovative products can reach the market sooner. Performing up-front simulation as part of the product development process can accelerate designing optimized products and reduce costly physical prototypes. To successfully implement simulation early in the product development process, simulation software must be easy-to-use and cover all the necessary physics that impact product designs.

Join us for this webinar to discover how AIM delivers unparalleled ease-of-use for simulation driven product development, and learn how design engineers can benefit from using simulation early in the product development process.

This webinar will be held on August 10th from 1:00 pm – 2:00 pm PT

Click Here to register for this webinar

AIM Webinar Title Page

Video Blog: Copying Time Steps from a Thermal Transient to a Static Structural Model in ANSYS Mechanical

Transient Thermal to Static Structural Load Transfer, ANSYS MechanicalIn this The Focus Video Blog, Joe Woodward shares a nice little trick he found when answering a tech support question.

When you want to take timesteps from a transient thermal analysis in ANSYS Mechanical and use the results as loads in a series of static simulations, in just a few mouse clicks.

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.

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