Updates and Enhancements in ANSYS Mechanical 19.1 – Webinar

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Stratasys – PolyJet Agilus 30 Webinar

Introducing New PolyJet Material: Agilus30

PADT is excited to introduce the newest polyjet material available from Stratasys, Agilus30! Agilus30 is a superior Rubber-like PolyJet photopolymer family ideal for advanced design verification and rapid prototyping.

Get more durable, tear-resistant prototypes that can stand up to repeated flexing and bending. With a Shore A value of 30 in clear or black, Agilus30 accurately simulates the look, feel and function of Rubber-like products. 3D print rubber surrounds, overmolds, soft-touch coatings, living hinges, jigs and fixtures, wearables, grips and seals with improved surface texture.

Agilus30 has applications in a number of areas, including:

  • Medical Models

  • Tooling needing rubber-like characteristics

  • Consumer Goods

  • Sporting Goods

  • General Prototyping

  • Overmolding & many more!

Want to know more about PolyJet’s toughest flexible material to date? 

Join PADT’s 3D Printing Application Engineer James Barker along with Stratasys Materials Business Manager Ken Burns for a presentation on the various benefits and attributes that Agilus30 has to offer, which machines are compatible with it, and how companies are making use of it’s unique capabilities.

Importing Material Properties from Solidworks into ANSYS Mechanical…Finally!

Finally! One of the most common questions we get from our customers who use Solidworks is “Why can’t I transfer my materials from Solidworks? I have to type in the values all over again every time.”  Unfortunately, until now, ANSYS has not been able to access the Solidworks material library to access that information.

There is great news with ANSYS 18.  ANSYS is now able to import the material properties from Solidworks and use them in an analysis within Workbench.  Let’s see how it works.

I have a Solidworks assembly that I downloaded from Grabcad.  The creator had pre-defined all the materials for this model as you can see below.

Once you bring in the geometry into Workbench, just ensure that the Material Properties item is checked under the Geometry cell’s properties.  If you don’t see the panel, just right-click on the geometry cell and click on Properties.

Once you are in ANSYS Mechanical, for example you will see that the parts are already pre-defined with the material specified in Solidworks .

The trick now is to find out where this material is getting stored. If we go to Engineering Data, the only thing we will see is Structural Steel. However when we go to Engineering Data Sources that is where we see a new material library called CADMaterials.  That will show you a list of all the materials and their properties that were imported from a CAD tool such as Solidworks, Creo, NX, etc.

You can of course copy the material and store it for future use in ANSYS like any other material.  This will save you from having to manually define all the materials for a part or assembly from scratch within ANSYS.

Please let us know if you have any questions and we’ll be happy to answer them for you.

Technology Trends in Fused Deposition Modeling

A few months ago, I did a post on the Technology Trends in Laser-based Metal Additive Manufacturing where I identified 5 key directions that technology was moving in. In this post, I want to do the same, but for a different technology that we also use on a regular basis at PADT: Fused Deposition Modeling (FDM).

1. New Materials with Improved Properties

Many companies have released and are continuously developing composite materials for FDM. Most involve carbon fibers and are discussed in this review. Arevo Labs and Mark Forged are two of many companies that offer composite materials for higher performance, the table below lists their current offerings (CF = Carbon Fiber, CNT = Carbon Nano Tubes). Virtual Foundry are also working on developing a metal rich filament (with about 89% metal, 11% binder polymer), which they claim can be used to make mostly-metal parts for non-functional purposes using existing FDM printers and a heat treatment to vaporize the binder. In short, while ABS and PLA dominate the market, there is a wide range of materials commercially available and this list is growing each year.

Company Composition
Arevo Labs CF, CNT in PAEK
CF in PEEK
Fiberglass in PARA
Mark Forged Micro-CF in Nylon
CF
Fiberglass
Fiberglass (High Strength High Temperature)
Kevlar

2. Improved Properties through Process Enhancements

Even with newer materials, a fundamental problem in FDM is the anisotropy of the parts and the fact that the build direction introduces weak interfaces. However, there are several efforts underway to improve the mechanical properties of FDM parts and this is an exciting space to follow with many approaches to this being taken. Some of these involve explicitly improving the interfacial strength: one of the ways this can be achieved is by pre-heating the base layer (as being investigated by Prof. Keng Hsu at the Arizona State University using lasers and presented at the RAPID 2016 conference). Another approach is being developed by a company called Essentium who combine microwave heating and CNT coated filaments as shown in the video below.

Taking a very different approach, Arevo labs has developed a 6-axis robotic FDM process that allows for conformal deposition of carbon fiber composites and uses an FEA solver to generate optimized toolpaths for improved properties.

3. Faster & Bigger

A lot of press has centered around FDM printers that make bigger parts and at higher deposition rates: one article discusses 4 of these companies that showcased their technologies at an Amsterdam trade show. Among the companies that showcased their technologies at RAPID was 3D Platform, that showed a $27,000 3D printer for FDM with a 1m x 1m x 0.5m printing platform. Some of the key questions for large form factor printers is if and how they deal with geometries needing supports and enabling higher temperature materials. Also, while FDM is well suited among the additive technologies for high throughput, large size prints, it does have competition in this space: Massivit is one company that in the video below shows the printing of a structure 5.6 feet tall in a mere 5 hours using what they call “Gel Dispensed Printing” that reduces the need for supports.

 4. Bioprinting Applications

Micro-extrusion through syringes or specialized nozzles is one of the key ways bioprinting systems operate – but this is technically not “fused” deposition in that it may not involve thermal modification of the material during deposition. However, FDM technology is being used for making scaffolds for bio-printing with synthetic, biodegradable or bio-compatible polymers such as PCL and PLGA. The idea is these scaffolds then form the structure for seeding cells (or in some cases the cells are bioprinted as well onto the scaffold). This technology is growing fast and something we are also investigating at PADT – watch this space for more updates.

5. Material Modeling Improvements

Modeling FDM is an important part of being able to use simulation/analysis to design better processes and parts for functional use. This may not get a lot of press compared to the items above, but is a particular interest of mine and I believe is a critical piece of the puzzle going to true part production with FDM. I have written a few blog posts on the challenges, approaches and a micromechanics view of FDM printed structures and materials. The idea behind all of these is to represent FDM structures mathematically with valid and accurate models so that their behavior can be predicted and designs truly optimized. This space is also growing fast, the most recent paper I have come across in this space is from the University of Wisconsin-Madison that was published May 12, 2016.

Conclusion

Judging by media hype, metal 3D printing and 3D bioprinting are currently dominating the media spotlight – and for good reasons. But FDM has many things going for it: low cost of entry and manufacturing, user-friendliness and high market penetration. And the technology growth has no sign of abating: the most recent, 2016 Wohlers report assesses that there are over 300 manufacturers of FDM printers, though rumor on the street has it that there are over a thousand manufacturers coming up – in China alone. And as the 5 trends above show, FDM has a lot more to offer the world beyond being just the most rapidly scaling technology – and there are people working worldwide on these opportunities. When a process is as simple and elegant as extruding material from a hot nozzle, usable innovations will naturally follow.

Checking Hyper-Elastic Material Models

non-linear-thumbWhen using hyper-elastic materials, analyst often have little material data to assist them. Fortunate engineers will have a tensile stress-strain curve; a lucky few will also have a simple shear stress-strain curve as well. Where do you start?

To gain confidence in the procedure which is typically used, a set of FEA models were run in a closed loop. The loop consists of assuming some material parameters, running FEA models based upon those parameters, and then using the FEA results to recover the material parameters using ANSYS’s built in hyper-elastic curve fitting.

To isolate the material model from boundary conditions effects, simple FEA models that are 3D but have 1D stress states are used. The figures below show tensile and shear models that can be used to verify material models.
cs1

For this article, a 2 Parameter Mooney-Rivlin material model with values consistent with typical Imperial units was selected. The figure below shows the data entry including a value of zero for d which indicates that the material is fully incompressible.
cs2

The tensile test FEA model was run with this 2 parameter MR model. The engineering stress-strain results were extracted from the results using /post26 APDL. The results are graphed and listed in the figure below. We use APDL because there are some calculations involved with getting engineering results. For example, the engineering stress was calculated by dividing the reaction force at node n1 by the original area like this:

RFORCE,2,n1,F,z,Fz_2
QUOT,3,2, , , , , ,-1/area_,1,

cs3This test data was then used in ANSYS’s curve fitting routine. The results of the curve fitting are shown below. The parameters from the curve fitting results are < 0.01% different than the assumed inputs. This is a reassuring result. Note that this is one instance in ANSYS that you are required to use engineering data (for hyper-elastic curve fitting only).
cs4

In recent versions of ANSYS, a hyper-elastic response function was introduced. This allows the user to enter the test data and use it without curve fitting. The figure below shows how uniaxial tension test data is entered and the response function activated to use it.
cs5

As expected, the response function matched the /post26 output exactly. This method offers a clear advantage in that the user doesn’t need to assume a material model.
cs6

The next step in this verification process was to run some simple shear FEA models to compare the curve fitting results. The plot below shows the engineering shear stress-strain curve using the 2 parameter MR model from above.
cs7

The data was curve fitted as shown in the figure below. This time both the uniaxial tension and simple shear data are entered. The resulting 2 parameter model differs (<2%) from the entered model.
cs8

These new values were used in the FEA models. As shown in the figures below, the change in material parameters (<2%) did not significantly change the tensile or shear stress-strain results (<1%). This raises some interesting questions regarding the 2 parameter MR model that will be explored at a later date.
cs9

Efficient Engineering Data, Part 2: Setting Default Materials and Assignments aka No, You’re Not Stuck with Structural Steel for the Rest of Your Life

Longer ago than I care to admit, I wrote an article about creating and using your own material libraries in Workbench. This is the long awaited follow-up, which concerns setting the default Engineering Data materials and default material assignments in Mechanical and other analysis editors.

imageNote:
Part of the reason it’s taken me this long is that I moved to New Mexico to help staff PADT’s new office there, and to shadow Walter White. It has been a hectic, exhausting endeavor but I’m here and I’m finally settled in. If you’re in New Mexico and are interested in ANSYS, engineering services, product development, or rapid prototyping (e.g. 3D printing), please feel free to contact me.

In order to make the best use of the procedures here, you will probably want to know how to create your own material libraries. Part 1 describes how to do this. This will also work with the material libraries that come with the ANSYS installation, though.

Pick Favorites

The first step is to get into Engineering Data and expose the material libraries by clicking on the book stack button ( image ). Then, drag the materials of your choice from the appropriate library(ies) to the Favorites Data Source. These can include materials you want to have available in Mechanical by default as well as materials that you would like to consolidate into a single location for quick access. At this point, the default material availability and assignments have not been altered. These will be handled in the next couple of steps.

image

Drag and Drop Materials to Favorites

Set Default Material Availability

To specify which materials will be immediately available for assignment in future analyses, go to the Favorites Data Source and check all applicable materials in column D. Though not assigned to the immediate set of engineering data, these will be on the default list of available materials in subsequent analyses, i.e. when you create a new analysis in the same project schematic or when you exit and reopen Workbench.

image

Check to Add to Default List of Available Materials

image

Materials Immediately Available Inside Mechanical

Set Default Material Assignment

Now our most commonly used materials are immediately available in our analysis editor. But Structural Steel still lingers. In many, if not most, cases, we would prefer our default assignment to be something else.

The fix is easy. Once again, go to the Favorites Data Source, right click the material you wish to have as your default material, and select Default Solid Material (and if you’re doing Emag or CFD, you can set your default fluid or field material with the right-click menu too). Your default solid material will now replace Structural Steel in subsequent analyses.

image

Example: Aluminum 6061-T651 Set as Default Material Assignment

image

Becomes Default Material Assignment in Analysis

Note that you can stop at any step in this process. If you want to consolidate favorite materials, but don’t want to have them immediately in your analysis editor, you can do that. If you want a default list of materials to select from without specifying a default material assignment, you can do that too. More than likely, though, you’ll want to do all three.