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    This website is an independent forum for discussing finite element simulations of all types of polymers. To perform an accurate FE simulation requires 3 types of inputs:
    • Geometries
    • Material models
    • Applied loads and boundary conditions

    The specification of the material models is typically the most challenging, and is therefore the focus of this site. I have been working in this field for close to 20 years, and this site now has more than 10,000 posts and 16,000 members. My goal of running this website is to provide expert advice on how to perform proper computer simulations of polymers, and to discuss some of the tools that I have developed (PolyUMod and MCalibration). Researchers and users are encouraged to submit results and to request information.

    This two-day web-based course covers a review of polymer mechanics theory, techniques and tools for experimentally characterizing polymers, and hands-on training on how to perform accurate finite element simulations of polymer components. The training class is targeted to people with an interest in designing and analyzing the mechanical performance of parts made from plastics, rubbers, thermosets, or other types of polymers.

    By the end of the class you will be able to:
    • Design a relevant experimental test program for a new polymer material
    • Know the strengths and weaknesses of various material models, and be able to select an appropriate material model for finite element simulations.
    • Use experimental data to calibrate the selected material model.

    Contact us soon if you want to register!

    Through my research and industrial consulting I have noticed that there is a huge need for more advanced material models than what is provided by Abaqus, ANSYS, LS-DYNA, and other FE software. To overcome this limitation I developed the PolyUMod library of advanced material models that are significantly more accurate and provide the ability to capture the mechanical response of virtually all polymers, including everything from simple non-linear elasticity to large strain anisotropic viscoplasticity at different temperatures. The PolyUMod library also contains a large number of failure models that can be used to predict when a material fail during monotonic or cyclic loading.

    If you ever need to accurately predict the non-linear behavior of an elastic, thermoplastic, or other polymer, then you should check out the PolyUMod library and PolyUMod.com!

    Most FE software has the capability to calibrate simple material models, such as hyperelasticity and linear viscoelasticity. But the calibration functions do not give you much flexibility about what experimental data to use and how the calibrations should be performed. MCalibration is an application that is much more powerful and faster. It contains functions for cleaning up experimental data, it contains a library of already calibrated material models, and it can calibrate all material models Abaqus, ANSYS, and the PolyUMod library. Many of the commonly used viscoplastic material models in Abaqus and ANSYS are directly built into MCalibration. That means you can calibrate those models very fast without even using a FE solver. MCalibration is awesomely great. Contact me if you would like a trial license.

    The schedule for my 2015 training classes is now available. The classes cover the following topics: polymer mechanics, experimental testing, material model selection, and advanced finite element modeling techniques.

    Both online (web-based) and in-person (classroom-style) training classes are available. The training classes are targeted to people with an interest in learning the state of the art in testing and analyzing the mechanical performance of parts made from plastics, rubbers, thermosets, or other types of polymers.

    I also give custom training classes directly to different companies. Contact me if you want more information.

    Experimental testing can be performed for different reasons. Sometimes the purpose is simple to make sure that a material satisfies a given set of requires property values. Other times the purpose is to obtain sufficient experimental data to calibrate a suitable material model. When the goal of the testing is to calibrate a material model then the testing can be performed using "smart experiments" in order to obtain as much information as possible using as few tests. The required number of tests will depend on the material behavior and the material model that will be used. If a material is isotropic then it is frequently sufficient to perform only uniaxial tests with multiple load-relax-unload cycles.

    When possible, I also typically recommend that validation tests be performed. Validation tests are specific tests that are typically multiaxial and are specifically designed to probe the material in a way that is similar to the intended application. The calibrated material model will then be used in Finite Element (FE) simulations of the validation experiments. If the calibrated material model match the validation results then the material model likely provides a reasonable representation of the true material response. Validation experiments are often performed using Small Punch testing, V-notch shear testing, or Indentation testing.

    Contact me if you are interested in obtaining a quotation for experimental characterization of validation testing.

    I created a short movie that demonstrates the MCalibration software. If you ever need to calibrate a material model for use with Abaqus, ANSYS, or LS-DYNA, then you should check out MCalibration. This software can calibrate all user-material models in the PolyUMod library, and also all built-in material models in Abaqus.

    A new version of MCalibration and PolyUMod was just released (v.2.6.0). The new version contains a large number of interesting and useful new features, for example:
    • Restructured the material models by FE solver.
    • Selecting one or more load cases now highlights the corresponding graph curves.
    • Improved the convergence of anisotropic viscoplastic material models.
    • Various bug fixes.

    Check out the following page for more info, you can also read the detailed change log here.

    You can now follow me (and PolyUMod + MCalibration) on Twitter: @PolymerFEM
    Info about updates, new features, etc, will be provided.

    We have created a new website specifically for the PolyUMod library of material model. The new website, PolyUMod.com, contains lots of information about how to accurately perform Test-Calibrate-Simulate workflows using the PolyUMod library of advanced user-material models for Abaqus, ANSYS and other non-linear FE solvers.

    We encourage everyone who is interested in accurate FE simulations of polymers and rubbers to checkout PolyUMod.com!
    by Published on 2011-12-15 07:52
    Article Preview

    ANSYS version 14.5 was recently released and it seems like it contains a large number of nice improvements. I am also happy to announce that the current version of the PolyUMod library works great also with this new version of ANSYS.

    A new version of the PolyUMod library has also been released. This new version (2.2.5) contains numerous improvements to both the MCalibration software and the PolyUMod library. For example, MCalibration can now calibrate any of the built-in material models in ANSYS Mechanical.
    by Published on 2011-10-30 21:02

    Here is a tutorial on how to use MCalibration to simultaneously calibrate a material model to both traditional stress-strain data, and dynamic storage modulus (E') and loss modulus data (E''). The attached pdf-file and MCalibration files contain all the details.
    One of the most useful features of MCalibration is the ability to calibrate a material model simultaneously using many different types of experimental data.
    by Published on 2011-08-22 14:55

    I gave a presentation on advanced FE modeling of PLLA intereference screws at the ANSYS User's conference in Boston on Sep 14, 2011. In my presentation I discussed how the design of degradable screws can be optimized for use in Anterior cruciate ligament (ACL) reconstruction surgery. PLLA is a non-linear viscoplastic material that can be accurately modeled using the PolyUMod library.

    If you are looking for free, high quality experimental data for various polymers, then you might be interested in learning that you can download and use the experimental data from the following links:

    Also note that I provide experimental testing services for all kinds of polymers through Veryst Engineering. Send me a private message if you are interested in having your material tested and a suitable material model calibrated.

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