Modeling Hyperelastics with Response Function
Hello, I have a few general questions on using the Response Function:
Is there any reason to use the classical hyperelastic constitutive models (neo-hookean, blatz-ko, arruda-boyce, etc) if I have, or can acquire, test data from a set of samples and want to use the Response Function model?
In addition to that, lets say my Instron output provides 13,000 stress/strain data points and I want to upload that as a CSV into the uniaxial tension test data, will the number of data points affect my overall solution time? Is there a limit to the amount of input data?
Last question: If I have a case of multiaxial loading in my model, which data sets (compression, shear, volumetric, biaxial etc) are recommended to fully define the stress strain response?
Thanks for your help! These questions are not related to a specific working analysis, I am just planning how I may use Response Function in the future.
Answers
Hello @nds88,
The response functions can be determined directly from experimental data, bypassing the need to fit the potential function's parameters to the experimental data. This is one advantage over other models. Also, there is no limit to the amount of input data and will not slow the solution.
The kind of tests required depend on whether you material is compressible or incompressible(volumetric tests are not needed). Also you need to make sure that the tests you perform are not redundant. For example, uniaxial tension and eqibiaxial tension give you the same information.
Please have a look at the help documentation for more info regarding testing and models - 4.6. Hyperelasticity (ansys.com) 6.1. Hyperelastic Material Curve-Fitting (ansys.com).
Also check out this video https://www.youtube.com/watch?v=ulRqLp6TPYw&feature=emb_title
Regards,
Ishan.
https://forum.ansys.com/discussion/3978/how-to-access-the-ansys-online-help
Thank you for the reply, I guess my only unanswered question is when would it be beneficial to use the classical constitutive models?