Polynomial model problem

[lfce]

Dear All,

I am currently working on a program to find hyper-elastic parameters, and I am using an inverse finite element method. I have experimented with different hyper-elastic models but I am having a hard time being able to get the polynomial model to give me a non linear response. Everytime I run the polynomial model I get very linear responses, whereas I am trying to get a non linear one. I am not sure what I should do/I am doing wrong. Any help would be greatly appreciated.

Regards,

 

[IceBreakerSours]

Are you using experimental data and the evaluate option to determine your coefficients or are you using coefficients directly? Do you have the NLGEOM flag on? What kind of analysis are you running? What elements do you have in the model? What's the loading? There are many questions.

Are you new to this forum? If so, please read these FAQ:

http://www.eng-tips.com/faqs.cfm?fid=376

http://www.eng-tips.com/faqs.cfm?fid=1083

 

[lfce]

I am using experimental data, I am trying to obtain the hyperelastic parameters of the experimental data (Determine the coefficients for n=3 polynomial), I do have the NLGEOM = YES, I have C3D8H elements, the shape itself is a cylinder and I am indenting th middle of the top surface of the cylinder. what else would i need to answer?

 

[IceBreakerSours]

Are you using the evaluate option? If you don't know about it, look at the relevant sections in the CAE User's Manual.

Are you new to this forum? If so, please read these FAQ:

http://www.eng-tips.com/faqs.cfm?fid=376

http://www.eng-tips.com/faqs.cfm?fid=1083