What modulus to use - TANGENT OR SEECANT modulus ?

[SAK123]

Is there any guidelines on when the tangent and when the secant modulus should be used in modeling ? I am modeling fabric material so the behavior is non-linear but several people at my office think tangent modulus should be used whereas others think secant modulus should be used in modeling behavior.

I searched the web and nothing provides direction on what is more suitable for FEA non-linear fabric material behavior.

Thanks for any input.

Regards -

 

[SWComposites]

What type of analysis are you running (stress, vibration, bucking, ...), and what type of results do you want to obtain (stress, displacement, modes, ....)?

Is this bare fabric? composite?

 

[SAK123]

I am running a static stress analysis interested in stresses with a side interest in displacements. The element is membrane type - i.e. no bending stress. Material is not modeled as a composite - it is modeled as an Orthotropic type.

 

[SWComposites]

I don't think you should use either "modulus". For a nonlinear analysis you should input the stress-strain curve for the material. If you want to predict failure you will need to select a failure criteria and input the appropriate material strength parameters.

 

[abaqusmaster]

I am agree with SWComposites, I think you should use a combination of elastic and plastic material properties.

Regards,

Mohammad Shahbazi

http://www.OmranAfzar.com