Viscoelastic model in ABAQUS

[Hugh]

Dr Bergstrom

Im sorry to bother you and this is probably a silly question but I am currently doing a project on stress waves in elastic and viscoelastic bars using ABAQUS CAE. My elastic model works perfectly but I am having problems with the PMMA model.

I have frequency dependant data for the PMMA and am able to obtain the real and imaginary values for shear and bulk modulus at different frequencies. I entered this information for a viscoelastic material into Domain:time and time:frequency and also entered the values for elastic Youngs modulus and poissons ratio but this doesnt seem to work and I dont get any values for the Prony series. Then when I evaluate the material it plots graphs for the test data which look sensible but my material graphs are just linear often with a constant value of zero.

I realise this is probably a stupid question but I would appreciate
any suggestions of how to overcome this.

Thankyou

[Jorgen]

It sounds like you are not using using appropriate material parameters, or your experimental data does not include relevant information for the range of frequencies that are active in your application. Note that the Linear Viscoelasticity (LVE) model will give a linear elastic response for really "fast" and really "slow" loading.

- Jorgen