@Johan Thanks a lot for your feedback sir.

Well the polymer that i am using is thermosetting polymer not theromplastic.I want to know your comment regarding poisson ratio of thermosetting polymers. Also can you recommend some papers or book where i can find all these information easily. In addition, i am  also thinking to do torsion test to find G from where i can find poisson ratio .What you suggest on this.

Once again thanks a lot for your feedback

Regards

Zulfiqar ALi

Dear Ali,

polymers are viscoelastic materials. The equation you are using are suitable for "linear elastic materials". Similar equations (formally) can be written for viscoelastic materials in the Laplace domain. Please, be carefull (for example, what is the loading rate you used to perform the tensile tests? If you change the crosshead speed from 1 mm/min to  10mm/min you will see substantial change of the measured properties. For instance the "apparent" modulus and the strength  will increase, the elongation at break will decrease, and so on...)

Anyway, following your general question, may I suggest reading the following papers:

-GRASSIA L., D'AMORE A., SIMON S.L. (2010). On the Viscoelastic Poisson's ratio of Amorphous Polymers. JOURNAL OF RHEOLOGY, vol. 54, p. 1009-1022, ISSN: 0148-6055

-GRASSIA L., D'AMORE A. (2009). The Relative Placement of Linear Viscoelastic Functions in Amorphous Glassy Polymers.. JOURNAL OF RHEOLOGY, vol. 53, p. 339-356, ISSN: 0148-6055, doi: 10.1122/1.3056631

Dear Alberto D'Amore,

Thanks alot for your feedback.

I will look at these papers.

Thanks