for VTI material, Abaqus uses engineering constants and require the input of Ep,Et,mu_p,mu_pt,Gtp the 5 independent values. I am not sure how to input them. We did 2 experiments for two samples one is vertical and the other is horizontal. for each sample, we have E and mu, i.e. for vertical(Ev, muv) and horizontal sample(Eh,mu_h). Then, now how to translate these Ev, mu_v and E_h, mu_h into these above 5 required inputs? Can I just do like this, i.e. using E_p=Eh, Et=Ev, mu_p=mu_h. Then what about mu_pt and Gpt? I don't know how to input them? I appreciate your help. Thanks