Supplementary Document : Tutorial on Nonlinear Material Model

Manuscript received November 20, 2014. Of course, things can get complicated in nonlinear problems with large deformations (and rotations) because the final deformed area may be different from the initial area, among other things [1]. Stress is in fact a tensor [1]. It can be written in any of several forms as follows [1]. (Cauchy stress tensor shown in Fig. 2) In 3-D it can be written as, σ = σ11 σ12 σ13 σ21 σ22 σ23 σ31 σ32 σ33  = σxx σxy σxz σyx σyy σyz σzx σzy σzz  = σxx τxy τxz τyx σyy τyz τzx τzy σzz 