cauchy stress, first piola kirchoff stress, second piola kirchof stress
Some basic questions involving cauchy stress, first piola kirchof stress and second piola kirchof stress:
1) We know that Cauchy stress involved deformed areas-therefore this (Cauchy stress) has an obvious physical interpretation
2)Now, first piola kirchof stress is expressed as:
S = JF^-1 . sigma
where, J is the jacobian of the deformation gradient which physically is the measure of the volume change produced by a deformation.
F is the deformation gradient
sigma is Cauchy stress.
