function preStrain = femlib_getPreStrain
% function preStress = femlib_getPreStrain
%
%
% Dr. A. I. Hanna (2007)
% recall that the stress is defined by
% stress = [du/dx, dv/dy, dw/dz, du/dy + dv/dx, du/dz + dw/dx, dv/dz +dw/dy];
%preStrain = [-1 0 0 0 0 0]'; % lateral growth
%preStrain = [0 -1 0 0 0 0]'; % longitudal growth
%preStrain = [0 0 -1 0 0 0]'; % vertical growth
%preStrain = [0 0 0 -1 0 0]'; % pure shear yz-plane
%preStrain = [0 0 0 0 -1 0]'; % pure shear xz-plane
%preStrain = [0 0 0 0 0 -1]'; % pure shear xy-plane
preStrain = [-1 -1 0 0 0 0]'; % uniform growth xy
%preStrain = [-1 -1 -1 0 0 0]'; % uniform growth xyz
return;