= Objective second-rank tensor
{title2=$J^*=QJQ^T$}
An objective spatial second-rank <tensor> transforms by the displayed rule under every rigid observer change $x^*=c(t)+Q(t)x$. This permits time-dependent rotations, not merely constant rotations. <Cauchy stress tensor> is objective because contact traction and surface normal both rotate by Q. The symmetric <rate-of-strain tensor> is objective because the additional observer spin in the <velocity gradient> is antisymmetric.
Back to article page
