In the principal tensor profile method, a tensor is specified using its diagonal (principal) components with respect to its principal axes. The node serves as a placeholder for separate component and axis nodes.
The component nodes represent the diagonal components of a tensor: two in two-dimensional problems (XX and YY) or three in three-dimensional problems (XX, YY and ZZ). These function just like the scalar profile quantity nodes in a typical composite vector profile method.
The axis nodes represent the directions of the tensor's principal axes. Only two principal axes need to be specified (XX and YY), which must not be parallel to each other. The third principal axis is deduced internally as being orthogonal to the other two. The magnitude of the axis vectors is ignored, only their directions are important. The axis nodes function just like vector profile quantity nodes, including the ability to specify a coordinate system for each axis vector. The coordinate system may often be the same for both axes but need not be.
The design allows you to specify profile methods for each component and axis separately. To do this, open the Principal Tensor node and work with the scalar and vector profile quantities as you did with the profile node.