A constitutive model for material growth and its application to three-dimensional finite element analysis

This paper describes a material model, in which the materials under consideration grow up in a particular direction while re-organizing themselves to the surroundings. The structural reorganization is modeled as the rearrangement of anisotropy. Two models are proposed; one is that the anisotropic vector is embedded just as in fiber-reinforced materials, and the other is that the vector behaves like a float. In order to apply the present model to boundary-value problems, a three-dimensional finite element formulation is obtained with reference to the total-Lagrangian approach. Here we evaluate the performance of the model in terms of anisotropic growth; (a) adaptation behavior of a quasi-isotropy in the initial state, and (b) monotonic growth in helical direction.