Method for Identifying Stochastic Information of Heterogeneous Materials

摘要

A method for identifying stochastic information of a heterogeneous material utilizes physical loading measurements that are input into a global optimization process. The optimization process executes, in parallel, a force-driven non-linear finite element simulation and a displacement-driven finite element simulation of a constitutive model of the heterogeneous material. The constitutive models model the spatially varying random material properties (i.e. stochastic properties) using the Karhunen-Loeve expansion, thereby introducing the stochastic parameters, including spatial mean, spatial variance, and correlation length for example into the models. Stress and strain values for both the force-driven and displacement driven finite element analyses are input into an objective function, whereupon the finite element simulations are updated after each iteration of the optimization process is performed until the objective function is minimized to a desired level. This results in the identification of optimized stochastic parameters associated with the heterogeneous material under investigation.

主权项

1. A method for identifying one or more stochastic parameters of a heterogeneous material, the method comprising:
obtaining force measurement data and displacement data of the heterogeneous material; executing an optimization process on a computer, whereby said boundary force measurement data is used as boundary conditions by a first finite element simulation and said displacement data are used as boundary conditions by a second finite element simulation; executing said first simulation on a model of the material at the computer, said model having at least one stochastic parameter, whereby said first simulation subjects said model to a boundary force to identify a first set of stress and strain values; executing said second simulation on said model of the material at the computer, whereby said second simulation subjects said second material model to a boundary displacement to identify a second set of stress and strain values; inputting the first and second sets of stresses and strain values into an objective function executed at the computer; determining whether said objective function has been minimized to a desired level; and updating said at least one stochastic parameter of said first and second model and repeating said first and second simulations until said objective function is minimized to a predetermined value, so as to optimize said at least one stochastic parameter associated with the material.