Implementation of a Bond Model, Including Dilation, for Reinforced Materials in aFinite Element Analysis

摘要

The objective of this research was to develop a composite finite element analysisthat is capable of including the nonlinear, elastic-plastic response of the bond between reinforcing fibers or bars and matrix material. This bond is very important in determining the behavior of reinforced weak or brittle matrix materials, such as reinforced-concrete or ceramic-matrix composites. A composite element captures the response of a reinforced material without the expense of a discrete model which treats each constituent with different element or material types. This report documents the development, implementation, and verification of the composite element with bond modeling capabilities. The numerical implementation of the plasticity-based bond model during testing reproduced the salient features of the theoretical bond model as a stand-alone unit prior to its implementation in the finite element setting. After the composite finite element was incorporated in a finite element code, analyses of published beam and bond tension tests were conducted. The predicted results compared favorably with the published data, considering the limitations of modeling the behavior of the matrix and the reinforcement as linear elastic. The beam analyses illustrated the ease with which the composite analysis can be applied to practical problems. The bond tension tests clearly demonstrated the element's capacity to model bond behavior.