Incremental displacement collocation method for the evaluation of tension softening curves of quasi-brittle materials

Abstract

In this paper, the use of incremental displacement collocation method (IDCM) for the evaluation of the tension softening curve of quasi-brittle materials is presented. By varying the residual tensile stress on the tension softening curve (TSC) for each loading step, the measured displacements are matched with the computed displacements at selected locations. By gradually increasing the loading step, the complete TSC can be determined in a step-by-step manner. As distinct global and local deformation responses are employed in the IDCM, the ill-posed problem commonly encountered in other inverse analyses is avoided. The effectiveness of the IDCM is demonstrated by obtaining TSCs of quasi-brittle materials, such as mortar, concrete and graphite, in the forms of bilinear, tri-linear and exponential curves.