Chapter 10 - Computer Program for Mixed-Mode Type Crack Analysis in Concrete Using EFCM (CAIC-M12.FOR)

Abstract

This chapter focuses on a crack-analysis computer program, CAIC-M12.FOR, for mixed-mode crack analysis. The program CAIC-M12.FOR has been developed by extending the mode-I crack analysis program CAIC-M1.FOR, and except for the fracture mode involved, the main features, structure, and flow of the program are basically the same as those of CAIC-M1.FOR. It performs crack analysis of the mixed-mode type (mode I + mode II) in structural concrete. However, solving a mixed-mode crack problem requires additional operations of setting pairs of unit cohesive forces in the direction tangential to the crack surface, calculating sliding displacement and other coupled influence coefficients, and formulating the crack equation for mixed-mode fracture. Two types of shear-transfer model are employed in the program—the bilinear type and the trilinear type—and the variables are used to define these models. The chapter explains the formulation of the crack equation for mixed-mode fracture in matrix form, how the direction of shear force is determined based on the direction of crack surface sliding, and subroutines that have been added in CAIC-M12.FOR for mixed-mode crack analysis. Furthermore, the usage of the program in crack analysis is illustrated by solving a problem.