chapter  3
44 Pages

2 Softening Stress-Strain Relations

Since the cracks in concrete are not straight but tortuous, and the microcracking zone in front of the continuous fracture is not likely to develop along a straight line, the behavior of the fracture process zone can equally well be described by stress-strain relations with strain-softening, i.e., declining stress at increasing strain. This approach is quite convenient for computer programming since no separation of the nodes of two adjacent elements needs to be introduced and fracture is handled by adjustments of the incremental stiffness of finite elements, basically in the same way as any inelastic behavior.