Shape effects of the traction-separation law on the global response of the dynamic fracture for pipeline steels.

A recently reported four-parameter cohesive zone model (CZM) has applications in dynamic fracture such as the drop-weight tear test simulation. In this paper, the CZM method is utilized to analyze the global response of the dynamic fracture problems. And the two key CZM parameters, maximum traction and cohesive energy, are determined from the nominal stress-strain (SS) curve by considering the damage scalar and a simulation of the tensile test, respectively. The other two parameters, S0 and Sm, are related to the shapes of the traction-separation law (TSL), which characterize its stiffness and softening shape, respectively. The influences of TSL's shape on the global response such as the nominal SS curves and the load-displacement curves are analyzed by the finite element method. Evident (TSL's) shape effects are found in the case of high-speed dynamic fracture of pipeline steels, which is completely different from quasi-static models. [ABSTRACT FROM AUTHOR]