Micromechanical fracture model for ductile-brittle bimaterial interfaces
The micromechanical properties of a bimaterial interface depend on the (i) bonded slip and friction parameters (ii) release of fracture energy during crack growth and (iii) propagation, residual energy and shape formulations defining the failure envelope. A non-empirical fracture model is proposed for a ductile-brittle bimaterial interface. Such interfaces occur in Steel-Concrete (SC) composite wall modules, which are building blocks of nuclear and containment facilities. Similar bimaterial interfaces can occur in geotechnical structures, aerospace, ceramics and other composite applications. The thesis identifies the primary microstructural failure modes associated with such interfaces. A controlled volume fracture model for adhesively bonded interfaces is used in conjunction with Rice’s path independent J-Integral to correlate the strain energy release rate(SERR) to traction slip parameters. The linear elastic fracture model is modified to account for plasticity effects in the process zone and derive the crack tip opening displacement (CTOD). Numerical evaluation of fracture toughness parameters is performed to study impinging effects and determination of stress intensity factors. Depending on the nature of interface under consideration; appropriate tension softening/hardening laws are incorporated to capture the phase transformation of crack propagation in the expression of J for remote integral paths.
Tomar, Purdue University.
Mechanics|Civil engineering|Materials science
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