Thermo-Mechanical Crack Growth Investigation in Foam Core Graphite Epoxy Laminated Sandwich Structure Using Phase Field Method

Abstract

Foam core sandwich composite structures have wide structural applications in aerospace; they are subjected to thermo-mechanical loading environments during their service life. Therefore, it is necessary to predict the fracture behavior of these composite structures accurately. In this work, a computational framework based on the well-proven, computationally efficient hybrid PFM associated with an orthogonal decomposition scheme is presented and implemented to predict the thermo-mechanical crack growth phenomena in an orthotropic multi-material layered system (foam core graphite epoxy laminated composite sandwich structure) under the combined effect of mechanical loading and thermal environment (heating or cooling). The thermo-mechanical fracture response of the laminated composite sandwich structure (LCSS) is analyzed for crack initiation, crack growth, and load-bearing capacity. Both the crack intersection and crack merging phenomena are captured during the failure of LCSS under thermal cooling and thermal heating, accompanied by mechanical load. The performance of the LCSS is analyzed by comparing the structural load capacity, crack nucleation threshold, and fracture energy of the structure in multiple numerical cases. The presented methodology, based on a hybrid phase field method and orthogonal strain decomposition scheme, is validated for structural problems from existing literature under the thermo-mechanical loading and further extended to LCSS structure cases.