Fracture in foam core composite sandwich beams under mixed-mode I/II/III loading conditions

Abstract

Static fracture in foam core composite sandwich beams under mixed-mode I/II/III crack loading conditions is studied theoretically by the Mixed Mode Flexure (MMF) beam configuration. The basic idea of this paper is that mixed-mode I/II/III crack loading conditions can be generated by loading the MMF sandwich beam by an inclined force (usually, the MMF beam, loaded by a vertical force, is used for investigating mixed-mode I/II fracture in continuously fiber reinforced polymer composites). Three-dimensional finite element simulations of the MMF sandwich beam are performed using the ANSYS program system. The methods of linear-elastic fracture mechanics are applied. The fracture behavior is studied in terms of the strain energy release rate. The virtual crack closure technique is applied to analyze the strain energy release rate mode components distribution along the crack front in the MMF beam at the force inclination varying from 0° (force parallel to the crack front) to 90° (vertical force). The analysis revealed that the MMF beam loaded by an inclined force can be used to study the mixed-mode I/II/III fracture in foam core composite sandwich beams over wide mixed-mode ratios ranges.