The effect of embedded devices on structural integrity of composite laminates

Integration of functional devices within structural materials is an efficient method to implement and design multifunctional materials and structures. However, embedded devices in composite structures typically cause a geometric discontinuity, which results in a significant effect on the structural integrity of the composite. Herein, we have presented an experimental and numerical investigation into the effect of embedded devices on the tensile properties of carbon/epoxy laminates. The embedded devices considered in this study are embedded thin film lithium energy cells within composited laminates to form energy storage structural composites. During static tensile testing, the damage evolution was monitored by acoustic emission measurement and several specimens were observed through optical micrograph at different load levels to determine the progressive damage. Testing results demonstrate that delamination at the interface between composite and integrated device is a significant damage mechanism in tensile performance degradation and the delamination propagation depends on the ply angle of the SUS/θ interface. A two-dimensional plane strain finite element model using ABAQUS code was developed to study damage initiation using stress analysis and the behavior for delamination propagation using a fracture mechanics approach. Numerical results demonstrate that the different effects of “slipping” and “frictional forces” on crack propagation can be modeled to introduce different critical release rate.