Elastic Index of the Work-Done of FRP

抄録

The elasto-plastic behavior of fiber-glass reinforced plastics (FRP) appears to be caused by the cracks progressing along the interface between different constituents and propagating across the matrix. This paper reports an investigation on the relationship between the value of strain applied in the FRP specimen and the state of micro-fracture by considering the value of elastic index of work-done (E.I.W). For the plastics reinforced by the glass fabrics which has systematic structure, the E.I.W. decreased rapidly at the knee point. After the strain passed the knee, it recovered again, and even a small reduction occurred in a certain region. The large reduction of the E.I.W. at the knee is due to the cracks inside of woof strands, and the later small reduction is due to the cracks inside of warp strands. Specially the transition of E.I.W. by step-wise increasing of strain shows the progress and propagation of cracks in the corresponding parts of FRP.