The Study of the First Mode Energy Release Rate of Composite Material

The composite material is an advanced material, which have the higher stiffness / weight ratio and can be designed based on the designer concept. The major failure reason of the composite laminate is from the de-lamination between the laminas. The causes of de-lamination may come from the external loading, environmental change or corrosion, or. the micro-defects inside of the composite laminate during the manufacturing processing. The de-lamination is easily observed because the required critical energy is lower. Generally, the de-lamination propagation criteria are judged by using the critical energy release rate (GⅠ; GⅡ; GⅢ). In this research three different methods included the theoretical analysis, experimental test, and finite element method are applied to calculate the first mode strain energy release rate of composite -materials. In theoretical analysis, the linear elasticity theory for double cantilever beam is applied to calculate the GⅠ values. The experimental works are also conducted; the double cantilever beam (DCB) is designed and performed the tests to get the loading and deflection, then combined with the compliance method to find the GⅠ values. In finite element analysis, the model with 2D singular element and 3D regular element are applied to get the nodal force and nodal displacement that can be used to calculate the GⅠ values. The results agree very well among these three methods.

並列關鍵字

Composite material ； First mode energy release rate ； Double Cantilever beam ； Singular element

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