Composite material I-type layered bridging law determination method based on correction beam theory

Abstract

The invention relates to a composite material I-type layered bridging law determination method based on a modified beam theory, which comprises the following steps: (1) carrying out a composite material laminated plate I-type layered test, and measuring a P-delta curve of the composite material laminated plate I-type layered test; (2) establishing a two-dimensional correction beam mechanical modelof the sample under the I-type load; (3) inputting the P-delta curve, the material basic attribute and the geometric dimension into the model calculation program, performing iterative calculation inMatlab software, and determining a layering length a, an initial crack tip opening displacement delta * and an energy release rate GIc; and (4) establishing a relationship between GIc and delta * to obtain a bridging law sigma g (delta *). The method is suitable for determining the bridging law in the I-type layered expansion process of the composite laminate at any laying angle, and has the advantages that (1) the method only needs to take the P-delta curve of the sample as input, the crack position does not need to be observed, and test devices are reduced; (2) the method is realized by using a Matlab program, so that the calculation cost is relatively low; and (3) the method can be used for determining the I-type bridging law of the composite laminate at high temperature.

Description

technical field [0001] The invention relates to the determination of the bridging law in the process of delamination expansion of composite material laminated boards under the action of I-type load, and is suitable for resin-based composite material laminated boards widely used in aerospace vehicle structures. Background technique [0002] Fiber-reinforced composites are widely used in aerospace structures due to their excellent mechanical properties such as high specific strength, specific stiffness, and corrosion resistance. However, due to its weak interlayer properties, it is highly prone to delamination, leading to severe damage to the structure without any external signs. Therefore, accurately simulating the delamination behavior of fiber-reinforced composites is crucial in structural design. However, fiber reinforcement and material delamination are often accompanied by large-scale fiber bridging. The existence of fiber bridging makes the stress distribution at the c...

AI Technical Summary

Problems solved by technology

This method is easy to implement but requires constant adjustment of the camera focal length to focus on the crack tip position during the test, which undoubtedly introduces equipment errors

Looking at the above types of technologies, although they can obtain relatively accurate results, they lack versatility. In engineering practice, it is hoped to propose a relatively simple bridging law determination scheme

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