Prediction method for mixed type delamination resistance curve of composite

Abstract

The invention relates to a prediction method for a mixed type delamination resistance curve of a composite. The prediction method comprises the following steps: (1) designing and manufacturing a carbon fiber reinforced composite laminate sample; (2) respectively carrying out an I type delamination experiment, an II type delamination experiment and an I/II mixed type delamination experiment by adopting a double cantilever beam, an end part notch bending device and a mixed mode bending device; (3) determining an I type delamination resistance curve, an II type delamination resistance curve and an I/II mixed type delamination resistance curve of the sample; (4) fitting data by adopting a delamination resistance curve theoretical formula, and determining fracture toughness initial values and stable values as well as fiber bridging lengths of different delamination experiments; (5) respectively fitting the fracture toughness initial values and stable values at different mixing ratios by adopting a B-K criterion, so that criterion coefficients etainit and etaprop are obtained; and (6) establishing a mixed type delamination resistance curve prediction formula with a loading mixing ratio as an independent variable. The prediction method provided by the invention predicts a delamination resistance curve at any other mixing ratio by virtue of delamination fracture toughness testing on acarbon fiber reinforced composite laminate at a specific mixing ratio, is convenient for engineering application and can reduce experimental cost.

Description

technical field [0001] The invention relates to the technical field of prediction of fiber-reinforced composite material mixed-type delamination resistance curve, in particular to a method for predicting the delamination fracture toughness value of carbon fiber-reinforced composite material laminates at any mixing ratio. Background technique [0002] Due to their high specific strength and specific stiffness, carbon fiber reinforced composites are widely used in aerospace and other fields to reduce structural weight and improve fuel efficiency. The laminate structure is a commonly used configuration in engineering practice. Since the out-of-plane performance is much lower than the in-plane performance, delamination damage is prone to occur. The emergence and expansion of delamination damage will cause a significant decrease in structural strength and stiffness, and even lead to catastrophic accidents without warning, which seriously restrict the application of composite mate...

AI Technical Summary

Problems solved by technology

[0004] A large number of existing experimental studies have shown that the loading and mixing ratio has a significant effect on the fracture toughness of composite laminates

Delamination may occur at any mixing ratio, and the experimental determination of the fracture toughness of composite materials at all mixing ratios will consume a large amount of experimental resources, and it is impossible to exhaust all possible situations through experimental means

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