A method for testing the normal strength between layers of composite materials

Abstract

The invention discloses a method for testing the normal strength between the layers of a composite material, and belongs to the technical field of composite materials and material performance testing.According to the method, the specimen is a square flat plate block-like body; during the paving adhesion, a polytetrafluoroethylene film doing not cover the test area is inserted between the upper paving layer and the lower paving layer of the predetermined testing interface, and curing molding is performed; and the strength between the layers of the composite material is tested by using a testing device. According to the present invention, the method is used for testing the normal strength between the layers of the composite material, and breaks through the limitation on the interlayer performance of the to-be-tested specimen in the conventional method; and the corresponding size of the hollowed-out zone of the PTFE film can be designed according to the interlayer performance of the to-be-tested composite material, such that the normal damage load between the layers in the test can be controlled, and the interlayer damage of the composite material precedes the adhesive damage betweenthe metal block and the specimen so as to ensure the damage mode.

Description

technical field [0001] The invention belongs to the technical field of composite materials and material performance testing, and relates to a method for testing the interlayer normal strength of composite materials and a method for designing and manufacturing test pieces thereof. Background technique [0002] Composite materials have the characteristics of light weight and high strength, and have been widely used in sports, aviation, aerospace and other fields. Advanced composite materials specifically refer to composite materials that can be used in the main load-bearing structure or secondary load-bearing structure, and whose stiffness and strength properties are equivalent to or exceeding aluminum alloys. At present, it mainly refers to boron fibers, carbon fibers, and aramid fibers with higher strength and modulus. Reinforced composite materials. Although the performance of this type of composite material is equivalent to or stronger than that of metal, its interlayer p...

AI Technical Summary

Problems solved by technology

Although the performance of this type of composite material is equivalent to or stronger than that of metal, its interlayer performance is very low, and the interlayer is only carried by the interlayer interface, which is an area that is easily damaged. Therefore, its interlayer strength must be measured. For quality and performance evaluation of composite materials

[0003] At present, there is no test method for the interlayer normal strength of carbon fiber composite materials. Although GB / T 4944 can measure the interlayer tensile strength of glass fiber laminates, it requires that the bond strength between the specimen and the metal is higher than that of the test specimen. However, the interlaminar performance of advanced composite materials is often higher than the bonding strength of the adhesive, which will cause the failure mode of the specimen to be contrary to the expectation, making the measured properties inaccurate

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