Measuring Method of Residual Stress Distribution of Composite Sheet Based on Incremental Cut Method

Abstract

The invention belongs to the field of residual stress measurement of composite materials, and relates to a method for measuring the residual stress distribution of composite material plates based on the incremental cutting method. The method comprises: determining a measuring position and a measuring direction for a composite material plate to be measured, and pasting a plurality of strain gaugesat corresponding positions; connecting the strain gauges to a static strain tester, and connecting the static strain tester to a computer to record data in real time; performing incremental cutting onthe back surfaces of positions where the plate is pasted with strain gauges by using a numerical control cutting machine, and the strain value of each strain gauge at each position along with the cutting depth can be obtained after cutting is completed, wherein the incremental cutting is performed by cutting the plate several times with a fixed back cutting depth and the depth of the cutting depends on the purpose of the measurement; obtaining the stress distribution at the positions of all the strain gauges by using a finite element model; and finally, performing corresponding measurements on other directions and positions by changing the direction in which the strain gauges are pasted and cut.

Description

technical field [0001] The invention belongs to the field of residual stress measurement of composite materials, and relates to a method for measuring residual stress distribution of composite material plates based on an incremental cutting method. Background technique [0002] During the molding process of the composite material, due to the difference in the thermal expansion coefficient of the fiber and the matrix and the difference in the internal and external cooling rates, obvious residual stress will be generated during the cooling process. The generation of residual stress will cause the plate to warp and deform. There are many adverse effects in the use process. Therefore, in order to achieve the purpose of controlling the residual stress, the measurement of the residual stress of the composite material is particularly critical. At present, the commonly used residual stress measurement methods are mainly divided into two categories: non-destructive testing and destr...

AI Technical Summary

Problems solved by technology

However, such methods are costly and require high levels of equipment and personnel, which is not conducive to practical engineering applications.

Destructive testing is widely used in engineering practice, mainly including blind hole method and cutting method. Among them, blind hole method is widely used, but this method is mainly for isotropic materials, and composite materials have anisotropic characteristics, so it is not suitable Use this method to detect

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