Perspective Measurement Of Deformation Field Distributions Inside Resin Matrix Composites By Laser Wavenumber Scanning Interferometry

With the rapid development of resin matrix composites, it is desirable to establish more reasonable and perfect theory to study the mechanical properties of composite materials caused by fracture, collision, tension, stress. There are many methods for measuring the mechanical properties of composite materials.This paper use laser wavenumber scanning interferometry which based on Michelson interferometer to measure the internal compression displacement, out of plane displacement or strain fields,when bearing external force or load.How to set up the laser wavenumber scanning interferometry system is described detailedly in three aspects of optical system, mechanical system and image acquisition. Optical system is constituted by a semiconductor laser, convex lens, cube beam splitter, polarizer, reference optical wedge, the sample, or the like. In mechanical system, the design of integrated mechanical structure and the three point loading device of compression displacement and out of plane displacement are mainly introduced. In image acquisition system, the main parameters of the CCD industrial camera are shown. In addition, the measurement principle of laser wave number scanning interferometry is described in detail, including the principle of wavenumber scanning, and the calculation formula of out of plane displacement field, compression displacement field, out of plane strain field, performance index. Then, the experimental methods and the data processing procedure for the double layer resin matrix composite and glass fiber-reinforced resin matrix composite are presented respectively. Finally, the compression displacement field distributions of the double layer resin matrix composite, and the out of plane displacement field and out of plane strain field distributions of the glass fiber reinforced resin matrix composites are given.Experimental results show that, the samples’ actual force conditions are basically consistent with the distributions of compression displacement field or out of plane displacement field or strain field. The relationship between displacement fields and the loadings is linear, and the absolute value of the out of plane strain fields are also increased with the increasing of loadings. Therefore, it indicates the correctness of the algorithm, the feasibility of the system, and shows that the experimental system has good stability and reliability. Laser wavenumber scanning interferometry is a new type of mechanical testing technology, which is suitable for transparent and semi transparent composite materials, and can be used to measure the three-dimensional deformation fields in the interior of the resin matrix composites.