Study on Stress Intensity Factor of PMMA with Double Cracks Using Coherent Gradient Sensing (CGS) Technique

Abstract

In this paper, the principle of coherent gradient sensing (CGS) technology is briefly introduced. Fracture behaviour of the PMMA specimens with single or double cracks under three-point-bending are studied using the CGS optical method. A series of CGS fringe patterns under different loading are abtained. With these fringes, stress intensity factors are caculated. The influences of the different spacing on stress intensity factors are discussed. These results will be useful for researching on strength of PMMA materials.

Modal analysis of a beam with bilateral breathing oblique cracks

“…K Mazanoglu and M Sabuncu 1 transformed the breathing behavior of double-edge cracks into stress field variation by the Energy Method, and applied the Rayleigh-Ritz approximation method to investigate the flexural vibration of the cracked beam. L T Mao, C P Liu, K Chen, et al 2 investigated the fracture behavior of Polymethyl-Methacrylate (PMMA) plate specimens with double cracks under three-point-bending by the Coherent Gradient Sensing Technology, and discussed the effect of crack spacing on stress intensity factors. I A Khan and D R Parhi 3 established finite element model of the beam with double cracks by ANSYS, and conducted modal analysis of the cracked beam by numerical simulation method, which was verified by modal experiments.…”

The coherent gradient sensor for film curvature measurements at cryogenic temperature

“…According to the mismatch in thermal expansion coefficient between the film and substrate subjected to a high temperature environment, Dong et al [11] developed the CGS system to high temperature and presented the analysis expression of the stress based on the Stoney's formula [12] and its expansions [13][14][15][16][17]. In addition, CGS system is always used to investigate the deformation of crack tip and facture characteristics in the facture-mechanics [3,[18][19][20], such as the crack tip deformation, stress intensity factor, etc. Some good results are achieved by the CGS system.…”