805 / 2022-03-31 23:24:46

In-Situ Measurements of Interfacial Residual Stress between Alumina Particle and Epoxy Based on Photoelasticity Method

Micro-alumina epoxy composite,residual stress,Photoelasticity

Purpose/Aim

The residual stress in large-scale epoxy-based spacers is one of the main factors affecting the operation reliability of GIL/GIS. The detection of curing residual stress is critical for the quality control of epoxy insulation.

Experimental/Modeling methods

Photoelasticity method is used to build the detection system of the residual stress. Based on the photoelasticity test, the photoelastic stripes of the alumina-filled epoxy resin composites are directly observed by polarizing microscope after resin curing, and the interfacial residual stresses of each specimen are calculated according to the law of planar photoelasticity and the spherical stress-optical equation, and the main influencing factors and laws of interfacial residual stresses are summarized.

Results/discussion

The common feature of the photoelastic stripe diagram is the cross isotropic line, the closer the area to the interface the brighter the isotropic stripe, and the farther becomes darker, which indicates that the residual stress is reduced far from the interface.

Conclusions

According to the photoelastic principle, the specific values of interfacial residual stresses are calculated by observing the photoelastic striation diagram of spherical alumina, and the influence law of interfacial residual stresses is drawn from the experimental results. The residual stress detection system can effectively detect and evaluate the residual stress concentration caused by curing induced distortion and filler settlement.