Analysis of the influence of damp-heat aging on the shear failure of the adhesive joint of composite materials

Abstract

In this study, a comprehensive temperature and humidity environment chamber was used to accelerate the artificial aging of carbon fiber bonded joint specimens in wet and hot environments, and shear tests were conducted on non-aging and wet and hot aging specimens, respectively. At the same time, acoustic emission technology was used to monitor the damage to the specimen, and the influence of wet and heat aging on the shear properties and damage forms of the bonded joint was explored. It is found that under shearing load, the unaged bonded joint specimens first show delamination degumming damage with an energy distribution of about 1000 (mV*mS) and then fiber fracture damage with an energy distribution of more than 4000 (mV*mS). According to the load strain curve, it can be seen that the shear strength of the moisture-heat aging specimen decreases by 30% compared with that of the non-aging specimen, from 33.6 kN to 22.3 kN. According to the load energy curve, it can be seen that the rubber layer of the specimen is damaged at the inflection point of the load curve, the rubber layer of the non-aging specimen is damaged at 15 kN, and the rubber layer of the moisture-heat aging specimen is damaged at 8 kN. The test results show that the wet heat aging reduces the interlayer properties of the specimens. The structural adhesive delamination is serious, which leads to the damage of the aged specimens in advance compared with the non-aged specimens. The overall deformation of the specimens increases.