UV radiation effect on the adhesively single lap composite joints

In this study, the effects of UV rays on composite plates' single lap joints plates, composite plates and adhesive samples were investigated. Composite samples were exposed to UV rays for 300, 600, 900 and 1200 hours. With the data obtained according to the exposure time parameters, the mechanical properties of single lap joints samples, composite plate samples and adhesive samples were found and compared. The hardness values of composite plate samples decreased after exposure to UV rays for 600 hours, while the hardness values increased again in the 900-hour and 1200-hour exposure slices. As the exposure times of UV rays on the adhesive were increased, the hardness values tended to increase, albeit very small. The maximum rupture damage load increased as the exposure times of UV rays increased in single lap joints samples and composite plate samples. As composite plate samples increase UV exposure times, the modulus of elasticity and possion ratio decreased. In the adhesive samples, although the modulus of elasticity and the ratio of possion showed very small changes depending on the UV exposure time, there was no significant change in general. After static tensile tests, the type of damage that occurred in single lap joints samples was generally the combined damage type.