Experimental investigation on adhesively bonded U-shaped metallic joints using the Arcan test

An experimental investigation on adhesively bonded joints has been carried out by using an adhesive used in automotive applications. The main goal of this work is to characterize the mechanical behaviour of the adhesive joints subjected to different loading angles and understand whether the cataphoresis painting process can be used to cure the adhesive. To this aim, two different typical temperatures, used for the cataphoresis process, have been used for curing the studied adhesive. Arcan test has been used to characterize the mechanical behaviour of the adhesive joints by using five different loading angles: 0°(shear condition), 30°, 45°, 60°(combined shear-tensile), and 90°(tensile). The experimental tests showed that the adopted curing cycles conducted at 190 °C for 15 ′ and 160 °C for 45 ′ are both able to fully cure the adhesive, this was verified with Differential Scanning Calorimeter analysis (DSC). The two curing temperatures do not lead to significant differences in the maximum values of the strength. Arcan test conducted at different loading angles shows that the maximum value of the strength is obtained for the condition of shear loading (about 10 MPa nominal strength), while the lowest value is related to the condition of tensile loading (about 5 MPa nominal strength). Scanning Electron Microscope (SEM) analysis was used to assess the distribution of the hollow glass spheres that are embedded in this adhesive to set the thickness layer.