Investigating the strength of the ultrasonic welding of the polyamide 6 continuous fiber glass composite

Composites of continuous fibers have higher mechanical performance than short fibers, which is why they are produced and used significantly in the aviation industry. One of the new methods of joining composites is ultrasonic welding. In this process, by applying high power (100 to 2000 watts) and high frequency (15 to 100 kHz) vibrations to the joint of two parts, heat is generated in the joint and causes the two parts to stick together. In this research, the parameters of the ultrasonic welding of polyamide 6 glass composite, the effect of the interlayer film, and the direction of the fibers on the strength of the connection have been investigated. Ultimately, the ultrasonic welding connection has been compared with the adhesive bond. In examining the connection as an edge-to-edge connection, the samples were cut according to ASTM D5868 standard and subjected to a tensile-shear test after ultrasonic welding. Considering the average input parameters for time, pressure, and power, it was observed that using a pure polymer film layer as the interlayer film increases the welding strength. By changing the direction of the fibers of all layers by 90 degrees, the welding strength decreased a little. The amount of polymer and fiber protrusion increased, and the appearance quality decreased. In comparing the welding connection with the adhesive bond, the value of the welding strength was higher than the strength of the adhesive connection. Also, the time spent on the welding connection was much less than on the adhesive bonding.