Influence of Welding Process Parameters on Mechanical Properties of Coated Fabric Weld Seams

Weld seams in membrane structures exhibit a significantly higher failure probability than the base material and often act as initiation points for structural damage. Their mechanical properties are strongly influenced by welding process parameters, including temperature, time, and pressure. This work investigated the effects of welding parameters on the mechanical performance of Polyvinyl Chloride (PVC)- and Polytetrafluoroethylene (PTFE)-coated fabric weld seams through orthogonal experiments, analyzing the failure modes, mechanical characteristics, and microstructural variations of three weld configurations to reveal the failure mechanism and establish a high-accuracy strength prediction model. Joint efficiency is defined as the ratio of the ultimate bearing capacity of welded joints to that of the base material. For PVC-coated fabrics, the lap weld seams reached a joint efficiency of 108.23 %, with 78 % of specimens failing in the base material. The joint efficiency of single-covered and double-covered butt weld seams dropped to a minimum of 78.54 %, attributed to stress concentration and bending effects. For PTFE-coated fabrics, the maximum joint efficiency reached 101.57 %. The error of the established strength prediction model is less than or equal to 5 %. For the optimal parameter combination (380°C/80 s/0.5 MPa), the predicted strength is 6,954.98 N, with an error of only 0.89 % compared to the measured value.