Study on microstructure and tribological properties of hierarchical 3D braid applicable in heavy operating tribology conditions

Abstract The phenomenon of wear and friction in a variety of environments, including dry, seawater, and high temperatures, has always been a source of contention. Designing and fabricating parts that can function optimally in these conditions, such as self‐lubricating composites, is helpful. This work investigated the tribological and thermal properties of a three‐dimensional braid composite consisting of PTFE yarns and three types of reinforcement in the hierarchical structure under different operating conditions. In this study, the effect of different speeds was considered as well as effect of load. Roughness (Rq) and wear rate of the worn surface were also taken into account while evaluating the friction coefficient. By the response surface method (RSM) and D‐optimal design, the tests were planned experimentally so that the minimum test was performed. Statistical models from the analysis of experimental data by RSM revealed that the friction coefficient of all composites rises in dry conditions with increasing load and sliding speed. In contrast, in seawater conditions, the more difficult the test conditions, the friction took a positive trend. Glass fiber reinforced composites were temperature sensitive and behaved differently in different conditions. The most optimal cases were calculated and reported by the utility function. Furthermore, the coefficient of friction values obtained in all cases were desirable and reliable.