## 1 Introduction  
Reciprocating mud pumps, due to their strong versatility, have a wide range of applications in agricultural production, construction engineering and energy drilling. In the field of agriculture, mud pumps play an integral role in land reclamation, which is commonly seen in coal mine areas. Reclamation through mud pumps involves using water pumps to generate high-pressure water jets to wash dry soil. The broken soil forms a slurry mixture with water, which is then transported to the land reclamation area through mud pumps and pipelines. Hydraulic dredging units are vital hydraulic machinery in the fish farming industry, consisting of mud pumps, high-pressure water guns and delivery pipes used for digging or deepening fish ponds. In the field of construction, mud pumps can not only carry out reservoir silt removal and silt-solidified river Mike construction through water flushing excavation but also transport clear water and cement in foundation construction. In the field of energy drilling, mud pumps are crucial in geological exploration and oil drilling. Mud pumps serve as the core of the drilling fluid circulation system, providing high-pressure liquid to flush the drill bit and discharge the drilling fluid and thus greatly improving drilling efficiency. As the main component and major wearing parts of the mud pump equipment, the piston-cylinder liner friction pair has an important meaning to the stability and safety of the mud pump. The friction and wear performance and the temperature of the friction pair are important indicators of the mud pump which determine the life of the piston and the cylinder liner. How to reduce the friction and wear of the friction pair has always been a concern. The mud pump piston is made of rubber, and the cylinder liner is made of steel. Rubber materials are widely used in various friction and sealing parts. Relevant scholars' research on the friction and wear of these parts has mainly focused on rubber seals [1; 2; 3; 4], rubber tires [5; 6] and rubber conveyor belts [7]. For instance, [PERSON] et al. conducted research on O-rings [1]. They studied the effects of the pre-compression amount, fluid pressure and friction coefficient on the static and dynamic sealing performance of O-rings. Moreover, [PERSON] et al. delved into the significant impact of pressure on the rubber-sealing capabilities within an abrasive drilling environment [4]. They meticulously analyzed the wear process and mechanisms resulting from the invasion of micro-rock debris at the sealing interface. Additionally, they compared the characteristics of particle disintegration and the evolution of wear under varying conditions of high and low pressure. There are also unconventional rubber products, such as how [PERSON] et al. studied both the kinetic friction characterizations and the stick-slip motion phenomena for tubular rubber seals [8]. There are few pieces of research on the friction pairs of pumps, and they are mainly focused on friction pairs in the plunger pump [9; 10; 11; 12]. Moreover, [PERSON] et al. designed a composite texture combining micro-concave pits with variable depth grooves to improve the sealing performance of diesel engine piston pairs and reduce wear [13]. The research results show that the composite texture can produce an appropriate oil film thickness to resolve insufficient lubrication issues. The composite texture improved the lubrication and sealing performance of the piston, reducing the wear depth and average roughness. Bench tests also proved an enhancement in the sealing effect. Plunger pump and engine pistons [14], including piston rings as friction pairs [15], are all made of metal materials [16; 17]. There is limited research on non-metallic material pistons such as rubber and polyurethane pistons. Research on rubber pistons mainly focuses on medical injection devices or other scenarios that implement seals with rubber materials. Studies on mud pump pistons are scarce.