高等级海况下爆压冲击与重载摩擦耦合对微织构表面的损伤行为研究

The high sea states make the vessel in the swaying conditions, which may increase the possibility of severe wear and scuffing for the high power density diesel engine. To settle this problem, surface micro-texturing is an important method to improve the tribological properties of the frictional pair. Through simulating the working conditions of the diesel engine frictional pair, damage of micro-textured surface caused by the combined impact and friction effects under the peak pressure will be studied. Research contents include: (1) Distinguish the transient response features between the impact and friction behavior, nondimensionalize the characteristic factors which influence the transient response, and give the multi-factors acting rules of the transient damages. (2) Cumulative damage dynamic models of the micro-textured surface under the combined impact and friction effects will be established based on the chaos theory, so as to obtain the relationship among the characteristic factors, the characteristic parameters and the characteristic topography from the transient damage initiation to the cumulative damage failure. Then with the damage process definition of the micro-textured surface, the evolution rules of the damage states can be acquired. (3) From the aspects of the geometrical morphologies, materials transfer and tribological chemistry, the damage and failure mechanism will be revealed. After clarify the damage resistance rule of the micro-textured surface, it will give the damage failure suppression principles, and propose some micro-machining principles of the micro-textured surface which will accommodate the high sea states and harsh working conditions. The project research results will optimize the design of the micro-textured surface, and provide the theoretical foundations and technical support to improve the anti-damage performance of the micro-textured surface.

在高等级海况下，剧烈摇摆的舰船容易造成高强化柴油机磨损加剧、拉缸倾向严重，可以通过摩擦副表面微织构改善摩擦磨损性能，但需要考虑苛刻海况和工况等多重环境因素影响，研究爆发压力作用下冲击与摩擦耦合对于微织构表面的损伤行为。首先区分微织构表面对于冲击与摩擦行为的瞬态响应特征，无量纲化影响瞬态损伤的特征因素，量化描述瞬态损伤的多因素影响规律；其次基于混沌理论，建立冲击与摩擦耦合作用下微织构表面损伤累积的动力学模型，获得微织构表面从瞬态损伤到损伤累积失效过程中特征因素-特征参数-特征形貌的关联关系，界定微织构表面的损伤阶段，获得损伤状态演变规律；最后从几何形态、材料转移以及摩擦化学角度揭示微织构表面损伤失效机理，明晰微织构参数对于损伤的抵抗规律，给出表面微织构的失效抑制准则，提出微织构表面的制备原则。研究成果将为优化微织构表面设计，提高微织构表面抗损伤性能提供理论依据和技术支撑。

随着新一代船舶柴油机强化程度提高，处于高等级海况下的动力缸内各摩擦界面容易出现不均匀的载荷分布，无法形成稳定的润滑状态，造成缸套-活塞环摩擦界面磨损加剧，拉缸倾向严重，降低了柴油机运转的可靠性。研究表明，微织构表面能够降低摩擦界面的摩擦系数、抑制磨损，是解决上述问题的一种潜在手段。本项目针对缸套-活塞环摩擦副微织构表面的损伤行为开展基础研究，主要包括：强化工况下缸套-活塞环的损伤行为；微织构表面的制备及其摩擦磨损机理。.重要结果和关键数据如下：基于摩擦力的相空间轨迹，可以将贫油状态下的摩擦状态转化行为分为三个阶段，其中在拉缸损伤前的第二阶段出现摩擦力突降，可以作为缸套-活塞环摩擦副出现严重黏着磨损发生的征兆；各个摩擦阶段的表面形貌表明在拉缸损伤前缸套会经历“抛光磨损”阶段。抗拉缸损伤试验表明，活塞环喷钼涂层(NCM)的抗损伤时间要长于铬基陶瓷复合镀涂层（CKS），NCM/Fe配对副在往复式塑性剪切下主要是由于黏着磨损效应造成表面损伤，CKS/Fe配对副主要是由于磨粒磨损效应；而摩擦磨损试验表明，CuSn镀层在摩擦磨损过程中会镶嵌到缸套表面，使得缸套表面形貌呈现平坦凸峰，促进了缸套-活塞环表面的摩擦化学反应。研制了一套往复式电射流微织构表面形貌加工系统，当阴极速度为10 mm/s，电解液流量为45 mL/s，电源电压为10 V，电解时间为60 s时，可以获得最佳的圆形微织构形貌。基于缸套-活塞环摩擦状态表征和分析表明，微织构直径设计值为800 μm，面积占有率设计值为22%，排布方式为相交时，抗损伤时间最长。在贫油状态下，相邻微凹坑之间的区域首先出现微观黏着，进而形成两体磨粒磨损并逐渐造成微织构形貌损伤，最终在微坑中会逐渐覆盖磨屑团聚物，占据微坑空间。.项目研究成果将为改善缸套-活塞环摩擦磨损性能提供了理论依据和技术支撑。