基于双粗糙面热弹塑性接触摩擦与局部润滑退化的低副抗胶合性能研究

Scuffing is a serious wear failure, which is more common in high friction pairs such as gears. However, as the working conditions of the low friction pair tend to be more severer, the scuffing is also often to happen in a lot of low friction pairs. Cylinder liner - piston assembly and connecting rod bearing are coupled low friction pairs in internal combustion engines. Under the working conditions of the vessel engine and tank engine, cylinder scuffing and bearing burning phenomenon occurred frequently in recent years. It seriously affects the engine reliability. So, the project will study the anti-scuffing performance of low friction pairs. The calculating domain of low friction pairs is obviously larger than that of high friction pairs. At the same time the prediction of scuffing should be based on the accurate and detailed contact information. So we will firstly study the transient thermal elasto-plastic contact and friction of two rough surfaces with limited region and the artificial neural network mapping model of the mean contact response parameters in the region. Based on that, the high efficiency tribological analysis method for low friction pairs will be built after analyzing the interaction of the thermal elasto-plastic contact and friction with the body deformation of the low friction pairs and the degradation of local lubrication. Further, a coupled multi-body dynamic model, in which the cylinder liner - piston assembly and connecting rod bearing are included, will be built. Combined with the tribological analysis of the low friction pairs, the prediction method of the low friction pairs’ anti-scuffing performance under extreme engine conditions and system design conditions will be provided. Based on the above research, the design improvement and scuffing test method of the key low friction pairs will be investigated. By combining theoretical analysis with experimental verification, this project will provide theoretical and methodological support for improving the anti-scuffing ability of low friction pairs.

胶合是一种严重磨损失效，在齿轮等高副中较为常见。随着低副的工作条件趋于恶劣，很多低副也常发生胶合。缸套-活塞组和连杆瓦是发动机中相互耦合的关键低副，近年来在船舶和坦克发动机工况下，拉缸和烧瓦现象频繁发生，严重影响了整机可靠性。为此，本项目将研究低副的抗胶合性能。针对低副求解区域大、同时胶合预测又需要以精确接触信息为前提的特点，将探索有限域的双粗糙表面瞬态热弹塑性接触摩擦和区域内平均接触响应参数的神经网络映射方法。基于此，分析热弹塑性接触摩擦与低副的体变形和局部润滑退化的相互影响，建立高效率的低副摩擦学综合分析方法。进一步围绕缸套-活塞组和连杆瓦建立耦合多体动力学模型，并结合各低副的摩擦学分析，提出极端工况及系统设计条件下关键低副的抗胶合性能预测方法。基于上述研究，探讨关键低副的抗胶合设计改进和胶合试验方法。本研究通过理论分析和试验验证相结合，将为提高低副的抗胶合能力提供理论和方法支持。

本项目从工程摩擦副粗糙表面的精确接触分析入手，通过接触、变形、润滑等多学科耦合建模，研究了工程摩擦副的抗胶合性能。首先基于有限元分析方法，建立了双粗糙表面的瞬态弹塑性接触模型，揭示了工程摩擦副表面粗糙峰分布和织构特征对接触压力与真实接触面积的影响机理，分析了基于统计参数的传统接触模型与确定性接触模型的结果差异。然后，建立了工程摩擦副的热弹塑性接触、变形和油膜润滑耦合分析模型，基于变形影响系数矩阵实现了工程摩擦副体变形的快速计算，通过埃特金加速和强弱耦合复合求解流程实现了大计算域的弹流润滑高效率分析，在流-固-热耦合计算基础上对油膜温度和固体温度进行了仿真预测。以发动机连杆小头轴承为例，分析发现工作过程中轴承弹性变形达20多微米，油膜瞬时温升达90多度，因此变形和热效应对工程摩擦副的影响不可忽略。接下来，在极端重载条件下，基于流-固-热耦合建模，分析了局部温升、润滑性能下降和接触承载比例上升的演化过程。研究发现，接触承载面积发展到一定阶段后，温度急剧升高、润滑性能快速下降，预示着胶合失效的发生。同时，表面涂层、表面织构、宏观型线、润滑油供应、润滑油添加剂产生的摩擦膜等，都会对摩擦副的摩擦学性能，进而对胶合的发展过程产生重要影响。最后，通过摩擦磨损试验机的基础试验和发动机运行状态的在线试验，对各种抗胶合设计措施和摩擦学性能仿真手段进行了试验验证，发现合适的涂层能够大大延缓胶合发生时间，ZDDP润滑油添加剂能够在铁基缸套表面产生具有抗胶合作用的摩擦膜，基于模型仿真的发动机连杆小头轴承温度和活塞组摩擦力预测值与试验值非常接近，理论建模与试验结果具有很好的一致性。在上述研究基础上，取得了31篇SCI期刊论文、5项专利申请、5项软著登记等在内的学术成果，以本项目成果为内核实现了“发动机活塞环-缸套边界润滑分析软件”的开发和企业应用，研究成果为国产复杂装备的摩擦学设计提供了方法和工具支撑。