栓接结合部微观接触机理与动态特性建模研究

Bolted joints exist extensively in machines and mechanical structures, The continuity of the system are disrupted, and greatly influence the dynamic characteristic of whole machine structure. How to accurately obtain the dynamic characteristic of a whole structure at its design stage is a key question of analysis of mechanical system from single part to whole machine structure. This project studies the micro contact mechanism and dynamic characteristics of bolted joints. Firstly, the developed fractal geometry and stochastic process theory yields three-dimensional fractal surface topographies representive of the contacts between rough surfaces. Secondly, the theory criterion of elastic-plastic range is proposed by contact mechanics and energy dissipation theory, the model of interfaces are established based on theory criterion. Thirdly, the general contact stiffness and contact damping models of bolted joints are established in this project based on models of interfaces and models of bolted joints structure. Finally, the micro contact model of bolted joints can be verified with the structural dynamic experiment, clarifying microscopic contact mechanism and reviewing dynamic characteristic of bolted joints. This project not only provides theory and method support for dynamic characteristic of bolted joints, but also provides a key way to resolve for precise modeling and performance prediction of whole machine structure. The research has important theoretical and practical significance in promoting performance index of products of high-end manufacturing and improving research level of manufacturing science.

由于机械结构中存在大量栓接结合部，使得系统的连续性被破坏，极大地影响了整机性能，如何在图纸设计阶段准确获取其动态特性，是机械系统由单件走向整机分析所面临的关键性难题。项目研究栓接结合部在微观接触变形过程和微幅振动下微凸体间相互作用机制与复杂的接触动力学行为；提出利用随机过程和分形理论相结合表征机械加工表面三维形貌特征；利用能量耗散理论与接触力学确定栓接结合部弹、塑性变形区间，并建立结合面模型；综合考虑结合面间微凸体的相互作用机理和螺栓连接特性，建立栓接结合部接触刚度和接触阻尼模型；通过整体结构动力学实验，验证栓接结合部接触刚度与接触阻尼模型的正确性，阐明栓接结合部微观接触机理，揭示影响其动态特性的规律。项目的研究不仅为栓接结合部动态特性研究提供理论与方法支持，更为整机精量化建模和性能预测提供关键的解决途径，对提升我国高端制造产品的性能指标，提高制造科学的研究水平，具有重要的理论与实际意义。

由于机械结构中存在大量栓接结合部，使得系统的连续性被破坏，极大地影响了整机性能，如何在图纸设计阶段准确获取其动态特性，是机械系统由单件走向整机分析所面临的关键性难题。本项目对重型数控机床栓接结合部动态特性作了深入的试验分析与理论探讨，探索了栓接结合部微观形貌特征，掌握了栓接结合部在振动环境中的演化规律，并对栓接结合部在横向交变载荷作用下的振动特性进行了较为深入研究。在解决问题过程中所涉及到接触表面微观形貌的三维表征、接触过程弹塑性变形区间的理论判据、栓接结合部接触阻尼的能量耗散机理以及理论模型与有限单元模型的耦合等问题，均属于本学科前沿课题，其研究成果具有重要学术理论价值和广阔的工程应用前景，为整机精量化建模和性能预测提供了关键的解决途径，对提升我国高端制造产品的性能指标，提高制造科学的研究水平，具有重要的理论与实际意义。. 项目相关研究成果主要发表在《Journal of Mechanical Science and Technology》、《机械工程学报》、《振动工程学报》、《振动与冲击》等重要学术期刊。申请人以第一作者发表SCI/EI论文8篇，EI源期刊录用3篇，授权发明专利2项、实用新型2项，受理发明专利4项、实用新型4项，重要研究发现在国内学术会议分组讨论上交流3次。