基于细观力学与连续损伤的齿轮接触疲劳损伤演化机理研究

Gear contact fatigue failure mechanism is still unclear and due to that early tooth surface failures occur frequently in engineering practice, which severely impacts the performance and the reliabilities of machinery equipment. Traditional gear contact fatigue strength design method is not able to consider the influences of material microstructure and its deformation-mechanical behaviors, therefore it is difficult for which to reveal the underlying mechanism of gear contact fatigue damage. In view of this problem, from the viewpoint of meso-scale, this project uses the theories in continuous damage mechanics, crystal plasticity micro-mechanics, transmission mechanics and material testing and characterization technologies to study the gear contact fatigue damage evolution mechanism. A mesoscopic gear contact fatigue damage model, which combines the gear geometry and kinematics analysis, gear material microstructure model generation, and damaged coupled crystal plasticity constitutive equations derivation, will be developed. The evolutions of the mesoscopic stress strain fields, the crystal deformation behaviors as well as the damage during the gear contact fatigue process will be studied, and the contact fatigue crack initiation life will be predicted. The effects of the material microstructure and its deformation behaviors on the gear contact fatigue damage evolution and the contact fatigue life are to be determined. The experimental study of gear contact fatigue damage mechanism is to be conducted which will be used to verify the theoretical results. The projects is of great value in deepening acknowledgement to the intrinsic nature of gear contact fatigue damage process, which will support the further understanding of the gear contact failure mechanism and future anti-fatigue gear design theory in modern engineering practice.

齿轮接触疲劳失效机理不明确导致工程实际中经常发生早期齿面失效，严重影响装备性能与可靠性。传统齿轮接触疲劳强度设计方法无法考虑材料微结构及其形变力学行为的影响，难以揭示齿轮接触疲劳损伤内在机制。本项目从细观角度出发，采用连续损伤力学、晶体塑性细观力学、传动机械学、材料测试与表征多学科交叉方法，开展齿轮接触疲劳损伤演化机理研究。通过齿轮几何运动学分析、齿轮材料微结构建模和损伤耦合的晶体塑性细观本构推导，建立齿轮接触疲劳损伤细观模型，预测接触疲劳进程中齿轮表面及近表面细观应力应变场、晶体形变行为和疲劳损伤的演变历程和预估疲劳裂纹萌生寿命，阐明材料微结构特征及晶体形变行为对齿轮接触疲劳损伤演化和疲劳寿命的影响机制，并进行齿轮接触疲劳损伤机理试验研究验证理论模型。本项目预期成果有助于深化对齿轮接触疲劳损伤过程本质的认识，为进一步理解齿轮接触疲劳失效机理、发展现代齿轮抗疲劳设计提供理论支撑。

齿轮接触疲劳失效是制约现代高端装备性能和可靠性的重要瓶颈。本项目针对传统齿轮接触疲劳强度设计方法无法考虑材料微结构及其形变力学行为的影响，难以揭示齿轮接触疲劳损伤内在机制的问题，从细观角度出发，开展齿轮接触疲劳损伤演化机理研究。开展了齿轮近表层材料微观结构特征测试表征和重构，在连续损伤力学和晶体塑形理论的框架下，推导了集成晶体变形运动学、晶体塑性本构关系、损伤驱动力主导方程的损伤耦合晶体塑形本构关系，首次构建了包含材料晶体形貌、尺寸、相成分等微观结构特征和硬度梯度等宏观材料特征的跨尺度齿轮接触疲劳疲劳损伤数值模型；实现齿轮循环接触受载下，齿轮表层和近表层应力应变场、晶体形变行为和疲劳损伤演变历程描述，开发了面向失效物理本质的齿轮接触疲劳裂纹萌生寿命预估方法，实现疲劳裂纹萌生位置和疲劳寿命的精确预测；探究了齿轮钢材料晶体尺寸、形貌、初始取向、相成分等典型微观结构特征和硬化层梯度、微观形貌等齿轮宏观力学性能要素对齿轮接触疲劳损伤演变和疲劳寿命的影响，结合SEM、EBSD等先进测试表征技术，揭示了齿轮接触疲劳失效的内在细观机制。.通过本项目研究，解决了损伤耦合的齿轮材料晶体塑性细观本构关系和细观尺度的齿轮接触疲劳连续损伤模型两个科学问题，形成了一种细观尺度损伤机制的齿轮接触疲劳分析方法，发展了现代齿轮抗疲劳设计理论，具有重要理论意义和工程价值。项目研究成果发表SCI论文10篇，申请/授权发明专利2项，培养博士/硕士研究生6名，参与制定国家标准2项，撰写《齿轮接触疲劳理论与实践》专著，获教育部科学技术进步二等奖1项。

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