【作者】 陈亮；

【导师】 亓昌；

【作者基本信息】 大连理工大学 ， 车辆工程， 2025， 硕士

【摘要】 传动轴作为车辆传动系统中的关键部件,直接承受并传递驱动力,面临着复杂多变的载荷工况。在当前新能源及轻量化发展趋势下,传动轴设计不仅需要满足高强度、高可靠性要求,同时还需实现显著的质量优化,以降低车辆簧下质量,提升动力传递效率和燃油经济性,改善整车的动态性能。为此,本文基于钢-铝-碳纤维复合材料传动轴的设计理念,系统研究了多工况下的拓扑优化方法与复合材料轴管铺层优化方法。提出了一种面向重载汽车的新型高性能多材料传动轴轻量化设计方案,旨在通过合理的结构与材料配置,实现传动轴在强度、刚度、疲劳寿命等方面的全面优化。本文的研究内容与成果主要包括以下几方面:首先,基于实车工况,结合扭矩曲线与安装约束条件,系统分析了传动轴的典型载荷边界,建立了完整的有限元仿真模型。通过在不同工况下对传动轴各零部件进行应力与变形分析,获得了应力与变形的分布规律。将仿真结果与相关试验数据进行对比,验证了有限元模型的准确性和可靠性,为后续的轻量化设计与优化提供了坚实基础。其次,针对传动轴的各个零部件,开展了多工况拓扑优化设计。提出了基于变密度法与层次分析法的传动轴多工况拓扑优化方法,构建了多工况下的拓扑优化模型,充分考虑结构在多种载荷工况下的性能需求,确保优化设计的全面性与合理性。通过求解得到的最优材料分布方案,指导传动轴零部件的再设计与重建,特别是针对花键套、万向节叉等应力较低的部件,采用铝合金替代原钢制材料,进一步降低重量,优化效果通过有限元仿真验证,确保满足强度与刚度要求。再次,针对传动轴的轴管部分,采用碳纤维复合材料替代传统钢材,并开展了三阶段的铺层优化设计,包括自由尺寸优化、尺寸优化以及铺层顺序优化。基于经典层合板理论,确定了轴管在不同工况下的最优铺层数量、角度与顺序,实现了轴管在轻量化与力学性能之间的平衡。与此同时,针对碳纤维轴管与铝制接头的连接问题,设计了合理的连接结构,确保连接强度与耐久性,并通过有限元仿真验证其性能。最后,建立了多材料传动轴总成的系统级有限元仿真模型,综合分析各部件在典型工况下的应力分布与变形情况,验证了优化设计方案的可行性。仿真结果表明,优化后的多材料传动轴各部件最大应力均低于材料许用应力,结构性能满足设计要求。最终实现传动轴总成减重34.6%,在保障结构强度与刚度的基础上,疲劳寿命达到50万次,显著提升了传动轴的综合性能。本文研究为重载汽车高性能传动轴的轻量化设计提供了理论支撑与实践指导,所提出的多工况拓扑优化与铺层优化方法可为其他复杂载荷工况下的多材料结构设计提供参考,具有重要的工程应用价值和推广意义。更多还原

【Abstract】 As a critical component in the vehicle drivetrain system,the drive shaft directly bears and transmits driving forces while operating under complex and variable loading conditions.Under the current trends of new energy vehicles and lightweight design,drive shaft design must not only meet high-strength and high-reliability requirements but also achieve significant mass reduction.This optimizes the unsprung mass,enhances power transmission efficiency and fuel economy,and improves the overall dynamic performance of the vehicle.To address this,this paper presents a design concept based on a steel-aluminum-carbon fiber reinforced plastic(CFRP)composite drive shaft.It systematically investigates topology optimization methods under multi-loading conditions and ply optimization methods for the composite shaft tube.A novel lightweight design scheme for a high-performance multi-material drive shaft aimed at heavy-duty vehicles is proposed.This scheme aims to achieve comprehensive optimization of the drive shaft’s strength,stiffness,and fatigue life through rational structural and material configurations.The main research contents and achievements of this paper are summarized as follows:Firstly,based on actual vehicle operating conditions,combined with torque curves and installation constraints,the typical load boundaries of the drive shaft were systematically analyzed,and a comprehensive finite element simulation model was established.Stress and deformation analyses of each drive shaft component were conducted under various operating conditions to obtain their distribution patterns.The simulation results were compared with relevant experimental data,validating the accuracy and reliability of the finite element model.This provided a solid foundation for the subsequent lightweight design and optimization.Secondly,multi-condition topology optimization design was carried out for each drive shaft component.A multi-condition topology optimization method for the drive shaft,based on the variable density method(SIMP)and the analytic hierarchy process(AHP),was proposed.A topology optimization model under multiple loading conditions was constructed,fully considering the structural performance requirements across diverse load scenarios to ensure the comprehensiveness and rationality of the optimized design.The optimal material distribution schemes obtained from the solution guided the redesign and reconstruction of the drive shaft components.Particularly for components with lower stress concentrations,such as the spline sleeve and universal joint yoke,aluminum alloy was substituted for the original steel material to further reduce weight.The effectiveness of this optimization was validated through finite element simulation,ensuring that strength and stiffness requirements were met.Thirdly,for the shaft tube section of the drive shaft,CFRP was adopted to replace traditional steel.A three-stage ply optimization design was implemented,encompassing free-size optimization,size optimization,and stacking sequence optimization.Based on classical laminated plate theory,the optimal number of plies,ply angles,and stacking sequence for the shaft tube under different operating conditions were determined,achieving a balance between lightweighting and mechanical performance.Concurrently,a suitable connection structure was designed for the joint between the CFRP shaft tube and the aluminum alloy end fitting to ensure connection strength and durability.The performance of this joint was also verified via finite element simulation.Finally,a system-level finite element simulation model of the multi-material drive shaft assembly was established.A comprehensive analysis of the stress distribution and deformation of each component under typical operating conditions was performed,verifying the feasibility of the optimized design scheme.Simulation results demonstrated that the maximum stress in all components of the optimized multi-material drive shaft remained below the allowable stress of the respective materials,confirming that the structural performance met the design requirements.Ultimately,a total mass reduction of 34.6%for the drive shaft assembly was achieved.While ensuring structural strength and stiffness,the fatigue life reached 500,000cycles,significantly enhancing the comprehensive performance of the drive shaft.This research provides theoretical support and practical guidance for the lightweight design of high-performance drive shafts for heavy-duty vehicles.The proposed multi-condition topology optimization and ply optimization methods can serve as a reference for the design of other multi-material structures under complex loading conditions,holding significant engineering application value and potential for broader adoption.更多还原