【作者】 李红；

【导师】 成艾国； 陈涛；

【作者基本信息】 湖南大学 ， 机械工程， 2014， 硕士

【摘要】 汽车方向盘作为汽车转向系统的主要部件之一，其特性决定着整个转向系统的性能，从而影响整车的性能。因此方向盘作为汽车零部件中的关键部件，其设计显得尤为重要。方向盘的设计涉及许多学科，其中包括碰撞安全性、NVH性能、轻量化、结构强度等。传统的设计方法通常是先单独优化方向盘的某一性能，再校核其他性能，是一个反复修改反复校核的过程，设计开发周期较长。这种串行设计方法只是从单学科入手，忽略了不同学科之间的相互关系，不利于工程技术的发展。不同于传统的设计方法，多学科优化设计（Multidisciplinary DesignOptimization，MDO）通过特定的框架协调和控制各学科之间的相互作用，能够实现各个学科的并行设计。作为工程实际研究项目，本文以设计开发阶段的某款车为研究对象，将MDO方法应用到无气囊配置的方向盘骨架设计中，根据企业相关标准要求，协调方向盘的轻量化、碰撞安全性和NVH性能，最终实现多学科优化设计。本文首先通过对方向盘的碰撞安全性能和NVH性能进行研究，建立详细的方向盘有限元模型进行仿真计算分析，并通过试验验证了模型的有效性。由于详细有限元模型的建立和后期的求解计算需要花费大量的时间，而且在优化改进中修改模型比较困难，因此为方便方向盘的设计优化，建立了基于梁单元的方向盘骨架简化模型，进行仿真分析，并合理验证了简化模型的有效性，同时与详细有限元模型的结果进行了对比，结果表明梁单元简化模型在确保计算精度的同时能够有效提高计算效率。本文进一步基于梁单元简化模型，直接将梁单元截面进行尺寸参数化，通过实验设计构建了RBF近似模型用于代替仿真模型，运用基于协同优化算法的多学科设计优化方法，快速设计出最优的方向盘骨架截面结构，在满足方向盘的碰撞安全性能和NVH性能条件下，达到质量最轻的目的。研究结果表明：基于梁单元简化模型的多学科设计方法不仅对方向盘的正向设计有一定的指导意义，同时能够实现方向盘碰撞安全性能和NVH性能两学科的并行优化设计，大大缩短了设计周期。该研究不仅可用于方向盘的设计开发和改进，对汽车其他零部件的开发设计也具有一定的理论价值和实际指导意义，工程实用性较强。更多还原

【Abstract】 As one of main parts of steering system, the steering wheel determines theperformance of the overall steering system, thus having a great influence on vehicledriving performance. Therefore, as the key component of automotive parts, the designof the steering wheel is very important. The design of steering wheel needs to takeinto account many disciplines, including impact safety, NVH performance,lightweight and structural strength, etc. The traditional design method usuallyoptimizes one performance of the steering wheel at first, and then checks otherproperties. It is a modified repeatedly and checking repeatedly process, so thedevelopment cycle becomes longer. This serial design approach just starts from asingle discipline, ignoring the relationship between different disciplines. So it is notconducive to the development of engineering technology. Unlike the traditionaldesign method, the multidisciplinary design optimization (MDO) uses a specificframework to coordinate and control the interaction between the various disciplines,in this way parallel design can be achieved in various disciplines. As an engineeringresearch project, in this paper, based on the vehicle in design development phase, theMDO method was applied to design of the steering wheel skeleton without airbagconfiguration. According to the enterprise standards, this paper ultimately reachedmultidisciplinary design optimization by coordinating lightweight, impact safety andNVH performance of steering wheel.Firstly, based on analysis of the impact safety and NVH performance withsteering wheel, detailed finite element model of the steering wheel was established toexecute simulated analysis. Then the validity of the model was reasonably verifiedthrough the test. The comparation showed high consistence, indicating high reliabilityof the detailed finite element model. Since it takes a lot of time to establish and solvethe detailed finite element model, and the model is very difficult to modify foroptimization, the method of establishing a simplified model based on beam elementswas applied to make simulate study to facilitate design optimization of the steeringwheel. And the validity of this simplified model was reasonably verified. At the sametime, the result was compared with the result of detailed finite element model, andthe study showed that the simplified model of beam elements can improvecomputational efficiency while ensuring accuracy. In this dissertation, further based on the simplified model of beam elements,through the direct parameterization of cross-section on beam elements and the MDOthat adopted collaborative optimization(CO) framework, RBF approximation modelswere built instead of simulation model through the design of experiments in order tomeet performances of the impact safety and the NVH and to reach the goal ofminimum weight at the same time. The results show that: appling the simplifiedmodel of beam elements, the MDO approach not just guides forward design of thesteering wheel but achieves in parallel optimization design with two disciplines ofimpact safety and NVH performance, then the design cycle becomes shorter. Thestudy has a certain theoretical and practical significance on development andimprovement of other parts for the automotive, as a consequence, the engineeringpracticability is very strong.更多还原