A body frame composed of thin sheet metal is a crucial structure that determines the safety performance of a vehicle.Designing a correct weight and high-performance automotive body is an emerging engineering problem.T...A body frame composed of thin sheet metal is a crucial structure that determines the safety performance of a vehicle.Designing a correct weight and high-performance automotive body is an emerging engineering problem.To improve the performance of the automotive frame,we attempt to reconstruct its design criteria based on statistical and mechanical approaches.At first,a fundamental study on the frame strength is conducted and a cross-sectional shape optimization problem is developed for designing the cross-sectional shape of an automobile frame having a very high mass efficiency for strength.Shape optimization is carried out using the nonlinear finite element method and a meta-modeling-based genetic algorithm.Data analysis of the obtained set of optimal results is performed to identify the dominant design variables by employing the smoothing spline analysis of variance,the principal component analysis,and the self-organizing map technique.The relationship between the cross-sectional shape and the objective function is also analyzed by hierarchical clustering.A design guideline is obtained from these statistical approach results.A comparison between the statistically obtained design guideline and the conventional one based on the designers’experience is performed based on mechanical interpretation of the optimal cross-sectional frame.Finally,a mechanically reasonable new general-purpose design guideline is proposed for the cross-sectional shape of the automotive frame.展开更多
文摘A body frame composed of thin sheet metal is a crucial structure that determines the safety performance of a vehicle.Designing a correct weight and high-performance automotive body is an emerging engineering problem.To improve the performance of the automotive frame,we attempt to reconstruct its design criteria based on statistical and mechanical approaches.At first,a fundamental study on the frame strength is conducted and a cross-sectional shape optimization problem is developed for designing the cross-sectional shape of an automobile frame having a very high mass efficiency for strength.Shape optimization is carried out using the nonlinear finite element method and a meta-modeling-based genetic algorithm.Data analysis of the obtained set of optimal results is performed to identify the dominant design variables by employing the smoothing spline analysis of variance,the principal component analysis,and the self-organizing map technique.The relationship between the cross-sectional shape and the objective function is also analyzed by hierarchical clustering.A design guideline is obtained from these statistical approach results.A comparison between the statistically obtained design guideline and the conventional one based on the designers’experience is performed based on mechanical interpretation of the optimal cross-sectional frame.Finally,a mechanically reasonable new general-purpose design guideline is proposed for the cross-sectional shape of the automotive frame.
文摘在这份报纸，侵犯喷气的 underexpanded 的流动地从方面比率 1， 3 和 5 的矩形的嘴发出了数字地并且试验性地被学习。二维的温度和压力分布被使用红外线的照相机和分别地扫描设备和一台步进马达的一个压力的联合测量。侵犯的板上的停滞压力的变化表明 hysteretic 现象在为 3.0 和 5.0 的方面比率增加并且减少压力比率期间存在。方面比率 1.0 的嘴引起了最大的全部的压力损失 p c / p 0 =，这也被发现 0.27 在 p 的压力比率 0 / p b = 6.5 在 p c 是墙上的停滞中心压力的地方， p 0 在上游的停滞压力， p b 周围的压力。另外的二张嘴证明压力损失 p c / p 0 =0.52 并且 0.55 被方面比率的嘴完成 3,0 和 5.0 分别地。在计算和实验之间的比较相当好，出现三维在喷气冲击波优化并且组织。然而，在在 3.5 和 4.5 的压力比率之间的实验观察的压力变化的磁滞现象不能在计算被证实。关键词可压缩的流动 - 冲击波 - 下面膨胀的矩形的侵犯喷气 - CFD CLC 数字
