轿车侧碰中车门抗撞性的快速优化

针对汽车侧面碰撞时吸收能量的重要部件——车门结构,进行了快速抗撞性优化设计。将提高车门结构吸能量作为优化目标,选择主要部件的板厚为设计变量,建立抗撞性优化问题的数学模型。基于均匀试验设计方法快速合理地分布样本点。根据多项式响应面方法构造原优化问题的高精度近似模型。采用粒子群优化算法对近似模型进行优化设计。优化结果证明了本文提出的快速抗撞性优化设计方案的可行性及有效性,对车辆被动安全分析具有较高的工程应用价值。     

具有圆弧形诱导凹槽薄壁圆管抗撞性分析

为了提高薄壁构件抗撞性,本文采用Hypermesh软件建立圆截面薄壁构件和具有圆弧形诱导凹槽结构的有限元模型,并应用非线性有限元软件Ls-dyna对其抗撞性进行了数值模拟分析.研究在轴向冲击载荷下均匀分布诱导凹槽结构对薄壁构件吸能性和最大峰值冲击载荷的影响,并对两种结构的抗撞性进行了比较,数值计算结果表明设置的诱导凹槽结构在不影响薄壁构件吸能能力的情况下,能够显著降低最大峰值冲击载荷.     

基于iSIGHT的薄壁方管抗撞性尺寸优化

针对薄壁方管的抗撞性尺寸优化问题,利用多学科设计优化软件iSIGHT集成HyperMesh和ANSYS／LSYNA,建立优化设计仿真流程及平台,运用拉丁方方法进行DOE分析与优化设计研究．在此基础上,建立Kriging近似模型,以比吸能最优为优化目标,采用多岛遗传算法对建立的近似模型进行优化,并在优化的过程中生成新的设计点更新近似模型,提高模型精度．优化计算过程表明,上述方法提高了优化设计的效率,最终优化结果不仅满足结构吸能的要求,也满足轻量化的要求．     

微型客车概念设计阶段车身结构抗撞性分析

提出了应用车辆结构正面抗撞性的参数化模型进行微型客车概念设计的方法。分析了底部吸能结构的主要刚度参数的变化对乘员舱变形、车体减速度和底部吸能特性的影响,阐述了在概念设计阶段运用参数化模型控制底部吸能结构吸能特性及与乘员舱刚度参数的匹配,从而保证整车的正面抗撞性能。给出了微型客车概念设计阶段车身结构抗撞性设计指标、设计过程与方法,实现了通过参数化模型来快速确定正面碰撞时车身各部分的吸能指标,从而为详细结构设计提供重要依据。     

基于数值仿真的膨胀式压溃管阻抗性能研究

为了研究膨胀式压溃管阻抗性能,进行了数值仿真与实物试验对比,验证了数值仿真方法的有效性,并总结了两种研究方法的差异点.基于数值仿真软件平台并运用ALE自适应算法研究了压溃管装置诱导锥面角、壁厚和直径等主要设计参数对膨胀式压溃管阻抗力的影响关系.结合实际压溃管装置的性能特性,提出实际生产中通过控制压溃管装置参数来实现快速设计开发的方法.研究结果表明:当诱导面的锥角在15°～45°之间时,角度越大,压溃管的阻抗力越大;壁厚增大时,压溃管的阻抗力增大;直径对压溃管阻抗力的影响很小.压溃管设计时,应先根据安装空间尺寸确定压溃管直径,再通过控制变量,以壁厚作为粗筛条件进行仿真来确定壁厚范围,最后根据性能需求对诱导锥面角等参数进行匹配性仿真优化和最终设计.     

车用吸能部件吸能特性的改进

为了改进汽车上吸能部件的吸能特性,提高汽车正面抗撞性,对常用的圆形截面和矩形截面吸能部件的变形模式和轴向压皱刚度的特性进行了研究;利用拓扑优化的方法,从调整吸能部件轴向压皱刚度观点出发,建立拓扑优化模型进行优化分析。在上述研究的基础上,提出一种新型的碰撞吸能部件,该吸能部件侧壁上沿轴向方向布置了中凹凹槽。有限元分析结果表明:在不增加部件质量、不占用更大空间的条件下,该新型吸能部件具有良好的变形模式,在变形吸能的过程中能够提供较为平稳的轴向反作用力;与圆形截面和矩形截面吸能部件相比,新吸能部件吸收冲击能量的能力显著提高。     

汽车吸能盒结构优化模拟分析

采用LS-DYNA软件对汽车吸能盒进行了8种方案的准静态仿真研究.分析了不同诱导结构、不同材料的填充物对吸能盒的压溃模式、载荷变化和能量吸收情况的影响,并选出方案6为最优方案,可为汽车低速碰撞下吸能盒的设计提供参考.     

基于虾螯结构的仿生夹层板设计及数值模拟

探索了基于虾螯轮廓外形设计的仿生夹层板（BSP）的耐撞性。按照拉伸试验获得的材料本构参数设置了Hyperworks有限元模型,制造了BSP样件,并试验验证了有限元模型有效性。比较了BSP-L0、BSP-L180、BSP-T0、BSP-T180四种配置方案的耐撞性指标,选择BSP-T0方案进一步研究。分析了圆弧高度比γ和梯形晶元窄底宽度B对BSP-T0耐撞性的影响规律,得到γ比B对BSP-T0耐撞性的影响更大。利用遗传学算法进行参数优化,Pareto前沿的一个最优解为比吸能SEA=3.080 kJ/kg、峰值载荷PF=30.700 kN、平均压溃效率CFE=86.884%,相应参数γ=0.355,B=4.23 mm,预测与仿真结果误差均在2%以内,预测效果理想,本文研究成果可为夹层结构设计提供新思路。     

内凹三角形负泊松比结构耐撞性多目标优化设计

为设计出具有良好耐撞性的车辆碰撞吸能结构,以内凹三角形负泊松比多胞结构为研究对象,通过显式动力有限元软件LS-DYNA建立了此吸能结构的轴向冲击有限元模型。结合最优拉丁超立方设计方法,构建了此吸能结构的峰值冲击力PCF和比吸能SEA关于长胞壁尺寸a与胞壁厚度b的多项式代理模型,采用第二代非劣排序遗传算法(NSGA-II)进行多目标优化设计,并基于适应度函数C获取一妥协解。优化结果表明:胞壁厚度比长胞壁尺寸对此吸能结构耐撞性影响更显著,通过合理匹配壁厚和长胞壁长度,能有效降低峰值冲击力,提高比吸能。     

汽车正面25%重叠率碰撞车身前端结构设计

基于Pam-Crash/Safe软件建立了正面25%重叠率碰撞工况车辆-假人有限元基础模型。简化了前端主要吸能构件弯曲和压溃的性能表达,以结构件侵入量作为约束条件,将总目标吸能量分解到子构件上,根据其可压溃长度计算出所需的平均反力。最后,设计断面参数以满足平均反力和吸能量的要求。结果表明,所设计的前端结构能够满足正面25%重叠率碰撞等3种正面碰撞工况的法规要求。本文方法不仅提高了结构优化效率,还在一定程度上实现了"正向设计"。     

Grey Relational Analysis Coupled with Principal Component Analysis Method For Optimization Design of Novel Crash Box Structure

Crashworthiness and lightweight optimization design of the crash box are studied in this paper. For the initial model, a physical test was performed to verify the model. Then, a parametric model using mesh morphing technology is used to optimize and decrease the maximum collision force (MCF) and increase specific energy absorption (SEA) while ensure mass is not increased. Because MCF and SEA are two conflicting objectives, grey relational analysis (GRA) and principal component analysis (PCA) are employed for design optimization of the crash box. Furthermore, multi-objective analysis can convert to a single objective using the grey relational grade (GRG) simultaneously, hence, the proposed method can obtain the optimal combination of design parameters for the crash box. It can be concluded that the proposed method decreases the MCF and weight to 16.7% and 29.4% respectively, while increasing SEA to 16.4%. Meanwhile, the proposed method in comparison to the conventional NSGA-Ⅱ method, reduces the time cost by 103%. Hence, the proposed method can be properly applied to the optimization of the crash box.     

考虑汽车正面低速碰撞角度偏差的 吸能盒性能优化设计

汽车发生正面低速碰撞时,由于各种因素的影响,不能达到百分之百的正面碰撞。因此,运用非线性有限元LS-DYNA仿真软件对碰撞方向偏差±6°的汽车正面低速碰撞进行了仿真模拟,在确保吸能盒在正面碰撞过程中能够吸收一定能量的基础上,当汽车的碰撞角度发生偏差时也能够使吸能盒具有良好的吸能效果,保障车辆与乘员安全。并通过定义目标优化函数及仿真研究进行了吸能盒优化设计,得到优化后吸能盒的碰撞吸能数值及碰撞角度变化时碰撞吸能的变化情况,从而得出具最佳吸能性能吸能盒的设计变量,即吸能盒壁厚1.5 mm、长180 mm、边数为6,此结构下在碰撞角度偏差±6°时,其T值最小。     

船舶撞击桥梁后的结构损伤分析

船只对桥墩的冲撞使桥梁结构产生的变形与损伤,可以通过能量守恒、有限元数值仿真分析碰撞过程的受力状态.以一艘小型船只与某长江大桥桥梁碰撞为例,计算较轻微的船体碰撞后,冲撞对桥梁产生的作用力、船身破损区的变形与损伤,讨论了小船舶长年的大量撞击和累积对桥梁结构安全造成的隐患.     

Multi-objective robust design optimization of a novel negative Poisson’s ratio bumper system

Negative Poisson’s ratio (NPR) structure has outstanding performances in lightweight and energy absorption, and it can be widely applied in automotive industries. By combining the front anti-collision beam, crash box and NPR structure, a novel NPR bumper system for improving the crashworthiness is first proposed in the work. The performances of the NPR bumper system are detailed studied by comparing to traditional bumper system and aluminum foam filled bumper system. To achieve the rapid design while considering perturbation induced by parameter uncertainties, a multi-objective robust design optimization method of the NPR bumper system is also proposed. The parametric model of the bumper system is constructed by combining the full parametric model of the traditional bumper system and the parametric model of the NPR structure. Optimal Latin hypercube sampling technique and dual response surface method are combined to construct the surrogate models. The multi-objective robust optimization results of the NPR bumper system are then obtained by applying the multi-objective particle swarm optimization algorithm and six sigma criteria. The results yielded from the optimizations indicate that the energy absorption capacity is improved significantly by the NPR bumper system and its performances are further optimized efficiently by the multi-objective robust design optimization method.     

水平地震作用下框架高度对钢筋用量的影响

为了在建筑抗震设计中节省钢筋用量,提出了一种优化钢筋混凝土框架结构单位面积配筋量的方法.该方法探索楼层数m变化对构件内力分布和配筋量的影响,将一个矩形规则建筑作为研究对象,采用底部剪力法计算其在水平地震荷载影响下的构件内力,从而得到m与构件配筋体积之间的函数关系,进而转化为m与单位面积配筋量之间的关系.以m为优化变量,利用Matlab进行快速计算,并通过具体案例进行演示.结果表明,该方法具有一定的可行性,并得到m的最佳范围为6~11.     

Collision performance of bitubular tubes with diaphragms

A numerical study of bitubular tubes with diaphragms compared with single and bitubular tubes subjected to dynamic axial impact force was presented. At first, the energy absorption response of the composite structure under axial loading was analyzed by finite element simulation. The results show that the efficiency of energy absorption can be improved by introducing diaphragms to the double-walled columns. Then, the effect of the amount and location of diaphragms, the shape and the size of the inner tubes, and the thickness of the composite structures were also studied numerically. The collision performance of the composite structure is affected by the deformation of diaphragms, as well as the interaction of outer and inner tube. The non-uniform distribution of diaphragms can improve the energy absorption efficiency of structures for a constant number of diaphragms. The specific energy absorption of the hexagonal inner tube is the highest, followed by the circular, octagonal and square ones.     

Best compromising crashworthiness design of automotive S-rail using TOPSIS and modified NSGAⅡ

In order to reduce both the weight of vehicles and the damage of occupants in a crash event simultaneously, it is necessary to perform a multi-objective optimal design of the automotive energy absorbing components. Modified non-dominated sorting genetic algorithm II(NSGA II) was used for multi-objective optimization of automotive S-rail considering absorbed energy(E), peak crushing force(Fmax) and mass of the structure(W) as three conflicting objective functions. In the multi-objective optimization problem(MOP), E and Fmax are defined by polynomial models extracted using the software GEvo M based on train and test data obtained from numerical simulation of quasi-static crushing of the S-rail using ABAQUS. Finally, the nearest to ideal point(NIP)method and technique for ordering preferences by similarity to ideal solution(TOPSIS) method are used to find the some trade-off optimum design points from all non-dominated optimum design points represented by the Pareto fronts. Results represent that the optimum design point obtained from TOPSIS method exhibits better trade-off in comparison with that of optimum design point obtained from NIP method.     

基于拼装参数优化的盾构机管片拼装节能技术

地铁隧道通常由成千上万的环管片拼接而成,为减少盾构机在管片拼装过程中的能量消耗,提出基于运动参数优化的管片拼装节能技术.以Ф3.2 m试验盾构为研究对象,在分析管片定位时管片拼装机构各自由度运动与受力状况的基础上,建立管片拼装机在完成同一环不同位置管片的定位工作过程中系统做功与能量分布的数学模型,通过解决以消耗能量为目标函数、管片目标位置为约束条件的优化问题,得到在实现最小能量消耗的拼装过程中各执行器运动参数确定原则与求解方法.通过对比计算3种不同拼装路径下拼装机消耗能量情况表明,使用参数优化选择方法确定的拼装路径最高可达到4%的节能效果,在实际隧道掘进中累计节能效果将更加明显.     

一种使用遗传算法进行物流配送成本优化方法

在物流配送业务中,配送成本的优化是降低企业成本、提高经济效益的关键。根据物流配送业务的 特点,建立了成本优化模型。该模型将同一客户需求的货物分成急需货物和普通货物,在有时间要求和运力有限的 情况下,这种货物分类处理的方式为降低配送成本提供了新思路。在此基础上,构建了成本优化遗传算法,给出了 算法实现的具体方法、步骤。实例计算结果表明,该方法能快速、高效地收敛于一个优异的解,在物流配送成本优化 中能获得较好的优化结果。