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矩形薄壁空心直梁是汽车纵梁经常采用的结构形式,并且是承受正面碰撞的主要部件,其结构的耐撞性及碰撞吸能优化是现代汽车研究的重要内容.以矩形薄壁梁为研究对象,基于动态有限元分析模型,利用LS-DYNA软件中的OPT模块技术,研究矩形薄壁梁横截面的边长比变化对其耐撞性能的影响,对薄壁直梁在轴向冲击载荷下的耐撞性能进行了优化仿真.优化结果表明,当矩形两个边长的比值为0.6时,结构的碰撞力峰值最小,吸收的塑性变形能最大,具有最好的耐撞性能. 相似文献
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《压力容器》2019,(11):25-33
采用有限元弹塑性屈曲分析,考虑椭圆封头的最大形状偏差并在过渡区施加局部厚度减薄缺陷,针对不同材料和厚径比δ_e/D_i,较为系统地讨论了内压标准椭圆封头结构屈曲载荷P_(cr)与极限载荷P_L的变化规律。研究结果表明,厚径比小于某临界值时,屈曲载荷低于极限载荷,分析模型发生屈曲破坏;厚径比大于某临界值时,屈曲载荷高于极限载荷,分析模型发生强度破坏。不同材料分析模型厚径比临界值存在一定差异,对高强钢13MnNiMoR材料而言,GB 150—2011标准防止标准椭圆封头内压弹性屈曲失效的厚径比规定偏于冒进。本文结果可为内压薄壁标准椭圆封头设计准则提供指导。 相似文献
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针对高强度钢在车身结构设计中的应用成本与效率问题,提出一种车顶结构耐撞性设计方法,并对某车型进行优化设计。首先进行全局灵敏度分析,筛选出影响车顶强度的主要承载部件;然后将高强度钢的选型作为离散设计变量,厚度作为连续设计变量,同时对材料成本和总质量进行约束,建立车顶结构耐撞性优化的数学模型;最后,采用移动最小二乘法构造近似模型,结合遗传算法对主要承载部件进行优化设计。结果表明:在部件总质量和材料成本的控制下,车顶承载能力提高18.53%。该方法为高强度钢在车顶结构耐撞性优化设计中的应用提供了一种选型参考。 相似文献
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B柱是车身重要的承载结构件,对侧面碰撞安全具有重要影响,同时B柱也是轻量化设计的重要单元。根据B柱的结构特点和在车辆侧面碰撞中的结构形态,搭建B柱侧面碰撞仿真分析模型;根据分析结果和零件的可制造性分析,基于正交试验法对B柱的材料和厚度进行设计,并根据乘员的相对位置对激光拼焊的焊缝进行设计;根据侧面碰撞的侵入量和侵入速度对比,选出最优激光拼焊设计方案;基于侧面碰撞分析模型,对轻量化设计前后B柱的安全性进行对比分析。结果可知:随拼焊线向底部移动,危险区域的最大减薄率并不是线性增减,在可选取范围内将焊缝位置确定为距离底端380mm的位置;B柱选择拼焊板结构,下部材料为DP780,厚度为1.8mm,上部材料为DP590,厚度为1.6mm;采用激光拼焊结构的B柱重量减轻23.1%,各位置测量点的侵入量最高减少18.6%(D4位置),满足结构耐撞性的要求。 相似文献
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基于协同优化和多目标遗传算法的车身结构多学科优化设计 总被引:14,自引:0,他引:14
在汽车车身结构NVH和侧面碰撞安全性研究中,实施多学科多目标优化的可行性设计。通过试验设计制定试验方案并进行数据采样,构建考虑整车侧撞安全性、白车身模态、静态弯曲刚度、扭转刚度和轻量化等性能的响应面近似模型,然后对车身结构分别进行确定性和可靠性轻量化单目标设计。最后,运用多目标遗传算法结合多学科协同优化对车身结构进行多目标优化设计,获取Pareto最优化解集。研究结果表明:可靠性优化设计较确定性优化设计而言,能考虑产品设计和生产过程中的不确定性因素,保证产品稳健性;车身结构的多目标优化设计全面考虑了车身结构轻量化、NVH和碰撞安全性能等多学科之间的耦合和解耦;设计者可按需选择其满意的优化结果,这将大幅缩减产品开发周期、降低产品开发成本。 相似文献
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Lightweight structure is an important method to increase vehicle fuel efficiency.High strength steel is applied for replacing mild steel in automotive structures to decrease thickness of parts for lightweight.However,the lightweight structures must show the improved capability for structural rigidity and crash energy absorption.Advanced high strength steels are attractive materials to achieve higher strength for energy absorption and reduce weight of vehicles.Currently,many research works focus on component level axial crash testing and simulation of high strength steels.However,the effects of high strength steel pans to the impact of auto body are not considered.The goal of this research is to study the application of hot forming high strength steeI(HFHSS)in order to evaluate the potential using in vehicle design for lightweight and passive safety.The performance of HFHSS is investigated by using both experimental and analytical techniques.In particular,the focus is on HFHSS which may have potential to enhance the passive safety for lightweight auto body.Automotive components made of HFHSS and general high strength steel(GHSS)are considered in this study.The material characterization of HFHSS is carried out through material experiments.The finite element method,in conjunction with the validated model is used to simulate the side impact of a car with GHSS and HFHSS parts according to China New Car Assessment Programme(C-NCAP)crash test.The deformation and acceleration characteristics of car body are analyzed and the injuries of an occupant are calculated.The results from the simulation analyses of HFHSS are compared with those of GHSS.The comparison indicates that the HFHSS parts on car body enhance the passive safety for the lightweight car body in side impact.Parts of HFHSS reduce weight of vehicle through thinner thickness offering higher strength of parts.Passive safety of lightweight car body is improved through reduction of crash deformation on car body by the application of HFHSS parts.The experiments and simulation are conducted to the HFHSS parts on auto body.The results demonstrate the feasibility of the application of HFHSS materials on automotive components for improved capability of passive safety and lightweight. 相似文献
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Horizontal cylinder-in-cylinder buckling under compression and torsion: Review and application to composite drill pipe 总被引:2,自引:0,他引:2
Nathan Wicks Brian L. Wardle Demos Pafitis 《International Journal of Mechanical Sciences》2008,50(3):538-549
Available analytical results and experiments on the structural behavior of constrained horizontal cylinders subjected to axial compression, torsion, and gravitational loads are reviewed. Such configurations are of interest to the oil-drilling field and provide static design expressions for steel tubulars. The buckling problem is similar to restrained railroad tracks and submerged/underwater pipelines under thermal expansion. Due to outer cylinder constraint and gravitational loads, analysis has shown that long cylinders initiate buckling at loads significantly higher than classical Euler buckling loads. For these constrained long cylinders, buckling initiates in a sinusoidal mode that snakes along the lower surface of the constraining cylinder. Classic analytical expressions hold that as the axial load increases, the cylinder achieves an overall helically buckled state in which the buckled cylinder forms a helix spiraling around the inner surface of the constraining cylinder. Torsion is shown to have little effect on either buckling load but controls the sense/direction of the helical buckling. Little experimental data exist on constrained cylinder buckling, and it is unclear how the initiating sinusoidal mode transitions to the helical mode. Implications of the buckling progression for composite cylinder applications are described including the finding that composites perform poorly relative to steel on the metric of buckling due to lower density and axial stiffness; composites perform well on the metric of lock-up length when friction is considered. Based on this review and findings for composite cylinders, recommendations are made for further work. 相似文献
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为了满足星载有源相控阵天线对轻量化以及承载、热控等多功能一体化的迫切需求,文中开展了轻质多功能结构相控阵天线的设计理论、制备工艺、控温特性和力学性能等研究,提出了一种基于多功能结构的星载有源相控阵天线一体化设计技术,利用轻质多功能复合安装板结构,合并平面正交一体桁架热管,在内部空间嵌埋有源功能模块,融合低剖面辐射阵面形成天线功能,制备了集控温、承载、电磁辐射于一体的多功能结构的轻质相控阵天线,并对多功能结构天线子阵进行了一体化设计和验证。结果表明,多功能结构天线系统布局改善了微波部件互联的性能,提高了有源阵列的散热和辐射效率以及系统性能,显著减小了天线阵列的剖面,大幅降低了有源阵列天线的重量。 相似文献
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工程中通常采用有限元中的线性屈曲方法和非线性屈曲方法来求解壳体的屈曲载荷。对于复杂结构(如钢安全壳),若直接采用非线性屈曲方法求解,除计算工作量大外,还不容易得到符合实际要求的临界载荷。因此,工程中常通过线弹性方法来获得符合实际要求的临界载荷。介绍了壳体屈曲的线弹性理论解,然后利用ANSYS软件求解圆柱壳受轴向和侧向外压的屈曲载荷,并与理论解进行了对比;最后通过对比前人的试验结果与线弹性理论得到的上临界值来剖析"能力减弱系数"的含义和合理性。结果表明:采用线弹性方法来求解壳体屈曲问题是可行的,但必须进一步考虑"能力减弱系数"、"安全系数"和"塑性折减系数"后才能得到工程上所需的临界屈曲载荷值。 相似文献