基于正交试验-形貌优化法的钢铝复合车架设计

以某国产SUV车架为研究对象,建立车架有限元模型,对车架进行弯曲、扭转刚度分析,并进行模态分析和模态试验,验证模型的有效性。利用正交试验法确定材料轻量化部件,并将这些部件的钢材料替换成铝合金,得到钢铝复合轻量化车架。针对钢铝复合车架刚度和模态性能的减弱问题,采用折衷规划法的多目标形貌优化对部件进行优化改进,提高车架的刚度和模态性能。研究结果表明,采用正交试验结合多目标形貌优化法得到的新车架在质量减轻6.7kg的同时提高了刚度和模态性能,达到了良好的轻量化设计效果。     

基于多目标优化的钢-铝混合轻量化车架设计

以国产某SUV车架为研究对象,建立了车架有限元模型,对车架进行弯曲刚度、扭转刚度分析,并进行模态分析和模态试验,验证模型的有效性。利用正交试验法确定了材料轻量化部件,并将这些部件的钢材料替换成铝合金,得到钢-铝混合轻量化车架。针对钢-铝混合轻量化车架刚度和模态性能的减弱问题,采用基于折中规划法的多目标形貌优化方法对部件进行优化改进,提高了车架的刚度和模态性能。设计结果表明,使用钢、铝材料结合多目标优化方法设计的钢-铝混合轻量化车架相比原钢质车架在保证一定的刚度和模态性能条件下,质量减轻了6.7kg。     

基于HS-DOE法的钢铝混合摩托车车架性能分析与优化

为了快速评估和提高新型钢铝混合摩托车车架的安全性能,以某款钢铝混合摩托车车架为研究对象,采用HyperMesh软件对其进行性能分析与优化.建立钢铝混合摩托车车架有限元模型,研究钢铝混合摩托车车架在水平载荷、垂直载荷和坐垫载荷3种工况下的最大应力和最大位移.提出一种以Hammersley采样方法改进传统试验设计方法的哈默...     

某车型铝合金前副车架拓扑优化概念设计

首先采用虚拟路面整车模型动态提载的方法确立了原钢制副车架各硬点在典型工况下的载荷，以此载荷作为铝合金副车架拓扑优化概念设计阶段的载荷输入。在Hypermesh的Optistruct模块对原副车架包络体进行拓扑优化，将体积百分比和加权柔度作为优化响应，以最小化加权柔度为目标，以体积百分比为约束条件，并引入对称约束与制造约束，进行多工况拓扑优化，获得了副车架最佳受力结构。采用材料替换的方法以铝代钢，拓扑优化概念设计后的副车架在不低于原副车架性能目标的前提下实现减重1.84kg，轻量化率达11.5%。通过对概念阶段的铝合金副车架进行性能分析，结果表明，铝合金副车架满足设计要求，此方法对于副车架概念设计阶段具有一定的可行性。     

基于正交试验-组合优化的钢-镁车架设计

以某国产SUV车架为研究对象,建立车架的有限元模型,运用OptiStruct对车架进行弯曲、扭转刚度和模态分析,并进行模态试验,验证模型的有效性。利用正交试验法确定材料轻量化部件,并将这些部件的钢材料替换成镁合金,得到钢-镁车架。针对钢-镁车架刚度和模态性能的减弱问题,采用拓扑-形貌组合优化方法对部件进行优化设计,提高了车架的刚度和模态性能。设计结果表明,使用镁合金结合拓扑-形貌优化方法,设计的钢-镁车架相比原车架在质量减轻19.0kg的同时,刚度和模态性能得到一定的保证。     

钢铝材料结合的商用车车架多工况轻量化优化设计

为寻求有效的商用车轻量化方案,以某重型商用车车架为研究对象,建立有限元模型并进行自由模态分析和4种典型工况的静态分析,运用多学科优化软件HyperStudy建立车架优化模型,并对4种典型工况下的车架同时进行尺寸和材料的优化。研究结果表明,在保证可靠的强度和模态特性条件下,所设计的钢铝材料结合车架能够有效减小5.6%的质量。     

某微型电动商用车车架轻量化优化研究

针对某微型纯电动商用车自重的问题,对其车架结构尺寸、承载能力进行了研究,提出了一种车架轻量化优化设计思路。以车架横梁质量最小为目标函数,以车架横梁的截面尺寸边界条件、强度、刚度和稳定性为约束,建立了数学模型;通过Matlab中模拟退火智能算法工具箱,实现了对车架横梁截面尺寸的优化,得到了最优的车架横梁截面尺寸;利用CATIA软件建立了车架优化前后的三维模型,导入ANASYS Workbench软件建立了有限元模型,并在此基础上进行了静力学分析(满载弯曲与满载扭转)和模态分析。研究结果表明:车架优化后较优化前减重了13.43%;优化后的车架应力和变形满足材料Q235钢的使用条件;车架优化前后的低阶自由模态频率与路面激励频率重合率仅为4.8%,发生共振的可能性很小;车架轻量化优化设计思路合理。     

方程式赛车车架的轻量化设计

以大学生方程式赛车为实例,研究在满足整车振动频率、强度、刚度等约束的前提下,运用有限元分析软件对车架进行拓扑设计和尺寸优化.根据赛事规则,初步建立车架主体结构,运用ANSYS对车架结构进行拓扑设计,得到合理结构;以车架扭转刚度、车架结构性能等为评价标准,以管件尺寸为设计变量,对车架结构进行尺寸优化;通过试验验证,8字绕...     

工程机械车架结构分析及优化设计

以某型号道路工程车辆车架为研究对象,在CATIA软件中建立了该车架的3D模型,导入Hypermesh进行网格划分并建立其有限元模型,根据车辆的实际工作情况,构建满载静止和支撑两种工况然后进行强度分析,选择应力与变形较大的工况进一步计算其模态频率。构建以厚度为应变量的响应面模型,基于车架近似模型以车架的总质量和第一阶模态频率作为优化目标,以车架的强度作为约束条件进行多目标优化。优化结果表明:在满足车架整体性能要求的前提下,优化后的车架第一阶模态频率提高了6%,并且车架质量减轻了7%,证实了该优化设计方法的有效性,为后续工程车架的设计提供指导。     

巴哈赛车车架多目标拓扑优化设计

为了实现巴哈赛车车架的轻量化,以车架刚度和频率为优化目标,采用折衷规划法归一化子目标建立综合目标函数,运用灰色关联分析法评价子目标权重系数,对车架进行拓扑优化;根据拓扑优化的结果对车架进行二次设计,在保证刚度和安全使用条件下,对车架管件进行尺寸优化.分析结果表明,改进后的车架的刚度性能、强度性能和模态固有频率均有提高,车架减重24.1％,证明了优化设计的有效性和可行性,并为车架的相关设计提供了借鉴和参考.     

Two-stage design process of a frame-panel land vehicle structure employing topology and cross section optimization

A new structural design technology has been recently developed to build a new type of land vehicle in military use. While thick panels are only employed in conventional land vehicle structures, solid frames combined with relatively thin composite panels are employed for the new type of vehicle. The structural integrity of the new vehicle structure type is mainly guaranteed by the solid frames while composite panels are used to protect passengers and equipments of the vehicle. To design such a frame-panel structure, frame design needs to be done first. In this paper, a two-stage design process is proposed employing topology and cross section optimization methods. Overall frame arrangement of the new vehicle structure is obtained by the topology optimization in the first design stage and the detailed dimensions of the frames are obtained by the cross section optimization in the second design stage.     

电动轮自卸车车架结构抗疲劳轻量化设计

针对传统经验式设计的电动轮自卸车车架结构存在刚度不足、焊缝开裂、重量冗余,以及自身固有频率与非簧载质量激励频率接近而可能发生共振等问题,开展车架结构性能多目标优化设计的研究。首先,基于变密度法和SIMP插值模型对原始车架结构进行了考虑疲劳寿命约束的多目标拓扑优化设计,得到了满足静态多工况下柔度最小和多阶低阶固有频率最大的拓扑优化结构。再次,基于Kriging近似模型的抗疲劳轻量化设计,利用非支配排序多目标遗传算法进行全局寻优,优化后的车架结构质量比原始车架结构质量减少4.24%,且车架结构在同样载荷作用下的应力分布更加均匀,车架强度、刚度、动态特性和疲劳寿命等性能均得到改善。     

Durability evaluation of a composite bogie frame with bow-shaped side beams

In the current study, the static structural safety and durability of two composite bogie frame models were evaluated using a finite element analysis. Prior to evaluation, the in-plane and out-of-plane mechanical properties of the base material were measured. The fatigue property was also measured to evaluate the durability of two composite bogie frames. Based on material data, the static structural safety was examined using the Tsai-Wu failure criterion under ten different loading conditions. Stress combination data were used to evaluate durability of two composite bogie frames. Analysis results indicate that the maximum Tsai-Wu failure indices of the two composite bogie frames under a twisting load were 0.48 and 0.57. Based on the durability evaluation using Goodman diagrams, all combined stress data of the two models were within the endurance limit. In the bogie frames with a side beam height of 50 mm, the side beam bottom area was the most affected region. The joint center area revealed higher mean stress and stress amplitude values in the bogie frames with a side beam height of 150 mm.     

汽车衡承载架结构的有限元分析

针对SCS系列汽车衡承载架,使用ANSYS有限元分析软件,建立了汽车衡承载架有限元计算模型,进行了静态应力分析,得到承载架在不同工况下的位移及应力分布云图,找出了承载架的危险部位;对承载架进行了模态分析,得到承载架各阶固有频率及固有振型,重点对汽车的固有频率和承载架的固有频率进行对比,得出不同频率下的振动振型,以避免发生共振而提高称重精度。计算分析为汽车衡承载架的改型设计提供了参考依据。     

Structural design and performance of a rear support walking frame

Rear support walking frames provide predetermined vertical support for patients with dysfunctional lower limbs that have limited active control; the support is provided through a spring-loaded boom hinged on an upright stanchion mounted at the rear of a wheeled frame within which the patient ambulates. The application of these frames for total-body-involved cerebral palsy patients, in combination with a walking orthosis, has highlighted a number of practical problems that need to be addressed for the system to become fully viable. A composite material prototype walking frame has been developed that permits the patient to be transferred by a single carer without the need to use inappropriate manual handling techniques. The frame has improved structural properties, with stiffness in the sagittal and coronal planes increasing by between 50 and 100 per cent. Evaluation with patients showed that the greater structural stiffness permitted the objective of improved continuity of walking to be achieved. The strength of the frame is such that it can accommodate patients of up to 80 kg, more than twice that possible in the earlier system. Since the structural yield point is approximately twice the maximum working load, the device should not be prone to unacceptable fatigue characteristics. Despite the use of carbon composite materials (which have brittle failure characteristics), the mode of failure is of progressive collapse and is therefore inherently safe. The successful outcome of prototype testing has justified production development. Work is now proceeding on a design that incorporates further improvements in structural performance and ease of manufacture.     

Transient-spatial pattern mining of eddy current pulsed thermography using wavelet transform

Eddy current pulsed thermography（ECPT） is an emerging Non-destructive testing and evaluation（NDT E） technique, which uses hybrid eddy current and thermography NDT E techniques that enhances the detectability from their compensation. Currently, this technique is limited by the manual selection of proper contrast frames and the issue of improving the efficiency of defect detection of complex structure samples remains a challenge. In order to select a specific frame from transient thermal image sequences to maximize the contrast of thermal variation and defect pattern from complex structure samples, an energy driven approach to compute the coefficient energy of wavelet transform is proposed which has the potential of automatically selecting both optimal transient frame and spatial scale for defect detection using ECPT. According to analysis of the variation of different frequency component and the comparison study of the detection performance of different scale and wavelets, the frame at the end of heating phase is automatically selected as an optimal transient frame for defect detection. In addition, the detection capabilities of the complex structure samples can be enhanced through proper spatial scale and wavelet selection. The proposed method has successfully been applied to low speed impact damage detection of carbon fibre reinforced polymer（CFRP） composite as well as providing the guidance to improve the detectability of ECPT technique.     

异型高处作业吊篮检测架动态特性与瞬态响应分析

建立了异型高处作业吊篮检测架有限元计算模型,对检测架进行模态分析,获得检测架前8阶固有频率以及振动特性;同时对异型高处作业吊篮检测架进行瞬态响应分析,通过研究荷载起升瞬间所产成的动态响应,揭示了测试架在起升冲击荷载下的应力和位移随时间变化的规律,进而分析检测架结构在动态冲击下的影响,由此可发现结构潜在的设计缺陷,为检测架的进一步结构优化提供科学依据.     

扭转刚度测试方法及对构架疲劳强度影响

根据构架在线路运行中的扭曲状态和标准JIS E 4207：2004《铁路车辆-转向架-转向架构架设计通则》中规定的构架扭转刚度测试方法提出改进的刚度测试方法,新的测试方法简单且实用性较强,误差有效地控制在7%之内。构架根据结构设计形式的不同分为管梁型构架及箱梁型构架。利用新的扭转刚度测试方法分别对管梁型构架及箱梁型构架进行扭转刚度测试,同时理论分析两种类型构架扭转刚度不同的原因。利用ANSYS仿真分析软件对两种类型的转向架构架进行仿真分析,得出：构架扭转刚度的大小主要取决于测量的横截面积及横梁的结构形式,管梁型结构构架扭转刚度小于箱梁型结构构架的扭转刚度;在构架受扭转变形影响较大的区域,如横梁与侧梁的连接位置,由于箱梁型构架扭转模态频率较高,其动应力幅值较管梁型构架要小。