非标准带缆桩的设计研究

非标准带缆桩的设计关键是解决带缆桩强度的问题。详细分析比较了不同标准中关于带缆桩强度的校核原则,阐述安全系数的合理性。分别采用标准校核法和有限元分析法对标准带缆桩进行强度分析,推断带缆桩拖带载荷与其安全工作载荷的直接关系。有限元分析法同时揭示带缆桩基座对带缆桩整体强度的重要性,凸显了有限元分析法的全面性。针对非标准带缆桩设计提出建议,提供非标件设计实例,为带缆桩非标件的设计提供参考。     

非均布动荷载作用下沥青路面粘弹性有限元分析

不考虑超载情况,为探求非均布动荷载作用下沥青路面的动态响应及破坏规律,采用层状体系理论,建立ANSYS 3-D有限元半刚性基层路面结构模型,施加非均布动荷载,并对粘弹性路面模型各层的动态力学响应及不同车速下路表弯沉的变化进行分析。结果表明,水平应力的交变变化是使路面产生疲劳破坏的主要因素;当重载车辆车速在10~32 km/h之间时,路面的动态弯沉值显著大于静态弯沉值,对路面实际使用寿命的影响非常显著。     

电动汽车用新型交替极永磁游标电机研究

设计了一种应用于电动汽车直驱系统的双边Halbach交替极永磁游标电机,以提高电机输出性能为目标,利用二维有限元法对电机内、外定子调制齿尺寸,转子内、外侧永磁体阵列错位角度及磁极尺寸等关键技术参数进行优化,分析了电机的电磁性能,并将其与传统永磁游标电机进行了比较.结果表明:双边Halbach永磁体阵列错位一定角度后,能...     

Monitoring of ship damage condition during stranding

This study proposes a new procedure for the estimation of stranding forces and their contact positions. The method is based on the measurement of a few characteristic on-site parameters, i.e., the draughts and bending moments acting on a stranded ship. A procedure that estimates penetration into the ship bottom based on knowledge of the resistance versus penetration relationship is also presented. The seabed topology is parameterized by a paraboloid. This geometry can, in principle, characterize a wide range of obstructions, from sharp rocks to large shoals. Nonlinear finite element analysis is used to simulate various stranding situations and to generate the corresponding resistance versus penetration curves. The present method provides insight into the identification of real stranding scenarios in terms of the location of obstructions, their possible shapes and the corresponding resistance-penetration curves. The proposed methodology represents a first step towards a tool for quick decision making during salvage operations. The ultimate goal is to allow near real-time prediction of the risk of penetration into cargo tanks and hull girder failure. To demonstrate the effectiveness of the proposed method, it is applied to a simulated trial stranding scenario.     

半潜式起重平台上船体整体吊装有限元强度分析

为了保证半潜式平台上船体在吊装过程中的安全性,按照DNV相关原则和规定,利用CATIA软件进行了有限元强度分析。分析结果表明,在静态和吊装状态下,通过对薄弱部位的加强,吊装的安全性能够得到保障。     

基于ANYSY有限元理论的白车身制造误差分析

目前,白车身制造误差的诊断方法存在抽检频率低、样本量小及耗时长等问题。文章提出利用变形云图分析法来实现白车身制造误差的误差源诊断。综合有限元分析理论、黄金分割法和主方向法,以车门制造误差为分析对象,诊断出夹具变形为误差源。结果表明,此方法可用于装焊夹具的误差诊断,其结论在虚拟试验中得到验证。但有限元法在白车身误差分析中的应用是全新的研究课题,实用价值有待在生产环节中做进一步验证。     

汽车车身模具的数字化快速修复技术

针对存在局部物理缺陷或疲劳磨损的汽车车身冲压模具的可重用性,提出了缺陷特征提取和有限元分析耦合技术方案,实现了模具的数字化快速修复。以抽取模具点云中诸如缺陷边界、缺陷原形等特征为基础,并利用特征诱导技术恢复原始模具在缺陷处的基本特征形态。通过冲压过程的动态模拟来矫正基本的特征形态,修复模具在局部缺陷处的CAD模型,为最终以激光焊接技术和高速硬切削技术为基础实现模具的快速物理修复提供可靠的依据。     

轿车车身模态分析及结构优化设计

在保证车身结构力学特性的前提下,对白车身结构进行了简化,并以四边形板壳单元为主要离散单元,建立了某自主研发轿车白车身的模态分析有限元模型。通过对该有限元模型进行的自由模态分析,得到白车身的各阶模态频率和模态特性,为动态设计提供了参考依据。针对分析得到的局部不合理结构进行了零件结构和布局的优化设计,使整车刚度更趋合理。     

大客车结构有限元分析及轻量化设计

建立了某型大客车结构有限元模型,验证了该模型的正确性。完成了整车振动模态、扭转刚度的分析。在此基础上,以壳单元厚度为设计变量,以1阶扭转频率和扭转刚度为联合约束函数,以整车质量最轻为目标函数进行结构优化设计。通过对整车刚度、模态和强度的分析与校核,表明该大客车轻量化方案满足性能要求,具有可行性。     

Influence of external restraint distribution on welding buckling of thin plate butt joint北大核心CSCD

［Objectives］It is easy to produce buckling distortion when welding thin plate butt joints, which affects the construction period, cost and performance, but this can be controlled by applying external restraints. ［Methods ］ First, a butt welding test of a thin plate under external restraints is carried out, and the out-of-plane deformation is measured by the optical surface scanning method. At the same time, finite element (FE) models in a free state and external restraint state are established, and the thermal mechanical phenomena of the two models are subjected to thermal-elastic-plastic FE analysis (TEP FE). The influence of different external restraint distributions on the welding buckling distortion of the joints is then studied, and reasons for controlling welding buckling distortion are analyzed from the perspective of longitudinal plastic strain and longitudinal contraction force.［Results ］ The out-of-plane deformation of the corresponding model is in good agreement with the measured results, and milder than the out-of-plane deformation of the model in a free state. When external restraints are applied, the longitudinal plastic strain of the weld and its adjacent metal decreases, and the longitudinal contraction force of the thin plate also decreases.［Conclusions ］ The results verify that external restraints can effectively control welding buckling distortion, and the control effects are different depending on the external restraint distribution. © 2023 Chinese Journal of Ship Research. All rights reserved.