铝合金车轮13°冲击试验仿真分析

为了减少铝合金车轮性能检测的试验次数以提高车轮的设计研发效率,建立铝合金车轮13°冲击试验的数值模型进行仿真试验非常必要。在充分考虑冲击试验台静态与动态效果的基础上,建立包括冲头、车轮总成和试验台架的铝合金车轮冲击试验有限元模型,其中试验台架上的橡胶支座采用弹簧—阻尼单元进行模拟,且将轮胎安装所产生的车轮预应力作为初始条件,使用非线性有限元动力分析软件LS-DYNA对铝合金车轮冲击过程进行仿真分析。通过对车轮上若干测量点应变值的有限元仿真结果与试验结果的比较,确认与铝合金车轮实际台架试验相等效的计算机模拟试验平台的有效性。该计算机模拟试验平台的建立对铝合金车轮的前期设计开发具有重要的指导意义及应用价值。     

有限元分析中网格划分对轮合金轮毂强度分析的影响

计算机技术和仿真软件的进步,在整个机械行业中的作用正在不断凸显出来,作为新时期的软件技术,ANSYS有限元分析系统有力的推动了铝合金轮毂行业的发展。ANSYS有限元分析使铝合金轮毂在开发过程中形成了结构分析和强度改进的闭环系统。针对公司为某客户生产的一款铝合金轮毂在试制时13度冲击试验时失效情况,对有限元分析软件中的网格划分进行改进,虚拟冲击台架试验,通过分析结果,结合实际车轮试验失效情况,对车轮结构参数进行了修改,修改后车轮顺利通过了13度冲击试验。     

铝合金车轮虚拟冲击台架试验研究

针对某公司为客户生产的一款铝合金车轮在进行13°冲击试验时失效情况,采用有限元分析软件建立与实际试验相仿的虚拟冲击台架试验,通过分析结果,结合实际车轮试验失效情况,对车轮结构参数进行了修改,修改后车轮顺利通过了13°冲击试验。此虚拟冲击台架试验的建立可为车轮前期开发人员提供指导,缩短开发周期,降低开发成本。     

铝合金车轮90°冲击台架试验仿真方法研究

针对铝合金车轮在整车耐久道路试验中出现轮缘变形的问题,设计对比试验、找出问题发生的根本原因。通过90°冲击台架试验结果标定仿真模型,并通过仿真得出问题车轮90°冲击台架试验的轮辋变形量,得出评判车轮抗90°冲击性能的标准,为后续的车轮设计提供指导。     

铝合金车轮有限元仿真分析研究

车轮优化设计过程中,传统的实验分析方法周期长、费用成本高,本文采用有限元分析方法,跟据车轮实际运行状态,对车轮的弯曲试验过程构建物理模型,求解出载荷参数,通过有限元模块进行仿真分析,根据应力云图,对薄弱结构进行优化,并通过实际实验进行验证,试验结果表明有限元仿真分析在车轮优化设计过程中的有效性和可靠性。     

汽车车轮13°冲击试验的有限元模拟

为了减少车轮试验的测试次数,提高设计的效率,对车轮的冲击试验进行有限元模拟显得非常重要。依据轮毂的型号选用合适的轮胎,通过NX软件对轮毂、轮胎和冲击块进行三维建模,根据国家对冲击试验的标准,使用NX NASTRAN软件对模型施加了载荷和约束,对冲击试验的过程进行了有限元模拟,观察分析结果,找出冲击块下落过程中的最低位置即轮毂受到非线性应力最大的位置、轮毂受到应力集中的时间段和轮毂发生裂纹的危险区域,对轮毂的设计具有指导意义。     

汽车铸造铝合金车轮90°冲击试验对比分析

主要对轿车用铝合金车轮开展90°冲击试验进行验证,分析其受力状态,通过各种重复性好的90°冲击试验数据来验证铝合金车轮在实际使用工况的客观存在,并对比台架试验与车轮实际遭遇撞击后产生损坏的状况进行分析;为了降低安全隐患,提高行车安全,并针对国内复杂道路状况,建议各铝圈生产商增加90°冲击试验检查项目。     

基于应变损伤模型的复合材料层合板低速冲击数值模拟

提出了一种基于应变的复合材料损伤模型,考虑了复合材料冲击过程中出现的面内纤维断裂与压缩,基体开裂与挤裂。在使用Abaqus软件进行数值模拟计算时,自编的用户子程序VUMAT和Cohe-sive模型分别实现了复合材料面板的损伤和层间分层。通过对层合板在不同能量下的低速冲击的有限元模拟发现,模拟得到的分层损伤形状和面积、冲头最大挠度、接触力和凹坑深度都与试验结果吻合较好。     

硬质聚氨酯泡沫动态压缩本构模型研究及有限元仿真

硬质聚氨酯泡沫常被用于缓冲吸能结构,为了更好地在动态加载场景中对该材料进行设计及仿真,需要对其动态力学性能及本构模型进行研究。文章对硬质聚氨酯泡沫进行中低应变率下的动态压缩试验,并进一步分析了应变率对材料性能的影响;使用Avalle模型建立了描述材料压缩力学行为的本构模型,在模型中引入应变率项并基于试验数据的量化分析结果对模型进行了修正;在ABAQUS有限元软件中输入修正后的Avalle本构模型数据,对硬质聚氨酯泡沫进行冲击仿真。研究结果表明：硬质聚氨酯泡沫应力-应变响应对应变率具有敏感性,修正后的Avalle模型对多种应变率下的试验数据拟合较好,而基于该模型进行的有限元数值仿真在6 m/s及8 m/s的冲击条件下加速度峰值与试验数据误差分别为4.09%以及12.72%,模型可靠性较高。     

基于道路载荷的拖曳臂抗疲劳优化设计

为了评估及优化拖曳臂的疲劳耐久性能,以某车型拖曳臂为研究对象,进行了有限元分析和应变信号道路数据采集,将有限元分析结果与试验数据对比验证了有限元分析的准确性。针对拖曳臂疲劳失效原因进行了结构优化,根据道路数据生成了快速试验多级载荷谱,分别对优化前和优化后的拖曳臂进行了台架耐久试验,台架耐久试验结果与有限元仿真以及整车试车场路试结果一致。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

Limits of topographic measurement by the scanning tunnelling and atomic force microscopes

Parameters describing the topographic character of a surface (height, surface wavelength, slope and curvature) can be derived from equivalent sinusoidal profiles. The response of a surface-measuring instrument may be modelled in terms of instrument parameters such as stylus radius, and scanning range and resolution. The performance of the instrument may then be mapped as a zone in amplitude-wavelength (AW) space to show the sinusoidal profiles it is capable of measuring. In a first-order analysis the STM and AFM are considered as equivalent to contact-stylus instruments with a notional stylus radius equal to the tip radius plus the gap. Comparisons between different instruments and types of instrument are readily made by mapping in AW space. The error arising from convolution of the sinusoidal profile with that of the finite tip may be quantified and plotted as contours in AW space.