软包锂电池电芯封装铝塑膜外壳拉深工艺

通过拉深试验对铝塑膜材料特性进行分析,在DYNAFORM软件中定义铝塑膜材料属性并进行仿真试验。结合单因素试验和正交试验对影响铝塑膜拉深成形性能的各工艺参数进行显著性分析,采用响应曲面法、拉丁超立方试验设计和多目标粒子群优化算法相结合的方法对影响铝塑膜成形性能显著的参数（如压边力、模具圆角半径、摩擦因数和拉深速度）进行优化,优化后的铝塑膜拉深成形时,其壳体最薄处厚度为55 μm。试验验证了铝塑膜拉深成形工艺优化的结果可行。     

基于数值模拟的筒形件多道次拉深工艺与实验研究

分析了开水煲外壳零件成形的工艺特点,采用有限元分析软件Dynaform对其多道次拉深成形过程进行了数值模拟。首先确定出该零件合理的拉深系数分配,并在此基础上,选取影响最终成形质量的主要因素压边力、摩擦系数、模具圆角半径等为优化变量,通过正交试验,分析了零件关键位置的最大变薄率及表面质量情况,对上述工艺参数进行了优化。通过实践生产验证,经工艺优化后的成形零件质量得到一定程度的提高,取得了满意的结果。     

基于灰色系统理论的方盒件拉深稳健设计

利用灰色系统理论,以目标序列之间的关联度作为目标函数,将多目标优化转化为单目标优化问题.在板料成形的稳健设计中,通常需要满足多个目标,如不拉裂、不起皱、变形充分等质量要求,而且要满足响应波动减少的要求.对成形中可控因子进行试验设计,利用有限元分析软件获得拉深成形中各个目标对应的响应值.对计算获得的目标序列灰色关联度进行方差分析,得到各个因子各个水平对响应的影响程度,从而获得因子的最佳参数.最后利用最佳参数进行有限元分析,结果表明质量明显提高.研究表明,将灰色理论应用到板料拉深成形稳健设计中,取得较好的结果,说明该方法在多目标稳健设计中有很大的适用性.     

轿车发动机罩外板拉深成形数值模拟研究

通过对冲压成形过程进行数值模拟,可以预测成形过程中的材料流动趋势和应力应变分布,从而实现工艺参数的优化.基于数值模拟技术,对汽车发动机罩外板的拉深成形过程进行了研究.分别采用方板毛坯模型和剪角板毛坯模型对发动机罩外板的拉深成形过程进行分析,结合数值模拟结果和理论分析,得到了更为合理的板料尺寸,同时得出了相关的拉深成形工艺参数,该研究对实际生产具有一定的指导意义.     

基于冲压成形困难区域的拉延筋阻力稳健设计

汽车覆盖件冲压过程中,工艺参数和材料参数存在不确定性,这种不确定性导致工艺优化设计的难度增加。以冲压件成形困难的局部区域为质量评价区域,通过冲压因素敏感分析筛选出噪声因素和设计变量,将实验设计与响应面法相结合,构建评价指标与设计变量和噪声因素的响应面模型。在此基础上,将响应面模型、蒙特卡洛模拟技术与遗传算法相结合,建立了基于产品质量工程的稳健优化设计方法。实例分析结果表明,经稳健优化后,冲压件成形质量和工艺稳健性获得了显著提高。     

基于多目标遗传算法优化板料拉深成形工艺参数

利用人工神经网络构建了板料拉深成形的目标函数模型,建立了板料拉深成形工艺参数和性能评价指标之间的映射关系.以多种工艺参数(压边力、摩擦因数等)作为优化变量,多种成形缺陷(起皱、破裂等)作为优化目标,结合多目标遗传算法和数值模拟,建立了板料拉深成形工艺参数的优化设计模型,大大提高了优化的效率.以油底壳下盖为例,对其拉深成形工艺参数进行了优化,通过对优化结果进行数值模拟可以看出,该优化参数完全避免了各种缺陷的产生,这说明该优化算法具有较好的优化结果.     

基于6σ的稳健优化设计在薄板冲压成形中的应用

薄板冲压成形过程中,其设计变量和噪声因素都具有一定的波动,都存在不确定性。传统的优化设计由于忽略不确定因素的影响,当设计变量产生波动时,往往会导致设计最优目标超出约束界限或者目标函数对设计变量的波动极为敏感,从而使设计失效。采用自主开发的STLMesher软件建立了模具的参数化模型,在此基础上将试验设计、能代表实际冲压过程精度较高的近似模型和蒙特卡罗模拟技术相结合,构造了基于产品质量工程的6σ稳健优化设计方法。该方法在设计初始阶段就考虑了各种不确定因素的影响,因此在获得近似最优解的同时能够提高设计变量的可靠性和目标函数的稳健性,大幅提高产品的质量。在优化过程中调用的是近似模型,能大大减少调用有限元模型的次数,提高优化效率。算例表明,该方法具有较高的精度和较强的工程实用性。     

基于DYNAFORM发动机罩内板成形工艺的设计与优化

针对某车型发动机罩内板的成形工艺进行设计和优化,使用板料成形数值模拟软件DYNAFORM分析其拉伸成形过程并进行仿真;研究三种工艺方案即充液拉深加高压整形方案,纯刚性模拉深方案和充液拉深加局部刚模整形方案对发动机罩内板成形时的起皱、破裂和贴膜度问题的影响,得出一种最优化的成形工艺方案,为类型的零件生产起到了指导作用。     

TRIP600钢板成形汽车前纵梁冲压工艺研究

TRIP高强度钢板具有高强度、高应变率变形时的高动态吸能特性,符合现代汽车用钢材料的发展趋势。基于有限元法对TRIP600的汽车前纵梁冲压成形过程进行数值模拟,通过调整坯料外形,改善了成形质量;采用多元非线性回归模型分别拟合成形工艺参数(压边力、摩擦因数和拉深筋阻力)与破裂目标函数及回弹目标函数间的非线性关系,并基于NSGA-II多目标遗传算法,进行了成形工艺参数的优化,进一步提高了成形质量。     

应力松弛成形工艺稳健设计

针对热压罐升温速率波动导致的成形质量问题,提出基于容差模型和稳健ε-支持向量机的应力松弛成形工艺稳健设计方法,并给出一种改进的容差计算方法。该方法首先建立工艺参数优化数学模型,以塑性应变的导数为优化目标,以材料性能提升率为优化约束;建立优化目标响应曲面、优化约束响应曲面以及优化约束容差响应曲面,计算得优化约束容差并将其引入优化模型中;利用更新后的优化约束可以计算得到稳健的工艺可行域,最终在可行域内求解得到最佳工艺参数。分别采用原始工艺参数和优化工艺参数进行试验,在升温速率波动的影响下,采用优化工艺参数的试验件全部满足约束条件,而采用原始工艺参数的试验件中有30%不满足要求,验证了本文提出的工艺稳健设计方法的有效性和可靠性。     

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.     

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....     

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。     

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.     

ANGULAR DISTORTION ALLOWABLE VALUE AND ASSESS METHOD OF WELD ON COKE TOWER

A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.