折臂式随车起重机变幅机构动力学仿真分析

以某折臂式随车起重机为研究对象,建立其变幅机构力学模型,并对其动臂油缸受力情况进行分析研究。运用Pro/Engineer和ADAMS软件建立样机模型,求得动臂油缸受力,从而确定折臂式随车起重机液压系统的系统压力,并为其整个工作机构优化设计提供理论依据。     

基于ADAMS的折臂式随车起重机变幅机构铰点优化设计

以大吨位折臂式随车起重机为研究对象,利用动力学分析软件ADAMS,建立随车起重机的动力学仿真模型并对其进行全工况仿真,得到各构件受力及变幅液压缸受力情况,并采用优化设计方法、灵敏度分析,对变幅机构各铰点布置进行优化。优化分析结果表明,优化后结构更加紧凑,各铰点和动臂液压缸受力得到改善,提升结构可靠性,同时也验证了该优化设计方法可行有效。     

折臂式随车起重机动臂有限元分析

起重作业时,动臂作为重要承载部件会承受很大的复合外力,影响动臂的强度,甚至造成动臂变形。针对随车起重机动臂的强度刚度要求,利用Pro/E软件对某折臂式随车起重机进行三维建模,模拟起吊13t重物,进行动力学分析,得到动臂的受力曲线图,并以其中吊臂液压缸压力最大的工况为典型工况,进行ANSYS有限元分析,得到动臂的位移以及应力分布云图。分析结果表明,在多板焊接处存在应力集中现象,在设计中增加应力集中位置处的板厚,提高折臂式随车起重机的力学性能。     

基于ADAMS软件的QH400随车起重机运动学分析

根据运动学分析理论和所提供的模型的数据资料,从位移、速度、加速度三方面对QH400随车起重机进行了运动学分析,建立了运动学数学模型。利用ADAMS软件建立了QH400折臂式随车起重机变幅机构的仿真模型,并验证了模型的正确性。借助其三维模型,确定了几种典型工况下动臂液压缸、吊臂液压缸和伸缩液压缸的运动方式。运用ADAMS运算得出了特定工况下的吊点轨迹、速度和加速度,为起重机机构的后期动力学仿真、优化设计以及有限元分析等提供了参数和依据。     

基于ADAMS的折臂式随车起重机工作机构优化设计

以某折臂式随车起重机为研究对象,运用ADAMS建立参数化模型,并对折臂式随车起重机的工作机构进行优化设计,确定机构最佳参数。仿真结果表明,液压系统压力降低,冲击减小,机构更加紧凑。     

折臂式随车起重机的参数化起重特性研究

运用Matlab对矿用折臂式随车起重机进行特性研究。针对强度和整机稳的角度绘制起重特性曲线的异常繁琐和复杂,提出了参数化起重特性曲线的绘制方法,给出了Matlab GUI对话框的程序格式。并以某型折臂式随车起重机为例进行仿真计算,用参数化绘制出起重特性图,给出了Matlab计算程序运行时间的方法,证实了Matlab编程能实现起重特性图的快速绘制,为折臂式随车起重机的机构设计提供了一种高效便捷的方法。     

折臂式随车起重机底座有限元分析

以某折臂式随车起重机底座为研究对象,利用Pro/E建立底座简化后的三维模型,并联合有限元分析软件Ansys对随车起重机底座进行强度计算和有限元分析,得出了底座的应力和应变分布。通过对比5种工况分析,结果表明:设计的底座结构及选材能够满足强度和刚度要求,但安全余量不大,这对折臂式随车起重机底座的设计与改进有一定的参考价值。     

基于ADAMS的折臂式随车起重机受力计算

大吨位折臂式随车起重机变幅机构是由2个六连杆机构组成（见图1）,在大吨位折臂式随车起重机的开发设计过程中,需要根据随车起重机的最大起重力矩计算这2个六连杆机构中各连杆的受力,从而确定随车起重机液压系统的系统压力、动臂液压缸和吊臂液压缸缸径、额定起重量、     

工程起重机

正轮式起重机GJ20172071折臂式随车起重机动臂轻量化设计[刊,中]/赵云亮…//起重运输机械.-2016,(12).-27~30动臂是折臂式随车起重机的重要部件,其设计质量直接影响整机的工作可靠性。为实现动臂轻量化设计,提出了基于有限元技术与拓扑优化方法相结合的折臂式随车起重机动臂快速设计方法。通过该设计方法最终得到优化     

基于Matlab GUI的折臂式随车起重机运动学仿真

运用Matlab对折臂式随车起重机进行了运动学仿真研究,建立了折臂式随车起重机的运动学数学模型。针对吊点速度和加速度解析解异常繁琐和复杂,提出了吊点速度和加速度的数值解法,给出了Matlab GUI对话框的程序格式。并以某型号的折臂式随车起重机为例进行了仿真计算,实现了对包络图、速度和加速度图的绘制。给出了Matlab计算程序运行时间的办法,证实了Matlab编程能实现包络图、速度和加速度图的快速绘制,为折臂式随车起重机的机构设计提供了一种高效便捷的方法。     

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.     

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.