大吨位桥式起重机主梁跨端变截面处有限元分析

以起重量为200t,跨度为31m的桥式起重机为例,运用Visual C++6.0对ANSYS进行二次开发,借助ANSYS自带的参数化设计语言(APDL),根据桥式起重机桥架结构的特点采用自底向上的方法建立桥架结构的参数化有限元模型,并实现有限元分析过程的程序化.在此基础上,着力研究影响主梁跨端变截面处应力分布的各个因素,为今后大吨位桥式起重机主梁跨端变截面处的合理设计提供参考.     

大吨位桥式起重机主梁上盖板开门处有限元分析

以起重量为200t、跨度为31m的桥式起重机为例,运用Visual C++6.0对ANSYS进行二次开发,借助ANSYS自带的参数化设计语言(APDL),根据桥式起重机桥架结构的特点,采用自底向上的方法建立桥架结构的参数化有限元模型,并实现有限元分析过程的程序化。在此基础上,研究影响主梁上盖板开门处应力分布的各个因素,为今后大吨位桥式起重机主梁上盖板开门处的合理设计提供有益的参考。     

桥式起重机桥架箱形主梁的优化设计

桥式起重机桥架箱形主梁的传统设计一般采用偏于保守的简化计算方法,并且选用比较大的安全系数,所设计出的箱形主梁往往在一定程度上存在结构笨重、部分材料浪费和造价过高等问题,导致整机的性价比降低。本文应用 ANSYS 软件的优化设计模块,对起重机桥架的箱形主梁结构进行了优化设计分析。应用 ANSYS 软件的 APDL 语言,建立箱形主梁的参数化有限元模型,选取其截面尺寸作为设计变量,对其截面参数进行寻优,在满足其强度和刚度要求的前提下,使其质量减小,性价比提高。     

箱型梁桥架装置的有限元分析

对箱型梁桥架装置进行有限元分析。以桥式起重机的箱型主梁和桥架装置为研究对象,利用有限元分析软件ANSYS对箱型梁和桥架装置进行典型工况的有限元分析。通过三维软件建立有限元模型并导入ANSYS中,针对箱型主梁和桥架装置几种不同工况载荷和约束等条件下进行应力和应变分析,并得到变形图和应力分布图进行刚度和强度分析。随后进行提取4阶固有频率和振型进行模态分析,并对结构影响较大振型进行详细分析和说明。研究结果对箱型桥式起重机的桥架装置的设计提供理论依据。     

桥式起重机箱形主梁的结构优化与改进

对桥式起重机的主梁研究之后,针对国内箱形梁桥式起重机的主梁偏重、耗材多等缺点提出了新型结构的设想——波形腹板结构。借助有限元ANSYS工具,进行了新型腹板与原来的平直腹板的综合比较分析,得出了波形腹板在同等条件下,等效应力比平直腹板减少了38％左右的结论。应用这种腹板,可以大大减少腹板的材料及其上的加强筋,使桥式起重机的主梁结构优化,重量得以大大减轻,从而降低制造成本。     

起重机箱形梁波纹腹板的非线性屈曲分析

为了解决起重机箱形梁腹板薄壁化与剪切屈曲之间的矛盾,将波纹钢板应用于桥式起重机主梁,提出以波纹钢板代替传统直腹板的新型起重机主梁结构形式。采用Ansys中具有应力刚化及大变形功能的Shell181单元离散波纹钢板,分析中考虑材料非线性和结构初始几何缺陷的影响,利用有限元方法对结构进行非线性剪切屈曲分析,并通过实例研究波纹腹板箱梁波纹尺寸、腹板厚度以及上、下翼缘板厚度等因素对波纹腹板剪切屈曲极限载荷的影响,为波纹腹板箱形梁桥式起重机的设计提供参考。     

箱形主梁的三维参数化设计及有限元分析

根据QD系列桥式起重机箱形主梁的结构特点，介绍了基于SolidWorks平台的箱形主梁三维参数化设计方法，并实现了箱形主梁与有限元分析软件ANSYS之间的程序接口。对于设计人员来说，具有一定的参考价值和现实意义。     

基于拓扑优化的桥式起重机新型主梁设计

应用基于单元应力的渐进结构优化方法对某型号桥式起重机主梁截面进行拓扑优化,得到了矩形截面的桥式起重机主梁结构形式,随后采用变密度法(SIMP)对该主梁形式下的主、副腹板进行拓扑优化,根据拓扑优化结果,新型主梁主腹板仍然采用实腹结构,而副腹板则以桁架结构形式代替原有实腹结构形式,有限元计算结果证明,该结构形式在保证主梁结构强度、刚度条件下,可以大幅度减轻主梁重量。该新型主梁的设计方案为桥式起重机主梁轻量化设计提供了一种新思路。     

基于ANSYS的桥式起重机桥架结构设计及优化

针对桥式起重机桥架的轻量化设计问题,以跨度19. 3m、载荷10t的双梁桥式起重机箱型桥架在满载状态下的静强度和自振频率为分析对象。利用Creo软件建立桥架的三维实体模型,并无缝导入ANSYS Workbench中进行静态分析,通过对主梁中部危险截面和主梁与端梁连接处截面进行满载静应力分析,得到桥架的应力云图、应变云图。同时,以减少桥架的空间体积为目标进行结构优化,对优化后的桥架进行静应力分析和模态分析,验证桥架结构轻量化设计的合理性。     

大吨位桥式起重机桥架结构参数化建模及有限元分析

基于桥式起重机主梁结构的分析设计,运用参数化设计的方法建立主梁三维结构模型,使得模型结构尺寸的修改变得简单易行,并应用Ansys对主梁进行有限元分析。该方法对桥式起重机系列产品的设计具有借鉴价值。     

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.