岸边集装箱起重机节点板的有限元分析与比较

针对常见的长腰形节点板与圆形节点板,利用ANSYS软件对岸边集装箱起重机钢结构进行有限元建模,分析比较两种形状节点板的应力分布情况.通过分析对比,发现两种形状的节点板在应力分布上呈有相同的规律,也存在一些不同现象.结合二者优点,可使节点板的形状得到优化设计,有效地发挥自身作用,减少不必要的材料浪费.     

Thermal buckling behavior of laminated composite plates: a finite-element study

In this paper, the thermal buckling behavior of composite laminated plates under a uniform temperature distribution is studied. A finite element of four nodes and 32 degrees of freedom (DOF), previously developed for the bending and mechanical buckling of laminated composite plates, is extended to investigate the thermal buckling behavior of laminated composite plates. Based upon the classical plate theory, the present finite element is a combination of a linear isoparametric membrane element and a high precision rectangular Hermitian element. The numerical implementation of the present finite element allowed the comparison of the numerical obtained results with results obtained from the literature: 1) with element of the same order, 2) the first order shear deformation theory, 3) the high order shear deformation theory and 4) the three-dimensional solution. It was found that the obtained results were very close to the reference results and the proposed element offers a good convergence speed. Furthermore, a parametrical study was also conducted to investigate the effect of the anisotropy of composite materials on the critical buckling temperature of laminated plates. The study showed that: 1) the critical buckling temperature generally decreases with the increasing of the modulus ratio E _L/E _T and thermal expansion ratio α _T/α _L, and 2) the boundary conditions and the orientation angles significantly affect the critical buckling temperature of laminated plates.     

四环减速器内齿环板的有限元分析

为解决三环减速器振动大、温升高和运动平稳性差的问题，提出了一种新型减速装置——四环减速器。分析了这种新型减速器的工作原理及结构特点，导出了内齿环板的受力公式。分14种工况对内齿环板进行了有限元分析，为提高四环减速器性能设计提供了理论依据。     

A high-order shear element for nonlinear vibration analysis of composite layered plates and shells

This paper introduces a family of high-order facetted shell elements for linear and nonlinear stress and vibration analysis of composite layered plate and shell structures. Engineering slope angles are employed in element equations, and transverse stresses are expanded over the thickness. The lateral deflection is modelled by conforming or non-conforming Hermitian shape functions, within rectangular or paralellogrammic and triangular elements. Nonlinear terms associated with geometrical nonlinearity are also derived using a practical approach based upon the actual components of strain. A finite element programming package was designed employing the newly developed elements. Several case studies have been investigated and package results were compared with existing theoretical and/or experimental results. It has been proved that the developed elements can lead to accurate estimations of natural frequencies. The effect of fibre angles on natural frequencies has also been investigated with some case studies, and the results proved that the package can be a useful tool for the design optimization of composite layered plate and shell structures.     

G495发动机曲轴应力的有限元分析

用有限元法研究了G495发动机整体曲轴应力分布状态;对有限元分析过程中模型的选择、有限元网格的疏密、模型的简化程度等因素对计算结果的影响做了分析。     

The influence of corner stress singularities on the vibration characteristics of rhombic plates with combinations of simply supported and free edges

This paper offers accurate flexural vibration solutions for rhombic plates with simply supported and free edge conditions. A cornerstone here is that the analysis explicitly considers the bending stress singularities that occur in the two opposite, hinged–hinged and/or hinged–free corners having obtuse angles of the rhombic plates. These singularities become significant to the vibration solution as the rhombic plate becomes highly skewed (i.e. the obtuse angles increase). The classical Ritz method is employed with the assumed normal displacement field constructed from a hybrid set of (1) admissible and mathematically complete algebraic polynomials, and (2) comparison functions (termed here as “corner functions”) which account for the bending stress singularities at the obtuse hinged–hinged and/or hinged–free corners. It is shown that the corner functions accelerate the convergence of solutions, and that these functions are required if accurate solutions are to be obtained for highly skewed plates. Accurate nondimensional frequencies and normalized contours of the vibratory transverse displacement are presented for rhombic plates having a large enough skew angle of 75° (i.e. obtuse angles of 165°), so that the influence of the stress singularities is large. Frequencies and mode shapes of isosceles triangular, hinged–free plates are also available from the data presented.     

气缸的螺栓连接有限元应力分析

针对气缸螺栓连接选择不当造成应力集中、材料浪费、制造工艺复杂等问题,利用有限元方法进行分析,得到丰富数据,能够满足设计要求,并对结果通过理论计算加以论证。此方法也可用于受力形式和约束条件更加复杂的螺栓连接的设计。     

陆风X6车架有限元分析与结构优化

基于陆风X6的实体建模之上建立了其有限元模型,对各零部件之间的连接关系进行了模拟,并在此基础上进行了静态强度特性分析,得到了引起车架纵梁产生开裂原因的结果.对陆风X6车架进行了结构优化并在陆风x8上得到了应用,结果表明优化后的陆风x8车架结构克服了车架纵梁开裂的问题,对工程有一定的实用价值.     

具有局部应力集中的机械零件结构可靠性分析

针对具有局部应力集中的机械零件对实际工程结构的损害问题,采用神经网络技术模拟基本随机变量和应力集中系数之间的关系,能够直接获得应力集中系数的显性表达式。在这个基础上,将神经网络技术获得的应力集中系数的显性表达式和可靠性理论相结合,解决应力集中情况下的机械零件结构可靠性问题。结果表明:模拟得到的应力集中系数显性表达式能够直接应用到机械零件的可靠性分析中,获得可靠性计算结果。这将为工程结构的可靠性分析提供了理论依据,而且提出了机械零件结构可靠性分析的新方法。     

凸轮波发生器作用下柔轮截面应力有限元分析

建立了柔轮在凸轮波发生器作用下的有限元模型,进行了静力学接触分析.深入地分析了柔轮在凸轮波发生器作用下的截面应力特征,找出了柔轮的危险截面,得出在凸轮波发生器作用下危险截面是离端面距离为14.4 mm的截面的齿槽部分,为谐波齿轮传动的设计提供了重要的依据.     

A new approach for bending analysis of thin circular plates with large deflection

This paper is concerned with bending analysis of an axisymmetric simply supported circular plate with large deflection. Based on the linear theory of thin plates, the incremental load technique is developed for solving the bending problem of a thin circular plate with large deflection. In the proposed method, the total applied load is divided into various small load steps. In each load step, the plate stress behavior is simplified to be linear. The incremental formulations are presented for the deflection and stresses of the plate when external loads increase. A numerical example is given to show simplicity and accuracy of the present method. It is found that the proposed method can be an alternative useful tool for engineering applications.     

Free vibration analysis of functionally graded plates with multiple circular and non-circular cutouts

Cutouts are inevitable in structures due to practical consideration.In order to investigate the free vibration of functionally graded plates with multiple circular and non-circular cutouts,finite eleme...     

渐开线直齿圆柱齿轮齿根应力的有限元分析

根据啮合原理 ,建立了轮齿齿廓的精确模型。在此基础上 ,建立了整个齿轮平面有限元模型 ,并进行了分析计算。根据计算结果总结出了在对轮齿齿根应力进行有限元分析时 ,模型参数的选取原则 ,并对在该原则下建立的二维和三维模型分别进行了计算 ,将各种模型下的计算结果进行了比较 ,证明了所述原则的有效性     

Theory and comparison of the effect of composite and shape memory alloy stiffeners on stability of composite shells and plates

The effects of composite and shape memory alloy stiffeners on stability of composite cylindrical shells and rectangular plates subjected to a compressive load are compared. The governing equations for reinforced cylindrical shells are developed based on the Love first approximation theory and smeared stiffeners technique. It is shown that composite stiffeners are more efficient in cylindrical shells, while shape memory alloy stiffeners may be preferable in plates or in long shallow shells. It is also proven that shape memory alloy stiffeners increase the upper and lower buckling loads, i.e. the linear buckling load and the minimum postbuckling load-carrying capacity of cylindrical shells modeled as single-degree-of-freedom systems by the same amount.     

残余应力引起的铣削变形有限元分析

应用弹性力学理论推导出了二维连续铣削过程中工件内应力再分布及其引起变形的计算递推公式.解决了有限元建模、初始应力加载、变形评估等仿真关键技术,建立了残余应力引起铣削变形的二维有限元仿真模型.最后对实例进行了仿真计算,分析了残余应力引起的加工变形规律,并用解析法对仿真结果的进行了验证.     

大型液压正铲挖掘机工作装置有限元分析及应力测试

针对某大型液压正铲挖掘机,使用Pro/Engineer软件对其工作装置进行实体建模,并对各部件(动臂、斗杆和铲斗)最不利工况的模型进行受力分析,求出各铰点和被动油缸的受力.分别建立各部件的有限元模型,然后应用ANSYS软件的静力分析模块对其进行有限元强度和刚度分析,得出各部件的应力和变形云图.最后采用静态应变仪对工作装置进行现场应力测试,将试验结果和理论计算进行比较,对有限元分析结果进行了验证.从而为改进挖掘机设计、提高挖掘机工作的稳定性提供了理论依据.     

The stress and strain concentrations of out-of-plane bending plate containing a circular hole

The elastic stress and strain fields of a finite thickness plate containing a circular hole subjected to out-of-plane bending are systematically investigated using the finite element method. It is found that the stress and strain concentration factors of the finite thickness plate are different except at the notch root of the free surface even if the plate is in elasticity state. The through-thickness distributions of strain components are not linear with the distance from the mid-plane in the stress concentration region. The nonlinearity of these distributions is very severe near the free surface especially in thick plate. The Euler-Bernoulli hypothesis and Kane-Mindlin's plate theory may not be reasonable to be used in the stress concentration region especially near the free surface. The maximum stress and strain do not always occur on the free surface and their locations depend on the moment ratio and the plate thickness. The maximum stress and strain concentration factors occur on the free surface only in thin plates of small moment ratio. The differences between the maximum value and surface value of stress concentration factor increase with the plate thickness and the moment ratio. This relation of strain concentration factor is similar to the one of stress concentration factor. But the difference magnitude of stress concentration factor is larger than that of strain concentration factor in same plate.     

Polyharmonic (thin-plate) splines in the analysis of composite plates

In the present study a layerwise theory for composite and sandwich laminated plates is discretized by polyharmonic (thin-plates) splines. A composite and a sandwich plate examples are presented and discussed. The combination of adequate shear deformation theory and thin-plate splines allows a very accurate prediction of displacements and stresses.     

Effect of surface roughness on magneto‐hydrodynamic couple‐stress squeeze film lubrication between circular stepped plates

In this paper, a theoretical analysis of the problem of magneto‐hydrodynamic couple‐stress squeeze film lubrication between rough circular stepped plates is presented. The modified averaged Reynolds equation is derived for the two types of one‐dimensional roughness structures, namely the radial roughness pattern and the azimuthal roughness pattern. The closed‐form expressions are obtained for the mean squeeze film pressure, load‐carrying capacity and squeeze film time. The results are presented for different operating parameters. It is observed that the effect of azimuthal (radial) roughness pattern on the bearing surface is to increase (decrease) the mean load‐carrying capacity and squeeze film time. The applied magnetic field increases the load‐carrying capacity and lengthens the squeezing time. Copyright © 2012 John Wiley & Sons, Ltd.