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1.
有摩擦有间隙煌三维接触问题有限元法及应用   总被引:4,自引:0,他引:4  
介绍了一种求解三维弹性体间有摩擦、有间隙的接触问题有限元解法,文中推导出四种接触状态的接触条件。该方法通过赫兹问题验证,有限元解与精确解吻合较好。应用本方法对汽轮机汽缸法兰连接进行了应力计算,获得了法兰结合面上压应力分布规律并得出了一些重要结论。  相似文献   

2.
陈少华  李咏芳 《力学学报》2000,32(4):412-419
利用Kuowles与Sternberg提出的非线性弹性大变形应变能函数,对橡胶楔体与刚性缺口接触问题进行大变形渐近分析,推导了楔体尖端场的渐近方程,得到楔体尖端附近的应力应变场及应力的奇异性指数与橡胶楔体角度、刚性缺口角度及材料常数有关的表达式;楔尖附近同一半径上应力分量为常数,同时,利用非线性有限元理论编制了大变形有限元程序,考虑楔体尖端与缺口接触边界条件,计算得到了与分析解一致的结论,当缺口角  相似文献   

3.
接触问题应力分析的混合解法   总被引:3,自引:0,他引:3  
接触问题是一个极其复杂的非线性问题,单独使用数值方法或实验方法求解应力都有一定的困难.有限元计算与平面光弹性实验相结合的混合法是对接触问题进行应力分析简单而有效的途径.  相似文献   

4.
对考虑应力和无摩擦单侧接触位移约束的桁架拓扑优化问题进行了研究,采用解析方法,通过对典型算例不同初始接触间隙下的拓扑优化解的讨论,发现这一优化问题中存在解不唯一现象,研究也表明,接触状态对结构拓扑有一定影响,不同初始接触间隙可能导致不同的拓扑结构,对利用数值方法该问题进行了研究,为克服结构拓扑优化中奇异最优解问题,采用ε松弛方法建立桁架拓扑优化模型列式,并利用双层优化方法求解本拓扑优化问题,第一层,通过求解与原接触问题等价的二次规划问题来进行结构接触分析;第二层,利用第一层得到的位移及应力,采用ε-松弛方法进行结构拓扑优化。  相似文献   

5.
建议了二维蠕变损伤问题的有效模量法,基于热动理论提出了一个损伤演化方程,给出有效模量法和有交应力法的有限元解,并对两种方法进行了数值比较。  相似文献   

6.
采用材料力学中的平面弯曲理论、以及弹性理论中平面应力问题和平面应变问题的转换关系,分析方管在均匀外压作用下的变形、临界压力和应力,得到了方管最大变形、临界压力和最大应力的求解公式.运用有限元分析软件Marc建立有限元模型,分析了方管在外压作用下的变形、临界压力和应力情况.分析结果表明,最大应力出现在凹角处,最大位移出现在各面的中截面处,并将有限元解与本文解作比较,从而验证文本解的正确性.  相似文献   

7.
用拟弹性叠加、双重迭代法解弹塑性接触问题   总被引:6,自引:1,他引:5  
本文从混合变分法原理着手,对弹性接触问题提出一种新的数学模式,并从中导出有限元的近似公式。而后,利用拟弹性叠加、双重迭代给出一种快速解弹塑性接触问题的有限元算法。  相似文献   

8.
苗丹  刘一华 《应用力学学报》2016,(4):589-595,735
采用弹性力学的应力函数法,分析了上表面受均布载荷作用的上下层弹性模量和高度不同的双层叠合简支梁,对简支端提出了两种等效边界条件,得到了相应的两种解析解。运用有限元分析软件ANSYS,对不同组合的钢-铝双层叠合简支梁进行了数值计算,并与解析解进行了比较。结果表明:两种等效边界条件仅对弯曲正应力和位移有影响,对挤压应力和切应力没有影响;两种解析解的相对误差在1.2%以内;当跨高比超过6时,最大应力的解析解与有限元解的误差在4.4%以内;上下层对调后,两层中的应力基本不变;当上下层之间有摩擦时,弯曲正应力的外侧值大于内侧值,上、下层的中性层都由相应的几何中面向接触面偏移。  相似文献   

9.
本文应用广义变分原理,利用拉氏乘子法和罚函数法计入接触约束条件修正,建立了分析三维动力接触问题的一般有限元分析的理论模式;推导了处理这类问题的一种新的接触约束单元的接触刚度矩阵;采用增量求解模型解,研编了实施程序3DDCF;处理了方程中的病态问题、碰撞及能量释放条件问题。进行了算例考核,还首次给出了一个三维动力接触问题的算例结果。  相似文献   

10.
本文研究反应堆用石墨构件的应力分析问题。由于辐照石墨的蠕变响应是反应堆运行温度和快中子累积剂量的函数。因此使计算复杂化了。为了解决这个问题,本文提出应力变换法得到了有限元公式。对受辐照、有内热源、内外壁为放热条件的厚壁圆筒进行了求解。计算结果表明同解析解吻合得很好,并且具有简化计算和节省时间的优点。  相似文献   

11.
The coupling of the local contact problems between the components and the deformation of the components in the mechanical system were discovered. A series of coordinate systems have been founded to describe the mechanical system with the contact proble.ms. The method of isolating the boundary of contact body from others has been used to describe the constraint between the contacting points. A more generalized static mechanics model of the mechanical system with the contact problems has been founded through the principle of virtual work, As an application, the model was used to study the multi-teeth engagement problems in the inner meshed planet gear systems. The stress distribution of contact gears was got. A test has verified that the static contact model and the computational method are right.  相似文献   

12.
钢丝绳捻制成形接触问题的有限元分析   总被引:1,自引:0,他引:1  
基于虚功原理建立了钢丝绳捻制成形过程中考虑接触摩擦时的刚度方程,将小球分裂算法用于接触搜索,Augmented Lagrange法用于计算接触力.以钢丝绳一次捻制成形过程为例,分析了摩擦系数和自扭转系数对接触应力和加工应力域变的影响.研究结果表明。摩擦系数对剪应力的影响比对等效应力和等效塑性应变的影响大;考虑摩擦时钢线表面的轴向残余应力计算结果比无摩擦条件下的计算结果更接近实验结果.  相似文献   

13.
A theoretical model for calculating the stress and strain states of cabling structures with different loadings has been developed in this paper. We solve the problem for the first-and second-stage cable with tensile or bending strain. The contact and friction forces between the strands are presented by two-dimensional contact model. Several theo-retical models have been proposed to verify the results when the triplet subjected to the tensile strain, including contact force, contact stresses, and mechanical loss. It is found that loadings will affect the friction force and the mechanical loss of the triplet. The results show that the contact force and mechanical loss are dependent on the twist pitch. A shorter twist pitch can lead to higher contact force, while the trend of mechanical loss with twist pitch is compli-cated. The mechanical loss may be reduced by adjusting the twist pitch reasonably. The present model provides a simple analysis method to investigate the mechanical behaviors in multistage-structures under different loads.  相似文献   

14.
在弹性接触问题有限元混合法的基础上,把材料非线性和表面非线性两种迭代过程耦合,在瞬态温度场分析中将伽辽金法和向后差分法结合,并用混合法进行热接触迭代,把瞬态温度场分析和弹塑性接触分析耦合。提出了一种瞬态耦合热弹塑性接触有限元分析方法,并已成功地用于核容器的密封分析。  相似文献   

15.
The refined discrete mathematical model of a simple helical wire rope strand is developed. The effect of the transverse contraction of the wire strand through Poisson’s ratio and also through local contact deformations (wire flattening) has been studied in detail. In order to express the interwire contact deformation in terms of the parameters describing the strand deformation, we formulate a two-dimensional model interwire contact problem. The interwire contact interaction is treated as a frictionless unilateral plain strain problem. The nonlinear model interwire contact problem has been solved by the method of matched asymptotic expansions. The constitutive equations for a helical wire rope strand, which take into account both the Poisson’s ratio effect and the effect of contact deformation, are obtained in a closed form.  相似文献   

16.
用声显微镜技术测量真实接触面积的研究   总被引:1,自引:0,他引:1  
为了研究表面接触对润滑状态的影响,利用THSAM-5超声显微镜配以专门设计的辅助试验装置,测得了铝片-钢球的真实接触面积分别随载荷和加载时间变化的声学像,以及润滑剂的存在对测量结果的影响,发现真实接触面积是随着加载时间的延长而增大,而且载荷越大,真实接触面积越大,这是接触点发生塑性变形的结果。研究表明,声显微镜技术是测量真实接触面积的一种可行方法,但要将其作为一种定量测量手段却还有待于进一步的研究  相似文献   

17.
This paper deals with the interaction between a vehicle and a slab track using the model of moving wheel for both frequency and time-domain. The vehicle is reduced to a moving two-mass oscillator and the slab track is considered as an infinite structure consisting of elastically supported double Euler–Bernoulli beams. In order to perform the time-domain analysis, a semi-analytical method based on the outstanding properties of the time-domain Green’s functions of the slab track has been developed. The method allows the computing of the non-linear wheel/rail contact (the contact loss and the non-linear contact stiffness). The vehicle/track interaction due to the polygonal wheel and the corrugated rail has been investigated and the running velocity and non-linear wheel/rail contact influences have been pointed out.  相似文献   

18.
The absolute-retardation method of stress analysis has been developed and extended to the measurement of steady-state dynamic contact-stress distributions in an elastohydrodynamic rolling contact. The method has been shown to be applicable to the plane-strain conditions appearing in such a contact, and many of the difficulties of the technique associated with the use of conventional interferometers have been eliminated by forming the absolute-retardation interferogram from reflections at the front and back surfaces of an optically plane parallel birefringent model using a laser light source. Some results illustrating the success and limitations of the technique in the study of the elastohydrodynamic problem are discussed.  相似文献   

19.
回转支承构件牵引滚动接触应力解析   总被引:1,自引:0,他引:1       下载免费PDF全文
回转支承构件是重型机械的重要基础元件,其失效往往导致灾难性的设备事故和人身事故以及巨大的经济损失.及时、充分地了解回转支承构件牵引滚动接触应力分布特点,对于保证整机安全生产和提高企业经济效益具有非常重要的意义.本文将回转支承构件接触模型简化为轴线平行的圆柱体二维平面应变模型,从接触力学理论中McEwen关于轴线平行的圆柱体二维法向接触理论出发,重点讨论牵引滚动与常规法向接触状态的切向分布力的相同点和不同点,从而推导出牵引滚动接触状态下接触区应力场各应力分量解析式,将McEw-en法向理论公式推广到法、切向复合分布力综合作用下.在此基础上,探讨了表面拉应力与摩擦系数的关系,摩擦系数越大则表面拉应力水平越高.最后,运用材料力学二向应力状态受力分析方法,计算了接触应力场最大剪应力位置、大小和方向角与深度的关系,发现与无表面摩擦情况相比,最大主剪应力发生位置变浅,幅值反而变小.  相似文献   

20.
近年来随着非连续介质力学方法的发展,离散元法成为了颗粒材料的物理力学特性研究的重要工具。而对于任意形状复杂块体,精确的接触检测算法一直是离散元法的难题之一。本文基于几何对偶理论,在耦合模拟器CoSim (Coupling Simulator)的块体离散元框架下开发了多面体接触重叠算法。该算法融合了GJK (Gilbert-Johnson-Keerthi)和快速凸包等算法,能够准确计算重叠多面体,进而从接触重叠体中提取接触点、法线方向、接触面积和嵌入深度等接触特性。通过颗粒碰撞测试和砌体结构破坏试验,验证了该算法的准确性和适用性,能够解决多面体的接触问题。  相似文献   

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