冷氢化反应器筒体与封头连接处的应力分析

采用Ansys有限元分析软件,对冷氢化FBR筒体与球形封头连接处进行了应力分析,并对过渡段沿厚度方向应力分布和边缘应力的局部性效应进行了阐述。     

压力容器中边缘应力和局部高应力叠加影响研究

对压力容器中开孔接管靠近筒体与封头连接处的结构模型，采用有限元应力分析法分析筒体与封头连接处边缘应力和接管与筒体相贯区局部高应力叠加影响规律，通过建立不同的模型（开孔率不同，开孔和筒体与封头连接处距离不同）进行对比。结果表明，两种应力会相互影响，且开孔率越大，相互影响越大。当开孔率达到0.52时，接管与筒体相贯区的一次局部薄膜应力受筒体与封头连接处边缘应力的影响会增大10.27%，封头过渡区的一次局部薄膜应力受接管与筒体相贯区高应力的影响会增大18.8%。     

锥形封头的应力分析

本文采用电测法,通过对锥形封头和与封头相连接的部分圆筒体的应力分布进行实验测定,绘出了应力分布曲线图,由于锥形封头和筒体两部分连接处曲率不同,受压后,在连接处会产生边缘力系—边缘力矩和边缘剪力,使得折边区及其两侧一定距离内的筒体和封头中的应力分布比较复杂,某些位置会出现较高的局部应力等重要的结论。     

基于热结构耦合技术的制氢变换炉卸料口接管强度研究

以制氢变换炉卸料口为研究对象,采用热结构耦合方法,计算斜接管与筒体连接处的应力强度。通过对比不同角度斜接管的应力强度,得到斜接管的最优角度。对接管连接处作不同半径的倒圆角后可知:随着倒角半径的增大,斜接管与筒体连接处的最大应力值显著降低。     

焦炭塔过渡段区域的热应力有限元分析

本文应用Ansys有限元软件,以中石化茂名分公司提供的焦炭塔原始数据为条件,建立焦炭塔有限元模型,分析焦炭塔各个操作阶段塔筒体和锥体的过渡段(锻件)的应力分布情况。结果表明:焦炭塔过渡段的应力在升温阶段或者是降温阶段达到最大值或最小值。环向应力、轴向应力和Mises等效应力在筒体与过渡段连接焊缝附近和过渡段与裙座连接焊缝附近达到峰值。     

基于ABAQUS的碟形封头的应力分析与安全评定

借助有限元软件ABAQUS,针对压力容器上的碟形封头进行了应力分析及安全评定。结果表明,在封头与筒体连接处以及封头直边段与球面过渡处应力较大,成为薄弱区域。并在过渡处由内壁向外壁取参考路径,进行应力线性化,得到该封头强度满足要求。     

基于ANSYS Workbench的球冠形封头与筒体连接处的应力分析

本文采用有限元模拟分析技术,借助于ANSYS Workbench,比较分析当筒体壁厚小于球冠形封头厚度时,在封头与筒体连接处设置或不设置直边段时,连接边缘的应力变化情况。通过分析实验结果,明确指出该情况下在其连接处设置直边段十分必要。     

基于ANSYS的立式厚壁压力容器应力分析

应用ANSYS软件分析了立式厚壁压力容器工作时筒体与封头的应力分布。结果表明:最大等效应力处于在筒体的内壁区域;等效应力从筒体或封头内壁到筒体或封头外壁呈近乎线性下降。筒体与封头的连接处附近外壁和内壁的等效应力变化最大。     

压力容器无折边锥壳小端与圆筒体连接处加强的判定

根据无折边锥壳小端与筒体连接处的不连续分析得出的壳体中轴向应力σL 和周向应力σθ 的表达式 ,通过对最大压缩应力σL 限定条件的分析和讨论 ,得出了适用于以锥底 (r=rmax)处的最大应力为基准将锥体设计成等厚壳体时 ,无折边锥壳小端与筒体连接处加强计算的判定条件。     

高压容器筒体与封头连接区有限元应力分析

高压容器筒体与封头连接区是高压容器的高应力区之一,对其进行了三维有限元分析,获得了连接区的应力分布信息.结果表明:高压容器筒体与封头连接区最大应力强度出现在过渡区与球壳连接处.     

基于Matlab高压容器双锥环密封圆形平端盖的优化设计

以平端盖直径方向弯曲应力和双锥密封环向开槽处危险截面综合应力都不超过材料的许用应力为非线性约束条件,以圆形平端盖受力主螺栓中心圆直径Db和厚度H作为设计变量,应用Matlab非线性约束最小优化工具(fmincon函数)建立高压双锥密封圆形平端盖体积最小的优化设计模型,编制Matlab语言求解。实例计算结果表明,该优化设计是一种较为先进实用的机械设计方法,对高压双锥密封平端盖优化设计具有一定的参考价值。     

降低厚壁圆筒与接管连接处应力峰值的方法

本文介绍了一种降低厚壁圆筒与接管连接处应力峰值的方法。文中指出如果在厚壁圆筒上开长轴在环向上的椭圆孔,为了使开孔能与普通的圆形接管连接,其最佳的椭圆孔通道为：其长短半轴之比由容器内表面的变化到容器外表面的圆形。并以试验结果加以证实。     

整体多层包扎式高压容器筒体与球形封头连接区应力状态有限元分析

建立了整体多层包扎式高压容器多层筒体与球形封头连接区有限元接触分析模型,得到了端部阶梯式连接结构的应力分布状况,并与相同尺寸非多层结构的应力分布进行了比较。结果表明,两种结构内外壁应力变化趋势相似,在连接区出现明显的应力集中,连接处轴向应力上升趋势大于周向应力,达到最大应力值后迅速衰减。     

Internal Stresses Adjacent to a Hole Through a Multilayer Wiring Board

The normal displacement field close to copper plated-through holes (PTH) in multilayer laminated circuit boards that is generated during thermal expansion is strongly inhomogeneous. By adhering a thin, and therefore flexible, microscope cover slip to the top surface of the laminate, Fizeau optical interference fringes can be generated between the cover slip and an adjacent optical flat and used to map the displacement field; the precise distribution of these fringes changes when the distance between the two is changed by thermally expanding or contracting the laminate. Thin plate elasticity theory applied to the cover slip permits the distribution of normal stress in the laminate to be estimated. Moving radially outwards from the centre of a PTH the normal stress is found to oscillate in sign in a highly damped manner such that the amplitude is insignificant beyond the first cycle. The largest normal stresses in the laminate are found to act at a radial distance corresponding to the outer edge of the copper surface pad. Thus, with increase of temperature, there develops a circular locus of tensile normal stress in the laminate\pad combination at a radius less than, but immediately adjacent to, the edge of the pad and a locus of normal compression in the laminate alone at a radius slightly greater than that for the outside edge of the pad. Both the tensile and compressive peaks increase at a rate of 1.6 MPa/K. With decrease of temperature the opposite holds true except that the stressing rate is lower at 0.6 MPa/K. The fact that, independent of whether the temperature is increased or decreased from room temperature, there exist annular regions of tensile stress within and normal to the plane of the laminate explains the occurrence during changes of temperature of hidden delaminations, including, in multilayer circuit boards, debonding of interlayer copper conductors. The similarity of this configuration to bolt holes in composite structures is discussed.     

Internal Stresses Adjacent to a Hole Through a Multilayer Wiring Board

The normal displacement field close to copper plated-through holes (PTH) in multilayer laminated circuit boards that is generated during thermal expansion is strongly inhomogeneous. By adhering a thin, and therefore flexible, microscope cover slip to the top surface of the laminate, Fizeau optical interference fringes can be generated between the cover slip and an adjacent optical flat and used to map the displacement field; the precise distribution of these fringes changes when the distance between the two is changed by thermally expanding or contracting the laminate. Thin plate elasticity theory applied to the cover slip permits the distribution of normal stress in the laminate to be estimated. Moving radially outwards from the centre of a PTH the normal stress is found to oscillate in sign in a highly damped manner such that the amplitude is insignificant beyond the first cycle. The largest normal stresses in the laminate are found to act at a radial distance corresponding to the outer edge of the copper surface pad. Thus, with increase of temperature, there develops a circular locus of tensile normal stress in the laminate\pad combination at a radius less than, but immediately adjacent to, the edge of the pad and a locus of normal compression in the laminate alone at a radius slightly greater than that for the outside edge of the pad. Both the tensile and compressive peaks increase at a rate of 1.6 MPa/K. With decrease of temperature the opposite holds true except that the stressing rate is lower at 0.6 MPa/K. The fact that, independent of whether the temperature is increased or decreased from room temperature, there exist annular regions of tensile stress within and normal to the plane of the laminate explains the occurrence during changes of temperature of hidden delaminations, including, in multilayer circuit boards, debonding of interlayer copper conductors. The similarity of this configuration to bolt holes in composite structures is discussed.     

地震载荷下拉杆直径对球罐的影响分析

在地震载荷条件下,使用ANSYS8.0软件分析了1000m3球罐的拉杆直径变化对球罐应力的影响。分析结果表明,球罐的最大应力点位于球罐与盖板连接处外壁面的上侧,拉杆直径的变化对球罐与盖板连接处的应力影响较大,对其他部位的应力影响相对较小,在选择球罐的拉杆直径时应充分考虑拉杆对球罐应力的影响。     

天圆地方结构的应力分析

针对天圆地方结构进行有限元分析计算,结果表明三角形平板区域位移及应力最大,需对其危险截面进行强度评定.从《Roark's Formulas for Stress and Strain》手册查得三角形平板的最大挠度和最大应力计算公式,为该结构的工程设计提供可参考的方法.     

有限元分析在平盖设计中的应用

利用有限元软件对平盖加筋的结构进行了模拟,得到了应力分布云图和位移分布图及位移变化曲线,并采用第四强度理论对其进行了强度校核。所得结论对今后平盖结构设计具有指导作用。     

Adherence and Rolling Kinetics of a Rigid Cylinder in Contact with a Natural Rubber Surface

Equilibrium conditions of a rigid cylinder in contact with the flat and smooth surface of a natural rubber sample are studied using concepts of fracture mechanics, such as the strain energy release rate or the stress intensity factor. It is shown that an equilibrium contact area exists if the applied force per unit axial length is greater than a negative critical value, closely related to the cylinder radius and mechanical and superficial properties of the elastic solid. Due to the intervention of molecular attraction forces, of van der Waals type, a light cylinder rolls under an inclined rubber surface and it is displayed that the rolling speed is the same when the cylinder rolls upon the same inclined surface. It has been verified that if a flat rubber substrate, with an adequate length, is rotated at constant angular velocity, a steel cylinder rolls alternately upon and under the surface, unceasingly without falling down.     

平盖开孔的有限元分析及其补强方法的探讨

为了使平盖开孔补强结构更为合理、可靠,使用圆形平板的理论解和有限元分析方法,对不同开孔直径的27个平盖模型进行了应力计算和分析比较,进一步探讨了不同的开孔补强方法。结果表明,对于开孔率小于0.5的平盖开孔补强采用均匀增加平盖厚度的方法,不能解决孔边产生的应力集中问题,难以达到补强的效果;而采用外加补强元件的方法,则应明确其补强范围应在2d范围内。