共查询到18条相似文献,搜索用时 296 毫秒
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基于双剪统一强度理论的圆板塑性极限分析 总被引:1,自引:0,他引:1
通过对轴对称弯曲圆板在塑性极限状态下应力和弯曲内力的分布研究,建立了双剪统一强度理论下用弯矩表示的屈服条件,即广义双剪统一屈服条件。该广义双剪统一屈服条件是一条对称的外凸闭合折线,可应用于由各种拉压强度比及剪压强度比材料构成的圆板和环板的塑性极限分析。对均布荷载作用下的简(固)支圆板进行了塑性极限分析,得出了圆板的塑性极限荷载、塑性极限状态时的内力场和速度场,分析了拉压强度比α以及中间剪应力影响系数b对塑性极限承载力的影响。 相似文献
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轴向冲击载荷下圆锥壳的塑性屈曲 总被引:1,自引:0,他引:1
本文用文献[1]中建议的能量原理研究了轴向冲击载荷下小锥角圆锥壳的轴对称塑性屈曲问题,获得了临界冲击速度和线性屈曲模态的表达式,并与文献[1]中圆柱壳的相应结果进行了比较。 相似文献
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基于缩减弹性模量的理念,建立计算加肋轴对称组合壳塑性极限载荷的有限元方法。定义轴对称壳单元的"弹性状态"、"局部屈服状态"和"截面屈服状态",并提出判断条件。提出肋骨单元屈服的判断条件。外载荷分成若干载荷步,分步加载,通过缩减"局部屈服"壳单元和屈服的肋骨单元的弹性模量,模拟组合壳的弹塑性应力状态,直至组合壳达到"截面屈服"的塑性极限状态,从而得到组合壳的塑性极限载荷。编制了有限元计算程序,算例表明该方法计算速度快,计算精度较高,可用于工程计算。 相似文献
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用双剪强度理论解混凝土板冲切的轴对称问题 总被引:19,自引:6,他引:13
本文采用双剪强度理论,对混凝土板轴对称冲切破坏强度进行了计算。采用刚塑性模型,给出轴对称破坏机构,得到极限应力圆的包络线为二条直线,再利用虚功方程求得破坏荷载的上限。公式形式简单,与已有结果相比符合很好。 相似文献
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《振动与冲击》2019,(15)
为了研究和对比风力发电塔筒在极端动力荷载作用(风和地震)下的破坏模式,对于某典型风电塔通过ABAQUS建立考虑土-结构相互作用和叶片建模的精细有限元模型,开展了一系列非线性时程分析。风场由Turbsim软件人工生成,风荷载由风机设计软件FAST计算得到;地震选用适用于硬土场地的典型记录。分析结果表明,塑性铰大部分出现在塔筒几何非连续处,一旦局部全截面塑性铰稳定出现,即面临倒塌。在强风下,风速的能量在风电塔低频分布较高,塔筒受基本模态控制,在底部出现全截面塑性铰和倒塌;在强震下,地震动的能量在风电塔高频也分布较高,塔筒受高阶模态影响,虽然塑性铰首先在底部出现,但全截面塑性铰与倒塌位置在中部或上部,并且不同的天然地震动可能导致不同的倒塌位置。 相似文献
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Finite element (FE) modeling based on axisymmetrical cells was performed for relating the phase-stress partition and residual phase stress in metal matrix composites (MMCs) to the reinforcement volume fraction and shape, matrix hardening behavior and applied strain levels. The phase stress is defined as mean effective stresses in the constituent phases. The elastic, plastic phase-stress partition behavior during loading, and the resultant residual stress in matrix followed unloading are delineated. A set of formulas is given for predicting the value of the phase stress in each phase, and residual stress in matrix from the inclusion volume fraction and aspect ratio, as well as matrix hardening exponent and applied strain level. 相似文献
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本文讨论孔边有加强环的球壳圆孔应力集中的轴对称问题。导出了径向弯矩、环向轴力、径向轴力的内力集中系数公式。文中对各种几何参数(孔洞尺寸,环梁截面尺寸,环梁与壳面的偏心距)下的内力分布作了详尽的讨论。就泊松比ν=0,壳面作用有法向面荷载q和孔边作用有线荷载p的情况,分别作了径向弯矩,环向轴力,径向轴力的内力集中系数表格。对于加强环内的弯矩,也给出了计算公式和表格。这些表格可供设计单位直接应用。①②③ 相似文献
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Y. Sugano 《International Journal of Engineering Science》1979,17(8):927-939
The transient thermal stresses in a transversely isotropic, finite, solid, circular cylinder resulting from a unsteady-state, axisymmetrical temperature field are examined. A general method of solution based upon a set of stress functions is presented for the case of an arbitrary internal heat-generation. The temperature field is exactly determined by combined use of finite Fourier-cosine and finite Hankel transforms. Numerical calculations are carried out for various cases of the thermal and elastic anisotropies of the materials. 相似文献
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In this study, an axisymmetrical problem for a penny-shaped crack under radial shear is considered. The crack is located parallel to the surface of a halfspace, which is subjected to initial stress parallel to the crack plane. An approach proposed by Guz (1983) in the framework of the three-dimensional linearised solid mechanics is used. Analysis involves reducing the problem to a system of Fredholm integral equations of the second kind, where the solutions are identified with harmonic potential functions. The representations of the stress intensity factors K
I and K
II near the crack edges are obtained. These stress intensity factors are both influenced by the initial stress. 相似文献
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本文采用非局部弹性理论研究了三维圆盘状Ⅰ型裂纹问题。给出了轴对称问题的影响函数,导出了圆盘状Ⅰ型裂纹非局部理论解的对偶积分方程。对具有无界核积分方程的求解问题提出了一种有效的解决方法,使无界核问题转化为有界核问题。给出了圆盘状Ⅰ型裂纹问题裂纹尖端应力场的数值解,结果表明,非局部理论消除了本文三维问题裂纹尖端应力场的奇异性,文中还对裂纹尖端应力场的大小和分布等进行了研究。 相似文献
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F. J. Gallego J. J. Anza 《International journal for numerical methods in engineering》1989,28(6):1249-1264
The static elastic contact problem is approached using Lagrange multipliers, leading to a mixed finite element problem. A non-linear friction law is introduced explicitly and the non-local character of the friction phenomena is implicitly assumed. In order to avoid stress oscillations near singular points, a perturbed Lagrangian functional is considered. The algorithms herein proposed do not impose nodal dependencies over the contact surfaces, allowing for the independent discretization of both bodies. The method is able to model simultaneous contact over different regions of any geometrical shape. Computer code, examples and results presented here are restricted to axisymmetrical and bidimensional cases. 相似文献