THE NONLINEAR NUMERICAL ANALYSIS METHOD FOR FRAMES

This paper gives the direct formulas of stiffness matrixes of two kinds of Kirchhoffnonlinear elements under total-Lagrange coordinate.For the first one,it includes not onlythe quadric terms of increments of strain and displacement but also.the influence ofrotations.For the second one,it is simplifies and its nonlinear is considered by taking intoaccount the influence of axial force on the equilibrium epuation in the linear beam.theory.The nonlinear equation obtained from both of the above-said elements is solved bymixed Newton-Raphson method,and by comparing the results obtained from two kinds ofnonlinear beam some important conclusions that we can know how to use them right aregiven in our paper.     

STRESS CONCENTRATION AND STRESS INTENSITY FACTORS FOP AN INFINITE PLANE WITH SEVERAL ROWS OF ELLIPTIC HOLES AND CRACKS

This paper deals with the stress concentration in plane withswveral arbitrarily distributed elliptic holes.By using thefunctions of complex variables,the stress functions in whichthe interactions of neighbouring holes are taken into considera-tion can be constructed.By applying the conformed mappingmethod to satisfy the boundary conditions of each hole,the go-verning equations can then be transformed into a set of simul-taneous equations through boundary integrals.Moreover,theproblems with crack can be derived by changing the ellipticalrates of the ellipses.thereby an approximate solution of crack-ing problem may be obtained.Some computing examples are given in the paper.     

一般杆系结构的非线性数值分析

本文在total-Lagrange坐标系下,对Kirchhoff梁给出了考虑几何非线性的两种梁单元刚度的显式表达式.一种是一般的非线性梁元,它既考虑了应变增量和位移增量间的二次项,又计及了刚体位移的影响,另一种是简化的非线性梁元,它只在线性梁的平衡方程中直接加入了轴力对弯曲的影响.非线性方程采用混合法求解,文中通过一些算例的数值计算,对两种单元作了比较详细的分析和评估.     

Stress concentration and stress intensity factors fop an infinite plane with several rows of elliptic holes and cracks

This paper deals with the stress concentration in plane with swveral arbitrarily distributed elliptic holes. By using the functions of complex variables, the stress functions in which the interactions of neighbouring holes are taken into consideration can be constructed. By applying the conformed mapping method to satisfy the boundary conditions of each hole, the governing equations can then be transformed into a set of simultaneous equations through boundary integrals. Moreover, the problems with crack can be derived by changing the elliptical rates of the ellipses, thereby an approximate solution of cracking problem may be obtained. Some computing examples are given in the paper.     

组合加肋旋转壳的强度和稳定性有限元分析

本文对轴对称加肋旋转壳及其组合壳体(锥-锥,锥-柱,球-柱壳等)在轴对称静载荷作用下的线弹性强度和稳定性计算,采用性能良好的轴对称拟协调单元推导了有限元的计算列式,并将计算结果与静水压力下的锥-柱-锥结合壳,加肋锥-柱结合壳的其它计算结果和实验结果进行比较。     

无限大板包含任意排列多个椭圆孔洞的应力集中和多裂纹的应力强度因子计算

对于无限平面上任意排列的多个椭圆孔的应力集中,采用复变函数方法,直接构造能够反映各孔相互影响的应力函数,通过依次映射方法来满足各孔的边界条件,再利用围线积分方法化为线性代数方程求解.对于裂纹情况,将裂纹化为相应的椭圆,通过应力集中系数近似求得应力强度因子值.文中给出若干计算结果.