ON THE NONLINEAR STABILITY OF A TRUNCATED SHALLOW SPHERICAL SHELL UNDER A CONCENTRATED LOAD

In this paper, the axisymmetric nonlinear stability of a clamped truncated shallow spherical shell with a nondeformable rigid body at the center under a concentrated load is investigated by use of the modified iteration method. The analytic formulas of second approximation for determining the upper and lower critical buckling loads are obtained.     

波纹圆板的特征关系式

波纹圆板在精密仪器的灵敏弹性元件中起着很重要的作用。然而,这种弹性元件的理论研究至今还很不充分。造成这种状况的主要原因是波纹圆板本身形状复杂,参数很多,特别是大挠度非线性微分方程组在数学上求解极困难。以往的理论计算大致可分为两类。一类是采用壳体的大挠度方程来求解,如文献[1]用方法求得了浅正弦     

大跨度双层网壳的非线性动态响应

网壳结构在大跨度结构中得到广泛应用．在建立了双层网格扁球壳的非线性强迫振动微分方程的基础上,研究了在边缘滑动固定的边界条件下,双层网格扁球壳的非线性动态响应问题．用突变理论建立了该网壳的尖点突变模型,得出了突变的临界方程,并阐述了网壳参数对该结构动态屈曲的影响．     

均布载荷作用下带边缘大波纹膜片的非线性弯曲

采用轴对称旋转壳体的简化Reissner方程，研究了在均布载荷作用下具有硬中心的带边缘大波纹膜片的非线性弯曲问题．应用积分方程方法，获得了具有夹紧固定和滑动固定两种外边界的膜片的特征关系，即荷载-中心挠度曲线．作为算例，给出了夹紧固定膜片中的应力分布．     

Nonlinear Bending Theory of Diagonal Square Pyramid Reticulated Shallow Shells

ＩｎｔｒｏｄｕｃｔｉｏｎＤｏｕｂｌｅ＿ｄｅｃｋｒｅｔｉｃｕｌａｔｅｄｓｈｅｌｌｓａｓａｍａｉｎｆｏｒｍｏｆｌａｒｇｅｓｐａｃｅｓｔｒｕｃｔｕｒｅｓ,ａｒｅｗｉｄｅｌｙｕｓｅｄｉｎｃｉｖｉｌｅｎｇｉｎｅｅｒｉｎｇａｎｄｍａｎｙｏｔｈｅｒｆｉｅｌｄｓ[1,2 ].Ｏｎｅｏｆｔｈｅｍｉｓｔｈｅｄｉａｇｏｎａｌｓｑｕａｒｅｐｙｒａｍｉｄｒｅｔｉｃｕｌａｔｅｄｓｈａｌｌｏｗｓｈｅｌｌ.Ｔｈｅｓｈｅｌｌｃｏｎｓｉｓｔｓｏｆｒｅｖｅｒｓｅｓｑｕａｒｅｐｙｒａｍｉｄｓｗｈｏｓｅｖｅｒｔｅｘｅｓａｒｅｌｉｎｋｅｄｂｙｌｏ…     

FURTHER STUDY ON LARGE DEFLECTION OF CIRCULAR SANDWICH PLATES

In this paper.a nonlinear solution is first presented for a circular sandwich plate withthe flexure rigidity of the the face layers taken into accounl In solving the nonlinear bendingequations,a modified power series method is proposed.The uniformly distributed loadingand the clamped but sliding boundary condition are also assumed.Then our results arecompared with those from Liu Ren-huai and Shi-Yun-fang.The present solution can beused as a more accurate basis in engineering applications.     

Nonlinear Bending of Circular Sandwich Plates

In this paper,fundamental equations and boundary conditions of non-linear axisymmetrical bending theory for the circular sandwich plates with asoft core are derived by means of the method of calculus of variations.Especial-ly in the case of very thin faces,the preceding fundamental epuations andboundary conditions simplity considerably.For example,a circular sandwichplate with edge clamped but free to slip under the action of uniform lateralload is considered.A more accurate solution of this problem has been ob-tained by means of the modified iteration method.     

复合材料面层夹层扁壳非线性精化理论及应用

考虑面层横向剪切变形以及横向剪应力在面层和芯层粘结处连续,应用Hamilton原理建立了正交铺设复合材料面层夹层扁壳新的非线性精化理论。在静力问题情形,控制方程和边界条件化简为用四个基本未知函数表述。作为理论的应用,分析了简支边界条件下正交铺设复合材料面层夹层圆柱壳和夹层球壳的非线性弯曲,得到了其挠度响应和层间应力响应。     

一种考虑层间位移和横向剪应力连续条件的层合板理论

本文建立了一种新的层合板理论。该理论满足层间位移和横向剪应力连续条件以及上下表面横向剪应力协调条件，其控制方程仅包含五个未知量。数值算例表明该理论具有很高的精度。     

大跨机库桁架屋盖结构原型动力特性的实验研究

通过对跨度为(100+150m)的机库桁架屋盖结构的现场环境激励结构动力特性测试,利用谱分析方法对实测数据进行了分析,得出了结构的自振频率和振型.采用结构分析软件Midas建立屋盖的空间模型,采用特征向量法,得到了该结构的动力固有特性.有限元计算结果与动力试验结果在前3阶基本周期有相同的差异,各自所对应的振型吻合较好.结果表明环境激励下识别出该屋盖的低阶模态,可作为该机库的有限元模型修正和健康监测的基础.