损伤对粘弹性矩形板非线性动力特性的影响

研究了考虑损伤效应的粘弹性矩形板在横向周期载荷作用下的非线性动力学问题．基于Von Karman方程、Boltzmann叠加原理和连续损伤力学理论,建立了以中面位移表示的考虑损伤效应的粘弹性薄板的非线性动力学方程,然后,应用有限差分法和Newmark法进行求解,并与相应的文献作出了比较．具体讨论了外载荷参数和板的几何尺寸对含损伤效应的粘弹性板非线性动力响应的影响．数值结果表明,考虑损伤效应时,结构的非线性动力响应会发生显著的变化．     

正交各向异性材料的混合硬化弹塑性本构方程

建立了混合硬化正交各向异性材料的屈服准则,进而推导了与之相关的塑性流动法则.根据简单应力状态的实验曲线,可得到广义等效应力-应变关系.初始屈服曲面与材料的弹性常数有关,材料退化为各向同性且只考虑各向同性硬化时,屈服函数退化为Huber-Mises屈服函数,相关的本构方程退化为Prandtl-Reuss方程.     

Delamination growth for composite laminated cylindrical shells under external pressure

The delamination growth may occur in delaminated cylindrical shells under external pressure.This will lead to failure of structure.By using the variational principle of moving boundary and considering the contact effect between delamination regions,in this work,the delamination growth was investigated for cylindrical shells under the action of external pressure.At the same time,according to the Griffith criterion,the formulas of energy release rate along the delamination front were obtained.In the numerical calculation,the delamination growth of axisymmetrical laminated cylindrical shells was analyzed,and the effects of delamination sizes and depths,the geometrical parameters, the material properties,and the laminate stacking sequences on delamination growth were discussed.     

考虑接触效应的具脱层轴对称层合圆板的非线性动力响应

基于von Karman板理论,利用三分区模型,建立了在面内压力和横向荷载联合作用下具脱层的轴对称正交层合圆板的非线性运动微分方程,其中,考虑了横向剪切效应和脱层接触效应.在此基础上,利用正交配点法进行了求解,并着重讨论了脱层之间的接触效应对结构非线性动力响应的影响.     

考虑损伤效应的开孔浅球壳的非线性动力响应与动力屈曲

研究损伤对开孔浅球壳非线性动力响应与动力屈曲的影响.基于Talreja张量内变量损伤模型,建立了纤维增强复合材料板壳弯曲问题的损伤本构关系,导出了考虑损伤效应的具轴对称变形正交各向异性开孔浅球壳的非线性运动控制方程.对未知函数在空间域采用正交点配置法离散,时间域采用Newm ark-β方法离散.数值结果表明,由于损伤导致结构刚度不断削弱,结构振幅增大而频率减小,结构的动力临界屈曲载荷降低.     

单轴转动截锥扁壳的全局分岔与混沌

考虑－受横向周期载荷作用下单轴转动的截锥扁壳，利用Melnikov方法讨论了该动力系统的同宿轨分岔，次谐分岔；并用数值方法进行模拟，研究该系统的混沌运动，从所得出的相平面图，时间历程图和庞加莱映射图业看，在一定参数组合下，该系统确实存在混沌运动。     

弹性地基上间断中厚矩形板的非线性静力分析

研究弹性地基上带传力杆的间断中厚矩形板的非线性静力特性。荷载在传力杆中的传递由竖向弹簧模拟,其弹簧刚度取决于传力杆的特性以及杆与板间的相互作用。根据能量变分原理,考虑地基耦合效应,建立了双参数地基上带传力杆的间断矩形中厚板的非线性静力控制方程。构造出一组满足所有边界条件的试探函数,应用伽辽金法对该组非线性方程进行求解。数值算例中,讨论了传力杆参数、板的结构参数及地基参数对弹性地基上间断矩形中厚板的非线性静力特性的影响。     

NONLINEAR VIBRATION FOR MODERATE THICKNESS RECTANGULAR CRACKED PLATES INCLUDING COUPLED EFFECT OF ELASTIC FOUNDATION

IntroductionThe moderate thickness plates on elastic foundation are a kind of important structure instructural engineering. The mechanic characters of the plates on elastic foundation withdifferent boundary conditions have been received considerable atten…     

Nonlinear free vibration analysis of piezoelastic laminated plates with interface damage

This paper presents a nonlinear model for piezoelastic laminated plates with damage effect of the intra-layers and inter-laminar interfaces. Discontinuity of displacement and electric potential on the interfaces are depicted by three shape functions. By using the Hamilton variation principle, the three-dimensional nonlinear dynamic equations of piezoelastic laminated plates with damage effect are derived. Then, by using the Galerkin method, a mathematical solution is presented. In the numerical studies, effects of various factors on the natural frequencies and nonlinear amplitude-frequency response of the simply-supported peizoelastic laminated plates with interfacial imperfections are discussed. These factors include different damage models, thickness of the piezoelectric layer, side-to-thickness ratio, and length-to-width ratio.     

湿热条件下具脱层压电层合梁的后屈曲及脱层扩展分析

考虑湿热条件、横向剪切变形、几何非线性和压电效应的影响,建立具脱层压电层合梁的本构关系和非线性平衡微分方程,采用有限差分法和迭代法对问题进行求解;在此基础上.应用Griffith准则,导出了脱层前缘处的能量释放率表达式,讨论了不同因素对压电层合梁后屈曲性能和脱层扩展的影响.