粘性介质中的长壳在冲击载荷作用下的刚塑性动力响应

本文研究了粘性介质中的固支长圆柱壳受均布冲击侧压时的塑性动力响应,得到了解析解,并对此解进行了讨论。当介质阻尼参数β趋于零时,本文结果与无阻尼解一致。文中还画出了阻尼参数及壳体的长度参数对长壳运动时间的影响曲线。     

冲击载荷作用下阻尼介质中刚塑性圆板的动力响应

1.引言阻尼介质对结构塑性动力响应的影响属于流体与固体的耦合运动。在分析中往往将流体对固体的作用采用一个相当的阻力来代替。当流体为水时,这一阻力可表示为f=α(?)。其中,f为圆板单位面积上流体阻力;α为阻尼系数,它与流体介质密度及其波速有关;(?)为圆板横向速度。Kumar在1982年曾采用此方法得到了矩形载荷作用下简支圆板在阻尼介质中的动力响应完全解。但同样的结果早在1963年就由苏联学者     

阶梯形悬臂梁在脉冲载荷作用下塑性动力响应的完全解

本文采用双塑性铰模型,分析了阶梯形悬臂梁自由端受矩形脉冲载荷作用时的刚塑性动力响应,给出了整个响应过程封闭形式的完全解,讨论了一些主要参数对最终挠度的影响。     

冲击载荷作用下钢筋混凝土结构动力响应仿真

运用动态有限元技术对冲击性载荷作用下钢筋混凝土结构的动力响应进行细观结构的仿真分析，建立分离式材料模型，获得射弹在钢筋混凝土中的侵彻深度与弹坑半径，得出钢筋配筋率、配筋方式、配筋位置以及混凝土材料性质等相关因素的影响规律，并针对结果进行分析和讨论，为防护工程设计提供了参考依据。     

刚塑性矩形板在冲击载荷作用下的一个新的界限

通过加权残数法，给出了考虑有限变形时刚塑性板在冲击载荷下的能量守恒方程。广义屈服条件由Mij和Nij表示，通过将非光滑屈服函数用其内切和外接光滑函数代替，从而得到板位移的上、下界限解。采用此方法对一矩形板受横向冲击载荷进行了分析，计算结果与有关文献符合较好。     

端头带有质量块的悬臂梁在冲击载荷下的剪切失效

以飞射物撞击构件引起破坏为工程背景,研究端头带有质量块的悬臂梁受到冲击载荷作用后发生剪切失效的可能性。分析表明:在初始速度间断面上是否发生失效取决于无量纲初始动能和质量块尺寸与梁厚之比,而与梁的长度无关;质量块的转动惯量对于剪切失效具有不可忽略的影响。     

含切口悬臂梁的大变形塑性冲击动力响应

本文分析了含切口的悬臂梁受飞射物撞击的刚塑性动力响应的完全解,推导了考虑几何大变形效应的“双铰模式”的动力学方程,给出了计算方法和计算结果,最后讨论了耗散能的分配和切口对梁最终变形的影响。     

载荷作用区域对刚塑性简支梁动力响应的影响

本文研究了载荷作用区域大小对刚塑性简(固)支梁塑性动力响应的影响,得到了中、高载界限值的表达式,并对它进行了详细的讨论。文中还给出了中载和高载情况时各相的具体解答。     

端头带有质量块的悬臂梁在冲击载荷下的两种剪切失效模型

剪切失效是强动载荷作用下结构失效的重要模式。本文给出了计及梁的转动惯量时端头带有质量块的悬臂梁结构受到冲击载荷作用后发生剪切失效的无量纲判据。分析表明，在初始速度间断面上是否发生剪切失效取决于质量块初始动能和质量块尺寸与梁厚之比，而与梁的长度无关。梁的转动惯量对于剪切失效具有不可忽略的影响。     

ELASTIC EFFECT IN DYNAMIC RESPONSE OF PLASTIC CANTILEVER BEAMS TO IMPACT

A lumped masses-springs model is proposed to analyze the dynamicresponse of an elastic-plastic cantilever beam resulting from impact. The numericalresults are in good agreement with those by finite-element approaches. The simplifiedmodel can catch the most essential features of elastic-plastic response of beams; inparticular, it demonstrates the effect of elastic deformation on the distribution ofbending moment and energy dissipation, and provides valuable quatitative results.     

弹塑性悬臂梁结构动力响应中的弹性效应

本文提出由一组质量－弹簧构成的力学系统来研究弹塑性悬臂梁的动力响应问题，其数值结果与有限元解吻合得相当好，这种简化模型能够反映出梁动力响应中的本质特性，还特别显示出梁中弹性对弯矩分布和能量耗散的影响，提供了很有价值的计算结果．     

ANALYSIS OF THE LARGE DEFLECTION DYNAMIC RESPONSE OF RIGID-PLASTIC CIRCULAR PLATE RESTING ON FLUID

A study is presented for the large deflection dynamic response of rigid-plastic circular plate resting on potential fluid under a rectangular pressure pulse load.By virtue of Hankel integral transform technique,this interaction problem is reduced toa problem of dynamic plastic response of the plate in vacuum.The closed-formsolutions are derived for both middle and high pressure loads by solving the equationsof motion with the large deflection in the range where both bending moments andmembrane forces are important.Some numerical results are given.     

圆柱壳在侧向非对称冲击载荷下的塑性动力屈曲

采用塑性动力屈曲能量准则，对圆柱壳非均匀局部径向冲击下的塑性动力屈曲进行了研究。文中分别采用弹性的角弹簧和位移弹簧模拟非屈曲部分对屈曲部分的影响，推导了有关模态和临界速度的冲击公式，并与有关的实验结果进行了比较，分析了两种边界对塑性动力屈曲的影响。     

局部冲击作用下刚塑性平板的动力响应和失效模式

基于理想刚塑性的材料模型假定,同时考虑靶板弯曲塑性变形和剪切滑动,完整地分析了平板受刚性体撞击或受局部压力脉冲冲击的动力响应和失效模式。得到了撞击物侵彻深度、靶板穿透条件、塑性变形范围等特征变形破坏参数的解析表达式。讨论了撞击物速度、压力脉冲的冲量和形状等参量对响应和破坏模式的影响。比较了刚塑性理论分析结果与相关的实验和弹塑性数值计算结果。     

置于液体表面上的梁的塑性动力响应分析

本文讨论了置于液体表面上的梁在一般的非对称变形模式下的塑性动力响应问题。文中采用了复域内格林函数解法,将势函数的Herbert问题转化为对Cauchy型奇异积分方程的求解。并用此方法讨论了简支梁和悬臂梁的塑性动力响应问题。结果表明,这类问题的已有的解均为本文给出的一般变形模式下解的特例。     

ELASTIC-PLASTIC DYNAMIC RESPONSE OF A CANTILEVER BEAM SUBJECTED TO OBLIQUE IMPACT AT ITS TIP

By employing large deformation governing equations expressed in the form of finite difference, the dynamic responses of an elastic, perfectly plastic cantilever subjected to an oblique impact at its tip was numerically studied. Through analyzing the instantaneous distribution of the yield function （φ = ｜M/Mo｜ ＋ （N/No）^2）, bending moment and axial force during the early stage of the response, the elastic-plastic deformation mechanism and the influence of axial component of an oblique impact on the dynamic response of a cantilever beam were discussed. The present analysis shows that the deformation mechanism of an elastic-plastic cantilever subjected to an oblique impact consists of four phases, i.e. ‘the expanding compressed plastic region＇ mode; the ‘generalized traveling plastic hinge＇ and ‘shrinking plastic region＇ mixed mode; the ‘stationary plastic hinge＇ mode and ‘elastic vibration＇ mode. Compared with the two-phase deformation mode obtained by using the rigid, perfectly plastic approach, the mode of shrinking plastic region that occurred instantly after the oblique impact and the mode of stationary hinge were both confirmed. The primary features of the deformation mechanism are captured by both analysis methods. It has also been found that the beam＇s deformation is mainly controlled by the axial component of the oblique impact in the early phase of the dynamic response, the deformation mechanism is obviously different from the case of a transverse impact. With further development of the response, the axial component attenuates rapidly and gives negligible contribution to the yielding of the beam cross-section. At the same time, the bending moments along the cantilever develop gradually and dominate the beam＇s deformation. The numerical results indicate that the mass, impact speed and oblique angle are the important factors that influence the elastic-plastic dynamic response of a cantilever beam.