共查询到17条相似文献,搜索用时 78 毫秒
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采用Reddy 的板高阶剪切变形简化理论研究了含分层损伤复合材料层合板的非线性动力稳定性问题。建立了分层模型, 推导了考虑几何非线性和阻尼效应的Methieu 方程, 给出了该方程的解析解表达式; 研究了参数振动解的稳定性; 然后通过典型数例讨论了分层损伤对层合板固有频率、屈曲临界力以及动力稳定区域的影响; 研究了保守与非保守体系的外载荷的激励频率对层合板第一参数振动的振幅的影响, 以及线性、非线性阻尼对非保守体系的最大牵引深度的影响。由典型算例讨论可知, 随着复合材料层合板分层损伤的扩大, 其动力稳定性能逐渐减弱, 特别是损伤接近层合板的中面时, 分层损伤对其动力稳定性能的影响最大。 相似文献
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本文利用von Karman 非线性薄板理论, 求解了复合材料中有横向纤维搭桥作用的圆形薄膜脱层的后屈曲问题, 获得了桥联脱层均匀扩展的能量释放率和断裂韧性。通过大量的计算和分析得到一个重要结论: 搭桥纤维的存在不仅对脱层的初始扩展起到了增韧作用, 而且避免了脱层扩展的灾难性。同时定量地给出了搭桥作用对脱层初始扩展的增韧程度, 并且确定了桥联脱层扩展稳定与不稳定的分区, 对不稳定脱层还给出了失稳扩展的范围及动态效应的估计。 相似文献
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复合材料层合矩形板非线性湿热振动 总被引:1,自引:1,他引:0
在考虑湿热影响的基础上,研究了复合材料层合矩形板的非线性湿热振动,并讨论分析了湿度、温度、长宽比对复合材料层合矩形板非经性固有振动周期的影响。 相似文献
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含脱层单向铺设层合梁非线性后屈曲分析 总被引:1,自引:0,他引:1
采用四分区模型,将含脱层单向铺设复合材料层合板梁分为4个子梁,根据复合材料层合理论,考虑后屈曲路径上位于脱层界面上、下子梁之间的局部受力与变形机制,建立了子梁之间接触力与变形之间的非线性定量关系。在此基础上,结合可伸长梁的几何非线性理论,推导出了计及接触效应的各子梁的非线性后屈曲控制方程。设定简支板梁的边界条件以及脱层前沿处各子梁之间力和位移的连续性条件,通过对控制方程和定解条件归一化,采用小参数摄动法求解,并根据梁的平衡微分方程的特点,解析其通解与特解的构造,获得了含脱层单向铺设层合梁受轴向压力作用的临界屈曲荷载及后屈曲平衡路径的理论解。通过对含脱层单向铺设的复合材料层合梁进行数值分析,综合讨论了脱层长度和深度等对层合板梁的临界屈曲载荷及接触性能的影响,并将所得的理论解与ABAQUS有限元分析得到的结果进行对比,结果表明二者高度吻合。研究发现梁的屈曲模态包含宏观的整体失效模态和界面的微观屈曲模态。梁的屈曲荷载和接触性能都是其固有属性,前者受梁的几何参数和材料参数的影响较显著,而后者则主要受脱层的位置和大小影响。 相似文献
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基于能综合考虑温度效应以及横向线应变和剪切应变的高阶计算模型 ,研究受热复合材料层合板的非线性热振动 ,推导了非线性有限元方程并给出了相应的数值分析方法 ,通过数值算例与已有文献相比较 ,证明了本文理论和算法的精确有效性。文中还以大量数值算例研究了温度效应对幅频曲线的影响。 相似文献
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A hyperbolic shear deformation theory is used for the free vibration analysis of generally layered composite beams with arbitrary boundary conditions. The variationally consistent governing differential equations and boundary conditions are derived by employing Hamilton's principle. The dynamic stiffness method is applied to calculate the vibration frequencies of the laminated beams with the help of Wittrick–Williams algorithm. Examples of application of the hyperbolic shear deformation theory for the free vibration analysis of the laminated beams with a couple of different boundary conditions are presented. The present results are compared to the numerical solutions and experimental results available in the literature. 相似文献
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Abstract: A fracture energy approach for modelling mixed-mode delamination of composite materials and other bonded structures is introduced. The model is incorporated within an explicit finite element (FE) code and ties layered shell elements together via a stiffness condition, a failure criterion and post-failure damage law. The procedure for predictive modelling of delamination using the approach is described and the set of required input parameters is presented. A benchmark test comparing experimental results for a continuous filament random E-glass/polyester composite and explicit FE simulations for standard fracture toughness tests for a range of mode mixities is included. 相似文献
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运用非线性振动的模态方法对非线性动力吸振器进行了动力学分析,研究了该类吸振器的反共振工作点、工作点的稳定性以及阻尼对反共振工作点的影响. 相似文献
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This paper presents some simulation results of nonlinear dynamic responses for a laminated composite beam embedded by actuators of the giant magnetostrictive material (Terfenol-D) subjected to external magnetic fields, where the giant magnetostrictive materials utilizing the realignment of magnetic moments in response to applied magnetic fields generate nonlinear strains and forces significantly larger than those generated by other smart materials. To utilize the full potential application of the materials in the function and safety designs, e.g., active control of vibrations, the analysis of dynamic responses is requested in the designs as accurately as possible on the basis of those inherent nonlineary constitutive relations among stain, force and applied magnetic field existed in the materials. Here, a numerical code for the nonlinear vibration of laminated beams is proposed on the basis of a nonlinearly coupling constitutive model which fully behaves for the characteristics what are measured in experiments. It is found from this code that the natural frequency of the laminated beams changes with both the bias magnetic field and the pre-stresses, and the dynamic responses excited by an alternating magnetic field of simple harmonic form display strong nonlinear characteristics, for example, the frequency multiplication and the ultraharmonic resonance phenomena. 相似文献
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