共查询到19条相似文献,搜索用时 71 毫秒
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为有效分析压电复合材料层合板在热、电和载荷下的单向耦合热电弹性问题,基于变分渐近方法(VAM)建立热电弹性简化模型。首先根据虚功原理推导三维压电复合板总势能泛函。然后基于变分渐近法,利用板固有的小参数将三维总势能泛函渐近扩展为系列二维泛函,同时将近似泛函转换为Reissner形式以便实际工程应用。最后建立三维场重构关系以正确预测沿厚度方向的应力分布。计算结果显示:基于该模型重构的沿厚度方向横向剪切应力较古典层合理论和一阶剪切变形理论精确度更好,与三维有限元精确解相一致,表明该模型在压电复合材料层合板应力预测上的有效性。 相似文献
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为有效分析非均质功能梯度板在载荷下的力学性能, 基于变分渐近方法(VAM)建立高保真简化模型。根据Hamilton扩展原则建立功能梯度板的三维能量方程;利用板固有小参数将三维能量渐近扩展为系列二维近似能量方程, 从而将三维各向异性弹性问题简化为沿板厚向的一维分析和二维板分析;提供重构关系以准确预测沿厚度方向的三维场分布。通过SiC-Al功能梯度板的柱形弯曲算例验证:基于该理论和模型重构的位移和应力分量与三维精确解相一致;在应变很小时, 可考虑任意大位移和全局旋转, 并可准确捕捉板所有的几何非线性。 相似文献
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基于变分渐近法建立具有周期性微结构的金属基复合材料(MMCs)细观力学模型及相应的增量方程,以准确预测其典型的热弹塑性行为和初始屈服面。利用细、宏观尺度比很小的特点,对单胞变分能量泛函变化进行渐近扩展,计算得到有效瞬时弹塑性刚度矩阵和热应力矩阵;利用迭代均质化及局域化技术模拟MMCs的非线性热弹塑性性能,并通过有限元技术实现相应的数值模型。算例分析表明:该模型能较好地预测MMCs的初始屈服面,并模拟热弹塑性耦合行为,研究成果为MMCs的进一步研究和实际应用提供了技术支撑。 相似文献
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为有效分析三维压电复合材料壳体结构非线性、 单向耦合压电弹性问题, 基于变分渐近方法(VAM)建立了壳体结构在机械和电场作用下的简化模型。推导了基于旋转张量分解概念的压电复合材料三维壳体能量表达式; 利用变分渐近法将三维壳体严格拆分为二维壳体线性分析和沿法线方向的一维非线性分析; 进行了降维后近似能量推导及Reissner-Mindlin形式转换; 提供了三维场重构关系以得到沿厚度方向的准确应力分布。通过对由4层压电复合材料构成的壳体柱形弯曲算例分析表明: 基于该理论和重构过程开发的变分渐近程序VAPAS重构生成的三维应力场精确性较一阶剪切变形理论和古典层合理论更好, 与三维有限元精确解相吻合, 表明该压电复合材料壳体模型的有效性。 相似文献
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A paper focuses on the use of the efficient approach to exact 3D elasticity solutions of cross-ply and angle-ply laminated composite plates. This approach is based on the new method of sampling surfaces (SaS) developed recently by the authors. We introduce inside the nth layer In not equally spaced SaS parallel to the midsurface of the plate and choose displacements of these surfaces as fundamental plate unknowns. Such an idea permits the representation of the proposed higher order layer-wise plate theory in a very compact form. This fact gives in turn the opportunity to derive the exact 3D solutions of elasticity for thick and thin laminated composite plates with a prescribed accuracy by utilizing a sufficiently large number of SaS, which are located at interfaces and Chebyshev polynomial nodes. 相似文献
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采用ABAQUS软件建立了圆锥头弹体正冲击复合材料层合板的有限元模型,并与已有文献结果进行对比验证了模型的可靠性,进而研究圆锥头弹体以不同的入射角度冲击复合材料层合板时初始速度与剩余速度的关系、复合材料层合板的破坏形态及弹体发生跳弹的规律。结果表明:弹体以90°入射角冲击复合材料层合板,在距离临界速度较大时,弹体的剩余速度与初始速度呈线性关系;不同的初始速度对复合材料层合板的损伤面积和破坏机制也不相同;弹体的入射角度越小、复合材料层合板越厚,越容易产生跳弹现象,并给出了入射角度和铺陈层数对跳弹现象的影响规律。该研究可为各种防护装备的设计和优化提供参考。 相似文献
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A super finite element method that exhibits coarse-mesh accuracy is used to predict the transient response of laminated composite plates and cylindrical shells subjected to non-penetrating impact by projectiles. The governing equations are based on the classical theories of thin laminated plates and shells taking into account the von Karman kinematics assumptions for moderately large deflections. A non-linear Hertzian-type contact law accounting for curvatures of the colliding bodies is adopted to calculate the impact force . The theoretical basis of the present finite element model is verified by analysing impact-loaded laminated composite plate and shell structures that have previously been studied through analytical or other numerical procedures. The predictive capability of the present numerical approach is successfully demonstrated through comparisons between experimentally-measured and computed force-time histories for impact of carbon fibre-reinforced plastic (CFRP) plates. The current computational model offers a relatively simple and efficient means of predicting the structural impact response of laminated composite plates and shells. 相似文献
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A V Krishna Murty 《Sadhana》1987,11(3-4):357-365
Formulation of appropriate governing equations, simpler than the three-dimensional equations of elasticity yet capable of
predicting, fairly accurately, all important response parameters such as stress and strain, is attempted in modelling a structural
component. Several theoretical models are available in the literature for the analyses of plates. The emergence of fibre-reinforced
plastics as an attractive form of structural construction, added a new complexity to the modelling considerations of laminates
by requiring the estimation of the interlaminar stresses and strains. In this paper, modelling considerations of laminated
composite plates are discussed. The classical laminated plate theory and higher-order shear deformation models are reviewed
to bring out their interlaminar stress predictive capabilities, and some new modelling possibilities are indicated.
This work has been supported by the Aeronautics Research and Development Board, Ministry of Defence, Government of India. 相似文献
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Adnan Golubović Ismet Demirdžić Samir Muzaferija 《International journal for numerical methods in engineering》2017,109(11):1607-1620
A numerical procedure for analysis of general laminated plates under transverse load is developed utilizing the Mindlin plate theory, the finite volume discretization, and a segregated solution algorithm. The force and moment balance equations with the laminate constitutive relations are written in the form of a generic transport equation. In order to obtain discrete counterparts of the governing equations, the plate is subdivided into N control volumes by a Cartesian numerical mesh. As a result, five sets of N linear equations with N unknowns are obtained and solved using the conjugate gradient method with preconditioning. For the method validation, a number of test cases are designed to cover thick and thin laminated plates with aspect ratio (width to thickness) from 4 to 100. Simply supported orthotropic, symmetric cross‐ply, and angle‐ply laminated plates under uniform and sinusoidal pressure loads are solved, and results are compared with available analytical solutions. The shear correction factor of 5/6 is utilized throughout the procedure, which is consistent with test cases used in the reviewed literature. Comparisons of the finite volume method results for maximum deflections at the center of the plate and the Navier solutions obtained for aspect ratios 10, 20, and 100 shows a very good agreement. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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Thermal buckling of cross-ply laminated composite and sandwich plates according to a global higher-order deformation theory 总被引:4,自引:0,他引:4
A two-dimensional global higher-order deformation theory is presented for thermal buckling of cross-ply laminated composite and sandwich plates. By using the method of power series expansion of continuous displacement components, a set of fundamental governing equations which can take into account the effects of both transverse shear and normal stresses is derived through the principle of virtual work. Several sets of truncated Mth-order approximate theories are applied to solve the eigenvalue problems of a simply supported multilayered plate. Modal transverse shear and normal stresses can be calculated by integrating the three-dimensional equations of equilibrium in the thickness direction, and satisfying the continuity conditions at the interface between layers and stress boundary conditions at the external surfaces. Numerical results are compared with those of the published three-dimensional layerwise theory in which both in-plane and normal displacements are assumed to be C0 continuous in the continuity conditions at the interface between layers. Effects of the difference of displacement continuity conditions between the three-dimensional layerwise theory and the global higher-order theory are clarified in thermal buckling problems of multilayered composite plates. 相似文献
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External variations in temperature and moisture are of primary importance for the long term behaviour of structures made of polymer matrix composites, because they induce residual stresses within laminated composite plates. It was shown (Hahn et al., 1978; Benkeddad et al., 1995, 1996; Tounsi et al., 2000, 2002, 2004; Adda-Bedia et al., 2001; Tounsi and Adda-Bedia, 2003a, b) that the heterogeneity and the anisotropy of such plates, have an influence on the distribution of transient hygroscopic stresses through the thickness of composite plates. The aim of the present paper is to present a simplified approach for the calculation of transient hygroscopic stresses within unidirectional laminates in the case where these latter are exposed to the cyclic and unsymmetric environmental conditions. Several examples are presented to assess such stresses and to demonstrate the efficiency of the used method. These stresses have to be taken into consideration for the design of composite structures submitted to a moist environment. 相似文献
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以层合板结构的临界屈曲载荷系数最大化为优化目标,基于改进型模拟退火算法对层合板结构铺设角度和铺层顺序进行优化。由于层合板结构的铺层角度是离散变量,模拟退火算法适合求解离散变量的优化问题。利用模拟退火算法优化层合板铺层,在算法内采用并行计算、引入记忆功能同时设置双阈值终止准则,有效地提高了优化过程的收敛速度,同时避免优化过程中出现局部最优解。以临界屈曲载荷系数作为目标函数,选取复合材料层合板的铺设角度顺序为设计变量,采用改进的模拟退火算法得出复合材料层合板的最优铺设角度以及铺层顺序。 相似文献