共查询到19条相似文献,搜索用时 125 毫秒
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爆炸载荷作用下加筋板的失效模式分析及结构优化设计 总被引:5,自引:0,他引:5
通过对爆炸载荷下具有1根加强筋的固支矩形加筋板的有限元模拟,探讨了抗爆加筋板结构优化设计方法,分析了加筋板的失效模式以及加强筋相对刚度和冲击载荷强度对加筋板失效模式的影响,指出了失效模式Ⅰ下的3种变形模态以及失效模式Ⅱ下的2种子失效模式,得到了失效模式Ⅰ下加强筋和加筋板最大挠度的近似计算公式,提出了单根加筋板的两种失效模式的判别条件,并对具有1根加强筋的固支矩形加筋板抗爆结构进行了优化设计。结果表明,通过数值模拟或模型实验可以求得任意加筋板结构由发生塑性大变形到发生破损的临界条件,从而确定抗爆性能最强时加筋板的质量与加强筋横截面尺寸及间距间的关系,实现对抗爆加筋板结构的优化设计。 相似文献
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弹性体的正则方程和加筋板的固有频率分析 总被引:8,自引:0,他引:8
应用弹性力学的Hamilton正则方程理论和其半解析法,为整体加筋板的固有频率分析提出了一种新颖的数学模型. 采用同一种平面元素离散板和加强筋,并分别建立板和加强筋的线性方程组. 考虑到板和加强筋连接界面上应力和位移的连续性,联立板和加强筋的方程得到全结构的方程组和求解固有频率的特征方程. 主要优越性表现为:结构的旋转惯性、剪切变形等都得到了考虑,且不限制结构的板厚度和加强筋的高度. 多个数值实例的收敛分析和结果证明了方法是可靠的. 该方法很容易被修改用来分析加筋壳、加筋压电材料层合板或带有压电材料传感器和驱动器块的板壳问题. 相似文献
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复合材料加筋板壳结构的后屈曲强度及破坏分析程序系统 总被引:2,自引:0,他引:2
本文介绍适用于复合材料(含各向同性材料)层合加筋板壳结构的后屈曲强度及破坏分析的程序系统的功能特点、原理和结构、通过一个受压剪载荷作用的加筋层合矩形板的破坏分析,并与试验结果作了比较,说明该程序系统的正确、可靠性。 相似文献
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基于近场动力学方法,综合分析了破片的速度、层合板的铺层方式、加筋板的筋条尺寸和破片相对筋条的冲击位置对结构损伤模式和破片剩余速度的影响。结果显示:高速破片冲击作用下,层合板会发生侵彻和穿透现象,层合板的损伤模式以基体损伤为主,且随着破片冲击速度的增大,板上下表面的损伤区域呈现出一种先增大后减小的趋势;高速破片冲击作用下,层合的板损伤扩展方向和纤维铺设方向有关,对于纤维铺层方向相同的层合板,其上下表面的损伤扩展方向一般与纤维方向相同;加筋板通过增加少量质量可以获得比层合板更好的抗破片冲击性能,且加筋板的筋条尺寸和破片相对筋条的冲击位置对加筋板的损伤具有明显影响。 相似文献
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加筋薄壁结构常被用于航空航天结构的轻量化设计.随着结构尺寸和几何特征的增加,需要更加精细的网格来满足分析精度的要求.传统的等几何方法采用NURBS张量积形式的拓扑结构,使得在分析过程中难以实现局部细化,而全局细化则会增加不必要的自由度.为了提升加筋板壳结构的数值分析精度和效率,提出一种基于RPHT (rational polynomial splines over hierarchical T-meshes)样条的加筋板壳自适应等几何屈曲分析方法.样条网格可以沿着加筋路径进行自适应的局部细化,有效提升低自由度下加筋板壳结构等几何屈曲分析的精度.首先,蒙皮和筋条分别采用RPHT样条曲面和NURBS样条曲线进行建模,几何建模与数值仿真采用统一的几何语言,实现建模与分析的一体化.其次,采用几何投影算法和样条插值算法实现筋条与蒙皮之间的高效高精度强耦合,并建立基于加筋路径驱动自适应网格细化方法.最后,曲线加筋板和网格加筋壳两个算例验证本方法的高效性和鲁棒性,通过与基于NURBS的等几何分析进行对比,本方法能够明显降低分析模型的总自由度. 相似文献
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加筋板在爆炸与冲击防护中应用广泛,而其动力响应的快速求解一直是工程中关注的重点。对于径向均匀加筋的圆板,基于刚度叠加思想,提出了一种将其等效为各向同性平板的方法,用于分析其在脉冲载荷下弹性阶段的动力响应。结合理论推导与数值方法,显式地给出了简洁的等效平板厚度公式。经验证,提出的等效方法建立了加筋圆板与均质圆板间的内在联系,适用于多种加筋尺寸、材料及载荷形式。等效圆板与加筋圆板的最大挠度偏差不超过6%,低阶振动频率偏差不超过10%。相比于直接对加筋圆板进行计算,等效分析方法大大提高了求解效率,且保证了很高的计算精度,在冲击响应预测和结构优化等工程应用中具有重要意义。 相似文献
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Gui-Lan Yu Yue-Sheng Wang Jian Lan 《Archive of Applied Mechanics (Ingenieur Archiv)》2010,80(6):687-697
Vibration localization in periodically stiffened double-leaf multi-span panels is studied by employing the transfer matrix
method. The localization factors of the ordered and disordered systems are calculated based on the Lyapunov exponent. The
numerical results show that the propagation of vibration in rib-stiffened periodic double-leaf panels exhibits passbands and
stopbands. The vibration localization phenomenon occurs and is enhanced with the increasing disorder of span-length. The torsional
rigidities of the stiffeners have a significant effect on the pass bands and the localization factor. With the torsional rigidity
of the stiffeners increasing, the vibration localization factor first decreases, then increases and finally tends to be the
situation of the rib-stiffened single-leaf panels. It is also noted that for the double-leaf panels a passband appears among
the lower dimensionless frequencies for some particular values of torsional rigidity of the stiffeners while a stopband always
exists for the single-leaf panels. 相似文献
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本文采用一种新的半解析法,即独特利用Heaviside函数建立与加筋板等效的变刚度模型来开展复合材料双向正交加筋板在横向载荷下的弯曲挠度分析.此模型可以准确地描述筋条在板面上的分布,以及由于筋条的存在而导致的板面刚度不均匀分布.使用Galerkin加权残值法求解该模型的控制方程,得到不同边界条件和载荷情况下的级数解.对于双向正交加筋板,将此半解析法的结果与传统均匀化方法和使用商业有限元软件ABAQUS建立的有限元模型所得到的弯曲挠度结果比较,验证了此方法的准确性和优越性.不同于传统均匀化方法,本双向正交加筋板的弯曲挠度半解析法可精确、有效地获取加筋间的局部弯曲挠度,可以促进复合材料结构的设计分析与优化的研究进展. 相似文献
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M. Bagheri A. A. Jafari M. Sadeghifar 《Archive of Applied Mechanics (Ingenieur Archiv)》2011,81(11):1639-1649
In this research, the general axial and radial buckling optimization of ring-stiffened cylindrical shells is implemented by
the genetic algorithm (GA). The stiffened shell is subjected to four constraints including the fundamental frequency, the
structural weight, the axial buckling load, and the radial buckling load. In addition, six design variables including shell
thickness, number of stiffeners, stiffeners width and height, stiffeners eccentricity distribution order, and stiffeners spacing
distribution order are considered. In analytical solution, the Ritz method is applied and stiffeners are treated as discrete
elements. The effect of the weighting coefficients of the objective functions on the optimum solution is studied. The results
show that optimized stiffening a cylindrical shell leads to a lower structural weight, higher natural frequencies, and larger
axial and radial buckling loads, simultaneously. In addition, the upper and lower bounds of the design variables influence
the optimum results considerably. It is also found that the distributions of eccentricity and spacing of the stiffeners influence
the magnitudes of the axial and radial buckling loads considerably. 相似文献
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E. Al-Shareedah 《基于设计的结构力学与机械力学》2013,41(4):493-505
ABSTRACT An alternative method to the orthotropic plate analogy for analysis of plates strengthened by longitudinal equidistant stiffeners is introduced and is shown to give accurate results, compared with the finite element method. The alternative method uses the concept of undetermined multipliers. Its capabilities in the study of plates strengthened by stiffeners is demonstrated, and design criteria are obtained. 相似文献
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《International Journal of Solids and Structures》2006,43(6):1357-1371
Based on the semi-analytical solution of the state-vector equation theory, a novel mathematical model for free vibration analysis of stiffened laminated plates is developed by separate consideration of plate and stiffeners. The method accounts for the compatibility of displacements and stresses on the interface between the plate and stiffeners, the transverse shear deformation, and naturally the rotary inertia of the plate and stiffeners. Meanwhile, there is no restriction on the thickness of plate and the height of stiffeners. To demonstrate the excellent predictive capability of the model, several examples are analyzed numerically. The model presented in this paper can also be easily modified to solve the problems of stiffened piezolaminated plates and shells, or plates and shells with piezoelectric material patches. 相似文献
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Chen Suhuan Yang Zhijun 《Acta Mechanica Solida Sinica》2005,18(4):365-373
The plate-shell structures with stiffeners are widely used in a broad range of engineering structures. This study presents the layout optimization of stiffeners. The minimum weight of stiffeners is taken as the objective function with the global stiffness constraint. In the layout optimization, the stiffeners should be placed at the locations with high strain energy/or stress. Conversely, elements of stiffeners with a small strain energy/or stress are considered to be used inefficiently and can be removed. Thus, to identify the element efficiency so that most inefficiently used elements of stiffeners can be removed, the element sensitivity of the strain energy of stiffeners is introduced, and a search criterion for locations of stiffeners is presented. The layout optimization approach is given for determining which elements of the stiffeners need to be kept or removed. In each iterative design, a high efficiency reanalysis approach is used to reduce the computational effort. The present approach is implemented for the layout optimization of stiffeners for a bunker loaded by the hydrostatic pressure. The numerical results show that the present approach is effective for dealing with layout optimization of stiffeners for plate-shell structures. 相似文献
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The nonlinear analysis with an analytical approach on dynamic torsional buckling of stiffened functionally graded thin toroidal shell segments is investigated. The shell is reinforced by inside stiffeners and surrounded by elastic foundations in a thermal environment and under a time-dependent torsional load. The governing equations are derived based on the Donnell shell theory with the von K′arm′an geometrical nonlinearity,the Stein and McE lman assumption, the smeared stiffeners technique, and the Galerkin method. A deflection function with three terms is chosen. The thermal parameters of the uniform temperature rise and nonlinear temperature conduction law are found in an explicit form. A closed-form expression for determining the static critical torsional load is obtained. A critical dynamic torsional load is found by the fourth-order Runge-Kutta method and the Budiansky-Roth criterion. The effects of stiffeners, foundations, material,and dimensional parameters on dynamic responses of shells are considered. 相似文献
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四边固定加劲板的非线性自由振动 总被引:1,自引:0,他引:1
针对工程中常用的加劲板, 研究了非线性振动的求解方法与振动特性. 将加劲板分为板与加劲肋两个部分考虑, 其中板视为考虑几何非线性的大挠度板, 加劲肋视为Euler梁. 假定加劲板的位移, 利用Lagrange方程结合系统能量和振型叠加推导了加劲板的动力平衡方程. 运用椭圆函数及摄动法计算加劲板非线性振动的单模态解, 多模态解则通过增量迭代法进行求解. 最后, 结合有限元软件ANSYS对一个四边固定且不可移动的加劲板进行分析, 讨论解的收敛性, 并分析两个方向设置不同数量加劲肋的情况下非线性自振频率与振幅的关系, 得到了一些加劲板非线性振动特性. 相似文献