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复合材料加筋板剪切屈曲特性研究 总被引:2,自引:0,他引:2
《机械强度》2013,(3):288-291
分别应用半经验工程算法和有限元软件MSC.Patran/Nastran对复合材料加筋板进行剪切稳定性计算,得到结构的失稳临界载荷;开展复合材料加筋板剪切稳定性试验,得到结构的屈曲形式、失稳载荷、破坏过程及破坏载荷。实验结果表明,复合材料加筋板的破坏形式主要表现为筋条的脱胶和蒙皮的破损,该型结构具有一定的后屈曲承载能力。研究表明,工程算法、有限元计算结果与试验所得局部屈曲载荷较吻合,说明工程算法和有限元模拟方法可以用来对该型结构的稳定性能进行分析,从而为该型结构的优化设计及工程应用提供分析参考。 相似文献
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铝合金搅拌摩擦焊接加筋板剪切稳定性能研究 总被引:1,自引:0,他引:1
对2024-T3铝合金搅拌摩擦焊接加筋壁板的剪切稳定性能进行试验研究,得到该结构的剪切失稳形式及屈曲载荷、承载能力及破坏形式。应用有限元法对该焊接加筋壁板结构进行简化建模,对该结构的稳定性和承载能力进行计算,将计算结果与试验结果进行比较。试验及有限元计算结果表明,结构的剪切失稳形式表现为筋条间平板的局部屈曲;屈曲后结构进入张力场受力状态,破坏形式主要表现为平板的塑性变形和边缘撕裂、筋条的弯扭变形以及焊接区的局部脱焊;出现脱焊现象的试验件其承载能力较未出现脱焊现象的试验件下降7.7%;线性和非线性屈曲计算所得屈曲载荷分别比试验平均值高出18.4%和26.2%,而非线性计算所得承载能力比试验平均值高出5.7%,焊接引起的初始缺陷对结构承载能力的影响小于对屈曲载荷的影响;有限元分析得到的结构屈曲形式和失效形式与试验现象吻合,验证了有限元模型的合理性,但其仍需要进一步改进以考虑初始缺陷来减小计算误差。 相似文献
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分别选取复合材料加筋板结构中三处典型位置进行落锤冲击损伤试验,产生穿透损伤,对损伤试件进行轴向压缩试验,得到屈曲失稳载荷及破坏载荷,并将试验结果与完好试件的试验结果进行对比,分析穿透损伤对结构压缩承载能力的影响。结果表明,筋条区蒙皮的冲击穿透损伤会使得结构的压缩局部屈曲载荷和压缩强度有较为明显的下降,而筋条间蒙皮和筋条凸缘处的穿透损伤对结构的压缩结果影响较小。另外,试验表明,含筋条凸缘穿透损伤的结构在压缩破坏过程中会出现较为明显的损伤扩展。试验结果可以为该型结构的工程应用提供有价值的参考。 相似文献
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《机械强度》2016,(4):875-880
应用非线性有限元方法对加筋板的压缩稳定性进行建模数值计算,通过定义加筋板有限元模型中四边节点的约束条件模拟压缩稳定性试验中承载端简支、固支边界条件以及常用的刀口支持、螺栓顶压、夹板夹持等侧边支持夹具,根据有限元计算结果分析承载端和侧边边界条件对加筋板压缩稳定性能的影响。计算结果表明,当承载端边界约束条件为固支时,结构的屈曲载荷与承载能力均比承载端简支时有一定的增加;当承载端简支时,结构的屈曲形式与破坏失效形式随侧边边界约束条件的不同而不同,相比于侧边自由的情况,侧边施加约束可以增加结构的屈曲载荷与承载能力;当承载端固支时,不同侧边边界约束条件下结构的屈曲形式与屈曲载荷基本相同,相比于侧边自由的情况,侧边施加约束可以增加结构的承载能力。 相似文献
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制备了CCF300碳纤维/BA9916-II环氧树脂复合材料加筋壁板,研究了该加筋壁板在干态和湿热状态下的压缩行为;建立加筋壁板有限元模型,使用经验公式对湿热环境下的材料参数进行修正,通过模拟分析了不同状态加筋壁板的压缩屈曲与后屈曲行为,并进行了试验验证。结果表明:加筋壁板在干态与吸湿状态下均有较强的后屈曲承载能力;湿热环境会对加筋壁板稳定性与承载能力造成较大负面影响,随吸湿时间延长,其屈曲及破坏载荷均呈先快后慢的下降趋势;模拟得到干态加筋壁板的屈曲载荷和破坏载荷与试验结果的相对误差分别为3.1%和5.2%,吸湿饱和态下的相对误差分别为5.6%和6.9%,误差较小,证明了所采用模拟方法的准确性和所建立有限元模型的合理性。 相似文献
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《机械科学与技术》2014,(12):1912-1915
工程结构的有限元数值分析往往采用粗网格模型,这导致压、剪或其联合载荷作用下的薄壁加筋结构初始屈曲临界载荷计算误差过大,而采用四边简支板的工程校核方法强化了实际约束效应,进一步加大了误差。为此,采用p-收敛的升阶谱元法,计算复合材料四边简支及弹性支承层合板的屈曲特征值;同时提取粗网格单元的实际应力状态,对复合材料薄壁加筋结构局域初始屈曲临界载荷进行了分析计算。结果表明:谱单元方法可很好的收敛于四边简支板的理论解,计算效率较高;局域薄壁加筋结构的谱单元方法可高效收敛于整体薄壁加筋结构的局部稳定性解,且能计及加强筋对复合材料层合板的弹性支承作用,更准确的模拟了加筋板的实际约束效应。 相似文献
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Most researches on the static performance of stiffened panel joined by friction stir welding(FSW) mainly focus on the compression stability rather than shear stability. To evaluate the potential of FSW as a replacement for traditional rivet fastening for stiffened panel assembly in aviation application, finite element method(FEM) is applied to compare compression and shear stability performances of FSW stiffened panels with stability performances of riveted stiffened panels. FEMs of 2024-T3 aluminum alloy FSW and riveted stiffened panels are developed and nonlinear static analysis method is applied to obtain buckling pattern, buckling load and load carrying capability of each panel model. The accuracy of each FEM of FSW stiffened panel is evaluated by stability experiment of FSW stiffened panel specimens with identical geometry and boundary condition and the accuracy of each FEM of riveted stiffened panel is evaluated by semi-empirical calculation formulas. It is found that FEMs without considering weld-induced initial imperfections notably overestimate the static strengths of FSW stiffened panels. FEM results show that, buckling patterns of both FSW and riveted compression stiffened panels represent local buckling of plate between stiffeners. The initial buckling waves of FSW stiffened panel emerge uniformly in each plate between stiffeners while those of riveted panel mainly emerge in the mid-plate. Buckling patterns of both FSW and riveted shear stiffened panels represent local buckling of plate close to the loading corner. FEM results indicate that, shear buckling of FSW stiffened panel is less sensitive to the initial imperfections than compression buckling. Load carrying capability of FSW stiffened panel is less sensitive to the initial imperfections than initial buckling. It can be concluded that buckling loads of FSW panels are a bit lower than those of riveted panels whereas carrying capabilities of FSW panels are almost equivalent to those of riveted panels with identical geometries. Finite elem 相似文献
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应用非线性有限元计算技术研究了加筋壁板结构试验件在受压状态下的非线性变形及稳定性特性,所得到的结果与试验吻合。为真实模拟机翼中的加筋壁板结构在空气动力作用下的稳定性问题,又针对典型机翼模型进行了更为细致的非线性屈曲分析。最后,将两次模拟结果进行比较,给出了根据结构的加载响应曲线判断结构的屈曲类型、结构的屈曲临界点以及分析结构后屈曲承载能力的方法。 相似文献
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A. Ghorbanpour Arani Sh. Maghamikia M. Mohammadimehr A. Arefmanesh 《Journal of Mechanical Science and Technology》2011,25(3):809-820
In this paper, the buckling analysis of laminated composite plates reinforced by single-walled carbon nanotubes (SWCNTs) is
carried out using an analytical approach as well as the finite element method. The developed model is based on the classical
laminated plate theory (CLPT) and the third-order shear deformation theory for moderately thick laminated plates. The critical
buckling loads for the symmetrical layup are determined for different support edges. The Mori-Tanaka method is employed to
calculate the effective elastic modulus of composites having aligned oriented straight nanotubes. The effect of the agglomeration
of the randomly oriented straight nanotubes on the critical buckling load is also analyzed. The results of analytical solution
are compared and verified with the FEM calculations The critical buckling loads obtained by the finite element and the analytical
methods for different layup and boundary conditions are in good agreement with each other. In this article, the effects of
the carbon nanotubes (CNTs) orientation angle, the edge conditions, and the aspect ratio on the critical buckling load are
also demonstrated using both the analytical and finite element methods. 相似文献
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A. K. L. Srivastava P. K. Datta A. H. Sheikh 《International Journal of Mechanical Sciences》2003,45(1):1299-93
The buckling and vibration characteristics of stiffened plates subjected to in-plane partial and concentrated edge loadings are studied using finite element method. The initial stresses are obtained considering the pre-buckling conditions. Buckling loads and vibration frequencies are determined for different plate aspect ratios, edge conditions and different partial non-uniform edge loading cases. The non-uniform loading may also be caused due to the supports on the edges. The analysis presented determines the stresses all over the region for different kinds of loading and edge conditions. In the structural modelling, the plate and the stiffeners are treated as separate elements where the compatibility between these two types of elements is maintained. The vibration characteristics are discussed and the results are compared with those available in the literature. Buckling results show that the stiffened plate is less susceptible to buckling for position of loading near the supported edges and near the position of stiffeners as well. 相似文献
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An efficient procedure to obtain the optimal stacking sequence and the minimum weight of stiffened laminated composite curved
panels under several loading conditions and stiffener layouts has been developed based on the finite element method and the
genetic algorithm that is powerful for the problem with integer variables. Often, designing composite laminates ends up with
a stacking sequence optimization that may be formulated as an integer programming problem. This procedure is applied for a
problem to find the stacking sequence having a maximum critical buckling load factor and the minimum weight. The object function
in this case is the weight of a stiffened laminated composite shell. Three different types of stiffener layouts with different
loading conditions are investigated to see how these parameters influence on the stacking sequence optimization of the panel
and the stiffeners. It is noticed from the results that the optimal stacking sequence and lay-up angles vary depending on
the types of loading and stiffener spacing. 相似文献
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以含穿透中央筋条的切口模拟离散源损伤,对无增强、Z-pin增强、改进锁式缝合增强、Tufting缝合增强复合材料加筋板进行轴向压缩试验,研究含离散源损伤Z向增强加筋板的损伤扩展模式与破坏特征。结果表明,壁板和筋条间的Z向增强有效控制了壁板与筋条的脱粘,提高了加筋板的屈曲载荷。切口前端的分层只引起局部的屈曲,沿切口方向未切断筋条的断裂和壁板边缘的突然压溃导致加筋板的最终破坏。三维有限元渐进损伤分析结果显示,选用Hashin判据作为失效判据,可以很好地模拟含离散源损伤复合材料加筋板的轴向压缩渐进损伤过程。采用线约束模拟壁板与筋条翼缘之间的Z向增强是合理的,线约束的引入在损伤扩展至筋条下方壁板区域后有效控制了损伤的扩展。 相似文献