共查询到18条相似文献,搜索用时 156 毫秒
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应用微分几何理论,推导出纤维缠绕复合材料壳体的非测地线缠绕轨迹、包角方程及绕丝头运动方程,得到缠绕过程的动态仿真模拟数据。将封头处变化的缠绕角、厚度等实际工艺参数直接用于壳体结构的理论分析。采用叠层的增量本构关系,模拟层合板壳结构的损伤过程,建立了损伤后刚度衰减模型及刚度退化准则,并通过实验确定了刚度衰减系数。应用此模型对纤维缠绕复合材料压力容器进行了数值分析。结果表明:纤维缠绕复合材料压力容器封头处损伤会导致其弯曲刚度降低,这是影响轴向变形的重要因素。 相似文献
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线型设计是纤维增强树脂(FRP)复合材料缠绕壳体设计的一项重要研究内容,它对壳体FRP复合材料缠绕制品的质量起关键作用。本文针对不等开口极孔或不同形状封头的FRP复合材料压力容器壳体,基于非测地线缠绕方程,提出了一套非测地线缠绕线型设计方法,建立了根据已知缠绕线型和芯模转角来确定相应的切点数和纱片宽度的计算模型,开发出了一套FRP复合材料缠绕壳体仿真软件系统,对非测地线缠绕线型进行了计算机图像仿真与检验。结果表明:各个设计区间的仿真结果满足设计要求,没有出现缠绕角突变、纤维分布不规律和纤维在局部严重重叠等异常现象。该仿真软件系统可以为工程人员在实际壳体缠绕之前提供参考,缩短缠绕线型迭代试错周期,同时也为后续缠绕角及缠绕顺序等缠绕参数的优化奠定了基础。 相似文献
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在考虑剪切变形的Von Karman大变形小应变假设下,基于全Lagrange描述方法,将平面内带有旋转自由度的GSQ24壳体单元用于板壳结构的几何非线性分析,给出了板壳结构大变形下的小位移刚度矩阵、初应力刚度矩阵、初位移刚度矩阵有限元列式。同时,文中也给出了既考虑材料非线性,又考虑几何非线性的强非线性问题的板壳结构分析时的有限元列式。数值算例与变分法和级数解结果比较,表明本文方法的可行性。 相似文献
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纤维缠绕复合材料的纤维束具有交叉起伏形态特征,该形态对复合材料结构的力学行为有显著的影响。本文采用数值仿真和实验手段研究了纤维缠绕复合材料平板结构的拉伸力学行为。实验方面,开展纤维缠绕复合材料平板的准静态拉伸实验,通过数字图像相关技术(DIC)监测其表面应变场的演化过程,研究交叉起伏特征对载荷-位移曲线和应变分布特征的影响;数值分析方面,构建包含纤维缠绕形态的介观有限元模型,基于3D Hashin失效准则开展渐进损伤过程模拟,并引入了复合材料的剪切非线性行为。选取层合板结构为参照组,同时开展实验和数值分析。实验结果表明:对于层合结构,缠绕结构的整体刚度更低,失效位移更大,失效载荷基本相同,且缠绕结构菱形特征单元中部纤维交叉起伏区域存在明显的应变集中现象。所构建的有限元模型和实验结果吻合较好,呈现出纤维起伏区域的应变集中、失效起始和扩展行为。 相似文献
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复合材料纤维张力缠绕技术通过提高纤维的张力水平可充分发挥纤维高强、高模优势,在成型过程中对结构进行预紧,成为解决高速转动部件径向变形大、界面强度低等问题新的有效途径。将每一层纤维的张力缠绕等效为一个含预应力复合材料薄环的叠加,基于正交各向异性复合材料缠绕层和各向同性金属芯模弹性变形理论,建立了纤维张力缠绕力学解析模型,得到芯模和缠绕层预应力场随缠绕层数及缠绕张力的变化规律,并通过复合材料纤维张力工艺试验验证了力学解析模型的正确性。研究发现了纤维张力缠绕中预应力“饱和”现象,并确定了影响张力缠绕预应力场的两个主要参数:缠绕层环径向刚度比Eθ/Er和张力大小T(r),为复合材料纤维张力缠绕成型工艺提供理论支撑。 相似文献
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针对纤维缠绕复合材料结构中存在纤维束交叉起伏和铺层走向交替的特点,建立了一种分析缠绕图型对缠绕复合材料结构力学性能影响的有限元方法。采用ABAQUS有限元软件,分析了考虑纤维束交叉起伏和铺层走向交替后缠绕复合材料圆柱壳的应力、应变分布规律,并且研究了缠绕图型对缠绕圆柱壳屈曲临界载荷的影响。结果表明:采用层合板模型计算得到的圆柱壳的应力分布比较均匀;考虑纤维束交叉起伏和铺层走向交替后,缠绕复合材料圆柱壳的应力不再均匀分布,应力云图出现规则分布的菱形图案,在菱形区域中纤维交叉起伏和铺层走向交替处的应力有明显的波动。本实验有限元模型中的菱形特征单元可以反映缠绕复合材料纤维交叉起伏和铺层走向交替的实际情况。 相似文献
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Non-linear bending analysis of moderately thick laminated conical panels under various thermo-mechanical loadings and boundary conditions is presented using the generalized differential quadrature (GDQ) method together with the Newton–Raphson iterative scheme. The stiffness coefficients are assumed to be functions of the meridional and circumferential coordinates in panels for the realistic applications. In the first case of orthotropic open conical shell panels, the orientation of fibers are assumed to be in the meridional and circumferential directions. The stiffness coefficients of this type of fiber-reinforced panel are usually assumed to be constant. It is shown that due to the geometry of the conical surface, thickness of laminate will be changed along the meridional direction. The effect of stiffness variation on the non-linear response of panel is considered for the first time. In the second type, open conical shell panel can be made by cutting from a filament wound circular conical shell. In this case, thickness and ply orientation are functions of the shell coordinates. In this paper, different path definitions for variable stiffness filament wound shells are considered. The inclusion of this geometric complicating effect in large deformation analysis will add considerably to the complication and cost of a solution scheme. Paper presents some results to show when these assumptions have a significant effect on the end result. Assuming the effects of shear deformation and initial curvature, based on the first-order shear deformation theory (FSDT) and von Kármán-type of geometric non-linearity, the governing system of equations is obtained. Comparisons of the predictions with those available in the literature and finite element analyses show very good agreement. More results for panels with particular boundary conditions and thermo-mechanical load are presented for future references. For the sake of brevity, numerical results which presented in this paper are limited to deflection responses only. 相似文献
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采用细观刚度模型的有限元分析(FEA)与改进的逐渐累积损伤方法相结合,建立了缠绕复合材料圆管轴向拉伸失效的分析方法与流程,以揭示缠绕线型对缠绕复合材料损伤失效的影响。对沿圆周方向分布有1个、3个和5个单胞的3种不同线型的缠绕复合材料圆管试件进行轴向拉伸破坏实验,获得其失效形式、平均拉伸强度及其随缠绕线型的变化规律。研究表明:缠绕复合材料圆管轴向拉伸失效主要以丧失承载能力的功能失效为主,缠绕线型对其拉伸强度有一定的影响;数值分析结果表明,轴向拉伸过程中,主要损伤为基体开裂与基纤剪切,纤维交叉容易引起损伤起始与扩展。 相似文献
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针对缠绕复合材料交叉起伏区域的细观结构,建立了一种细观分析模型。首先,将纤维交叉起伏区域划分为环向交叉起伏区和螺旋交叉起伏区2种类型;然后,以缠绕面为基准,用平行横截面将起伏区域空间结构模型离散化为多个子模型,运用纤维束起伏角、富树脂区域尺寸、纤维束的体积分数、纤维束的横截面形状及尺寸等细观参数来描述缠绕复合材料交叉起伏区域的细观结构。基于所建立的细观模型及层合板理论,提出了缠绕复合材料交叉起伏区域的等效刚度计算方法。通过算例研究了纤维束截面、纤维束起伏角以及富树脂区体积分数等细观参数对局部区域等效刚度的影响。结果表明:环向交叉起伏区的弹性模量比螺旋交叉起伏区下降得更为明显;在富树脂区域,弹性模量和剪切模量降低较为明显,而泊松比则有所增大。纤维束厚度增加及纤维束截面变化对交叉起伏区域等效刚度会产生明显影响。 相似文献
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The creation of high-strength co-extruded polypropylene (PP) tapes allows the production of recyclable “all-polypropylene”
(all-PP) composite products, with a large temperature processing window and a high fibre volume fraction. Available technologies
for all-PP composites are mostly based on manufacturing processes such as thermoforming of pre-consolidated sheets. The objective
of this research is to assess the potential of filament winding as a manufacturing process for all-PP composites made directly
from co-extruded tapes or woven fabric. Filament wound pipes or rings were tested either by the split-disk method or a hydrostatic
pressure test in order to determine the hoop properties, while an optical strain mapping system was used to measure the deformation
of the pipe surfaces. 相似文献
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This paper presents a process model for simulating the manufacturing process of prepreg filament wound composite tubes developed
based on the finite element analysis. The model relates the process variables, such as degree of cure, viscosity, material
property and temperature etc., to the parameters characterizing (residual stresses, warpage deformation) the composite tube
and the mandrel. From the simulating results, several important trends in both the data and model are observed (1) Low temperature
will go with low reaction rate and the reaction starts under low temperature will later compared with high temperature; (2)
The results using CHILE model after demolding will smaller than the one using linear elasticity which assumes a stress-free
prior to cool-down. After the mandrel (mold) is removed, some residual stresses, especially hoop stress will be released.
(3) Remarkable stress concentration appeared in the transition zone between the boss and cylinder. In order to prevent the
structural failure due to interlaminar shear or delamination, both the outer surface of the cylinder and the inner of the
boss should have the same ply orientation angle. 相似文献
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提出并设计了一种新型纤维缠绕复合材料夹芯圆柱体吸能结构单元。为探讨其在准静态压缩载荷作用下初始损伤的产生、扩展及演变规律,基于ABAQUS建立该单元数值分析模型,并开展了准静态压缩试验。数值模拟与试验现象综合分析表明,准静态压缩载荷作用下单元结构的响应具有三阶段特征,包括初始线弹性压缩阶段、渐进损伤阶段和结构破坏阶段。固体浮力芯材在压缩载荷作用下产生塑性损伤变形和剪切断裂破坏,纤维缠绕复合材料表层在芯材横向膨胀效应引起的环向应力作用下发生环向纤维的拉伸断裂破坏,导致单元结构稳态吸能过程的终止。研究结果表明,该单元比吸能效率远高于传统的复合材料圆柱壳结构。 相似文献
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A new generation of composite pressure vessels for large scale market applications has been studied in this work. The vessels consist on a thermoplastic liner wrapped with a filament winding glass fibre reinforced polymer matrix structure. A high density polyethylene (HDPE) was selected as liner and a thermosetting resin used as matrix in the glass reinforced filament wound laminate. 相似文献