【作者】 崔昭霞；

【导师】 李庆芬；

【作者基本信息】 哈尔滨工程大学 ， 固体力学， 2003， 博士

【摘要】 随着复合材料在各个领域的广泛应用，作为××××发动机燃烧室的纤维缠绕复合材料壳体在航天领域中越来越受到人们的重视。本文以某发动机技术研究院的“纤维缠绕××××发动机壳体的应力变形及损伤研究”项目为研究背景。由设计方案A研制的××××发动机壳体称为A壳体。为满足弹头质量增加的需要，在设计方案A的基础上研制了B壳体，但B壳体在试验中发生了低压爆破。针对××××发动机B壳体发生低压爆破的问题，应用复合理论、网格理论和非线性有限元法对B壳体进行了宏观应力应变分析，从而确定了B壳体低压爆破的原因是由于损伤所致。在此基础上，深入地研究了壳体损伤发生概率最大、而危害又相当明显的典型损伤类型——基体开裂和分层损伤，分别采用能量法和剪切滞后方法建立基体开裂和分层损伤的模型，对损伤的机理和损伤对壳体性能的影响进行了深入的研究。 首先，采用网格理论、复合理论和非线性有限元方法对××××发动机壳体的应力和变形情况进行分析与计算。在非线性有限元建模过程中，对壳体缠绕角度和厚度进行了修正，针对××××发动机这样的大型结构，首次采用一种四边形复合材料单元，实现了能够在单元内部沿厚度方向进行离散化，使得在划分单元总数较少的情况下，计算结果比较精确。通过对网格理论、复合理论和非线性有限元方法计算结果与试验值之间的相互比较，可以看出：非线性有限元计算结果介于网格理论和复合理论之间，且有限元计算结果与复合理论结果更加接近，表明在水检压力下壳体筒段确实存在着基体开裂等损伤。在最大压力为水检压力的作用下，应用有限元计算出壳体的整体变形以及不同部位的各种应力(不同应力分量)和位移分量，与试验结果均比较吻合，证明采用大变形方法分析壳体宏观应力和变形是合理的，A壳体与B壳体的应力、变形情况基本相同，B壳体发生低压爆破不是由于结构参数的调整造成，而是由于各种试验导致的累积损伤造成的。哈尔滨工程大学博士学位论文 其次，采用能量法建立了纤维缠绕壳体筒段同时受到均匀内压和轴向拉伸载荷作用时的表面分层损伤临界分层屈曲分析模型，探讨了壳体筒段表面分层损伤屈曲扩展的机理。研究结果表明:壳体筒段受轴向拉伸和内压载荷作用时，轴向和环向载荷的比率不同，母层和子层可能发生拉伸屈曲，也可能发生收缩屈曲，或者同时发生拉伸和压缩屈曲;母层与子层各向异性存在差异，即泊松比与剪切模量不匹配时，将使子层板的边界上承受压缩和剪切作用，当分层达到临界状态则发生屈曲，当母层与子层的各向异性差异越大，则发生分层屈曲的可能性越大;分层损伤的屈曲应变值与子层自身的弹性模量、分层子层的形状、厚度以及圆柱半径等因素有关。 第三，研究了在应力较高时横向开裂裂纹的裂尖引发的分层损伤现象。建立了包含分层损伤的完全抛物线分析模型，依此模型计算材料的宏观刚度性能，并与没有考虑分层损伤的不完全抛物线模型和完全抛物线模型进行了比较。结果表明，在应力较高的情况下，考虑了分层的完全抛物线模型与试验结果符合程度最好。更多还原

【Abstract】 The filament-wound case (FWC) plays a more and more important role in the solid rocket motor chamber structure (SRMCS) with composite material widely used in spaceflight fields. The work of this thesis is under the engineering background of project -Study on distortion and damage of filament-wound SRMCS. Case A we called here is a type of SRMCS based on designing method A. Case B was redesigned based on Case A in order to meet the needs of enhancive warhead mass, but it burst under low pressure. In order to find out the reason of bursting under low pressure, macro stress and strain of SRMCS were analyzed by using compound theory, netting theory and nonlinear finite element method (FEM). It was concluded that the damages of the SRMCS led to the bursting of Case B under low pressure. Then it was necessary to study the matrix crack and delamination damages in detail, which occurred with the maximum probability and played the most important role on FWC failure. Two models about damage analysis were established by using energy method and shear lag method. The mechanism of damage and the effect to structure performance caused by damage are studied further.First, three kinds of analytical methods including netting theory, compound theory and nonlinear FEM were performed to obtain the stresses and deformations of SRMCS. Based upon the facts that parameters were unequal in thickness and winding angle along the meridional direction, some fitting formulations were proposed in the FEM model. This FEM model could also represent geometrical nonlinear behavior by considering large displacements. A kind of quadrilateral composite element was firstly used in large structures such as SRMCS, in which at least five layers can be contained in one element along thickness direction, thusthe calculation results will be more precise although divided the structure into less elements. By way of comparing the results obtained from netting theory, compound theory, nonlinear FEM and experimental test, the conclusion could be drawn that matrix crack damage surely existed in the cylinder part of structure. When the structure was subject to internal pressure up to 6.8MPa, which was the maximum loading of hydrostatic test, the deformation of the global structure and stress and strain distributed in any parts of structure were obtained. A fairly good agreement was obtained between the analysis and the test results. And it was proved that it is reasonable to analyze the FWC using nonlinear FEM. The results of case A and case B were about the same, thus it was displayed that modifying structure did not cause the bursting under low pressure but the damages of the structure.Second, an analytical model was developed to assess the critical buckling problem of near surface interlaminar rectangular defects in the cylindrical part of SRMCS under axis and interior pressure loads. The relationships between critical strain value and the parameters of geometry and radius of cylindrical were discussed. With the different loading ratio of parallel to axis and normal to axis direction, damage defects will occur bulking problem. By varying the degree of material anisotropy relative to the loading axis such as Poisson’s ratio and shear modulus, crack growth bulking strain value parallel to or normal to the loading axis is different. The parameters controlling the growth or arrest of the delamination damage are identified as the geometry and the depth of defects and radius of cylindrical etc.At last, it was investigated that the delamination damage is often induced by the tip of matrix damage under higher stress. A complete parabolic shear-lag analysis containing delamination damage induced by transverse cracks wasproposed and applied to predict the global properties of materials. The predictions from the complete parabolic shear-lag analysis without containing the delamination, incomplete parabolic shear-lag model and the complete parabolic shear-lag analysis proposed in this paper have been compared. The results show the complete parabolic sh更多还原