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The strength reduction of the composite structures due to damage and development of damage simulation method

复合材料结构损伤引起的强度降低及损伤模拟方法的发展

基本信息

批准号：
17560080
负责人：
SUEMASU Hiroshi
金额：
$ 2.37万
依托单位：
Sophia University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2007
项目状态：
已结题

项目摘要

Fiber reinforced composite materials and their structures are susceptible to miner damage, such as matrix cracks and delaminations, due to various causes such as foreign object impacts, inadequate process controls, etc. The structural performance is often reduced by the damage. The damage problem is still a serious issue for the damage tolerant design of composite structures how to consider the effect of the damage on the strength and various properties. By using damage analysis tools we worked to investigate damage appearance and growth and identify the rupture strength of the composite laminates and structures. In the numerical analysis we studied on the problem occurring during the damage analysis using the cohesive damage model and stiffness reduction model. We worked particularly on the following four themes.・On failure of pressure vessel from the initial matrix damage and the guideline of pressure vessel design・Impact damage and reduction of compressive strength・Failure from the … More stress concentration area under compression load・Oscillating stress singularity and fracture mechanism of adhesively bonded dissimilar materials interfaceWe could publish 7 journal papers and present the findings at more than 20 conferences. To show the damage accumulation process and to predict the failure strength, an efficient and stable analytical tool is essential. We introduced a cohesive element with added Gauss points where the failure is judged at every Gauss point. This element also enabled us not only to determine the damaged portions depending on the stress distribution but also to define the initial damage independently of the finite element mesh. This is similar function as the extended finite element method. We also conducted the Gauss point base failure analysis using a solid damage element to simulate the compression failure problem. In the analysis we tried to use explicit solution method to overcome unstable damage growth problem. The result showed quite similar damage pattern to the experimentally observed one. Less

纤维增强复合材料及其结构容易受到损伤，如基体裂纹和分层，由于各种原因，如异物的影响，过程控制不充分等，结构性能往往会降低损伤。如何考虑损伤对复合材料结构强度和各项性能的影响，仍然是复合材料结构损伤容限设计的一个重要问题。通过使用损伤分析工具，我们致力于研究损伤的外观和增长，并确定复合材料层合板和结构的断裂强度。在数值分析中，我们研究了在使用粘聚损伤模型和刚度折减模型进行损伤分析时出现的问题。我们特别关注以下四个主题。·从初始基体损伤看压力容器失效与压力容器设计准则·冲击损伤与抗压强度降低· ...更多信息压缩载荷下的应力集中区·异种材料界面的振荡应力奇异性和断裂机制我们可以发表7篇期刊论文，并在20多个会议上发表研究结果。为了显示损伤累积过程和预测失效强度，一个有效和稳定的分析工具是必不可少的。我们引入了一个附加高斯点的内聚单元，在每个高斯点处判断失效。该单元不仅可以根据应力分布确定损伤部位，而且可以独立于有限元网格确定初始损伤。这与扩展有限元法具有相似的功能。我们还进行了高斯点基地的破坏分析，使用固体损伤单元来模拟压缩破坏问题。在分析中，我们尝试使用显式求解方法来克服不稳定的损伤增长问题。结果表明，相当相似的破坏模式的实验观察之一。少