• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文会议>ASME(American Society of Mechanical Engineers) Turbo Expo vol.4; 20060506-11; Barcelona(ES) >NUMERICAL EVALUATION OF MODE I STRESS INTENSITY FACTOR AS A FUNCTION OF MATERIAL ORIENTATION FOR BX-265 FOAM INSULATION MATERIAL
【24h】

NUMERICAL EVALUATION OF MODE I STRESS INTENSITY FACTOR AS A FUNCTION OF MATERIAL ORIENTATION FOR BX-265 FOAM INSULATION MATERIAL

机译：基于BX-265泡沫绝缘材料材料定向功能的I型应力强度因子的数值评估

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Foam, a cellular material, is found all around us. Bone and cork are examples of biological cell materials. Many forms of man-made foam have found practical applications as insulating materials. NASA uses the BX-265 foam insulation material on the external tank (ET) for the Space Shuttle. This is a type of Spray-on Foam Insulation (SOFI), similar to the material used to insulate attics in residential construction. This foam material is a good insulator and is very lightweight, making it suitable for space applications. Breakup of segments of this foam insulation on the shuttle ET impacting the shuttle thermal protection tiles during liftoff is believed to have caused the space shuttle Columbia failure during re-entry. NASA engineers are very interested in understanding the processes that govern the breakup/fracture of this complex material from the shuttle ET. The foam is anisotropic in nature and the required stress and fracture mechanics analysis must include the effects of the direction dependence on material properties. Material testing at NASA MSFC has indicated that the foam can be modeled as a transversely isotropic material. As a first step toward understanding the fracture mechanics of this material, we present a general theoretical and numerical framework for computing stress intensity factors (SIFs), under mixed-mode loading conditions, taking into account the material anisotropy. We present mode I SIFs for middle tension - M(T) - test specimens, using 3D finite element stress analysis (ANSYS) and FRANC3D fracture analysis software, developed by the Cornell Fracture Group. Mode I SIF values are presented for a range of foam material orientations. Also, NASA has recorded the failure load for various M(T) specimens. For a linear analysis, the mode I SIF will scale with the far-field load. This allows us to numerically estimate the mode I fracture toughness for this material. The results represent a quantitative basis for evaluating the strength and fracture properties of anisotropic foam insulation material.
机译：泡沫，一种泡沫材料，遍布我们周围。骨头和软木塞是生物细胞材料的例子。已经发现许多形式的人造泡沫作为绝缘材料的实际应用。 NASA在航天飞机外舱（ET）上使用BX-265泡沫绝缘材料。这是一种喷涂泡沫绝缘（SOFI），类似于用于住宅建筑中阁楼绝缘的材料。这种泡沫材料是一种很好的绝缘体，非常轻巧，非常适合太空应用。据信，航天飞机ET上这种泡沫绝缘材料的破裂破坏了升空过程中对航天飞机隔热砖的影响，从而导致了哥伦比亚号航天飞机在再次进入时失灵。 NASA工程师对了解控制航天飞机ET复杂材料破裂/断裂的过程非常感兴趣。泡沫本质上是各向异性的，所需的应力和断裂力学分析必须包括方向依赖性对材料性能的影响。在NASA MSFC上进行的材料测试表明，可以将泡沫建模为横向各向同性的材料。作为了解这种材料的断裂力学的第一步，我们提出了一种在混合模式载荷条件下考虑材料各向异性的计算应力强度因子（SIF）的通用理论和数值框架。我们使用康奈尔断裂集团开发的3D有限元应力分析（ANSYS）和FRANC3D断裂分析软件，为中等拉伸强度（M）的试样提供了I型SIF。模式I的SIF值针对一系列泡沫材料的方向给出。此外，NASA记录了各种M（T）标本的破坏载荷。对于线性分析，模式I SIF将随远场负载缩放。这使我们能够从数字上估算这种材料的I型断裂韧性。结果代表了评估各向异性泡沫绝缘材料的强度和断裂性能的定量基础。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号