Advancing the Techniques of Thermoleastic Fracture Mechanics of Composite Materials

推进复合材料热弹性断裂力学技术

• 批准号: 9713356
• 负责人: John Nairn
• 金额: $ 16.97万
• 依托单位: University of Utah
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-09-15 至 2001-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9713356&HistoricalAwards=false
• 关键词: Advancing; Techniques; Thermoleastic; Fracture; Mechanics

CMS 9713356 PI: John A. Nairn University of Utah New techniques for solving fracture problems in composites that treat the residual stresses commonly arising in composite materials by using thermoelastic fracture mechanics formulations are developed using a four-pronged approach: the derivation of new exact thermoelastic fracture analyses specific for composites; the development of approximate techniques including variational fracture mechanics, the analysis of observed finite fracture events, and experimental verification. The exact techniques provide new tools for analysis of composite fracture and are used in place of stress intensity factor techniques, which are powerful for isotropic and homogeneous materials, but are much less useful for composites. The approximate techniques are aimed at finding general tools for accurately determining the quantities appearing in the exact analyses. These techniques will be based on new variational theorems that will make it possible to derive useful upper and lower bounds for energy release rate. The term "finite fracture events" refers to the observation that composites often fail by a series of discrete fracture events (e.g., fiber fracture, ply cracking, or debonding) rather than by continuous crack growth. The present work develops fracture mechanics tools for dealing with such discrete fracture events. All analysis methods are verified by application to real and relevant failure processes in composite materials.

CMS 9713356 PI：John A.犹他州奈恩大学 解决复合材料断裂问题的新技术，处理通常出现的残余应力 复合 材料 通过 使用热弹性的 使用四管齐下的方法开发断裂力学公式：推导新的精确热弹性断裂分析 专用于复合材料;发展 近似 技术包括 变分 断裂力学，观察到的有限断裂事件的分析，和实验验证。 精确的技术提供了新的工具，用于分析复合材料的断裂，并用于代替应力强度因子技术，这是强大的各向同性和均匀的材料，但对复合材料的有用性要小得多。近似的技术是 旨在 在 查找通用工具， 精确地确定出现在精确分析中的量。 这些技术将基于新的变分定理，这将使人们有可能获得有用的能量释放率的上限和下限。 术语“有限断裂事件”是指观察到复合材料经常由于一系列离散的断裂事件而失效（例如， 纤维断裂、层板开裂或脱粘），而不是 裂纹不断增长。 目前的工作开发了断裂力学工具，用于处理这种离散的断裂事件。通过对复合材料真实的破坏过程的分析，验证了本文方法的正确性。