Accelerated Testing of Durability of Composite Materials and Structures

复合材料和结构耐久性的加速测试

• 批准号: 9812758
• 负责人: Stephen Tsai
• 金额: $ 48万
• 依托单位: Stanford University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-10-01 至 2001-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9812758&HistoricalAwards=false
• 关键词: Accelerated; Testing; Durability; Composite; Materials

The main focus of the program will be upon polymeric composite materials. The program is comprehensive, ranging from basic research to technology applications for industry. The technical foundation of the work is that of the time- temperature superposition methodology for polymers. With this methodology, elevated temperature states can be used to accelerate time flow events. When properly viewed on logarithmic scales the acceleration effect is nothing less than dramatic. The method has been available and widely used for many years to characterize nondestructive properties such as relaxation functions. In vitally important work of very recent times, the method has been proven to apply to the time based irreversible properties controlling failure in polymeric based materials. This breakthrough work and approach will be carefully exploited through evaluation and expansion in the present program. The basic research component of this program will involve developing a theory of crack kinetics. Inherent flaws in bulk polymers and at interfaces progresses through growth stages under load, ultimately becoming of critical size to cause failure. This avenue will be explored in great detail, along with full statistical aspects of the problem. The work will be posed in the temperature dependent state in order to incorporate the time-temperature shift methodology. Common empirical formulations of damage accumulation, such as Miner's `law`, will be evaluated.

该计划的主要重点将是聚合物复合材料。该计划是全面的，从基础研究到工业技术应用。 这项工作的技术基础是聚合物的时间-温度叠加方法。通过这种方法，可以使用升高的温度状态来加速时间流事件。如果从对数尺度上正确地看，加速效应完全是戏剧性的。该方法已被广泛使用多年来表征非破坏性的性质，如松弛函数。在最近非常重要的工作中，该方法已被证明适用于基于时间的不可逆性能控制聚合物基材料的失效。这一突破性的工作和方法将通过评估和扩展在本计划中仔细利用。该计划的基础研究部分将涉及开发裂纹动力学理论。本体聚合物和界面处的固有缺陷在负载下通过生长阶段进展，最终成为导致失效的临界尺寸。我们将沿着对这一途径进行详细的探讨，并对这一问题进行全面的统计分析。工作将在温度依赖的状态，以纳入时间-温度变化的方法。将评价关于损害累积的常见经验公式，如迈纳“定律”。