Accelerated Testing of Durability of Composite Materials and Structures

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-温度叠加法。通过这种方法，温度升高状态可以用来加速时间流事件。当在对数尺度上正确地观察时，加速效应丝毫不亚于戏剧性。多年来，该方法已被广泛用于表征松弛函数等非破坏性性质。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质控制聚合物基材料的失效。这一突破性的工作和方法将在本计划中通过评估和扩展加以仔细开发。该计划的基础研究部分将涉及发展裂纹动力学理论。本体聚合物和界面上的固有缺陷在载荷作用下经历增长阶段，最终成为导致失效的关键尺寸。将非常详细地探讨这一途径，以及该问题的全部统计方面。这项工作将在依赖温度的状态下提出，以便纳入时间-温度移位方法。我们将评估常见的损害累积经验公式，例如Miner的‘定律’。

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.