Physical Mechanisms Governing the Intersonic and Supersonic Decohesion of Bimaterials: Effects of Interfacial Strength, Loading Rate and Confining Pressure

控制双材料间声速和超声速消聚的物理机制：界面强度、加载速率和围压的影响

• 批准号: 9813100
• 负责人: Ares Rosakis
• 金额: $ 24.38万
• 依托单位: California Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-02-01 至 2002-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9813100&HistoricalAwards=false
• 关键词: Physical; Mechanisms; Governing; Intersonic; Supersonic

An analytical study will be conducted of the physical phenomena associated with highly dynamic decohesion of bimaterial interfaces and simple unidirectional composites. Specific goals of the project are to establish the necessary conditions for dynamic bimaterial decohension in various regimes (subsonic, intersonic, and supersonic) and to characterize the associated physical phenomena. To accomplish these goals, material combinations and processing techniques will be chosen that allow for the variation of interfacial strength, confining pressure and mismatch of mechanical properties (most importantly wave speeds) across the interface. In addition, loading configurations will be selected that can provide a range of impact velocities. Analytical studies will be undertaken to develop a theoretical framework by which the experimentally observed transient intersonic and supersonic shear dominated mechanical fields can be qualified in terms of appropriate fracture parameters. Thermal fields resulting from the observed large scale frictional contact and the associated energy dissipation will also be investigated. Experimental measurements of the deformation fields and thermal fields in the vicinity of a dynamically loaded or propagating interfacial crack will be performed in real time using ultra-high speed optical and thermographic diagnostic techniques. The deformation fields will be characterized using high speed photography in conjunction with two optical techniques: Coherent Gradient Sensing (CGS) and dynamic photoelasticity. Temperature fields near shear dominated intersonic and supersonic intrfacial cracks willb measured using a recently developed high speed infrared camera in order to study local mechanisms of energy dissipation.

将进行分析研究的物理现象与双材料界面和简单的单向复合材料的高动态脱粘。 该项目的具体目标是建立动态双材料消粘在各种制度（亚音速，intersonic和超音速）的必要条件，并表征相关的物理现象。为了实现这些目标，将选择允许界面强度、围压和整个界面的机械性能（最重要的是波速）不匹配的材料组合和处理技术。 此外，将选择能够提供一系列冲击速度的加载配置。 将进行分析研究，以开发一个理论框架，通过该框架，实验观察到的瞬态intersonic和超音速剪切为主的机械场可以在适当的断裂参数方面进行资格。 也将研究所观察到的大规模摩擦接触和相关的能量耗散产生的温度场。 在动态加载或扩展界面裂纹附近的变形场和温度场的实验测量将使用超高速光学和热成像诊断技术在真实的时间内进行。 变形场的特点是使用高速摄影结合两种光学技术：相干梯度传感（CGS）和动态光弹性。 为了研究局部能量耗散机制，将利用新近研制的高速红外摄像机测量以剪切为主的跨音速和超音速面内裂纹附近的温度场。