investigation of Elasto-Plastic Interfacial Crack Tip Fields Using Infrared Interferometry

使用红外干涉测量法研究弹塑性界面裂纹尖端场

• 批准号: 9912066
• 负责人: Hareesh Tippur
• 金额: $ 18.15万
• 依托单位: Auburn University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-09-15 至 2004-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9912066&HistoricalAwards=false
• 关键词: investigation; Elasto; Plastic; Interfacial; Crack

The current understanding the influence of plasticity effects on the interfacial fracture has been modest despite of the practical significance in a wide range of dissimilar material systems including metal-ceramic, metal-metal and polymer-metal sandwiches. The work in this area has largely remained analytical/numerical in nature and experimental investigations are needed to further relate the local and global parameters and gain insight into the crack initiation and growth behaviors as in case of elastic counterparts. A detailed experimental study of the similarities of crack tip fields, mode-mixity, J-dominance, crack growth resistance, to name a few, would be valuable for modeling interfacial crack initiation and crack growth. To this end, an experimental effort on interfacial fracture behavior of bi-materials that are elastically similar but plastically dissimilar is proposed using a newly developed infrared interferometer. The research is aimed at gaining insight into the asymmetries introduced by plasticity near the interfacial crack tip in bimaterial specimens that are dissimilar in their plastic characteristics but identical elastically. The above effort will utilize an infrared Twyman-Green interferometer recently developed by the PI for investigating crack tip fields in full-field, real-time, non-contacting mode even in the presence of extensive plasticity and surface roughening. In this technique, the limitation of the surface roughness/texture encountered with the onset of plasticity/damage when using visible light has been circumvented through a favorable roughness to wavelength ratio. The method also offers advantages such as greater latitude in working with surfaces in 'as-is' condition and it does not need reference exposures.

尽管塑性效应在包括金属-陶瓷、金属-金属和聚合物-金属夹层结构在内的各种不同材料系统中具有实际意义，但目前对塑性效应对界面断裂的影响的理解是适度的。 该领域的工作在很大程度上仍然是分析/数值性质，需要进行实验研究来进一步关联局部和全局参数，并深入了解裂纹萌生和扩展行为，就像弹性对应物一样。 裂纹尖端场的相似性，模式混合，J-优势，裂纹扩展阻力，仅举几例，一个详细的实验研究，将是有价值的界面裂纹萌生和裂纹扩展建模。为此，提出了一种新开发的红外干涉仪的界面断裂行为的双材料，弹性相似，但塑性不同的实验努力。 该研究的目的是深入了解的不对称性引入的界面裂纹尖端附近的塑性在其塑性特性不同，但相同的弹性双材料试样。上述努力将利用PI最近开发的红外Twyman-Green干涉仪，用于调查裂纹尖端场的全场，实时，非接触模式，即使在存在广泛的塑性和表面粗糙化的情况下。在该技术中，通过有利的粗糙度与波长比，已经规避了当使用可见光时随着塑性/损伤的开始而遇到的表面粗糙度/纹理的限制。 该方法还提供了一些优点，例如在“原样”条件下处理表面时具有更大的自由度，并且不需要参考曝光。