Development of a Full-Field Digital Stress Gradient Sensor for Failure Characterization of Transparent Structural Materials

该奖项的研究目标是开发一种全场、非接触的光学技术，以量化由光学透明固体中的非均匀应力场引起的光线的角度偏转。该方法同时利用弹性光学效应和数字图像相关方法来提取透明固体中的正交应力梯度。利用可见光和近红外辐射验证了该方法在准静态和高应变率加载条件下研究固体破坏行为的可行性。这一新方法的成功开发将为实验固体力学提供一个强大的、补充的测量工具。光学透明性是许多工程应用中使用的固体的共同特征，包括电子显示器、汽车挡风玻璃、飞机车窗和舱盖、抗飓风车窗和头盔护目镜。该研究有助于了解此类材料在准静态和应力波加载条件下的破坏机理。在光学计量学和结构材料的机械特性的跨学科领域的本科生和研究生的教育和培训是这项研究不可或缺的。这项研究的结果将在一年一度的本科生和研究生招生活动中展示，以吸引K-12和代表性不足的学生进入工程学。调查结果还将纳入国际和平研究所教授的研究生课程，并通过档案期刊和会议出版物进行传播。

The research objective of this award is to develop a full-field, non-contact, optical technique to quantify angular deflections of light rays caused by non-uniform stress fields in optically transparent solids. The method exploits the elasto-optic effect in concurrence with the digital image correlation methodology to extract orthogonal stress gradients in transparent solids. The feasibility of the method to study failure behavior of solids under quasi-static and high strain rate loading conditions will be demonstrated using visible and near infrared radiation. The successful development of this new method will provide a powerful, complementary measurement tool for experimental solid mechanics. Optical transparency is a common characteristic of solids used in many engineering applications including electronic displays, automotive windshields, aircraft windows and canopies, hurricane resistant windows, and helmet visors. This research contributes towards understanding failure mechanics of such materials under quasi-static and stress wave loading conditions. Education and training of undergraduate and graduate students in interdisciplinary areas of optical metrology and mechanical characterization of structural materials is integral to this research. Findings from this research will be displayed during annual undergraduate and graduate recruitment events to attract K-12 and underrepresented students to engineering. The findings will also be integrated into graduate courses taught by the PI and disseminated through archival journals and conference publications.