Photoelasticity and Its Synergism with Finite Element Method

本计画的目标是透过将光弹性应力分析的实验纳入现有的课程，以提升机械工程教育。 光弹性是一种直观的、全场的技术，用于确定零件和结构中的应力。 除了在工业上的传统应用外，人们对利用光弹性来测试立体光刻制作的物体又产生了新的兴趣。 所有机械（以及较小程度的土木）工程专业的学生都可以从这个项目中受益。 在四门课程中引入了六个新的实验：材料力学，机械设计，仪器和实验方法，以及有限元法。 具体的教学目标是通过光弹性可视化增加对应力分布的概念性理解;获得光弹性及其优点/局限性的经验;并欣赏应力分析的实验和数值方法之间的协同作用。 对于计划的实验，需要一个透射偏振镜组、一个反射偏振镜组、附带附件和一个视频捕获设备。 该设备还可用于课堂演示，高级设计项目的测试，以及对K12学生的激励演示。 虽然有机构支助，但不足以购置这些精密光学仪器。 总的来说，学生的经验，在解决工程问题，必须选择适当的分析工具，并认识到，往往必须利用几个工具来验证结果，例如，通过实验手段验证数值解。

The goal of this project is to enhance mechanical engineering education by incorporating experiments in photoelastic stress analysis within the existing curriculum. Photoelasticity is a visual, full-field technique for determining stresses in parts and structures. In addition to its traditional use in industry, there is a renewed interest in using photoelasticity to test objects made by stereolithography. All mechanical (and to a lesser degree civil) engineering students can benefit from this project. Six new experiments are introduced in four courses: Mechanics of Materials, Machine Design, Instrumentation and Experimental Methods, and the Finite Element Method. Specific instructional objectives are to increase conceptual understanding of stress distribution through photoelastic visualization; gain experience with photoelasticity and its advantages/limitations; and appreciate the synergism between experimental and numerical methods of stress analysis. For the planned experiments, one transmission polariscope set, one reflection polariscope set, accompanying accessories, and a video capture device are needed. The equipment can also be used for in-class demonstrations, testing of senior design projects, and motivational presentations to K 12 students. Institutional support exists but is insufficient for the acquisition of these precision optical instruments. Overall, students experience that, in solving engineering problems, one has to choose the appropriate tool of analysis and recognize that quite often several tools must be utilized to validate the results, e.g., validation of numerical solutions by experimental means.