Leveraging Cost-Effective Custom Tensile Testing Apparatus for Improved Understanding of Stress and Strain Principles

We propose an innovative approach using affordable and easy-to-assemble test kits to enhance hands-on learning experiences in materials and manufacturing education. The paper addresses the common challenge faced by mechanical engineering departments in obtaining expensive lab equipment. By developing significantly cheaper yet effective test kits, our aim is to provide students with practical experience in experimental methodology, assembly, and problem-solving with the equipment. Our solution showcases the design of safe, easy-to-assemble, and reliable test kits that could be used in multiple experiments. These kits are orders of magnitude cheaper than standard equipment, costing only two to three hundred dollars compared to tens of thousands. While they may lack extra high accuracy, they still excel in achieving desired student learning outcomes. These kits rely on easy-to-make, open-source codes, and/or inexpensive off-the-shelf components. We developed and tested two kits through two design iterations: a personal universal testing machine and a personal foundry. Each kit allows students to run 2–3 experiments, providing them with the opportunity to experience assembly and full system integration for force, energy, mass, and information flows. Student surveys were conducted to understand their self-reported response to the effectiveness of these kits in achieving learning goals. More than 60% of students consistently reported that the kit gave them command over experimental methodology, assembly of pieces, resolution of issues with the test equipment, and conducting experiments with just a manual. While initially challenging for some students, overcoming these hurdles improved their understanding of experimental methodology and tension testing equipment design. This contrasts with conventional lab experiments where students often follow set protocols without needing to understand equipment workings. The hands-on nature of the kits not only increased student engagement but also fostered a sense of ownership and investment in the learning process. Some students expressed a desire to test their own designed items, indicating deeper engagement and interest. Overall, the findings suggest that the test kits offer a unique set of learning opportunities by providing students with an unguided build, study, and report challenge.