Student Understanding Of Normal And Shear Stress And Deformations In Axially Loaded Members

Knowledge necessary for engineering design and innovation refers to more than the ability to search for an equation that suits the situation, but the ability to understand, apply, and transfer information to new situations. Conceptual understanding describes this type of understanding. Performance on physics and engineering concept inventories in topics such as thermodynamics, statistics, and fluid mechanics indicates that students do not have understanding of fundamental engineering and physics concepts. Results from these concept inventories are useful for gauging performance and stirring interest and concern, but lack detailed information on student thinking about engineering concepts. The goal of this project is to investigate student conceptual understanding of normal and shear stress in an axially loaded member using clinical demonstration interviews. Student interviews were conducted where students completed researcher designed conceptual problems and discussed their lines of reasoning as they completed the problems. Students generally were consistent and correct in their understanding of normal stress and strain in the direction of the applied load, but displayed incorrect answers and logic relating to normal stress and strain perpendicular to the load, and shear strain and stress. Results are consistent with those from other studies in science and engineering, in that misconceptions exist and students do not have strong understandings of even fundamental concepts.