Teaching Stress Transformation Through Laboratory Experiments

This paper describes a hands-on laboratory solid mechanics project which was supervised as an independent study. The experimental study and analysis were focused on strain and stress transformation on cantilever beam subjected to bending within elastic range. A combination of five different metals and two types strain rosette arrangements were used in the experimentation. The project involves the design and construction of test facility and experimental analysis of tested piece. The samples of measured data and analysis are reported in this paper. The strains in rectangular and principal coordinates which were computed from measured strains enabled the stress in both coordinates to be determined. This analysis enables the students to determine experimentally, that the sum of normal strain and stresses are invariant. The teaching strategy employed to integrate fundamental theories with hands-on experiences is described. The effectiveness of the laboratory project in enhancing student learning of stress-strain transformation and project management skill was demonstrated by monitoring student performance improvements over the duration of the project. The success of this project leads to an experiment for teaching students stress-strain transformation in mechanics of materials laboratory.