Integrating Fracture Mechanics Into Undergraduate Design

Abstract

This paper describes the work that is under progress to develop instructional material and a computer program that will automate linear stress analysis in two-dimension. The computer program can be used in a variety of ways to educate students about the stress behavior near a variety of stress raisers, though the initial effort will be near cracks and other stress raisers in homogenous materials. By automation of stress analysis it is implied that the user will not need to know the methodology used in the computer program and will not need to know how to create the mesh needed to solve the problem. The user would only describe the boundary value problem, which will be facilitated by a user friendly interface and all analysis decision will be made inside the program. Development of e-handbooks on stress concentration factors and stress intensity factors will further reduce the demands on the user in describing the boundary value problems thus shifting the focus from analysis to use of analysis results in design.

Extreme Ductility in Freestanding Polystyrene Thin Films

“…The deformation typically initiated at the edges of the PTP gap and grew toward the center of the specimen (Figure a–c). This is probably due to a stress concentration present at the corner of the silicon where the thin film becomes freestanding . Annealing the films after placing them on the device exaggerated this artifact since the material would creep into the gap to form a kink where the film becomes unsupported, resulting in an even stronger stress singularity.…”