Search for: All records

This study presents the use of a 3D printing method to create kerf structures that can be formed into complex geometries. Kerfing is a subtractive manufacturing method to create flexible surfaces out of stiff planar materials such as metal or wood sheets by removing portions of the materials. The kerf structures are characterized by the kerf pattern, such as square interlocked Archimedean spiral and hexagon spiral domain, cell size, and cut density. By controlling the kerf pattern, spatial density, cell size, and material, the local properties of the structure can be controlled and optimized to achieve the desired local flexibility while minimizing the stresses developed in the kerf structure. Since subtractive manufacturing limits the patterns and materials that can be considered in kerf structures, FDM 3D printing is explored to fabricate kerf structures using polymers, such as Polylactic acid (PLA) and Thermoplastic polyurethane (TPU), where it is possible to vary microstructural topology and materials within the kerf structures. 3D printing enables the combination of the two different polymers and tuning printing factors to create multifunctional kerf structures. The multifunctional kerf structures can then be actuated using non-mechanical stimulations, such as thermal, to shape them into complex geometries. 

The aim of this paper is to describe a new MS Excel‐based approach for designing driveshafts for stiffness and fatigue strength. We analyze the efficacy of the approach in engaging students in an iterative design process and higher‐level qualitative decision‐making activities in an undergraduate class at Texas A&M University. Compared to conventional fixed cross‐section frames and trusses,there are few tools (barring Finite Element Packages) that facilitate rapid design evaluations of stepped shafts. The approach is based on a novel use of singularity functions to obtain explicit solutions for stepped shafts under concentrated loads.This approach allows for relatively easy implementation into Excel without the need for any numerical integration or other forms of approximation. Currently,the tedious calculations involved in the design of stepped shafts prevent instructors from exploring iterative changes in driveshaft design. The Excel tool that we have developed allows instructors and students to focus on iterative decision‐making. With this tool, open‐ended design questions are assigned even in exams since the entire iterative process takes less than 15–20 min. Student surveys and analysis of exam answers reveal that students have gained a considerable capability to make design decisions. They also indicate areas where improvement in design thinking is needed