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Full-Text Articles in Mechanical Engineering

Fracture Toughness And Fatigue Crack Growth Rate Characterization Of Inconel 718 Formed By Laser Powder Bed Fusion, Charles C. Hohnbaum Mar 2019

Fracture Toughness And Fatigue Crack Growth Rate Characterization Of Inconel 718 Formed By Laser Powder Bed Fusion, Charles C. Hohnbaum

Theses and Dissertations

Continuing improvement in the field of AM of metals provides the opportunity for direct fabrication of aerospace parts. AM was once used in large part for rapid prototyping but improvements in technology and increases in the knowledge base of AM materials has provided the opportunity for manufacture of AM parts for operational use. The ability to create low numbers of unique parts without having to invest in expensive tooling provides great economic incentive to utilize this technique. IN718 is the most common high temperature alloy used in the aerospace industry and lends itself readily to formation by LPBF. The superior …


A Method To Develop Neck Injury Criteria To Aid Design And Test Of Escape Systems Incorporating Helmet Mounted Displays, Jeffrey C. Parr Sep 2014

A Method To Develop Neck Injury Criteria To Aid Design And Test Of Escape Systems Incorporating Helmet Mounted Displays, Jeffrey C. Parr

Theses and Dissertations

HMDs are becoming common human-machine interface equipment in manned military flight, but introducing this equipment into the overall aircraft escape system poses new and significant system design, development, and test concerns. Although HMDs add capabilities, which improve operator performance, the increased capability is often accompanied by increased head supported mass. The increased mass can amplify the risk of pilot neck injury during ejection when compared to lighter legacy helmets. Currently no adequate USAF neck injury criteria exist to effectively guide the requirements, design, and test of escape systems for pilots with HMDs. This research effort presents a novel method to …


Reaction Based Grasp Force Assignment, Mark W. Hunter Jul 1996

Reaction Based Grasp Force Assignment, Mark W. Hunter

Theses and Dissertations

An iterative method is developed by which the contact forces required to apply an arbitrary wrench (six elements of force and moment) to a stably grasped object may be calculated quickly. The assignment of contact forces, given a required object wrench, is accomplished with the use of fuzzy logic. This concept is referred to as the fuzzy logic reactive system (FLRS). The solution is versatile with respect to goals inherent in the rulebase and the input parameters, and is also applicable for an arbitrary number of contacts. The goal presented in this research, to illustrate the concept of the FLRS, …