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Articles 1 - 6 of 6
Full-Text Articles in Mechanical Engineering
Rectangular Bursting Energy Absorber, John D. Reid, John R. Rohde, Dean L. Sicking
Rectangular Bursting Energy Absorber, John D. Reid, John R. Rohde, Dean L. Sicking
Department of Mechanical and Materials Engineering: Faculty Publications
A bursting energy absorber System having an impact head, and energy absorption mechanism. The energy absorbing mechanism has a generally rectangular mandrel for rupturing cooperating thin-walled generally rectangular tubes in a controlled rupture to absorb impact forces for a colliding vehicle. A frame may be used to mount the System to a truck, trailer, guardrail, median barrier end treatment, or a crash cushion. Stress concetrators such as saw cuts or scoring may be incorporated into the absorption tubes to selectively control rupturing and energy dissipation. The mandrels may be tapered, rectangulary shaped with beveled edges to reduce frictional forces along …
In Situ Corrosion Studies On The Battleship Uss Arizona, John D. Makinson, James D. Carr, Matthew A. Russell, David L. Conlin, Larry E. Murphy
In Situ Corrosion Studies On The Battleship Uss Arizona, John D. Makinson, James D. Carr, Matthew A. Russell, David L. Conlin, Larry E. Murphy
Department of Mechanical and Materials Engineering: Faculty Publications
U.S. National Park Service Submerged Resources Center archaeologists and University of Nebraska-Lincoln metallurgists are assessing hull corrosion by drilling through accumulated concretions and measuring pH and corrosion potentials. Concretion samples are being analyzed to determine the role of microbes in the corrosion process, identify chemical species, and measure electrical and physical properties. The lowest values of pH and E corr occur at the metal/concretion interface. Analysis suggests a variable corrosion rate supported by hydrogen discharge and/or oxygen reduction inside the concretion.
Design And Analysis For Melt Casting Metallic Fuel Pins Incorporating Volatile Actinides, Xiaolong Wu
Design And Analysis For Melt Casting Metallic Fuel Pins Incorporating Volatile Actinides, Xiaolong Wu
UNLV Theses, Dissertations, Professional Papers, and Capstones
Fundamental issues related to the selection of a metallic fuel casting furnace design are presented and discussed including heating mechanisms, casting issues, crucible design, and issues related to the mass transport of americium. The process of evaluating all of these different criteria is undertaken to select a concept that would have the greatest chance of success for casting americium in a metallic fuel rod. Based on this evaluation process, a concept for the casting of metallic fuel pins containing high vapor pressure materials is selected and discussed. The important physics of this concept include mass transport of americium from the …
Effects Of Shot-Peening On High Cycle Fretting Fatigue Behavior Of Ti-6al-4v, Halil I. Yuksel
Effects Of Shot-Peening On High Cycle Fretting Fatigue Behavior Of Ti-6al-4v, Halil I. Yuksel
Theses and Dissertations
Effects of Shot-peening on High Cycle Fretting Fatigue behavior of Ti-6Al-4V were investigated. Experiments were performed with 6.35 mm thick specimens which provided S/N curves. After the tests, it was observed that the specimens failed near the trailing edge of contact. Scanning Electron Microscopy showed that cracks initiated on the contact surface for 6.35 mm, and at the depth of specimen ranging from 200 to 300 microns for 3.81 mm thick specimens. Initial crack orientation was around 37 and 42 degrees respectively for 6.35 and 3.81 mm thicknesses. Finite Element Analysis (FEA) was conducted, and using FEA results, Smith-Watson-Topper, Findley, …
Examination Of Contact Width On Fretting Fatigue, Russell S. Magaziner
Examination Of Contact Width On Fretting Fatigue, Russell S. Magaziner
Theses and Dissertations
The primary goal of this study was to find the effects on the fretting fatigue life when systematically holding the fretting fatigue variables, peak contact pressure, maximum/minimum nominal bulk stress, and the ratio of shear traction to pressure force constant while varying the contact semi-width through changes in pad radius and normal load. Experimental tests were performed on a test setup capable of independent pad displacement. Analytical and finite element simulations of the different experimental tests were performed. The local mechanistic parameters were inspected. Five different critical plane based fatigue predictive parameters lacked effectiveness in predicting changes in life with …
Prediction Of Soakout Time Using Analytical Models, B. Chakravarthy, H. P. Cherukuri, R. G. Wilhelm
Prediction Of Soakout Time Using Analytical Models, B. Chakravarthy, H. P. Cherukuri, R. G. Wilhelm
Department of Mechanical and Materials Engineering: Faculty Publications
In precision manufacturing enterprises, machine parts at nonstandard temperatures are often soaked to standard temperature prior to making any dimensional measurements. The soakout times are usually determined using lumped heat-transfer models where the part temperatures are assumed to be uniform. This article discusses conditions under which lumped model assumptions are valid by comparing lumped analyses for various shapes and materials with the more general finite element results. In addition, the effect of ambient temperature cycling on part response is also studied.