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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.
Nanofatigue Studies Of Ultrathin Hard Carbon Overcoats Used In Magnetic Storage Devices, Xiaodong Li, Bharat Bhushan
Nanofatigue Studies Of Ultrathin Hard Carbon Overcoats Used In Magnetic Storage Devices, Xiaodong Li, Bharat Bhushan
Faculty Publications
A technique to perform nanofatigue experiments was developed. This technique utilizes a depth-sensing nanoindenter with harmonic force. The nanofatigue behavior of 20 nm thick amorphous carbon coatings was studied. The contact stiffness was monitored continuously throughout the test. The abrupt decrease in the contact stiffness indicates fatigue damage has occurred. The critical load amplitude, below which no fatigue damage occurs, was identified. It was found that the filtered cathodic arc coating exhibits longer fatigue life than a direct ion beam coating. Failure mechanisms of the coatings during fatigue are also discussed in conjunction with the hardness,elastic modulus, and fracture toughness, …
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.