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Mechanical Engineering Commons

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2011

Mechanical Engineering Faculty Works

Articles 1 - 10 of 10

Full-Text Articles in Mechanical Engineering

Innovative Manufacturing Process For Defect Free, Affordable, High Pressure, Thin Walled, Hydraulic Tubing, W. Miranda, G. Takiguchi, T. Shimabukuro, L. Mclennan, C. Agajanian, L. Quintero, D. Mismar, J. Abdulla, C. Andrews, M. Hahn, E. Fodran, E. W. Lee, H. Garmestani, R. D. Conner, D. Brick, J. Ogren, Omar S. Es-Said Oct 2011

Innovative Manufacturing Process For Defect Free, Affordable, High Pressure, Thin Walled, Hydraulic Tubing, W. Miranda, G. Takiguchi, T. Shimabukuro, L. Mclennan, C. Agajanian, L. Quintero, D. Mismar, J. Abdulla, C. Andrews, M. Hahn, E. Fodran, E. W. Lee, H. Garmestani, R. D. Conner, D. Brick, J. Ogren, Omar S. Es-Said

Mechanical Engineering Faculty Works

Various thermo-mechanical processes were performed on a standard and a low oxygen content Ti-6Al-4V alloy. Testing was performed to determine whether it was possible to achieve a combination of tensile properties comparable to those of Ti-3Al-2.5V by means of cold working and annealing Ti-6Al-4V from a thickness of 0.671 cm (0.264 in.) to that between 0.081 and 0.094 cm (0.032-0.037 in.), which had never been carried out before. The resulting mechanical properties of this study were compared to the mechanical properties of Ti-3Al-2.5V to determine whether Ti-6Al-4V could be used as a ...


On The Distortion And Warpage Of 7249 Aluminum Alloy After Quenching And Machining, N. Keleshian, R. Kyser, J. Rodriquez, C. Cueva, V. Vega, E. W. Lee, J. Ogren, Omar S. Es-Said Oct 2011

On The Distortion And Warpage Of 7249 Aluminum Alloy After Quenching And Machining, N. Keleshian, R. Kyser, J. Rodriquez, C. Cueva, V. Vega, E. W. Lee, J. Ogren, Omar S. Es-Said

Mechanical Engineering Faculty Works

The objective of this study is to determine the effect of solution treatment temperature, quenching media, and various machining sequences on the warpage behavior of aluminum 7249 alloy aged to T6 and T7' tempers. Large extrusions of 7249 aluminum alloy with fins were cut into 108 "T" sections. The samples were solution-treated, aged, and machined. Three solution temperatures (445, 474, and 505 A degrees C), two quenching media (water and 20% polyalkylene glycol), two aging treatments (T6 and T7'), and three machine sequences were used. The flatness of the samples was measured on the surfaces orthogonal to the z-axis. Three ...


Effect Of Stretch Orientation And Rolling Orientation On The Mechanical Properties Of 2195 Al-Cu-Li Alloy, Omar S. Es-Said, C. J. Parrish, C. A. Bradberry, J. Y. Hassoun, R. A. Parish, A. Nash, N. C. Smythe, K. N. Tran, T. Ruperto, E. W. Lee, D. Mitchell, C. Vinquist Oct 2011

Effect Of Stretch Orientation And Rolling Orientation On The Mechanical Properties Of 2195 Al-Cu-Li Alloy, Omar S. Es-Said, C. J. Parrish, C. A. Bradberry, J. Y. Hassoun, R. A. Parish, A. Nash, N. C. Smythe, K. N. Tran, T. Ruperto, E. W. Lee, D. Mitchell, C. Vinquist

Mechanical Engineering Faculty Works

Sheets of 2195 aluminum-lithium alloy were solution-treated at 507 A degrees C for 30 min. One set was stretched to 3-5% in the 0A degrees, 45A degrees, and 90A degrees angle with respect to the original rolling direction. Two other sets were rolled 6% reduction in thickness and 24% reduction in thickness in the 0A degrees, 45A degrees, and 90A degrees angle with respect to the original rolling direction. All specimens were aged at 143 A degrees C for 36 h. A second group of samples was rolled at 24 and 50% reduction in thickness after a solution treatment of ...


The Effect Of Layer Orientation On The Mechanical Properties And Microstructure Of A Polymer, V. Vega, J. Clements, T. Lam, A. Abad, B. Fritz, N. Ula, Omar S. Es-Said Aug 2011

The Effect Of Layer Orientation On The Mechanical Properties And Microstructure Of A Polymer, V. Vega, J. Clements, T. Lam, A. Abad, B. Fritz, N. Ula, Omar S. Es-Said

Mechanical Engineering Faculty Works

Rapid Prototyping (RP) is a method used everywhere from the entertainment industry to healthcare. Layer orientation is an important aspect of the final product. The objective of this research was to evaluate the effect of layer orientation on the mechanical strength and toughness of a polymer. The polymer used was a combination of two materials, ZP 130 and ZB 58, fused together in the Z Corporation Spectrum Z510 Rapid Prototyping Machine. ZP 130 is a powder composed of vinyl polymer (2-20%), sulfate salt (0-5%), and plaster that contains < 1% crystalline silica (50-95%). ZB 58 is a liquid composed of glycerol (1-10%), preservative (sorbic acid salt) (0-2%), surfactant (< 1%), pigment (< 1%), and water (85-95%). After removal from the machine the samples were sealed with Z bond 101 which is Beta-methoxyethyl cyanoacrylate (60-100%). The layer orientations studied were the crack arrestor, crack divider, and short transverse with various combinations of the three, for a total of seven orientations. The mechanical strength was evaluated using tensile testing and three-point bend testing. The toughness was evaluated by Izod impact testing. Five samples for tensile testing and three-point bend testing as well as 15 samples for the Izod impact test for each of the seven orientations were made. The total number of samples was 175. The crack arrestor orientation was the strongest main orientation for the tensile and three-point bend test. Weibull analysis was done on the Izod impact testing due to high variation in the results for the crack arrestor and short transverse directions. It was found that the layer orientation and surface roughness played a significant role in the penetration of the Z bond 101 coating and in the overall strength of the samples.


The Effects Of Retrogression And Reaging On Aluminum Alloy 2195, N. Ward, A. Tran, A. Abad, E. W. Lee, M. Hahn, E. Fordan, Omar S. Es-Said Aug 2011

The Effects Of Retrogression And Reaging On Aluminum Alloy 2195, N. Ward, A. Tran, A. Abad, E. W. Lee, M. Hahn, E. Fordan, Omar S. Es-Said

Mechanical Engineering Faculty Works

A retrogression and reaging (RRA) treatment was performed on 2195 Al-Li Alloy. The exposure times were from 5 to 60 min, and the temperatures were from 200 to 250 A degrees C. Samples that were exposed to a salt spray test had overall similar mechanical properties as compared to those that were not exposed. The percent elongation, however, was significantly deteriorated due to the salt spray exposure. The mechanical properties of the 2195 samples were compared to those of 2099 samples exposed to similar treatments in an earlier study.


The Effects Of Retrogression And Reaging On Aluminum Alloy 2099 (C458), N. Ward, A. Tran, A. Abad, E. W. Lee, M. Hahn, E. Fordan, Omar S. Es-Said Aug 2011

The Effects Of Retrogression And Reaging On Aluminum Alloy 2099 (C458), N. Ward, A. Tran, A. Abad, E. W. Lee, M. Hahn, E. Fordan, Omar S. Es-Said

Mechanical Engineering Faculty Works

The objective of this study was to investigate the feasibility of performing retrogression and reaging (RRA) heat treatments on 2099 aluminum-lithium alloy. The retrogression temperatures were 200-250 A degrees C and retrogression times were 5-60 min. Half of the samples were exposed to a salt fog environment. Interestingly, the samples exposed to salt spray had consistently higher mechanical tensile properties than those which were not exposed.


Analysis Of Heat Effects On Marine Corps Am2 Mat Mechanical Properties, V. Vega, U. N. Huynh, J. Holmes, J. Dechellis, P. Stoyanov, D. Piatkowski, E. W. Lee, J. Ogren, N. Drusina, Omar S. Es-Said Mar 2011

Analysis Of Heat Effects On Marine Corps Am2 Mat Mechanical Properties, V. Vega, U. N. Huynh, J. Holmes, J. Dechellis, P. Stoyanov, D. Piatkowski, E. W. Lee, J. Ogren, N. Drusina, Omar S. Es-Said

Mechanical Engineering Faculty Works

Navy AM2 mats are used as portable aircraft landing platforms for the Short Take-off/Vertical Landing (STOVL) aircraft operations. This investigation presents the study performed to determine whether the surface discoloration is a precursor to degradation in the mechanical property of the AM2 mat material. The red discoloration on the mat surfaces had a clear correlation with the decrease in yield strength, ultimate strength, and hardness properties.


Tensile Properties And Microstructures Of Laser-Formed Ti-6al-4v, J. Alcisto, A. Enriquez, H. Garcia, S. Hinkson, T. Steelman, E. Silverman, P. Valdovino, H. Gigerenzer, J. Foyos, J. Ogren, J. Dorey, K. Karg, T. Mcdonald, Omar S. Es-Said Mar 2011

Tensile Properties And Microstructures Of Laser-Formed Ti-6al-4v, J. Alcisto, A. Enriquez, H. Garcia, S. Hinkson, T. Steelman, E. Silverman, P. Valdovino, H. Gigerenzer, J. Foyos, J. Ogren, J. Dorey, K. Karg, T. Mcdonald, Omar S. Es-Said

Mechanical Engineering Faculty Works

The room temperature tensile properties of Ti-6Al-4V alloy prepared under two different processing routes were evaluated and compared. One group of samples was prepared by conventional casting-forging-rolling into flat plates. The other group was prepared by using Triton's Laser Free-Form Fabrication (LF3)(TM) processes, i.e., a laser was used to melt pre-alloyed powders of the required metallic composition as they were dropped onto a moveable substrate programmed to move in such a manner as to form a solid alloy plate. Five populations of Ti-6Al-4V were evaluated: a standard wrought form, an as-deposited form, a machined as-deposited form, a ...


Nanofluid Optical Property Characterization: Towards Efficient Direct Absorption Solar Collectors, R. A. Taylor, P. E. Phelan, Todd Otanicar, R. Adrian, R. Prasher Jan 2011

Nanofluid Optical Property Characterization: Towards Efficient Direct Absorption Solar Collectors, R. A. Taylor, P. E. Phelan, Todd Otanicar, R. Adrian, R. Prasher

Mechanical Engineering Faculty Works

Suspensions of nanoparticles (i.e., particles with diameters < 100 nm) in liquids, termed nanofluids, show remarkable thermal and optical property changes from the base liquid at low particle loadings. Recent studies also indicate that selected nanofluids may improve the efficiency of direct absorption solar thermal collectors. To determine the effectiveness of nanofluids in solar applications, their ability to convert light energy to thermal energy must be known. That is, their absorption of the solar spectrum must be established. Accordingly, this study compares model predictions to spectroscopic measurements of extinction coefficients over wavelengths that are important for solar energy (0.25 to 2.5 mu m). A simple addition of the base fluid and nanoparticle extinction coefficients is applied as an approximation of the effective nanofluid extinction coefficient. Comparisons with measured extinction coefficients reveal that the approximation works well with water-based nanofluids containing graphite nanoparticles but less well with metallic nanoparticles and/or oil-based fluids. For the materials used in this study, over 95% of incoming sunlight can be absorbed (in a nanofluid thickness >= 10 cm) with extremely low nanoparticle volume fractions - less than 1 x 10(-5), or 10 parts per million. Thus, nanofluids could be used to absorb sunlight with a negligible amount of viscosity and/or density (read: pumping power) increase.


Applicability Of Nanofluids In High Flux Solar Collectors, R. A. Taylor, P. E. Phelan, Todd Otanicar, C. A. Walker, M. Nguyen, S. Trimble, R. Prasher Jan 2011

Applicability Of Nanofluids In High Flux Solar Collectors, R. A. Taylor, P. E. Phelan, Todd Otanicar, C. A. Walker, M. Nguyen, S. Trimble, R. Prasher

Mechanical Engineering Faculty Works

Concentrated solar energy has become the input for an increasing number of experimental and commercial thermal systems over the past 10-15 years [M. Thirugnanasambandam et al., Renewable Sustainable Energy Rev. 14 (2010)]. Recent papers have indicated that the addition of nanoparticles to conventional working fluids (i.e., nanofluids) can improve heat transfer and solar collection [H. Tyagi et al., J. Sol. Energy Eng. 131, 4 (2009); P. E. Phelan et al., Annu. Rev. Heat Transfer 14 (2005)]. This work indicates that power tower solar collectors could benefit from the potential efficiency improvements that arise from using a nanofluid working fluid ...