Open Access. Powered by Scholars. Published by Universities.®

Engineering Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 18 of 18

Full-Text Articles in Engineering

The Fracture Behavior Of An Al–Mg–Si Alloy During Cyclic Fatigue, Diya Azzam, Craig Menzemer, Tirumalai Srivatsan Oct 2015

The Fracture Behavior Of An Al–Mg–Si Alloy During Cyclic Fatigue, Diya Azzam, Craig Menzemer, Tirumalai Srivatsan

Craig Menzemer

In this paper, is presented and discussed the cyclic fracture behavior of the Al–Mg–Si alloy 6063 that is a candidate used in luminaire light poles. The light poles were subject to fatigue deformation. Test sections were taken from the failed region of the light pole and carefully examined in a scanning electron microscope with the objective of rationalizing the macroscopic fracture mode and intrinsic micromechanisms governing fracture under cyclic loading. The fatigue fracture surface of the alloy revealed distinct regions of early microscopic crack growth, stable crack growth and unstable crack growth and overload. An array of fine striations was …


A Study To Evaluate And Understand The Response Of Aluminum Alloy 2026 Subjected To Tensile Deformation, Daniel Lam, Craig Menzemer, Tirumalai Srivatsan Oct 2015

A Study To Evaluate And Understand The Response Of Aluminum Alloy 2026 Subjected To Tensile Deformation, Daniel Lam, Craig Menzemer, Tirumalai Srivatsan

Craig Menzemer

The strain concentration factors were determined for aluminum alloy 2026 in the T3511 temper using multi-hole structural coupon specimens. Samples of the alloy were evaluated for both the 6.25 mm (0.25 in.) thick and 10 mm (0.4 in.) thick specimens and having widths of 50 mm (2 in.) and 100 mm (4 in.), respectively. For the case of the specimens that were 50 mm in width the mechanical tests were conducted for both the open hole and filled hole conditions and the corresponding strain concentration value was determined. Threaded fasteners having collars were used for the case of the filled …


Mechanisms Governing Fatigue, Damage, And Fracture Of Commercially Pure Titanium For Viable Aerospace Applications, Udaykar Bathini, Tirumalai Srivatsan, Anil Patnaik, Craig Menzemer Oct 2015

Mechanisms Governing Fatigue, Damage, And Fracture Of Commercially Pure Titanium For Viable Aerospace Applications, Udaykar Bathini, Tirumalai Srivatsan, Anil Patnaik, Craig Menzemer

Craig Menzemer

In this paper, the cyclic stress amplitude controlled high-cycle fatigue properties and final fracture behavior of commercially pure titanium (Grade 2) are presented and discussed. The material characterization was developed and put forth for selection and use in a spectrum of applications spanning the industries of aerospace, defense, chemical, marine, and commercial products. Test specimens were prepared from the as-received plate stock of the material with the stress axis both parallel (longitudinal) and perpendicular (transverse) to the rolling direction of the plate. The test specimens were cyclically deformed at a constant load ratio of 0.1, at different values of maximum …


Investigating And Understanding The Fatigue Response And Failure Of Built-Up Welded Beams Of A Titanium Alloy, Anil Patnaik, Narendra Poondla, Udaykar Bathini, Tirumalai Srivatsan, T. Quick Aug 2015

Investigating And Understanding The Fatigue Response And Failure Of Built-Up Welded Beams Of A Titanium Alloy, Anil Patnaik, Narendra Poondla, Udaykar Bathini, Tirumalai Srivatsan, T. Quick

Anil Patnaik

No abstract provided.


A Study Of The Microstructure And Hardness Of Two Titanium Alloys: Commercially Pure And Ti–6al–4v, Narendra Poondla, Tirumalai Srivatsan, Anil Patnaik, M. Petraroli Aug 2015

A Study Of The Microstructure And Hardness Of Two Titanium Alloys: Commercially Pure And Ti–6al–4v, Narendra Poondla, Tirumalai Srivatsan, Anil Patnaik, M. Petraroli

Anil Patnaik

In this paper, the microstructure and hardness of two titanium alloys was determined and the results are presented and briefly discussed. Samples of the alloy for microstructural examination were prepared from the as-provided stock using standard metallographic procedures and then examined in a low magnification light optical microscope. Both microhardness and macrohardness measurements were made across the polished surfaces of the two titanium materials. Both the microhardness and macrohardness of the Ti–6Al–4V alloy was noticeably higher than the commercially pure counterpart. The intrinsic influence of alloy composition and secondary processing, i.e., annealing, on microstructural development is presented and hardness of …


Mechanisms Governing Fatigue, Damage, And Fracture Of Commercially Pure Titanium For Viable Aerospace Applications, Udaykar Bathini, Tirumalai Srivatsan, Anil Patnaik, Craig Menzemer Aug 2015

Mechanisms Governing Fatigue, Damage, And Fracture Of Commercially Pure Titanium For Viable Aerospace Applications, Udaykar Bathini, Tirumalai Srivatsan, Anil Patnaik, Craig Menzemer

Anil Patnaik

In this paper, the cyclic stress amplitude controlled high-cycle fatigue properties and final fracture behavior of commercially pure titanium (Grade 2) are presented and discussed. The material characterization was developed and put forth for selection and use in a spectrum of applications spanning the industries of aerospace, defense, chemical, marine, and commercial products. Test specimens were prepared from the as-received plate stock of the material with the stress axis both parallel (longitudinal) and perpendicular (transverse) to the rolling direction of the plate. The test specimens were cyclically deformed at a constant load ratio of 0.1, at different values of maximum …


A Study Of Cyclic Fatigue, Damage Initiation, Damage Propagation, And Fracture Of Welded Titanium Alloy Plate, Tirumalai Srivatsan, Udaykar Bathini, Anil Patnaik, T. Quick Aug 2015

A Study Of Cyclic Fatigue, Damage Initiation, Damage Propagation, And Fracture Of Welded Titanium Alloy Plate, Tirumalai Srivatsan, Udaykar Bathini, Anil Patnaik, T. Quick

Anil Patnaik

In this paper, the influence of test specimen orientation and microstructure on cyclic stress-amplitude controlled fatigue response, damage initiation, damage propagation and fracture behavior of samples taken from a welded plate of titanium alloy is presented and discussed. Test specimens from the chosen alloy were prepared from an as-welded plate of the material with the stress axis both parallel (longitudinal) and perpendicular (transverse) to the deformed (rolling) direction of the plate. The test specimens were cyclically deformed at different values of maximum stress at a constant load ratio of 0.1, and the resultant cycles-to-failure was recorded. The fracture surfaces of …


Zeolite Membranes: Microstructure Characterization And Permeation Mechanisms, Miao Yu, R. Noble, J. Falconer Jun 2015

Zeolite Membranes: Microstructure Characterization And Permeation Mechanisms, Miao Yu, R. Noble, J. Falconer

Miao Yu

No abstract provided.


A Novel Technique For Microstructure Characterization Of Garnet Films, P.C. Wo, P.R. Munroe, Mikhail Vasiliev, Zonghan Xie, Kamal Alameh, V.A. Kotov Apr 2015

A Novel Technique For Microstructure Characterization Of Garnet Films, P.C. Wo, P.R. Munroe, Mikhail Vasiliev, Zonghan Xie, Kamal Alameh, V.A. Kotov

Mikhail Vasiliev

Bismuth-substituted iron garnet exhibits remarkable magneto-optical properties in magnetic photonic crystal (MPC) structures, and has the potential to improve performance in optical integrated circuits for communication networks and optical sensing applications. The microstructure and thickness of these garnet films has a strong influence over their optical, magnetic and magneto-optic (MO) properties. The thickness of these films has been measured indirectly via optical interference and ellipsometry, which are unable to map thickness variations due to surface roughness of both the film and the substrate. However, little direct observation has been carried out to provide detailed information about the microstructure of the …


The Quasi-Static And Cyclic Fatigue Fracture Behavior Of An Emerging Titanium Alloy, Kannan Manigandan, Tirumalai Srivatsan, Gregory Morscher Apr 2015

The Quasi-Static And Cyclic Fatigue Fracture Behavior Of An Emerging Titanium Alloy, Kannan Manigandan, Tirumalai Srivatsan, Gregory Morscher

Dr. Gregory N. Morscher

Sustained research and development efforts culminating in the emergence of new and improved titanium alloys have provided both the impetus and interest for studying their mechanical behavior under the extrinsic influence of loading spanning both static and dynamic. In this article, the quasi-static and cyclic fatigue fracture behavior of a titanium alloy (Ti-Al-V-Fe-O2) is highlighted. Test specimens of this titanium alloy were deformed both in quasi-static tension and cyclic stress amplitude–controlled fatigue. The quasi-static mechanical properties, cyclic fatigue response and microscopic mechanisms contributing to deformation and eventual fracture are highlighted in light of the competing and mutually interactive influences of …


An Investigation Of Nanoparticles Addition On Solidification Kinetics And Microstructure Development Of Tin–Lead Solder, D. Lin, S. Liu, T. Guo, Guo-Xiang Wang, T. Srivatsan, M. Petraroli Apr 2015

An Investigation Of Nanoparticles Addition On Solidification Kinetics And Microstructure Development Of Tin–Lead Solder, D. Lin, S. Liu, T. Guo, Guo-Xiang Wang, T. Srivatsan, M. Petraroli

Dr. Guo-Xiang Wang

High strength solders can be engineered by adding trace amounts of nanopowders into solder paste. An experimental study was conducted for a better understanding of the solidification kinetics and microstructure development of such nano-composite tin–lead solders. The composite solder pastes were prepared by mechanically mixing nanopowders of either copper or TiO2 with tin–lead powders (tens of microns in size). Solidification experiments of the composite solders were performed in an aluminum crucible with temperature variation during cooling and solidification being measured. For the titanium dioxide (TiO2) nanopowders-reinforced composite solders, the test data reveals the occurrence of melt undercooling …


Synthesis And Characterization Of Nano-Composite Lead-Free Solder, D. Lin, C. Kuo, T. Srivatsan, M. Petraroli, Guo-Xiang Wang Apr 2015

Synthesis And Characterization Of Nano-Composite Lead-Free Solder, D. Lin, C. Kuo, T. Srivatsan, M. Petraroli, Guo-Xiang Wang

Dr. Guo-Xiang Wang

A series of experiments conducted on a lead-free eutectic solder (Sn-3.5%Ag) have shown that addition of trace amounts of nanometer-sized particles does have an influence on mechanical properties of materials. In this study, three different types of nanoparticles (copper, nickel and iron) were chosen as the reinforcing candidate. For each particulate reinforcement the reflow process was performed under identical cooling conditions. Addition of trace amounts of nano-particles alters the kinetics governing solidification of the composite solder paste while concurrently exerting an influence on microstructural development, particularly the formation and presence of second phases in the solidified end product. The nano-sized …


Phase Formation And Hydrogen Ordering In Yttrium-Hydrogen System, Ke Wang, Jason Hattrick-Simpers, Leonid Bendersky Mar 2015

Phase Formation And Hydrogen Ordering In Yttrium-Hydrogen System, Ke Wang, Jason Hattrick-Simpers, Leonid Bendersky

Jason R. Hattrick-Simpers

No abstract provided.


Redox Stable Anodes For Solid Oxide Fuel Cells, Guoliang Xiao, Fanglin Chen Mar 2015

Redox Stable Anodes For Solid Oxide Fuel Cells, Guoliang Xiao, Fanglin Chen

Fanglin Chen

Solid oxide fuel cells (SOFCs) can convert chemical energy from the fuel directly to electrical energy with high efficiency and fuel flexibility. Ni-based cermets have been the most widely adopted anode for SOFCs. However, the conventional Ni-based anode has low tolerance to sulfur-contamination, is vulnerable to deactivation by carbon build-up (coking) from direct oxidation of hydrocarbon fuels, and suffers volume instability upon redox cycling. Among these limitations, the redox instability of the anode is particularly important and has been intensively studied since the SOFC anode may experience redox cycling during fuel cell operations even with the ideal pure hydrogen as …


Fuzzy Logic Based Model For Predicting Surface Roughness Of Machined Al-Si-Cu-Fe Die Casting Alloy Using Different Additives-Turning Jan 2015

Fuzzy Logic Based Model For Predicting Surface Roughness Of Machined Al-Si-Cu-Fe Die Casting Alloy Using Different Additives-Turning

Faculty of Engineering University of Malaya

This paper presents a fuzzy logic artificial intelligence technique for predicting the machining performance of Al-Si-Cu-Fe die casting alloy treated with different additives including strontium, bismuth and antimony to improve surface roughness. The Pareto-ANOVA optimization method was used to obtain the optimum parameter conditions for the machining process. Experiments were carried out using oblique dry CNC turning. The machining parameters of cutting speed, feed rate and depth of cut were optimized according to surface roughness values. The results indicated that a cutting speed of 250 m/min, a feed rate of 0.05 mm/rev, and a depth of cut of 0.15 mm …


Investigating The Machinability Of Al-Si-Cu Cast Alloy Containing Bismuth And Antimony Using Coated Carbide Insert Jan 2015

Investigating The Machinability Of Al-Si-Cu Cast Alloy Containing Bismuth And Antimony Using Coated Carbide Insert

Faculty of Engineering University of Malaya

Surface roughness and cutting force are two key measures that describe machined surface integrity and power requirement evaluation, respectively. This investigation presents the effect of melt treatment with addition of bismuth and antimony on machinability when turning Al-11% Si-2% Cu alloy. The experiments are carried out under oblique dry cutting conditions using a PVD TIN-coated insert at three cutting speeds of 70, 130 and 250 m/min, feed rates of 0.05, 0.1, 0.15 mm/rev, and 0.05 mm constant depth of cut. It was found that the Bi-containing workpiece possess the best surface roughness value and lowest cutting force due to formation …


Quantitative Analysis Of Interconnectivity Of Porous Biodegradable Scaffolds With Micro-Computed Tomography, Michael Moore, Esmaiel Jabbari, Erik Ritman, Lichun Lu, Bradford Currier, Anthony Windebank, Michael Yaszemski Jan 2015

Quantitative Analysis Of Interconnectivity Of Porous Biodegradable Scaffolds With Micro-Computed Tomography, Michael Moore, Esmaiel Jabbari, Erik Ritman, Lichun Lu, Bradford Currier, Anthony Windebank, Michael Yaszemski

Esmaiel Jabbari

No abstract provided.


Morphology And Structure Of Microcapsules Prepared By Interfacial Polycondensation Of Methylene Bis(Phenyl Isocyanate) With Hexamethylene Diamine, Esmaiel Jabbari Jan 2015

Morphology And Structure Of Microcapsules Prepared By Interfacial Polycondensation Of Methylene Bis(Phenyl Isocyanate) With Hexamethylene Diamine, Esmaiel Jabbari

Esmaiel Jabbari

No abstract provided.