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

Mechanical Engineering Commons™

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

Selected Works

2015

Discipline
Institution
Keyword
Publication
File Type

Articles 31 - 60 of 949

Full-Text Articles in Mechanical Engineering

Probe-Pulse Optimization For Nonresonant Suppression In Hybrid Fs/Ps Coherent Anti-Stokes Raman Scattering At High Temperature, Joseph D. Miller, Mikhail N. Slipchenko, Terrence R. Meyer Nov 2015

Probe-Pulse Optimization For Nonresonant Suppression In Hybrid Fs/Ps Coherent Anti-Stokes Raman Scattering At High Temperature, Joseph D. Miller, Mikhail N. Slipchenko, Terrence R. Meyer

Terrence R Meyer

Hybrid femtosecond/picosecond coherent anti-Stokes Raman scattering (fs/ps CARS) offers accurate thermometry at kHz rates for combustion diagnostics. In high-temperature flames, selection of probe-pulse characteristics is key to simultaneously optimizing signal-to-nonresonant-background ratio, signal strength, and spectral resolution. We demonstrate a simple method for enhancing signal-to-nonresonant-background ratio by using a narrowband Lorentzian filter to generate a time-asymmetric probe pulse with full-width-half-maximum (FWHM) pulse width of only 240 fs. This allows detection within just 310 fs after the Raman excitation for eliminating nonresonant background while retaining 45% of the resonant signal at 2000 K. The narrow linewidth is comparable to that of a …

Go to article

Single-Shot Gas-Phase Thermometry Using Purerotational Hybrid Femtosecond/Picosecond Coherent Anti-Stokes Raman Scattering, Joseph D. Miller, Sukesh Roy, Mikhail N. Slipchenko, James R. Gord, Terrence R. Meyer Nov 2015

Single-Shot Gas-Phase Thermometry Using Purerotational Hybrid Femtosecond/Picosecond Coherent Anti-Stokes Raman Scattering, Joseph D. Miller, Sukesh Roy, Mikhail N. Slipchenko, James R. Gord, Terrence R. Meyer

Terrence R Meyer

High-repetition-rate, single-laser-shot measurements are important for the investigation of unsteady flows where temperature and species concentrations can vary significantly. Here, we demonstrate singleshot, pure-rotational, hybrid femtosecond/picosecond coherent anti-Stokes Raman scattering (fs/ps RCARS) thermometry based on a kHz-rate fs laser source. Interferences that can affect nanosecond (ns) and ps CARS, such as nonresonant background and collisional dephasing, are eliminated by selecting an appropriate time delay between the 100-fs pump/Stokes pulses and the pulse-shaped 8.4-ps probe. A time- and frequency-domain theoretical model is introduced to account for rotational-level dependent collisional dephasing and indicates that the optimal probe-pulse time delay is 13.5 ps …

Go to article

Fast-Framing Ballistic Imaging Of Velocity In An Aerated Spray, David Sedarsky, James Gord, Campbell Carter, Terrence R. Meyer, Mark Linne Nov 2015

Fast-Framing Ballistic Imaging Of Velocity In An Aerated Spray, David Sedarsky, James Gord, Campbell Carter, Terrence R. Meyer, Mark Linne

Terrence R Meyer

We describe further development of ballistic imaging adapted for the liquid core of an atomizing spray. To fully understand spray breakup dynamics, one must measure the velocity and acceleration vectors that describe the forces active in primary breakup. This information is inaccessible to most optical diagnostics, as the signal is occluded by strong scattering in the medium. Ballistic imaging mitigates this scattering noise, resolving clean shadowgram-type images of structures within the dense spray region. We demonstrate that velocity data can be extracted from ballistic images of a spray relevant to fuel-injection applications, by implementing a simple, targeted correlation method for …

Go to article

Quantitative Time-Averaged Gas And Liquid Distributions Using X-Ray Fluorescence And Radiography In Atomizing Sprays, Christopher D. Radke, J. Patrick Mcmanamen, Alan L. Kastengren, Benjamin R. Halls, Terrence R. Meyer Nov 2015

Quantitative Time-Averaged Gas And Liquid Distributions Using X-Ray Fluorescence And Radiography In Atomizing Sprays, Christopher D. Radke, J. Patrick Mcmanamen, Alan L. Kastengren, Benjamin R. Halls, Terrence R. Meyer

Terrence R Meyer

A method for quantitative measurements of gas and liquid distributions is demonstrated using simultaneous x-ray fluorescence and radiography of both phases in an atomizing coaxial spray. Synchrotron radiation at 10.1 keV from the Advanced Photon Source at Argonne National Laboratory is used for x-ray fluorescence of argon gas and two tracer elements seeded into the liquid stream. Simultaneous time-resolved x-ray radiography combined with timeaveraged dual-tracer fluorescence measurements enabled corrections for reabsorption of x-ray fluorescence photons for accurate, line-of-sight averaged measurements of the distribution of the gas and liquid phases originating from the atomizing nozzle.

Go to article

100-Ps-Pulse-Duration, 100-J Burst-Mode Laser For Khz–Mhz Flow Diagnostics, Sukesh Roy, Joseph D. Miller, Mikhail N. Slipchenko, Paul S. Hsu, Jason G. Mance, Terrence R. Meyer, James R. Gord Nov 2015

100-Ps-Pulse-Duration, 100-J Burst-Mode Laser For Khz–Mhz Flow Diagnostics, Sukesh Roy, Joseph D. Miller, Mikhail N. Slipchenko, Paul S. Hsu, Jason G. Mance, Terrence R. Meyer, James R. Gord

Terrence R Meyer

A high-speed, master-oscillator power-amplifier burst-mode laser with ∼100 ps pulse duration is demonstrated with output energy up to 110 J per burst at 1064 nm and second-harmonic conversion efficiency up to 67% in a KD*P crystal. The output energy is distributed across 100 to 10,000 sequential laser pulses, with 10 kHz to 1 MHz repetition rate, respectively, over 10 ms burst duration. The performance of the 100 ps burst-mode laser is evaluated and been found to compare favorably with that of a similar design that employs a conventional ∼8 ns pulse duration. The nearly transform-limited spectral bandwidth of 0.15 cm−1 …

Go to article

Femtosecond Coherent Anti-Stokes Raman Scattering Measurement Of Gas Temperatures From Frequency-Spread Dephasing Of The Raman Coherence, Robert P. Lucht, Sukesh Roy, Terrence R. Meyer, James R. Gord Nov 2015

Femtosecond Coherent Anti-Stokes Raman Scattering Measurement Of Gas Temperatures From Frequency-Spread Dephasing Of The Raman Coherence, Robert P. Lucht, Sukesh Roy, Terrence R. Meyer, James R. Gord

Terrence R Meyer

Gas-phase temperatures and concentrations are measured from the magnitude and decay of the initial Raman coherence in femtosecond coherent anti-Stokes Raman scattering (CARS). A time-delayed probe beam is scattered from the Raman polarization induced by pump and Stokes beams to generate CARS signal; the dephasing rate of this initial coherence is determined by the temperature-sensitive frequency spread of the Raman transitions. Temperature is measured from the CARS signal decrease with increasing probe delay. Concentration is found from the ratio of the CARS and nonresonant background signals. Collision rates do not affect the determination of these quantities.

Go to article

Effects Of Repetitive Pulsing On Multi-Khz Planar Laser-Induced Incandescence Imaging In Laminar And Turbulent Flames, James Bennett Michael, Prabhakar Venkateswaran, Christopher R. Shaddix, Terrence R. Meyer Nov 2015

Effects Of Repetitive Pulsing On Multi-Khz Planar Laser-Induced Incandescence Imaging In Laminar And Turbulent Flames, James Bennett Michael, Prabhakar Venkateswaran, Christopher R. Shaddix, Terrence R. Meyer

Terrence R Meyer

Planar laser-induced incandescence (LII) imaging is reported at repetition rates up to 100 kHz using a burst-mode laser system to enable studies of soot formation dynamics in highly turbulent flames. To quantify the accuracy and uncertainty of relative soot volume fraction measurements, the temporal evolution of the LII field in laminar and turbulent flames is examined at various laser operating conditions. Under high-speed repetitive probing, it is found that LII signals are sensitive to changes in soot physical characteristics when operating at high laser fluences within the soot vaporization regime. For these laser conditions, strong planar LII signals are observed …

Go to article

Dual-Pump Vibrational/Rotational Femtosecond/ Picosecond Coherent Anti-Stokes Raman Scattering Temperature And Species Measurements, Chloe Elizabeth Dedic, Joseph D. Miller, Terrence R. Meyer Nov 2015

Dual-Pump Vibrational/Rotational Femtosecond/ Picosecond Coherent Anti-Stokes Raman Scattering Temperature And Species Measurements, Chloe Elizabeth Dedic, Joseph D. Miller, Terrence R. Meyer

Terrence R Meyer

A method for simultaneous ro-vibrational and pure-rotational hybrid femtosecond/picosecond coherent anti-Stokes Raman scattering (fs/ps CARS) is presented for multi-species detection and improved temperature sensitivity from room temperature to flame conditions. N2∕CH4 vibrational and N2∕O2∕H2 rotational Raman coherences are excited simultaneously using fs pump pulses at 660 and 798 nm, respectively, and a common fs Stokes pulse at 798 nm. A fourth narrowband 798 nm ps pulse probes all coherence states at a time delay that minimizes nonresonant background and the effects of collisions. The transition strength is concentration dependent, while the distribution among observed transitions is related to temperature through …

Go to article

Micro-Optical Initiation Of Nanoenergetic Materials Using A Temporally Tailored Variable-Pulse-Width Laser, Mikhail N. Slipchenko, Clint E. Moody, Joseph D. Miller, Sukesh Roy, James R. Gord, Terrence R. Meyer Nov 2015

Micro-Optical Initiation Of Nanoenergetic Materials Using A Temporally Tailored Variable-Pulse-Width Laser, Mikhail N. Slipchenko, Clint E. Moody, Joseph D. Miller, Sukesh Roy, James R. Gord, Terrence R. Meyer

Terrence R Meyer

Nanoenergetic materials can provide a significant enhancement in the rate of energy release as compared with microscale materials. The energy-release rate is strongly dependent not only on the primary particle size but also on the level of agglomeration, which is of particular interest for the inclusion of nanoenergetics in practical systems where agglomeration is desired or difficult to avoid. Unlike studies of nanoparticles or nanometer-size aggregates, which can be conducted with ultrafast or nanosecond lasers assuming uniform heating, microscale aggregates of nanoparticles are more sensitive to the thermophysical time scale of the heating process. To allow control over the rate …

Go to article

Quantitative Measurement Of Binary Liquid Distributions Using Multiple-Tracer X-Ray Fluorescence And Radiography, Benjamin R. Halls, Terrence R. Meyer, Alan L. Kastengren Nov 2015

Quantitative Measurement Of Binary Liquid Distributions Using Multiple-Tracer X-Ray Fluorescence And Radiography, Benjamin R. Halls, Terrence R. Meyer, Alan L. Kastengren

Terrence R Meyer

The complex geometry and large index-of-refraction gradients that occur near the point of impingement of binary liquid jets present a challenging environment for optical interrogation. A simultaneous quadruple-tracer x-ray fluorescence and line-of-sight radiography technique is proposed as a means of distinguishing and quantifying individual liquid component distributions prior to, during, and after jet impact. Two different pairs of fluorescence tracers are seeded into each liquid stream to maximize their attenuation ratio for reabsorption correction and differentiation of the two fluids during mixing. This approach for instantaneous correction of xray fluorescence reabsorption is compared with a more time-intensive approach of using …

Go to article

100 Khz Thousand-Frame Burst-Mode Planar Imaging In Turbulent Flames, James B. Michael, Prabhakar Venkateswaran, Joseph D. Miller, Mikhail N. Slipchenko, James R. Gord, Sukesh Roy, Terrence R. Meyer Nov 2015

100 Khz Thousand-Frame Burst-Mode Planar Imaging In Turbulent Flames, James B. Michael, Prabhakar Venkateswaran, Joseph D. Miller, Mikhail N. Slipchenko, James R. Gord, Sukesh Roy, Terrence R. Meyer

Terrence R Meyer

High-repetition-rate, burst-mode lasers can achieve higher energies per pulse compared with continuously pulsed systems, but the relatively few number of laser pulses in each burst has limited the temporal dynamic range of measurements in unsteady flames. A fivefold increase in the range of timescales that can be resolved by burst-mode laser-based imaging systems is reported in this work by extending a hybrid diode- and flashlamp-pumped Nd:YAGbased amplifier system to nearly 1000 pulses at 100 kHz during a 10 ms burst. This enables an unprecedented burstmode temporal dynamic range to capture turbulent fluctuations from 0.1 to 50 kHz in flames of …

Go to article

Spatially And Temporally Resolved Temperature And Shock-Speed Measurements Behind A Laser-Induced Blast Wave Of Energetic Nanoparticles, Sukesh Roy, Naibo Jiang, Han U. Stauffer, Jacob B. Schmidt, Waruna D. Kulatilaka, Terrence R. Meyer, Christopher E. Bunker, James R. Gord Nov 2015

Spatially And Temporally Resolved Temperature And Shock-Speed Measurements Behind A Laser-Induced Blast Wave Of Energetic Nanoparticles, Sukesh Roy, Naibo Jiang, Han U. Stauffer, Jacob B. Schmidt, Waruna D. Kulatilaka, Terrence R. Meyer, Christopher E. Bunker, James R. Gord

Terrence R Meyer

Spatially and temporally resolved temperature measurements behind an expanding blast wave are made using picosecond (ps) N2 coherent anti-Stokes Raman scattering (CARS) following laser flash heating of mixtures containing aluminum nanoparticles embedded in ammonium-nitrate oxidant. Production-front ps-CARS temperatures as high as 3600 ± 180 K-obtained for 50-nm-diameter commercially produced aluminum-nanoparticle samples-are observed. Time-resolved shadowgraph images of the evolving blast waves are also obtained to determine the shock-wave position and corresponding velocity. These results are compared with near-field blast-wave theory to extract relative rates of energy release for various particle diameters and passivating-layer compositions.

Go to article

Process Parameters And Foaming Agents Used In Manufacturing Of Aluminium Metallic Foams: A Review, Sri Ram Vikas K.,, N. Raghu Ram,, Ch. Kishore Reddy,, V.V. Sridhara Raju Nov 2015

Process Parameters And Foaming Agents Used In Manufacturing Of Aluminium Metallic Foams: A Review, Sri Ram Vikas K.,, N. Raghu Ram,, Ch. Kishore Reddy,, V.V. Sridhara Raju

Innovative Research Publications IRP India

Porous metals and metallic foams are composite materials in which one phase is gaseous and another phase is solid metal. The mechanical behavior of these materials depends mainly on the mechanical properties of the solid metallic phase, the structural configuration of the solid and the density of the composite ρc, relative to the density of the solid phase ρs. The primary distinction between a porous metal and metallic foam is the relative density, metal gas composites with a relative density (ρc/ρs) above 0.3 are generally considered porous materials, while those with a relative density below 0.3 are generally considered to …

Go to article

Experimentally Study The Effects Of Fins Height And Width H\W Ratio To The Fin Thermal Performance By Natural Convections, Hazim A.M. Al-Jewaree, Osama A.M. Alhamil Nov 2015

Experimentally Study The Effects Of Fins Height And Width H\W Ratio To The Fin Thermal Performance By Natural Convections, Hazim A.M. Al-Jewaree, Osama A.M. Alhamil

Innovative Research Publications IRP India

The industry revolution in thermal engineering started with fixed the extended surface area named a fin. Therefore, a lot off research work done in this field to enhance the performance of heat transfer . All, previous work reach to that any increase of heat transfer coefficient and the fin surface area will increase the heat transfer rate by natural convection. The research work summarized in this paper presents an experimental investigation on the effect of fin heights –width (H/w) ratios on the fin performance using rectangular plate type fins. The steady-state natural convection heat transfer from vertical rectangular fins extending …

Go to article

Experimentally Investigate The Heat Transfer Performance Of Annular Fins, Hazim A.M. Al-Jewaree, Osama A.M. Alhami Oct 2015

Experimentally Investigate The Heat Transfer Performance Of Annular Fins, Hazim A.M. Al-Jewaree, Osama A.M. Alhami

Innovative Research Publications IRP India

Performance of annular fins of different shapes subject to locally variable heat transfer coefficient is investigated experimentally in this paper. The performance of the fin expressed in terms of fin efficiency, effectiveness and thermal resistance as a function of the ambient temperature and fin geometry parameters has been presented in the literature in the form of curves known as the fin-efficiency curves for different types of fins without use the diamond shape, but in the present work, we study this shape with others. However, for cases in which the heat transfer from the fin is dominated by natural convection, the …

Go to article

الگو و دستورالعمل تهيه و تدوين پايان نامه کارشناسي ارشد, Dr Alireza Zolfaghari Oct 2015

الگو و دستورالعمل تهيه و تدوين پايان نامه کارشناسي ارشد, Dr Alireza Zolfaghari

Dr Alireza Zolfaghari

No abstract provided.

Go to article

Umass Amherst Green Building Guidelines 2013, Ludmilla Pavlova-Gillham, Ted Mendoza, Ezra Small, Patricia O'Flaherty, Nariman Mostafavi, Mohamed Farzinmoghadam, Somayeh Tabatabaee Pozveh Oct 2015

Umass Amherst Green Building Guidelines 2013, Ludmilla Pavlova-Gillham, Ted Mendoza, Ezra Small, Patricia O'Flaherty, Nariman Mostafavi, Mohamed Farzinmoghadam, Somayeh Tabatabaee Pozveh

Ludmilla D Pavlova

Facilities & Campus Services, Sustainable UMass and Campus Planning support sustainability and energy conservation initiatives by providing in-house resources to campus staff as well as designers and contractors working with the University. The UMass Amherst Green Building Guidelines provide a framework for approaching new construction and major renovation projects at UMass Amherst that are undergoing LEED certification by focusing the conversation on green building aspects that are most important to the campus. They are intended to be the beginning of a dynamic conversation between designers, environmental consultants and constructors, university stakeholders, and users of new high performance buildings.

Go to article

Umass Amherst Building Measurement, Verification, Coordination And Template Plan, Nariman Mostafavi, Ted Mendoza, Jeffrey G. Quackenbush, Sandy J. Beauregard, Jason J. Burbank, Mohamad Farzinmoghadam, Ludmilla Pavlova-Gillham, Kylie A. Landrey, Patricia O'Flaherty Oct 2015

Umass Amherst Building Measurement, Verification, Coordination And Template Plan, Nariman Mostafavi, Ted Mendoza, Jeffrey G. Quackenbush, Sandy J. Beauregard, Jason J. Burbank, Mohamad Farzinmoghadam, Ludmilla Pavlova-Gillham, Kylie A. Landrey, Patricia O'Flaherty

Ludmilla D Pavlova

Facilities & Campus Services, Sustainable UMass and Campus Planning support sustainability and energy conservation initiatives by providing in-house resources to campus staff as well as designers and contractors working with the University. The UMass Amherst Building Measurement, Verification, Coordination and Template Plan was begun in 2013 and finalized in 2015 as a resource to project teams that undertake the measurement and verification of building systems during the first year of occupancy of a new building and renovation project, particularly projects undergoing LEED certification.

Go to article

Umass Amherst Energy Modeling Guidelines, Nariman Mostafavi, Ted Mendoza, Jeffrey G. Quackenbush, Sandy J. Beauregard, Jason J. Burbank, Mohamad Farzinmoghadam, Ludmilla Pavlova-Gillham, Kylie A. Landrey Oct 2015

Umass Amherst Energy Modeling Guidelines, Nariman Mostafavi, Ted Mendoza, Jeffrey G. Quackenbush, Sandy J. Beauregard, Jason J. Burbank, Mohamad Farzinmoghadam, Ludmilla Pavlova-Gillham, Kylie A. Landrey

Ludmilla D Pavlova

Facilities & Campus Services, Sustainable UMass and Campus Planning support sustainability and energy conservation initiatives by providing in-house resources to campus staff as well as designers and contractors working with the University. The Campus energy Modeling Guidelines were developed in 2015 as a resource on how to: i) generate energy models for campus buildings; ii) provide quality assurance review of current energy models; and iii) share UMass Amherst energy modeling input parameters with project design teams for them to establish a baseline building energy profile.

Go to article

University Of Massachusetts Amherst 2012-2021 Capital Improvement Projects, Douglas Vigneau, Juanita Holler, John Mathews, Ludmilla Pavlova-Gillham, Ezra Small Oct 2015

University Of Massachusetts Amherst 2012-2021 Capital Improvement Projects, Douglas Vigneau, Juanita Holler, John Mathews, Ludmilla Pavlova-Gillham, Ezra Small

Ludmilla D Pavlova

In 2013 the University of Massachusetts, on behalf of the University of Massachusetts Building Authority and Massachusetts Division of Capital Asset Management and Maintenance (DCAMM), submitted an Expanded Environmental Notification Form for the University's 2012 - 2021 Capital Improvement Plan to the Executive Office of Energy and Environmental Affairs (EOEEA) Massachusetts Environmental Policy Act Office (MEPA). Taken individually, the majority of the Projects, comprising of 13 building/space, 7 site/landscape, and 5 facility/ utility scale improvement projects, do not require MEPA review as most of the Project sites are confined to infill areas on campus that are currently or have been …

Go to article

A High-Speed X-Ray Detector System For Noninvasive Fluid Flow Measurements, Timothy B. Morgan, Benjamin R. Halls, Terrence R. Meyer, Theodore J. Heindel Oct 2015

A High-Speed X-Ray Detector System For Noninvasive Fluid Flow Measurements, Timothy B. Morgan, Benjamin R. Halls, Terrence R. Meyer, Theodore J. Heindel

Terrence R Meyer

The opaque nature of many multiphase flows has long posed a significant challenge to the visualization and measurement of desired characteristics. To overcome this difficulty, X-ray imaging, both in the form of radiography and computed tomography, has been used successfully to quantify various multiphase flow phenomena. However, the relatively low temporal resolution of typical X-ray systems limit their use to moderately slow flows and time-average values. This paper discusses the development of an X-ray detection system capable of high-speed radiographic imaging that can be used to visualize multiphase flows. Details of the hardware will be given and then applied to …

Go to article

Developing Inquiry-Based Laboratory Exercises For A Mechanical Engineering Curriculum, Sriram Sundararajan, Leann E. Faidley, Terrence R. Meyer Oct 2015

Developing Inquiry-Based Laboratory Exercises For A Mechanical Engineering Curriculum, Sriram Sundararajan, Leann E. Faidley, Terrence R. Meyer

Terrence R Meyer

This paper describes the development of two inquiry-based experiments in a mechanical engineering curriculum at a land grant research-intensive university, aimed at providing students with the opportunity to design and perform experiments. One experiment in engineering measurements (system behavior) and one experiment in fluid dynamics were developed. In each case, students working on teams were posed with a scenario and question to answer. For example, in the system dynamics experiment, students were asked to verify that a thermal system and electrical system were mechanically equivalent systems. In the fluid dynamics experiment, students were asked to investigate drag coefficients for flow …

Go to article

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 …

Go to article

The Quasi-Static Deformation, Failure, And Fracture Behavior Of Titanium Alloy Gusset Plates Containing Bolt Holes, Therese Hurtuk, Craig Menzemer, Anil Patnaik, Tirumalai Srivatsan, Kannan Manigandan, T. Quick Oct 2015

The Quasi-Static Deformation, Failure, And Fracture Behavior Of Titanium Alloy Gusset Plates Containing Bolt Holes, Therese Hurtuk, Craig Menzemer, Anil Patnaik, Tirumalai Srivatsan, Kannan Manigandan, T. Quick

Craig Menzemer

In this article, the influence of bolt holes, specifically their number and layout on strength, deformation, and final fracture behavior of titanium alloy gusset plates under the influence of an external load is presented and discussed. Several plates having differences in both the number and layout of the bolt holes were precision machined and then deformed under quasi-static loading. The specific influence of number of bolt holes and their layout on maximum load-carrying capability and even fracture load was determined. The conjoint influence of bolt number, bolt layout pattern, nature of loading, contribution from local stress concentration, and intrinsic microstructural …

Go to article

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 …

Go to article

The Bolt Bearing Response And Tensile Deformation Capacity Of Plates Made From A Titanium Alloy, Nicholas Tinl, Craig Menzemer, Anil Patnaik, Tirumalai Srivatsan Oct 2015

The Bolt Bearing Response And Tensile Deformation Capacity Of Plates Made From A Titanium Alloy, Nicholas Tinl, Craig Menzemer, Anil Patnaik, Tirumalai Srivatsan

Craig Menzemer

In this article, the bearing capacity and elongation characteristics of bolt holes in a titanium alloy (i.e., Ti-6Al-4V) deformed in uniaxial tension is presented and discussed. The specific role played by bolt hole confinement on bearing capacity is highlighted. The nature of final fracture is examined and the intrinsic features present on the fracture surface are rationalized in concurrence with macroscopic mechanical response. The behavior of the candidate alloy (Ti-6Al-4V) is compared with conventionally preferred and chosen candidate materials steel and aluminum alloys. An empirical relationship suitable for purpose of structural design is proposed.

Go to article

An Investigation And Understanding Of The Mechanical Response Of Palmyrah Timber, Hatim Sobier, Craig Menzemer, Tirumalai Srivatsan Oct 2015

An Investigation And Understanding Of The Mechanical Response Of Palmyrah Timber, Hatim Sobier, Craig Menzemer, Tirumalai Srivatsan

Craig Menzemer

The Palmyrah tree flourishes in tropical areas around South East Asia, and particularly in Sri Lanka. Palmyrah is an important economic resource for the region, and has found use in structural applications for both residential dwellings and commercial buildings. While there is a great deal of local field experience with Palmyrah, the mechanical properties have not been well characterized or understood. In an effort to assist engineers with the design and efficient use of the timber, a study was undertaken to evaluate the mechanical response of Palmyrah and develop estimates of design allowable properties. Properties evaluated include static bending strength, …

Go to article

Understanding The Mechanical Response Of Built-Up Welded Beams Made From Commercially Pure Titanium And A Titanium Alloy, Anil Patnaik, Narendra Poondla, Craig Menzemer, Tirumalai Srivatsan Oct 2015

Understanding The Mechanical Response Of Built-Up Welded Beams Made From Commercially Pure Titanium And A Titanium Alloy, Anil Patnaik, Narendra Poondla, Craig Menzemer, Tirumalai Srivatsan

Craig Menzemer

During the last two decades, titanium has gradually grown in stature, strength and significance to take on the recognition of being a modern and high performance metal that is noticeably stronger and concurrently lighter than the most widely chosen and used steels in a spectrum of industrial applications. Technological innovations have necessitated reduction of part weight, cost and lead time, including concurrent enhancement of performance of structural parts and components made using titanium and its alloys. This has provided the impetus to develop economically viable structural design methodologies and specifications, while at the same time bringing forth innovative and economically …

Go to article

A Study Of Fatigue And Fracture Response Of Cantilevered Luminaire Structures Made From Aluminum Alloy 6063, Craig Menzemer, Diya Azzam, Tirumalai Srivatsan Oct 2015

A Study Of Fatigue And Fracture Response Of Cantilevered Luminaire Structures Made From Aluminum Alloy 6063, Craig Menzemer, Diya Azzam, Tirumalai Srivatsan

Craig Menzemer

In the experimental results elegantly and exhaustively elaborated upon in this paper the local stresses, obtained from finite element analysis, was used to develop estimates of the stress intensity factor (SIF). In combination with crack growth data, the fatigue lives of both the through-plate and an integrally stiffened socket connection were estimated using software developed by the U.S. Air Force (and referred to as AFGROW). The fatigue life estimates correlated well with the test results provided the crack growth rate data was obtained under conditions of minimal closure at higher stress ratios (of the order R = 0.7). In an …

Go to article

Isolating Corrosion Of Steel Plates Coupled With Titanium, Anil Patnaik, X. Shan, M. Adams, T. Srivatsan, Craig Menzemer, Joe Payer Oct 2015

Isolating Corrosion Of Steel Plates Coupled With Titanium, Anil Patnaik, X. Shan, M. Adams, T. Srivatsan, Craig Menzemer, Joe Payer

Craig Menzemer

Over twenty six percent of the bridges in the United States are structurally deficient or functionally obsolete. Corrosion of steel used in structures like bridges and buildings is a problem that has gained increased interest and focused concern. Steel is often the metal that is preferred for use in such applications due to a synergism of ease of availability, acceptable mechanical properties and cost effectiveness. Through the years, titanium has grown in strength, stature and significance to be recognized as an emerging high performance metal that is both stronger and lighter than steel. A distinctive property of titanium and its …

Go to article

First Prev Next Last