Engineering Commons^™

Making The Case For Crew-Centered Design (Ccd) In Merchant Shipping, Aditi Kataria, Gesa Praetorius, Jens-Uwe Schröder-Hinrichs, Michael Baldauf

Gesa Praetorius

Since 2003, the International Maritime Organization (IMO) has emphasised the need to address and integrate ergonomics knowledge in a concerted manner. However, there is little guidance on the application of this knowledge in the design of merchant vessels. Utilizing a mixed methods approach, the paper identifies the need for crew-centered design (CCD), highlighting the importance of using concepts derived from Human-Centred Design (HCD) to be able to design work spaces and operational procedures that facilitate the work of the crew on board. Drawing upon results obtained from accident analysis (utilising the Technique for the Retrospective and predictive Analysis of Cognitive …

Gravity-Induced Wrinkling In Subscale, Singly Curved Parabolic Gossamer Membrane, Jack Leifer, David Jones, Adam Cook

Jack Leifer

No abstract provided.

Three-Dimensional Acceleration Measurement Using Videogrammetry Tracking Data, Jack Leifer

Jack Leifer

In order to evaluate the feasibility of multi-point, non-contact, acceleration measurement, a high-speed, precision videogrammetry system has been assembled from commercially-available components and software. Consisting of three synchronized 640 X 480 pixel monochrome progressive scan CCD cameras each operated at 200 frames per second, this system has the capability to provide surface-wide position-versus-time data that are filtered and twice-differentiated to yield the desired acceleration tracking at multiple points on a moving body. The oscillating motion of targets mounted on the shaft of a modal shaker were tracked, and the accelerations calculated using the videogrammetry data were compared directly to conventional …

Experimental Validation Of Multistep Quantitative Crack Damage Assessment For Truss Structures By Finite Element Model Updating, Soon Lee, Gunjin Yun, Mohammad Rahimi, Shen Shang

Gunjin Yun

In this paper, a multistep damage quantification method has been experimentally validated by quantifying crack damage of load-carrying members of truss structures based on experimental vibration records. Damage quantifications are still challenging tasks for difficulties in interpreting response signals measured from engineering structures. Open crack depth is parameterized as a damage variable. The open crack in Euler–Bernoulli beam element is modeled by introducing local flexibility coefficients to the uncracked beam element with joint rotational flexibility. Mode shapes and natural frequencies measured from experimental modal testing of a damaged laboratory-size truss bridge are used in the finite element model updating for …

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 …

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 …

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 …

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.

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, …

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 …

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 …

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 …

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 …

Infuence Of Welding And Heat Treatment On Microstructure, Properties And Fracture Behaviour Of A Wrought Aluminium Alloy, Eric Hilty, Craig Menzemer, Kannan Manigandan, Tirumalai Srivatsan

Craig Menzemer

Welding of aluminium alloy, belonging to the 6XXX series, exerts an adverse influence on its strength. The loss of strength immediately adjacent to the welds can have an influence on overall behaviour of the structure or component. In this study, the technique of gas metal arc welding was used. The filler material used was a silicon-containing aluminium alloy. Subsequent to welding, the alloy (6061-T4) was subjected to post-weld heat treatment (PWHT) at 185°C for 6 h. Both the as-welded and artificially aged extrusions of aluminium alloy 6061 were examined for both microstructural development and resultant influence on mechanical properties. Light …

The Bearing Strength And Fracture Behavior Of Bolted Connections In Two Aluminum Alloys, Nicholas Tinl, Craig Menzemer, Kannan Manigandan, Tirumalai Srivatsan

Craig Menzemer

In this paper, the bearing capacity, taken as a combination of strength, elongation, and failure by fracture characteristics of bolt holes in two aluminum alloys, 5052-H32 and 6061-T6, that were deformed in uniaxial tension is presented and discussed. The specific role played by bolt hole confinement on the bearing capacity of each aluminum alloy is highlighted. An increase in the bearing ratio caused plastic deformation around the holes to gradually increase. For both the chosen aluminum alloys the average bearing ratio at the time of failure of the test sample was found to vary with end distance. The experimentally determined …

Decision Science For Housing And Community Development: Localized And Evidence‐Based Responses To Distressed Housing And Blighted Communities: Wiley Interview, Michael P. Johnson Jr., Jeffrey Keisler, Senay Solak, David A. Turcotte, Armagan Bayram, Rachel B. Drew

Michael P. Johnson

This is an interview with staff at John Wiley & Sons regarding my book "Decision Science for Housing and Community Development: Localized and Evidence‐Based Responses to Distressed Housing and Blighted Communities" that was published by Wiley in 2015. It describes the motivation for the book, essential knowledge my co-authors and I would like each reader to take away from the book, and our assessment of the book's contribution to research and practice.

Where Do We Stand On The Relationship Between Tau Biomarkers And Mild Cognitive Impairment?, Bryn Martin, Philip Allen

Philip A Allen

We present an editorial on a recent publication by Amlien et al. [2013] in which diffusion tensor imaging (DTI) was used to quantify longitudinal decreases in fractional anisotropy (FA) and increased radial diffusivity (D_R) in patients with mild cognitive impairment (MCI). These longitudinal alterations were found to be greater in MCI patients with high cerebrospinal fluid (CSF) tau levels at baseline and greater than healthy controls. Amlien et al. concluded that tau levels were an important early biomarker for predicting rate of disease progression and outcome. The results of this study are an interesting finding for possible predictive …

Task-Specific And General Cognitive Effects In Chiari Malformation Type I, Philip Allen, James Houston, Joshua Pollock, Christopher Buzzelli, Xuan Li, A. Harrington, Bryn Martin, Francis Loth, Mei-Ching Lien, Jahangir Maleki, Mark Luciano

Philip A Allen

Our objective was to use episodic memory and executive function tests to determine whether or not Chiari Malformation Type I (CM) patients experience cognitive dysfunction.

High School Bridge Program: A Multidisciplinary Stem Research Program, Jiang Zhe, Dennis Doverspike, Julie Zhao, Paul Lam, Craig Menzemer

Dennis Doverspike

A Science, Technology, Engineering and Math (STEM) summer Bridge Program was developed for high school students. The program was designed to encourage students to consider choosing an engineering major in college and to explore STEM as a future career. This was accomplished through a 10-week program involving multidisciplinary research activities. The participants in the program included 33 high school students. Among former participants in position to make a choice in terms of attending college, 100% had chosen to continue on in college, and 86% had chosen to major in a STEM area. The results indicated that that the program had …

Decision Science For Housing And Community Development: Localized And Evidence‐Based Responses To Distressed Housing And Blighted Communities, Michael P. Johnson Jr., Jeffrey Keisler, Senay Solak, David Turcotte, Armagan Bayram, Rachel B. Drew

Michael P. Johnson

A Parametric Analysis Of A Reservoir-Extended Porous Slider Bearing With Self-Circulation And Cavitation Effects, Joshus Johnson, Minel Braun, Kevin Kreider, Gerald Young

Gerald W Young

This work considers a porous slider bearing fed by an external contiguous reservoir. The bearing system consists of a lubricating film, a porous medium, and the external reservoir, which runs along the entire length of the porous medium. The Darcy model is used for modeling the flow inside the porous medium. The translational velocity of the reservoir wall and porous medium, together with the convergent-divergent slider lubricating film profile, acts to pump the fluid out of and into the lubricating film and the reservoir, respectively. Cavitation effects are modeled realistically using the switch function and modified equations of the Elrod …

One-Dimensional Approach To Modeling Damage Evolution In Galvanic Corrosion, Aaron Stenta, S. Basco, A. Smith, Curtis Clemons, Dimitry Golovaty, Kevin Kreider, Joseph Wilder, Gerald Young, Robert Lillard

Gerald W Young

A one-dimensional mathematical model is developed to describe time-dependent damage evolution in well-mixed (spatially uniform species concentrations) galvanic systems using an IR drop approach. An asymptotic procedure taking advantage of disparity in length scales (thin film approximation for the electrolyte thickness) is used to derive the model. Limitations that result from the reduction of dimension are described, along with an analysis demonstrating the ability of the 1D model to capture physical phenomena, such as area ratio effects. Computed potential, current density, and corrosion damage profiles are compared and verified with experimental data available in the literature and 2D galvanic corrosion …

An Adaptive Level Set Approach For Modeling Damage Due To Galvanic Corrosion, Joseph Wilder, Curtis Clemons, Dmitry Golovaty, Kevin Kreider, Gerald Young, R. Lillard

Gerald W Young

This article presents an approach to solving problems related to galvanic corrosion that involve moving boundaries (due to preferential corrosion of one of the metals in the system). The method incorporates an adaptive (node based, finite difference) grid technique for the treatment of boundary-related singularities that arise in the calculation of the electric potential. Simulation of the time evolution of the damage done by the corroding interface is performed using of a level set formulation. An analysis of the convergence of the method and a comparison with experimental data from the literature are included.

Index Theory For Locally Compact Noncommutative Geometries, Alan Carey, V Gayral, Adam Rennie, F Sukochev

Associate Professor Adam Rennie

Spectral triples for nonunital algebras model locally compact spaces in noncommutative geometry. In the present text, we prove the local index formula for spectral triples over nonunital algebras, without the assumption of local units in our algebra.

A Residue Formula For The Fundamental Hochschild 3-Cocycle For Suq(2), Ulrich Krahmer, Adam Rennie, Roger Senior

Associate Professor Adam Rennie

An analogue of a spectral triple over SUq(2) is constructed for which the usual assumption of bounded commutators with the Dirac operator fails. An analytic expression analogous to that for the Hochschild class of the Chern character for spectral triples yields a non-trivial twisted Hochschild 3-cocycle. The problems arising from the unbounded commutators are overcome by defining a residue functional using projections to cut down the Hilbert space.

Dense Domains, Symmetric Operators And Spectral Triples, Iain Forsyth, B Mesland, Adam Rennie

Associate Professor Adam Rennie

This article is about erroneous attempts to weaken the standard definition of unbounded Kasparov module (or spectral triple). This issue has been addressed previously, but here we present concrete counterexamples to claims in the literature that Fredholm modules can be obtained from these weaker variations of spectral triple. Our counterexamples are constructed using self-adjoint extensions of symmetric operators.

A Parametric Analysis Of A Reservoir-Extended Porous Slider Bearing With Self-Circulation And Cavitation Effects, Joshus Johnson, Minel Braun, Kevin Kreider, Gerald Young

Kevin L. Kreider

This work considers a porous slider bearing fed by an external contiguous reservoir. The bearing system consists of a lubricating film, a porous medium, and the external reservoir, which runs along the entire length of the porous medium. The Darcy model is used for modeling the flow inside the porous medium. The translational velocity of the reservoir wall and porous medium, together with the convergent-divergent slider lubricating film profile, acts to pump the fluid out of and into the lubricating film and the reservoir, respectively. Cavitation effects are modeled realistically using the switch function and modified equations of the Elrod …

One-Dimensional Approach To Modeling Damage Evolution In Galvanic Corrosion, Aaron Stenta, S. Basco, A. Smith, Curtis Clemons, Dimitry Golovaty, Kevin Kreider, Joseph Wilder, Gerald Young, Robert Lillard

Kevin L. Kreider

A one-dimensional mathematical model is developed to describe time-dependent damage evolution in well-mixed (spatially uniform species concentrations) galvanic systems using an IR drop approach. An asymptotic procedure taking advantage of disparity in length scales (thin film approximation for the electrolyte thickness) is used to derive the model. Limitations that result from the reduction of dimension are described, along with an analysis demonstrating the ability of the 1D model to capture physical phenomena, such as area ratio effects. Computed potential, current density, and corrosion damage profiles are compared and verified with experimental data available in the literature and 2D galvanic corrosion …

An Adaptive Level Set Approach For Modeling Damage Due To Galvanic Corrosion, Joseph Wilder, Curtis Clemons, Dmitry Golovaty, Kevin Kreider, Gerald Young, R. Lillard

Kevin L. Kreider

This article presents an approach to solving problems related to galvanic corrosion that involve moving boundaries (due to preferential corrosion of one of the metals in the system). The method incorporates an adaptive (node based, finite difference) grid technique for the treatment of boundary-related singularities that arise in the calculation of the electric potential. Simulation of the time evolution of the damage done by the corroding interface is performed using of a level set formulation. An analysis of the convergence of the method and a comparison with experimental data from the literature are included.

One-Dimensional Approach To Modeling Damage Evolution In Galvanic Corrosion, Aaron Stenta, S. Basco, A. Smith, Curtis Clemons, Dimitry Golovaty, Kevin Kreider, Joseph Wilder, Gerald Young, Robert Lillard

Dimitry Golovaty

A one-dimensional mathematical model is developed to describe time-dependent damage evolution in well-mixed (spatially uniform species concentrations) galvanic systems using an IR drop approach. An asymptotic procedure taking advantage of disparity in length scales (thin film approximation for the electrolyte thickness) is used to derive the model. Limitations that result from the reduction of dimension are described, along with an analysis demonstrating the ability of the 1D model to capture physical phenomena, such as area ratio effects. Computed potential, current density, and corrosion damage profiles are compared and verified with experimental data available in the literature and 2D galvanic corrosion …