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Full-Text Articles in Mechanical Engineering

Engineering Design: Representation And Reasoning, Clive Dym, David Brown Dec 2015

Engineering Design: Representation And Reasoning, Clive Dym, David Brown

David C. Brown

This text demonstrates that symbolic representation, and related problem-solving methods, offer significant opportunities to clarify and articulate concepts of design to give a better framework for design research and education. This edition includes recent work on design reasoning, computational design, AI in design, and design cognition, with pointers to the current literature.


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 ...


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 ...


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 ...


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.


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 ...


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 ...


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 ...


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 ...


High School Bridge Program: A Multidisciplinary Stem Research Program, Jiang Zhe, Dennis Doverspike, Julie Zhao, Paul C. Lam, Craig C. Menzemer Oct 2015

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

Craig Menzemer

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 ...


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 ...


An Evaluation Of A Stem Program For Middle School Students On Learning Disability Related Ieps, Paul C. Lam, Dennis Doverspike, Julie Zhao, Jiang Zhe, Craig C. Menzemer Oct 2015

An Evaluation Of A Stem Program For Middle School Students On Learning Disability Related Ieps, Paul C. Lam, Dennis Doverspike, Julie Zhao, Jiang Zhe, Craig C. Menzemer

Craig Menzemer

A year long Science, Technology, Engineering and Math (STEM) program was developed for middle schools students on Individualized Education Programs (IEPs) involving learning disabilities. The workshops were designed to encourage students both on IEPs and not on IEPs to explore STEM as a future career choice by building their knowledge and confidence. The participants in the workshops included 11 students on IEPs and 15 students not on IEPs. Parents also provided feedback regarding their attitudes toward the program. The results indicated that there were increases in student participant knowledge and career interest for both the students not on IEPs and ...


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 Oct 2015

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 ...


The Bearing Strength And Fracture Behavior Of Bolted Connections In Two Aluminum Alloys, Nicholas Tinl, Craig Menzemer, Kannan Manigandan, Tirumalai Srivatsan Oct 2015

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 ...


Extrinsic Influence Of Environment On The Corrosion Behaviour Of Enamel-Coated Steel Dowel Bars, Srikanth Bajaj, Anil Patnaik, Joe Payer, Robert Liang, Kannan Manigandan, Tirumalai Srivatsan Aug 2015

Extrinsic Influence Of Environment On The Corrosion Behaviour Of Enamel-Coated Steel Dowel Bars, Srikanth Bajaj, Anil Patnaik, Joe Payer, Robert Liang, Kannan Manigandan, Tirumalai Srivatsan

Robert Y. Liang

A new type of enamel coated dowel bars for use as concrete pavements has been recently developed and implemented. A gradual deterioration of such bars can occur due to corrosion occurring at locations of the fine microscopic cracks and other defects in the coating. The results of a study aimed at evaluating and understanding the corrosion resistance of such dowel bars is presented and comparisons made with corresponding epoxy-coated dowel bars. Identical defects were introduced onto the surface of the dowel bars with the two types of coatings. The extrinsic influence of environment and resultant corrosion based on type, location ...


Extrinsic Influence Of Environment On The Corrosion Behavior Of Enamel-Coated Steel Dowel Bars, Srikanth Bajaj, Anil Patnaik, Joe Payer, Robert Liang, K. Manigandan, Tirumalai Srivatsan Aug 2015

Extrinsic Influence Of Environment On The Corrosion Behavior Of Enamel-Coated Steel Dowel Bars, Srikanth Bajaj, Anil Patnaik, Joe Payer, Robert Liang, K. Manigandan, Tirumalai Srivatsan

Robert Y. Liang

A new type of enamel coated dowel bars for use as concrete pavements has been recently developed and implemented. A gradual deterioration of such bars can occur due to corrosion occurring at locations of the fine microscopic cracks and other defects in the coating. The results of a study aimed at evaluating and understanding the corrosion resistance of such dowel bars is presented and comparisons made with corresponding epoxy-coated dowel bars. Identical defects were introduced onto the surface of the dowel bars with the two types of coatings. The extrinsic influence of environment and resultant corrosion based on type, location ...


Non-Linear Interactions Of Acoustic Fields With Plates Under Harmonic Excitations, A. Nayfeh, S. Kelly Apr 2015

Non-Linear Interactions Of Acoustic Fields With Plates Under Harmonic Excitations, A. Nayfeh, S. Kelly

Dr. S. Graham Kelly

The method of renormalization is used to determine a uniformly valid expansion for the problem of non-linear interactions of acoustic fields with plates under harmonic excitations. The expansion obtained is in agreement with that obtained by Ginsberg, who used the method of strained co-ordinates to render the potential uniform and then used the method of renormalization to render the non-uniform pressure and velocity components calculated from the resulting potential uniform.


Stress Response Of A Rubber Block With Frictional Contact Under Axial Loading, J. Suh, S. Kelly Apr 2015

Stress Response Of A Rubber Block With Frictional Contact Under Axial Loading, J. Suh, S. Kelly

Dr. S. Graham Kelly

Rubber blocks (or springs) are structural components widely used in many applications. Design characteristics of a rubber block under axial loading are an apparent modulus (or compression modulus) and normal and shear stresses on contact surfaces. These are affected by a contact condition of the rubber block in contact with two rigid plates and the shape of the block. The problem of a rubber block bonded to two rigid plates has been solved using various approaches. In contrast, for a rubber block whose one surface is bonded to a rigid plate and the other surface in contact with a frictional ...


Development Of Normal Mode Theory For Multi-Degree-Of-Freedom Systems Using An Energy Inner Product, S. Kelly Apr 2015

Development Of Normal Mode Theory For Multi-Degree-Of-Freedom Systems Using An Energy Inner Product, S. Kelly

Dr. S. Graham Kelly

No abstract provided.


Fundamentals Of Mechanical Vibrations, S. Kelly Apr 2015

Fundamentals Of Mechanical Vibrations, S. Kelly

Dr. S. Graham Kelly

This text is designed for undergraduate courses in vibrations taught in departments of mechanical engineering. It provides detailed explanations of fundamental aspects of vibrations such as the derivation of differential equations, covers physical interpretation of phenomena using energy methods, and includes chapters on vibration control and nonlinear vibrations. Detailed coverage of the equivalent systems method allows modelling of all one-degree-of-freedom linear systems by a mass-spring-dashpot system.


Non-Linear Propagation Of Directional Spherical Waves, S. Kelly, A. Nayfeh Apr 2015

Non-Linear Propagation Of Directional Spherical Waves, S. Kelly, A. Nayfeh

Dr. S. Graham Kelly

The method of renormalization is used to determine a uniformly valid expansion for the problem of non-linear waves produced in a fluid by spatially non-uniform simple harmonic motion of the surface of a sphere. The effect of dimensionless quantities upon the acoustic shock-formation distance is examined.


Non-Linear Propagation Of General Directional Spherical Waves, S. Kelly, A. Nayfeh Apr 2015

Non-Linear Propagation Of General Directional Spherical Waves, S. Kelly, A. Nayfeh

Dr. S. Graham Kelly

The method of renormalization is used to determine a uniformly valid expansion for the problem of non-linear waves produced in a fluid by the general harmonic pulsations of a sphere. For a uniform expansion, only the radial distance needs to be strained. The effect of dimensionless quantities upon the shock-formation distance is examined.


Mechanics Of Rubber Shear Springs, A. Gent, J. Suh, S. Kelly Apr 2015

Mechanics Of Rubber Shear Springs, A. Gent, J. Suh, S. Kelly

Dr. S. Graham Kelly

FEA calculations have been carried out for a model rubber shear spring, consisting of a block of a highly elastic material, bonded between two rigid parallel plates and sheared by displacing one of the plates parallel to the other in its own plane. The block was prevented from deforming in the perpendicular direction, and thus was deformed in plane strain. Stress distributions along the bond-line and the center-line are reported and compared with those expected from the theory of large elastic deformations. Unexpected tensile stresses were found to develop in the interior of the sheared block. They are attributed to ...


Natural Frequency And Mode Shape Perturbations For Linear Multidegree Of Freedom Systems, S. Kelly Apr 2015

Natural Frequency And Mode Shape Perturbations For Linear Multidegree Of Freedom Systems, S. Kelly

Dr. S. Graham Kelly

No abstract provided.


Free Vibrations Of Elastically Connected Stretched Beams, S. Kelly, Shirish Srinivas Apr 2015

Free Vibrations Of Elastically Connected Stretched Beams, S. Kelly, Shirish Srinivas

Dr. S. Graham Kelly

A general theory for the determination of natural frequencies and mode shapes for a set of elastically connected axially loaded Euler–Bernoulli beams is developed. A normal-mode solution is applied to a set of non-dimensional coupled partial differential equations. The natural frequencies are the eigenvalues of a matrix of differential operators. The matrix operator is shown to be self-adjoint leading to an orthogonality condition for the mode shapes. In the special case of identical beams, it is shown that the natural frequencies are organized into sets of intramodal frequencies in which each mode shape is a product of a spatial ...


Nonlinear Phenomena In A Column Of Liquid In A Rotating Manometer, S. Kelly Apr 2015

Nonlinear Phenomena In A Column Of Liquid In A Rotating Manometer, S. Kelly

Dr. S. Graham Kelly

No abstract provided.


Free And Forced Vibrations Of Elastically Connected Structures, S. Kelly Apr 2015

Free And Forced Vibrations Of Elastically Connected Structures, S. Kelly

Dr. S. Graham Kelly

A general theory for the free and forced responses of elastically connected parallel structures is developed. It is shown that if the stiffness operator for an individual structure is self-adjoint with respect to an inner product defined for , then the stiffness operator for the set of elastically connected structures is self-adjoint with respect to an inner product defined on . This leads to the definition of energy inner products defined on . When a normal mode solution is used to develop the free response, it is shown that the natural frequencies are the square roots of the eigenvalues of an operator that ...


Shear Of Rubber Tube Springs, J. Suh, A. Gent, S. Kelly Apr 2015

Shear Of Rubber Tube Springs, J. Suh, A. Gent, S. Kelly

Dr. S. Graham Kelly

Rubber tube springs consist basically of cylindrical rubber tubes bonded on their inner and outer curved surfaces to rigid cylindrical tubes. They are widely used as flexible linkages, for example in vehicle suspensions. Rotation of one rigid tube with respect to the other about their common axis subjects the rubber tube to azimuthal shear. Displacement of one rigid tube with respect to the other along their common axis puts the rubber tube into axial shear. Using FEA, we have calculated the stresses set up in both cases, for a long rubber tube of a non-linearly elastic (neo-Hookean) material. The results ...


Non-Linear Propagation Of Directional Cylindrical Waves, S. Kelly, A. Nayfeh Apr 2015

Non-Linear Propagation Of Directional Cylindrical Waves, S. Kelly, A. Nayfeh

Dr. S. Graham Kelly

The method of renormalization is used to determine a uniformly valid expansion for the problem of non-linear waves produced in a fluid by the harmonic pulsations of a finite circular cylinder. For a uniform expansion, both the radial and axial distances need to be strained. The effect of dimensionless quantities upon the acoustic shock-formation distance is examined. The results show that the wave produced consists of a number of groups that propagate without any mutual interaction.


Schaum's Interactive Outline Of Mechanical Vibrations And Print Outline, S. Kelly Apr 2015

Schaum's Interactive Outline Of Mechanical Vibrations And Print Outline, S. Kelly

Dr. S. Graham Kelly

No abstract provided.