View All Items

Title: Weight function approach for stress analysis of the surface crack in a finite plate subjected to nonuniform stress fields.
Creator: Jani, Jayant Shivkumar., Florida Atlantic University, Arockiasamy, Madasamy, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The effects of various nonuniform stress fields on the stress intensity factors for the semi-elliptic surface crack (three-dimensional problem) in a finite plate are determined using the weight function approach. The formulation satisfies the linear elastic fracture mechanics criteria and the principle of conservation of energy. Based on the knowledge of stress intensity solutions for the reference load/stress system, the expression for the crack opening displacement function for the surface...
Show moreThe effects of various nonuniform stress fields on the stress intensity factors for the semi-elliptic surface crack (three-dimensional problem) in a finite plate are determined using the weight function approach. The formulation satisfies the linear elastic fracture mechanics criteria and the principle of conservation of energy. Based on the knowledge of stress intensity solutions for the reference load/stress system, the expression for the crack opening displacement function for the surface crack is derived. Using the crack opening displacement function and the reference stress intensity factor, the three-dimensional weight functions and subsequently the stress intensity solutions for the surface crack subjected to nonuniform stress fields are derived. The formulation is then applied to determine the effects of linear, quadratic, cubic, and pure bending stress fields on the stress intensity factor for the surface crack in a finite plate. In the initial stage of the study a two-dimensional problem of an edge-crack emanating from the weld-toe in a T-joint is considered. The effect of parameters such as plate thickness, weld-toe radius, and weld-flank angle on the stress intensity factor for an edge-crack is studied. Finite element analyses of the welded T-joints are performed to study the effects of plate thickness, weld-toe radius and the weld-flank angle on the local stress distribution. The ratio of plate thickness to weld-toe radius ranging from 13.09 to 153.93, and the weld-flank angles of 30, 45, and 60 degrees are considered in the analyses. Based on the results from FEM analyses, a parametric equation for the local stress concentration factor and a polynomial expression for the local stress distribution across the plate thickness are derived using the method of least squares and the polynomial curve-fitting technique.
Show less
Date Issued: 1990
PURL: http://purl.flvc.org/fcla/dt/12254
Subject Headings: Strains and stresses, Plates (Engineering), Fracture mechanics
Format: Document (PDF)

Title: THREE-DIMENSIONAL PHOTOELASTIC STRESS ANALYSIS OF A METAL-TO-METAL CONTACT BOLTED FLANGE.
Creator: Mahfuz, Hassan, Florida Atlantic University, Case, Robert O., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Three-dimensional photoelastic stress analysis techniques are used to determine the stress distribution in a metal-to-metal contact bolted flange. The flange belongs to a thin-walled stage support casing of a jet aircraft engine. Of special interest is the state of stress experienced at flange separation due to axial and bending loads during severe in-flight maneuvering. Details of model development, data collection and discussion of results for the stresses in the bolts and in the vicinity...
Show moreThree-dimensional photoelastic stress analysis techniques are used to determine the stress distribution in a metal-to-metal contact bolted flange. The flange belongs to a thin-walled stage support casing of a jet aircraft engine. Of special interest is the state of stress experienced at flange separation due to axial and bending loads during severe in-flight maneuvering. Details of model development, data collection and discussion of results for the stresses in the bolts and in the vicinity of the flange are presented.
Show less
Date Issued: 1986
PURL: http://purl.flvc.org/fcla/dt/14319
Subject Headings: Strains and stresses, Photoelasticity, Materials--Testing
Format: Document (PDF)

Title: Hybrid stress analysis using digitized photoelastic data and numerical methods.
Creator: Mahfuz, Hassan, Florida Atlantic University, Case, Robert O., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Equations of stress-difference elasticity, derived from the equations of equilibrium and compatibility for a two-dimensional stress field, are solved for arbitrarily digitized, singly and multiply connected domains. Photoelastic data determined experimentally along the boundary provide the boundary values for the solution of the three elliptic partial differential equations by the finite difference method. A computerized method is developed to generate grid mesh, weighting functions and nodal...
Show moreEquations of stress-difference elasticity, derived from the equations of equilibrium and compatibility for a two-dimensional stress field, are solved for arbitrarily digitized, singly and multiply connected domains. Photoelastic data determined experimentally along the boundary provide the boundary values for the solution of the three elliptic partial differential equations by the finite difference method. A computerized method is developed to generate grid mesh, weighting functions and nodal connectivity within the digitized boundary for the solution of these partial differential equations. A method is introduced to digitize the photoelastic fringes, namely isochromatics and isoclinics, and to estimate the values of sigma1 - sigma2, sigma x - sigma y and tau xy at each nodal point by an interpolation technique. Interpolated values of the stress parameters are used to improve the initial estimate and hence the convergence of the iterative solution of the system of equations. Superfluous boundary conditions are added from the digitized photoelastic data for further speeding up the rate of convergence. The boundary of the domain and the photoelastic fringes are digitized by physically traversing the cursor along the boundary, and the digitized information is scanned horizontally and vertically to generate internal and boundary nodal points. A linear search determines the nodal connectivity and isolates the boundary points for the input of the boundary values. A similar scanning method estimates the photoelastic parameters at each nodal point and also finds the points closest to the tint of passage of each photoelastic fringe. Stress values at these close points are determined without interpolation and are subsequently used as superfluous boundary conditions in the iteration scheme. Successive over-relaxation is applied to the classical Gauss-Seidel method for final enhancement of the convergence of the iteration process. The iteration scheme starts with an accelerating factor other than unity and estimates the spectral radius of the iteration matrix from the two vector norms. This information is used to estimate a temporary value of the optimum relaxation parameter, omega[opt], which is used for a fixed number of iterations to approximate a better value of the accelerating factor. The process is continued until two successive estimates differ by a given tolerance or the stopping criteria are reached. Detailed techniques of developing the code for mesh generation, photoelastic data collection and boundary value interpolation to solve the elliptic boundary value problems are presented. Three separate examples with varying stress gradients and fringe patterns are presented to test the validity of the code and the overall method. Results are compared with the analytical and experimental solutions, and the significant improvement in the rate of convergence is demonstrated.
Show less
Date Issued: 1989
PURL: http://purl.flvc.org/fcla/dt/11934
Subject Headings: Strains and stresses, Photoelasticity, Numerical analysis--Data processing
Format: Document (PDF)

Title: Stress distribution around a transverse circular opening through the midspan of a double reinforced beam.
Creator: Anesta, Heather R., College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
Abstract/Description: This manuscript predicts the behavior of a doubly reinforced concrete beam with a circular opening at its midspan by closely analyzing traditional beam theory and design. It then confirms these predictions with finite element modeling software while providing design suggestions. The analysis is limited to the tensile and compressive stresses and cracking behavior. The objectives are to determine the stress distribution around a circular opening that agrees with conventional beam theory. The...
Show moreThis manuscript predicts the behavior of a doubly reinforced concrete beam with a circular opening at its midspan by closely analyzing traditional beam theory and design. It then confirms these predictions with finite element modeling software while providing design suggestions. The analysis is limited to the tensile and compressive stresses and cracking behavior. The objectives are to determine the stress distribution around a circular opening that agrees with conventional beam theory. The beam behavior is examined from zero load to failure load. ANSYS is utilized in lieu of real world testing, and the appendix includes the finite element results for a beam including design recommendations. The results lay the foundation for a possible new design procedure of concrete beams with single or multiple circular openings. This research offers useful information that was unavailable previously. More research can be conducted to help designers to design lighter, more efficient concrete beams.
Show less
Date Issued: 2010
PURL: http://purl.flvc.org/FAU/2867327
Subject Headings: Reinforced concrete construction, Structural design, Strains and stresses, Fracture mechanics
Format: Document (PDF)

Title: Dynamic stability of fluid-conveying pipes on uniform or non-uniform elastic foundations.
Creator: Vittori, Pablo J., Florida Atlantic University, Elishakoff, Isaac, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The dynamic behavior of straight cantilever pipes conveying fluid is studied, establishing the conditions of stability for systems, which are only limited to move in a 2D-plane. Internal friction of pipe and the effect of the surrounding fluid are neglected. A universal stability curve showing boundary between the stable and unstable behaviors is constructed by finding solution to equation of motion by exact and high-dimensional approximate methods. Based on the Boobnov-Galerkin method, the...
Show moreThe dynamic behavior of straight cantilever pipes conveying fluid is studied, establishing the conditions of stability for systems, which are only limited to move in a 2D-plane. Internal friction of pipe and the effect of the surrounding fluid are neglected. A universal stability curve showing boundary between the stable and unstable behaviors is constructed by finding solution to equation of motion by exact and high-dimensional approximate methods. Based on the Boobnov-Galerkin method, the critical velocities for the fluid are obtained by using both the eigenfunctions of a cantilever beam (beam functions), as well as the utilization of Duncan's functions. Stability of cantilever pipes with uniform and non-uniform elastic foundations of two types are considered and discussed. Special emphasis is placed on the investigation of the paradoxical behavior previously reported in the literature.
Show less
Date Issued: 2004
PURL: http://purl.flvc.org/fcla/dt/13167
Subject Headings: Strains and stresses, Structural dynamics, Structural stability, Fluid dynamics, Vibration
Format: Document (PDF)

Title: Compression failure of sandwich specimens with and without face/core debonds.
Creator: Vadakkeveedu, Vinod P., Florida Atlantic University, Carlsson, Leif A., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The objective of this thesis is to report on an experimental study on the compressive behavior of foam cored sandwich composite specimens with and without face/core debond. A test fixture was designed which enables a precisely machined sandwich specimen instrumented with back-to-back strain gages to be loaded in edgewise compression. Tests were conducted on specimens without implanted face/core interface debonds over a range of core densities and gage lengths. The experimentally determined...
Show moreThe objective of this thesis is to report on an experimental study on the compressive behavior of foam cored sandwich composite specimens with and without face/core debond. A test fixture was designed which enables a precisely machined sandwich specimen instrumented with back-to-back strain gages to be loaded in edgewise compression. Tests were conducted on specimens without implanted face/core interface debonds over a range of core densities and gage lengths. The experimentally determined compression strengths and failure modes were compared to closed-form predictions and finite element analysis. Specimens with an implanted through-the-width face/core debond were also tested and mechanism of failure was analyzed using finite element analysis. Good agreement between collapse loads predicted using geometrically nonlinear analysis and experimentally measured strengths was observed.
Show less
Date Issued: 2003
PURL: http://purl.flvc.org/fcla/dt/13047
Subject Headings: Sandwich construction, Strains and stresses, Structural analysis (Engineering)
Format: Document (PDF)

Title: The finite element method as a parametric tool in the design and analysis of a pressure vessel having a threaded closure.
Creator: Merkl, Garrett Andrew., Florida Atlantic University, Case, Robert O., Tsai, Chi-Tay, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The finite element method is a very powerful tool used to analyze a variety of problems in engineering. This thesis looks at the finite element method as a tool and several important modeling features of concern. A well known finite element software package, ANSYS, will be used to demonstrate a diverse number of its capabilities, and several procedures followed in solving a specific engineering problem. The subject matter involves a nonlinear contact analysis of a pressure vessel having a...
Show moreThe finite element method is a very powerful tool used to analyze a variety of problems in engineering. This thesis looks at the finite element method as a tool and several important modeling features of concern. A well known finite element software package, ANSYS, will be used to demonstrate a diverse number of its capabilities, and several procedures followed in solving a specific engineering problem. The subject matter involves a nonlinear contact analysis of a pressure vessel having a threaded closure. The choice of this application is prompted by an interest in better understanding how the finite element method is implemented in the design and analysis of different pressure vessel parameters. A parametric finite element analysis was performed. Load and stress distributions along the threaded region of the vessel were examined for parameters including number of threads, thread pitch, diameter ratio, closure plug length, and thread profile.
Show less
Date Issued: 1996
PURL: http://purl.flvc.org/fcla/dt/15243
Subject Headings: Finite element method, Pressure vessels--Design and construction, Strains and stresses--Mathematical models
Format: Document (PDF)

$Fatigue and fracture of foam cores used in sandwich composites$

Title: Fatigue and fracture of foam cores used in sandwich composites.
Creator: Saenz, Elio., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: This study focused on the fracture and fatigue crack growth behavior in polyvinylchloride (PVC) and polyethersulfone (PES) foams. A new sandwich double cantilever beam (DCB) test specimen was implemented. Elastic foundation and finite element analysis and experimental testing confirmed that the DCB specimen is appropriate for static and cyclic crack propagation testing of soft polymer foams. A comprehensive experimental mechanical analysis was conducted on PVC foams of densities ranging from...
Show moreThis study focused on the fracture and fatigue crack growth behavior in polyvinylchloride (PVC) and polyethersulfone (PES) foams. A new sandwich double cantilever beam (DCB) test specimen was implemented. Elastic foundation and finite element analysis and experimental testing confirmed that the DCB specimen is appropriate for static and cyclic crack propagation testing of soft polymer foams. A comprehensive experimental mechanical analysis was conducted on PVC foams of densities ranging from 45 to 100 kg/m3 and PES foams of densities ranging from 60 to 130 kg/m3. An in-situ scanning electron microscope study on miniature foam fracture specimens showed that crack propagation in the PVC foam was inter-cellular and in the PES foam, failure occurred predominately by extensional failure of vertical cell edges. Sandwich DCB specimens were loaded cyclically as well. For the PVC foams, the crack growth rates were substantially influenced by the density. For the PES foams, there was no clear indication about the influence of foam density on the crack growth rate.
Show less
Date Issued: 2012
PURL: http://purl.flvc.org/FAU/3352829
Subject Headings: Sandwich construction, Composite materials, Fibrous composites, Strains and stresses, Management, Laminated materials, Plastics, Fatigue
Format: Document (PDF)

Title: Stress intensity factors and weight functions for surface cracks using boundary/finite element alternating methods.
Creator: Mu, Ruijia., Florida Atlantic University, Reddy, Dronnadula V., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: In the present investigation, the boundary/finite element alternating methods are used to evaluate the stress intensity factors and weight functions for surface crack problems. For two dimensional problems, Westergaard stress functions are used to find the analytical solutions for an infinite plate with an embedded crack, subjected to crack face tractions, and the boundary element method for the numerical solution. The stress intensity factors and weight functions for an arbitrary plate with...
Show moreIn the present investigation, the boundary/finite element alternating methods are used to evaluate the stress intensity factors and weight functions for surface crack problems. For two dimensional problems, Westergaard stress functions are used to find the analytical solutions for an infinite plate with an embedded crack, subjected to crack face tractions, and the boundary element method for the numerical solution. The stress intensity factors and weight functions for an arbitrary plate with an edge crack subjected to mixed mode loads are obtained by the alternating technique. For three dimensional problems, an elliptical coordinate system and the gravity potential functions are used to derive the three dimensional analytical solutions for an infinite solid with an embedded crack. The analytical solutions are derived for the cases of shear tractions and normal tractions, separately, by assuming that the tractions are symmetric about both the major and minor axes. Superposition gives the general solutions. The analytical solutions and the finite element method, in conjunction with alternating technique, are used to evaluate the stress intensity factors for a solid with a semi-elliptical surface crack, subjected to arbitrary loads. A general approach to evaluate the weight functions for a two dimensional plate with a three dimensional semi-elliptical surface crack is formulated. Numerical examples are evaluated using the formulation developed in the present investigation. The results show good agreement with those from classical solutions. The convergence characteristics of the alternating methods are also discussed. Finally, the formulation is applied to welded plate T-joints with edge/semi-elliptical surface cracks, subjected to three point bending, to obtain stress intensity factors.
Show less
Date Issued: 1992
PURL: http://purl.flvc.org/fcla/dt/12319
Subject Headings: Fracture mechanics, Finite element method--Data processing, Materials--Fatigue, Strains and stresses
Format: Document (PDF)

Title: Study of edge effects in laminated sandwich specimens.
Creator: Mankuzhy, Pradeep Prabhakaran., Florida Atlantic University, Merry, Stephanie L., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: Different methods have been employed to calculate the interlaminar stresses and to study the edge effect in a laminated sandwich specimens under uniaxial tension. However, Finite Element Analysis and Force Balance Method produced stress values which disagreed in both magnitude and sign, a controversy which exists in the case of composite laminates also. Experimental methods, photoelastic coating method and strain gaging, were attempted to obtain the strain distribution on the top surface of a...
Show moreDifferent methods have been employed to calculate the interlaminar stresses and to study the edge effect in a laminated sandwich specimens under uniaxial tension. However, Finite Element Analysis and Force Balance Method produced stress values which disagreed in both magnitude and sign, a controversy which exists in the case of composite laminates also. Experimental methods, photoelastic coating method and strain gaging, were attempted to obtain the strain distribution on the top surface of a sandwich specimen in three point bending. However, these conventional methods failed to show the sharp strain gradient that exists near the free edge. The Force Balance Method was simplified for sandwich specimens by considering the face laminate as a homogeneous and orthotropic material with averaged properties. Simplified expressions were also obtained for calculating the boundary layer thickness. The boundary layer thickness was found to vary linearly with core thickness for the cases considered.
Show less
Date Issued: 1989
PURL: http://purl.flvc.org/fcla/dt/14523
Subject Headings: Sandwich construction--Fatigue, Composite materials, Strains and stresses, Structural analysis (Engineering)
Format: Document (PDF)

Title: Behavior of precast single-cell segmental box bridges with external post-tensioning subjected to cyclic loading and temperature changes.
Creator: Sinha, Vikas., Florida Atlantic University, Arockiasamy, Madasamy, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The behavior of a precast single-cell segmental box bridge with external post-tensioning is studied based on a 1:3.5 scale model of the Long Key bridge in the Florida Keys. Constant amplitude fatigue loading was applied on the model at a critical location simulating HS20-44 AASHTO truck loading. The performance of the bridge model was evaluated in terms of deflections, strains in concrete and across the joints, and behavior of joints between the segments with increasing number of cycles of...
Show moreThe behavior of a precast single-cell segmental box bridge with external post-tensioning is studied based on a 1:3.5 scale model of the Long Key bridge in the Florida Keys. Constant amplitude fatigue loading was applied on the model at a critical location simulating HS20-44 AASHTO truck loading. The performance of the bridge model was evaluated in terms of deflections, strains in concrete and across the joints, and behavior of joints between the segments with increasing number of cycles of fatigue loading. Thermal response of the bridge model was also studied using finite element analysis and the predicted temperature distributions were compared with the experimental values.
Show less
Date Issued: 1991
PURL: http://purl.flvc.org/fcla/dt/14729
Subject Headings: Precast concrete construction--Fatigue, Post-tensioned prestressed concrete construction--Fatigue, Bridges, Box girder, Strains and stresses
Format: Document (PDF)

Title: Microcomputer and exsysp based expert system for selection and design of retaining structures.
Creator: Sinha, Anuradha., Florida Atlantic University, Arockiasamy, Madasamy, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
Abstract/Description: The automation of retaining structure selection and design by utilizing artificial intelligence tools is presented herein. The study involved the development of a microcomputer based expert system, RESTEX (REtaining STructure EXpert). The modules of the expert systems RETAININGEARTH, with M.1 knowledge base, and REFLEXYS have been updated and the resulting RESTEX modules are written in C using Exsys Professional for high speed and efficient utilization of memory. RESTEX is an interactive menu...
Show moreThe automation of retaining structure selection and design by utilizing artificial intelligence tools is presented herein. The study involved the development of a microcomputer based expert system, RESTEX (REtaining STructure EXpert). The modules of the expert systems RETAININGEARTH, with M.1 knowledge base, and REFLEXYS have been updated and the resulting RESTEX modules are written in C using Exsys Professional for high speed and efficient utilization of memory. RESTEX is an interactive menu-driven system consisting of modules for Structure Selection, Preliminary Design, Soils Classification, Stability Analysis, and Reinforcement Design. The system is capable of performing selection, analysis, and design of gravity walls, cantilever walls, counterfort walls, reinforced earth, gabion, cantilever and anchored sheet piles.
Show less
Date Issued: 1993
PURL: http://purl.flvc.org/fcla/dt/14937
Subject Headings: Precast concrete construction--Fatigue, Post-tensioned prestressed concrete construction--Fatigue, Bridges, Box girder, Strains and stresses
Format: Document (PDF)

Strains and stresses (11)	+ -
Fracture mechanics (3)	+ -
Bridges, Box girder (2)	+ -
Composite materials (2)	+ -
Photoelasticity (2)	+ -

Post-tensioned prestressed concrete construction--Fatigue (2)	+ -
Precast concrete construction--Fatigue (2)	+ -
Sandwich construction (2)	+ -
Structural analysis (Engineering) (2)	+ -
Fatigue (1)	+ -
Fibrous composites (1)	+ -
Finite element method (1)	+ -
Finite element method--Data processing (1)	+ -
Fluid dynamics (1)	+ -
Laminated materials (1)	+ -
Management (1)	+ -
Materials--Fatigue (1)	+ -
Materials--Testing (1)	+ -
Numerical analysis--Data processing (1)	+ -
Plastics (1)	+ -
Plates (Engineering) (1)	+ -
Pressure vessels--Design and construction (1)	+ -
Reinforced concrete construction (1)	+ -
Sandwich construction--Fatigue (1)	+ -
Strains and stresses--Mathematical models (1)	+ -
Structural design (1)	+ -
Structural dynamics (1)	+ -
Structural stability (1)	+ -
Vibration (1)	+ -

College of Engineering and Computer Science (12)	+ -
Department of Ocean and Mechanical Engineering (11)	+ -
Florida Atlantic University (10)	+ -
Arockiasamy, Madasamy (3)	+ -
Case, Robert O. (3)	+ -

Mahfuz, Hassan (2)	+ -
Anesta, Heather R. (1)	+ -
Carlsson, Leif A. (1)	+ -
Department of Civil, Environmental and Geomatics Engineering (1)	+ -
Elishakoff, Isaac (1)	+ -
Jani, Jayant Shivkumar. (1)	+ -
Mankuzhy, Pradeep Prabhakaran. (1)	+ -
Merkl, Garrett Andrew. (1)	+ -
Merry, Stephanie L. (1)	+ -
Mu, Ruijia. (1)	+ -
Reddy, Dronnadula V. (1)	+ -
Saenz, Elio. (1)	+ -
Sinha, Anuradha. (1)	+ -
Sinha, Vikas. (1)	+ -
Tsai, Chi-Tay (1)	+ -
Vadakkeveedu, Vinod P. (1)	+ -
Vittori, Pablo J. (1)	+ -

Search In

Sort Results By:

Narrow results by:

Collection

Topical Subject

Genre

Type of Resource

Language

Creator

Format

Owner