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FINITE ELEMENT SIMULATION OF SINGLE-LAP SHEAR TESTS UTILIZING THE COHESIVE ZONE APPROACH
Title
FINITE ELEMENT SIMULATION OF SINGLE-LAP SHEAR TESTS UTILIZING THE COHESIVE ZONE APPROACH.
Creator
Perez, Wilson A, Gordon, Ali P., University of Central Florida
Abstract / Description
Many applications require adhesives with high strength to withstand the exhaustive loads encountered in regular operation. In aerospace applications, advanced adhesives are needed to bond metals, ceramics, and composites under shear loading. The lap shear test is the experiment of choice for evaluating shear strength capabilities of adhesives. Specifically during single-lap shear testing, two overlapping rectangular tabs bonded by a thin adhesive layer are subject to tension. Shear is imposed...
Show moreMany applications require adhesives with high strength to withstand the exhaustive loads encountered in regular operation. In aerospace applications, advanced adhesives are needed to bond metals, ceramics, and composites under shear loading. The lap shear test is the experiment of choice for evaluating shear strength capabilities of adhesives. Specifically during single-lap shear testing, two overlapping rectangular tabs bonded by a thin adhesive layer are subject to tension. Shear is imposed as a result. Debonding occurs when the shear strength of the adhesive is surpassed by the load applied by the testing mechanism. This research develops a finite element model (FEM) and material model which allows mechanicians to accurately simulate bonded joints under mechanical loads. Data acquired from physical tests was utilized to correlate the finite element simulations. Lap shear testing has been conducted on various adhesives, specifically SA1-30-MOD, SA10-100, and SA10-05, single base methacrylate adhesives. The adhesives were tested on aluminum, stainless steel, and cold rolled steel adherends. The finite element model simulates what is observed during a physical single-lap shear test consisting of every combination of the mentioned materials. To accomplish this, a three-dimensional model was created and the cohesive zone approach was used to simulate debonding of the tabs from the adhesive. The thicknesses of the metallic tabs and the adhesive layer were recorded and incorporated into the model in order to achieve an accurate solution. From the data, force output and displacement of the tabs are utilized to create curves which were compared to the actual data. Stress and strain were then computed and plotted to verify the validity of the simulations. The modeling and constant determination approach developed here will continue to be used for newly-developed adhesives.
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Date Issued
2016
Identifier
CFH2000149, ucf:45973
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFH2000149
A PARAMETRIC STUDY OF MESO-SCALE PATTERNS FOR AUXETIC MECHANICAL BEHAVIOR OPTIMIZATION
Title
A PARAMETRIC STUDY OF MESO-SCALE PATTERNS FOR AUXETIC MECHANICAL BEHAVIOR OPTIMIZATION.
Creator
Schuler, Matthew C, Gordon, Ali P., University of Central Florida
Abstract / Description
This thesis focuses on the development, parameterization and optimization of a novel meso-scale pattern used to induce auxetic behavior, i.e., negative Poisson�s ratio, at the bulk scale. Currently, the majority of auxetic structures are too porous to be utilized in conventional load-bearing applications. For others, manufacturing methods have yet to realize the meso-scale pattern. Consequently, new auxetic structures must be developed in order to confer superior thermo-mechanical responses...
Show moreThis thesis focuses on the development, parameterization and optimization of a novel meso-scale pattern used to induce auxetic behavior, i.e., negative Poisson�s ratio, at the bulk scale. Currently, the majority of auxetic structures are too porous to be utilized in conventional load-bearing applications. For others, manufacturing methods have yet to realize the meso-scale pattern. Consequently, new auxetic structures must be developed in order to confer superior thermo-mechanical responses to structures at high temperature. Additionally, patterns that take into account manufacturing limitations, while maintaining the properties characteristically attached to negative Poisson�s Ratio materials, are ideal in order to utilize the potential of auxetic structures. A novel auxetic pattern is developed, numerically analyzed, and optimized via design of experiments. The parameters of the meso-structure are varied, and the bulk response is studied using finite element analysis (FEA). Various attributes of the elasto-plastic responses of the bulk structure are used as objectives to guide the optimization process
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Date Issued
2016
Identifier
CFH2000001, ucf:45595
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFH2000001
MECHANICAL CHARACTERIZATION OF ANISOTROPIC FUSED DEPOSITION MODELED POLYLACTIC ACID UNDER COMBINED MONOTONIC BENDING AND TORSION CONDITIONS
Title
MECHANICAL CHARACTERIZATION OF ANISOTROPIC FUSED DEPOSITION MODELED POLYLACTIC ACID UNDER COMBINED MONOTONIC BENDING AND TORSION CONDITIONS.
Creator
Santomauro, Aaron T, Gordon, Ali P., University of Central Florida
Abstract / Description
Mechanical strength of polylactic acid (PLA) is increasingly relevant with time because of its attractive mechanical properties and 3D printability. Additive manufacturing (AM) methods, such as fused deposition modeling (FDM), stereolithography (SLA), and selective laser sintering (SLS), serve a vital role in assisting designers with cheap and efficient generation of the desired components. This document presents research to investigate the anisotropic response of multi-oriented PLA subjected...
Show moreMechanical strength of polylactic acid (PLA) is increasingly relevant with time because of its attractive mechanical properties and 3D printability. Additive manufacturing (AM) methods, such as fused deposition modeling (FDM), stereolithography (SLA), and selective laser sintering (SLS), serve a vital role in assisting designers with cheap and efficient generation of the desired components. This document presents research to investigate the anisotropic response of multi-oriented PLA subjected to multiple monotonic loading conditions. Although empirical data has previously been captured for multi-oriented PLA under tensile and compressive loading conditions, the data has yet to be applied with regard to a representative component geometry. The tensile and compressive empirical data were ultimately used to develop elastic and yield constitutive models which aided in the characterization of PLA under torsion and bending. This representative component geometry is expected to experience a combined torsion and bending load condition in an effort to address this integral gap in the mechanical properties of multi-oriented PLA. In addition to the acquired empirical data, finite element analysis (FEA) and analytical modeling are employed to supplement the accurate modeling of future component analysis. As a result of the proposed array of experiments, the torsional and bending capabilities of PLA are forecasted to vary based on the print orientation. Lastly, the broader impact of this work is dedicated to addressing the material's capability to operate in environments which possess significant torsion and bending such as model aircraft wings and shafts for remote controlled cars.
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Date Issued
2019
Identifier
CFH2000550, ucf:45631
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFH2000550