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Joshi, Atul RavindraDesign and control of a three degree-of-freedom planar parallel robot
Master of Science (MS), Ohio University, 2003, Mechanical Engineering (Engineering)

This thesis has presented kinematics, hardware construction, and control architecture for the planar parallel 3-RPR manipulator built at Ohio University. This three-dof manipulator is actuated by three active pneumatic cylinder prismatic joints. The revolute joints are all passive. The workspace computation and analysis have also been presented in chapter 2.

In a limited workspace the robot can reach general planar poses (translation and rotation). Applications for this type of robot include manufacturing and assembly where high speed and accuracy are required in a relatively small workspace. Other applications are planar motion simulators and haptic interfaces. The 3-RPR hardware is controlled in real-time via a PC with a Simulink model reading LVDT feedback and commanding solenoid valves via the Quanser Multi-Q boards and Wincon software. The control architecture controls the three pneumatic cylinder lengths independently but simultaneously in this environment. The coordinated Cartesian control of the 3-RPR planar parallel robot via linearized independent prismatic link length control has been implemented. The Simulink block diagram is built, based on this control architecture.

The control routine for the Cartesian control modes (inverse pose control or resolved rate control) has been proposed and can be implemented as suggested in the concluding chapter. Future work suggests hardware improvements should be made to improve accuracy. Also, workspace optimization can be done for future work.

Committee:

Robert Williams, II. (Advisor)

Subjects:

Engineering, Mechanical

Keywords:

Kinematics Construction; Planar Parallel Manipulator; 3-RPR Manipulator; Three-Dof Manipulator; Active Pneumatic Joints; Haptic Interfaces; Simulink Model; Cartesian Control Modes; Cylinder Prismatic Joints

Page, Steven MInvestigation into the Behavior of Bolted Joints
Master of Science in Engineering (MSEgr), Wright State University, 2006, Mechanical Engineering
Models to capture the physics of jointed structures have been proposed for over 40 years. These models approximate the behavior of the joint under carefully developed operating conditions. When these conditions change, the model has to be changed. Recent developments in numeric codes like finite elements have created interest in incorporating joint models into the design process but joint models need to represent the joined structure over a broader operating range. This work investigates the dynamic response of a structure with a joint. Isolation of a few dominant effects may give way to a model able to capture a broader operating range. To isolate the effects of the joint two specimens were created. A specimen that is without a joint serves as a control. The second specimen is geometrically similar and contains a double lap joint with a bolt fastener. The differences between the specimens represent the effects of the bolt. Control variables of bolt tension, excitation level and sampling time were chosen. Amplitude response and hysteresis curves were recorded. This data was used to examine the non-linear response of the bolted specimen. Qualitative observations are included. The control specimen shows little effect from non-linear behavior in the frequency response. The bolted specimen shows non-linear behavior in the frequency response. When the joint is introduced to the geometry the system drops in amplitude, drops in resonant frequency, and demonstrates a non-linear softening effect. As the initial bolt tension is reduced the magnitudes of these changes increase. In addition when the system is allowed to dwell with a single sine wave at resonance the amplitude of the response often increases. Hysteresis curves reveal that more than a softening non-linearity affects the response. The curve shows a softening affect when displacing in one direction and a hardening affect when displacing in the opposite direction. This may be affected by the geometry as the control specimen demonstrates a tri-linear stiffness. It is evident that previous joint models do not capture all of the effects observed. Additional research to link the physical cause to the observed affect will aid in adjusting or creating a joint model to be used in numeric codes.

Committee:

Joseph Slater (Advisor)

Subjects:

Engineering, Mechanical

Keywords:

Bolted Joints; Joint damping; Structural mechanics of joints

Kaleps, IntsCharacterization of constraints and forces acting between loosely coupled bodies with application to human joint mechanics.
Doctor of Philosophy, The Ohio State University, 1981, Graduate School

Committee:

Not Provided (Other)

Subjects:

Engineering

Keywords:

Human mechanics;Joints;Dynamics

Pavliscak, Thomas JosephAn Investigation of the fretting-fatigue properties of metallic joints /
Doctor of Philosophy, The Ohio State University, 1968, Graduate School

Committee:

Not Provided (Other)

Subjects:

Engineering

Keywords:

Fretting corrosion;Joints

Filiano, Gina LRole of Joints and Rock Stresses in the Formation of Sandstone Caves in Northeastern Ohio
Master of Science, University of Akron, 2014, Geology
There are numerous caves and joints associated with the Pennsylvanian Sharon and the Mississippian Berea Sandstones in northeastern Ohio. The cave passages are formed along main vertical joint sets, therefore the origin of the caves has been proposed to have initiated by mechanical processes. These caves are located along sandstone knob margins, initially carved by streams and later altered by Pleistocene glaciers. Joint plane orientations were measured at four locations in glaciated terrain in northeastern Ohio where extensive caves were known: Camp Christopher, Virginia Kendall Ledges, and Liberty Park in Summit County, and Little Mountain in Lake County. Joint plane orientations were also documented at three locations in unglaciated southeast Ohio: Machan's Rock and Dundee Falls in Tuscarawas County, and Ash Cave and Rock House in Hocking County. Joints north of the glacial terminus were categorized into four sets: (J1) planar vertical joints that parallel the local knob margin, (J2) planar vertical joints that formed perpendicular to the knob margin, (J3) minor joints that strike northwest, and (J4) minor joints that strike northeast. Joints occurred in a lower frequency south of the glacial terminus and were divided into three sets: (J1) vertical joints that parallel the local topography, (J2) vertical joints that strike perpendicular to the local topography, and (J3) minor joints that strike northwest or northeast with respect to topography. Finite element models were created to simulate the stresses that would occur and potentially form these joint sets. Potential stress origins were determined for each joint set. Joints oriented parallel and perpendicular to the sandstone knobs most likely formed from valley stress relief due to the unloading glacier stresses. As the glacier retreated, the confining pressure was released exerting tensile stresses on the knob margins. Evidence supports glacial unloading as a cause of joint and cave formation in northeast Ohio. The northeast striking joints are interpreted to be related to the current maximum horizontal compression stress. After joints were formed, the stresses were reoriented, enabling a second set of joints to form normal to the northeast-striking joint set.

Committee:

Ira Sasowsky, Dr. (Advisor); David Steer, Dr. (Committee Member); Linda Barrett, Dr. (Committee Member); Ernian Pan, Dr. (Committee Member)

Subjects:

Geological; Geology

Keywords:

joints; Ohio; geology; sandstone caves; stresses

Rogers, Robert CraigExperimental analysis of steel dowels used in Y and YU type contraction joints for the repair of concrete pavements subjected to truck loading
Master of Science (MS), Ohio University, 1991, Civil Engineering (Engineering)
Experimental analysis of steel dowels used in Y and YU type contraction joints for the repair of concrete pavements subjected to truck loading

Committee:

Glen Hazen (Advisor)

Subjects:

Engineering, Civil

Keywords:

Experimental Analysis; Steel Dowels; Y and YU Type Contraction Joints; Concrete Pavements; Truck Loading

Butt, Aamir S.Finite element analysis of Y and YU type contraction joints for concrete pavements using steel dowels as load transfer devices
Master of Science (MS), Ohio University, 1990, Civil Engineering (Engineering)
Finite element analysis of Y and YU type contraction joints for concrete pavements using steel dowels as load transfer devices

Committee:

Shad Sargand (Advisor)

Subjects:

Engineering, Civil

Keywords:

Finite Element Analysis; Y and YU Type Contraction Joints; Concrete Pavements; Steel Dowels; Load Transfer Devices

Pannila, IndraExperimental and finite element analysis of Y and YU type contraction joints in concrete pavements
Master of Science (MS), Ohio University, 1995, Civil Engineering (Engineering)

Experimental and finite element analysis of Y and YU type contraction joints in concrete pavements

Committee:

Shad Sargand (Advisor)

Subjects:

Engineering, Civil

Keywords:

Finite Element; Y and YU Type Contraction Joints; Concrete Pavements

Thummalapalli, Vimal KumarBiomimetic Composite T-Joints
Master of Science (M.S.), University of Dayton, 2011, Materials Engineering

Composite structural joints, as observed throughout the natural world, have been systematically altered and proven via lengthy evolutionary processes. Biological fixed joints tend to exhibit unique attributes, including highly optimized fiber paths to minimize stress concentrations. In addition, since the joints consist of continuous, uncut fiber flow patterns, the joint does not inhibit the biological organism in the transportation of information, chemicals and food from one part of the body to the other. To the contrary, large sections of man-made composite material structures are often joined using bolted or bonded joints, which involve low strength and high stress concentrations. These methods are also expensive to achieve. Additional functions such as fluid transport, electrical signal delivery, and electrical and thermal conductivity across the joints typically require parasitic tubes, wires, and clips. By using the biomimetic methods, we seek to overcome the limitations which are present in the conventional methods. In the present work, biomimetic co-cured composite sandwich T-joints were constructed using unidirectional glass fiber, epoxy resin, and structural foam. The joints were fabricated using the wet lay-up vacuum bag resin infusion method. Foam sandwich T-joints with multiple continuous fiber architectures and sandwich foam thickness were prepared. The various joint designs were tested quasi-statically in bending of the T in a calibrated screw-driven load frame. Custom, purpose-designed fixtures were required to support the base of the joint during the bending load. The weight savings using the biomimetic approaches is discussed, as well as a comparison of failure modes versus fiber/core architectures is given.

In addition to developing structurally optimized, weight-efficient joints, a tremendous ancillary benefit to the approach is the ability to easily embed wires and micro tubes contiguous across the joined elements. This approach is key to achieving true robust structural multi-functionality.

Committee:

Steven Donaldson (Committee Chair); Thomas Whitney (Committee Member); Elias Toubia (Committee Chair)

Subjects:

Aerospace Engineering; Aerospace Materials; Automotive Engineering; Automotive Materials; Biology; Civil Engineering; Engineering; Materials Science; Mechanical Engineering; Mechanics; Naval Engineering; Plant Sciences; Polymers; Textile Research

Keywords:

Composites; Composite T-Joints; Sandwitch Structures; Biomimetics; Bionic

Fisher, Matthew JohnExperimental Evaluation of Reinforcement Methods for Concrete Beam-Column Joints
Master of Science, The Ohio State University, 2009, Civil Engineering

Prefabricated Cage System (PCS), a new method of reinforcement for concrete members, has recently been proposed as an alternative to traditional steel reinforcing bar (rebar) cage reinforcement. PCS involves the fabrication of a reinforcing cage cut from a hollow steel tube. The result is a monolithic reinforcing cage free from tied joints and hooked bars currently found in rebar cages. A criticism of PCS reinforcement to date has been a lack of research demonstrating the ability of the reinforcement to be used in a structural system, in which beams, columns, walls and floor slabs must all frame together and work concurrently to resist loadings.

Six beam-column joint specimens were constructed and tested under reverse cyclic loading to failure. The six specimens are divided into three groups, each group representing a different joint design. Within each of the three groups are equivalent PCS and rebar reinforced specimens. The overall load and deformation capacities of the PCS joints are compared to those of equivalent rebar joints. The results of the present study show that the PCS joints had a slightly higher strength and significantly greater deformation capacities than the equivalent rebar joints.

Committee:

Halil Sezen, PhD (Advisor); Hojjat Adeli, PhD (Committee Member); Shive Chaturvedi, PhD (Committee Member)

Subjects:

Engineering

Keywords:

Beam-column joints; steel reinforcement; reinforced concrete; shear failure

Riggs, Bryan EMULTI-SCALE COMPUTATIONAL MODELING OF NI-BASE SUPERALLOY BRAZED JOINTS FOR GAS TURBINE APPLICATIONS
Doctor of Philosophy, The Ohio State University, 2017, Welding Engineering
Brazed joints are commonly used in the manufacture and repair of aerospace components including high temperature gas turbine components made of Ni-base superalloys. For such critical applications, it is becoming increasingly important to account for the mechanical strength and reliability of the brazed joint. However, material properties of brazed joints are not readily available and methods for evaluating joint strength such as those listed in AWS C3.2 have inherent challenges compared with testing bulk materials. In addition, joint strength can be strongly influenced by the degree of interaction between the filler metal (FM) and the base metal (BM), the joint design, and presence of flaws or defects. As a result, there is interest in the development of a multi-scale computational model to predict the overall mechanical behavior and fitness-for-service of brazed joints. Therefore, the aim of this investigation was to generate data and methodology to support such a model for Ni-base superalloy brazed joints with conventional Ni-Cr-B based FMs. Based on a review of the technical literature a multi-scale modeling approach was proposed to predict the overall performance of brazed joints by relating mechanical properties to the brazed joint microstructure. This approach incorporates metallurgical characterization, thermodynamic/kinetic simulations, mechanical testing, fracture mechanics and finite element analysis (FEA) modeling to estimate joint properties based on the initial BM/FM composition and brazing process parameters. Experimental work was carried out in each of these areas to validate the multi-scale approach and develop improved techniques for quantifying brazed joint properties. Two Ni-base superalloys often used in gas turbine applications, Inconel 718 and CMSX-4, were selected for study and vacuum furnace brazed using two common FMs, BNi-2 and BNi-9. Metallurgical characterization of these brazed joints showed two primary microstructural regions; a soft, ductile a-Ni phase that formed at the joint interface and a hard, brittle multi-phase centerline eutectic. CrB and Ni3B type borides were identified in the eutectic region via electron probe micro-analysis, and a boron diffusion gradient was observed in the BM adjacent to the joint. The volume fraction of centerline eutectic was found to be highly dependent on the extent of the boron diffusion that occurred during brazing and therefore a function of the primary process parameters; hold time, temperature, FM/BM composition, and joint gap. Thermo-CalcTM and DICTRATM simulations were used to model the BM dissolution, isothermal solidification and phase transformations that occurred during brazing to predict the final joint microstructure based on these process parameters. Good agreement was found between experimental and simulated joint microstructures at various joint gaps demonstrating the application of these simulations for brazed joints. However, thermodynamic/kinetic databases available for brazing FMs were limited. A variety of mechanical testing was performed to determine the mechanical properties of CMSX-4/BNi-2 and IN718/BNi-2 brazed joints including small-scale tensile tests, standard-size butt joints and lap shear tests. Small-scale tensile testing provided a novel method for studying microstructure-property relationships in brazed joints and indicated that both joint strength and ductility decrease significantly with an increase in the volume fraction of centerline eutectic. In-situ observations during small-scale testing also showed strain localization and crack initiation occurs around the hard, eutectic phases in the joint microstructure during loading. The average tensile strength for standard-size IN718/BNi-2 butt joints containing a low volume fraction of centerline eutectic was found to be 152.8 ksi approximately 90% of the BM yield strength (~170 ksi). The average lap shear FM stress was found to decrease from 70 to 20 ksi for IN718/BNi-2 joints and from 50 to 15 ksi for CMSX-4/BNi-2 as the overlap was increased from 1T to 5T due to non-uniform stress/strain distribution across the joint. Digital image correlation techniques and FEA models of the lap shear brazed joints were developed to assess the strain distributions across the overlap. Results were used to validate the use of damage zone models for predicting the load carrying capacity of lap shear brazed joints and suggest that the damage zone is independent of the overlap length. To account for the presence of flaws and defects in fitness-for-service assessments of brazed joints determination of the average fracture toughness (KIC) is necessary. Currently no standard exists to measure the KIC for brazed joints, so three test methods were evaluated in this investigation on IN718/BNi-2 brazed joints. The compact tension and double cantilever beam test methods were found to give the most conservative KIC values of 16.42 and 14.42 ksivin respectively. Linear-elastic FEA models of the test specimens were used to validate the calculated KIC values. Similar to joint strength the fracture toughness appeared to be strongly influenced by the volume fraction of centerline eutectic phases. The data and methodology generated in this initial study provides validation for the proposed multi-scale computational model by demonstrating microstructure-property relationships in brazed joints and the ability to predict joint microstructure using simulation tools. Furthermore, an experimental framework and new techniques including small-scale tensile testing, digital image correlation and fracture mechanics were established to assist in future modeling efforts. Ultimately, successful development and implementation of multi-scale computational models for brazed joints will allow for the optimization of BM/FM compositions, brazing process optimization, improved reliability of brazed joints, and more efficient design and analysis of brazed components by accounting for the properties of the joint. In addition, the overall multi-scale modeling approach demonstrated in this investigation may also be applied for dissimilar joints in general, for example dissimilar metal welds used in oil and gas, petrochemical, nuclear and power generation industries.

Committee:

Boian Alexandrov, Ph.D. (Advisor); Avraham Benatar, Ph.D. (Advisor); Carolin Fink, Ph.D. (Committee Member)

Subjects:

Engineering; Materials Science

Keywords:

Brazing; Brazed Joints; Ni-base Superalloys; Microstructure; Modeling; Digital Image Correlation; Mechanical Properties

Kalpathy Venkiteswaran, VenkatasubramanianDevelopment of a Design Framework for Compliant Mechanisms using Pseudo-Rigid-Body Models
Doctor of Philosophy, The Ohio State University, 2017, Mechanical Engineering
Compliant mechanisms achieve motion by utilizing deformation of elastic members. They offer many advantages over conventional rigid-body mechanisms such as elimination of friction or wear and tear. They also offer greater accuracy and can usually be fabricated as a single part, without the need for assembly. They are used in a wide variety of applications, particularly in the fields of robotics and precision engineering. However, the deformation of different parts of a compliant mechanism makes the analysis and design of such devices a challenge. This dissertation seeks to address the need for a design framework for compliant mechanisms. Many compliant mechanisms use beam-like structures, or flexures. These elements are usually analyzed using beam theory, in the form of differential equations. In this work, a beam theory approximation combining shear, elongation and Poisson's effects is developed to improve the accuracy of our predictions. The beams are replaced by pseudo-rigid-body (PRB) models, which serve as a convenient tool for the analysis of compliant mechanisms. They are rigid-body approximations of compliant elements that replace the differential equations of beam theory with algebraic equations. PRB models can be developed for various types of compliant elements, and two new models are shown here for soft compliant joints and circular beams. The use of these models in design and analysis problems is also illustrated. A general method of representation and derivation of PRB models is presented, along with a list of various PRB models, to be used as part of a design framework. The reasons for the errors that creep into these models are also studied and guidelines suggested to eliminate them. The initial design of a mechanism for a specific application can be an arduous task, and this is also addressed using a new topology optimization process using PRB models. The overarching goal of setting up this framework is to streamline the process of design of compliant mechanisms. Using PRB models speeds up the computation involved in design optimization, as opposed to solving differential equations from beam theory or high-fidelity Finite Element Analysis. Better knowledge of accuracy and complexity of the models can help the designer choose the optimal PRB model for a specific application. The parameter optimization framework and the list of PRB models will provide researchers with tools for deriving the values for a PRB model. The topology optimization technique is capable of deducing a feasible solution from a large pool of possible design solutions. This may be extended to shape optimization as well. There are many applications for such methods, some of which are shown here, including compliant robotic manipulators, micropsine grippers for space applications and micro-scale force sensors.

Committee:

Haijun Su (Advisor); Carlos Castro (Committee Member); Mo-How Shen (Committee Member); Soheil Soghrati (Committee Member)

Subjects:

Mechanical Engineering

Keywords:

Compliant mechanisms; pseudo-rigid-body models; PRB models; PRBM; soft joints; compliant beams; extension effects; topology optimization; curved beams; shape deposition manufacturing; SDM

Moore, Thomas KittrellThe influence of hole processing and joint variables on the fatigue life of shear joints /
Doctor of Philosophy, The Ohio State University, 1977, Graduate School

Committee:

Not Provided (Other)

Subjects:

Engineering

Keywords:

Metals;Joints

Moeinzadeh, Manssour H.Two and three-dimensional dynamic modeling of human joint structures with special application to the knee joint.
Doctor of Philosophy, The Ohio State University, 1981, Graduate School

Committee:

Not Provided (Other)

Subjects:

Engineering

Keywords:

Joints;Knee

Swick, David A.Design of a comprehensive computer aided design package for the design of mechanical joints
Master of Science (MS), Ohio University, 1988, Mathematics Education (Education)

Design of a comprehensive computer aided design package for the design of mechanical joints

Committee:

Kenneth Halliday (Advisor)

Subjects:

Engineering, Mechanical

Keywords:

Computer Aided Design Package; Design of Mechanical Joints

Sander, Jason AndrewMechanical-Empirical Performance of U.S. 50 Joint Sealant Test Pavement
MS, University of Cincinnati, 2007, Engineering : Civil Engineering
Previous studies have suggested that joint sealing practices may significantly enhance concrete pavement ride quality and structural performance. Presented herein is a performance report for the U.S. 50 Ohio High Performance Concrete Pavement (HPCP) Joint Sealant Experiment near Athens, Ohio. The experimental concept and data analysis for this project conforms to guidelines established in the on-going Strategic Highway Research Program (SHRP) sealing effectiveness initiative. The development of a performance inspection plan for consistent collection of data related to the effectiveness of various joint sealants installed at the test site is described. Evaluation activities performed between the Fall of 1999 and the Spring of 2000 are detailed. The performance of the concrete pavement system is also documented by tracking development of structural distresses, ride quality consistency and through mechanistic evaluation of several features affecting concrete pavement performance. Several recommendations for future investigations are formulated based on the evaluation and mechanistic results.

Committee:

Dr. Anastasios Ioannides (Advisor)

Subjects:

Engineering, Civil

Keywords:

joint sealing; unsealed joints; concrete pavement joint sealants; SHRP sealing effectiveness initiative; mechanistic evaluation of drainage features; joint sealant effectiveness; mechanistic evaluation of load transfer devices

Walters, Shane A.Field performance of dowel bars
Master of Science (MS), Ohio University, 1999, Civil Engineering (Engineering)

Field performance of dowel bars

Committee:

Shad Sargand (Advisor)

Subjects:

Engineering, Civil

Keywords:

dowel bars; transverse rigid pavement joints; Falling Weight Deflectometer; fiberglass dowel bars

Bosel, TodFinite element analysis of Y and YU type contraction joints in concrete pavements
Master of Science (MS), Ohio University, 1990, Civil Engineering (Engineering)
Finite element analysis of Y and YU type contraction joints in concrete pavements

Committee:

S. Sargand (Advisor)

Subjects:

Engineering, Civil

Keywords:

Finite Element Analysis; Y and YU Type Contraction Joints; Concrete Pavements

Choksi, GaurangStress analysis of single LAP adhesive bonded joints
Master of Science (MS), Ohio University, 1984, Mechanical Engineering (Engineering)

Stress analysis of single LAP adhesive bonded joints

Committee:

Kenneth Halliday (Advisor)

Subjects:

Engineering, Mechanical

Keywords:

Stress Analysis; Single LAP Adhesive Bonded Joints; Finite Element Model

Chen, Shuenn-muhKinematic and passive resistive properties of human shoulder hip and elbow complexes /
Doctor of Philosophy, The Ohio State University, 1986, Graduate School

Committee:

Not Provided (Other)

Subjects:

Engineering

Keywords:

Human mechanics;Joints;Shoulder joint;Hip joint;Elbow

Cinadr, Edward MichaelTrue forces in dowels in rigid pavement joints
Master of Science (MS), Ohio University, 1997, Civil Engineering (Engineering)

True forces in dowels in rigid pavement joints

Committee:

Shad Sargand (Advisor)

Subjects:

Engineering, Civil

Keywords:

Falling Weight Test; Hermocouples; Dowel; Rigid Pavement Joints

Yen, Hsin-YiNew analysis and design procedures for ensuring gas turbine blades and adhesive bonded joints structural integrity and durability /
Doctor of Philosophy, The Ohio State University, 2000, Graduate School

Committee:

Not Provided (Other)

Subjects:

Engineering

Keywords:

Gas-turbines;Adhesive joints

Davies, Kent BertramOn the mechanics of failure in bolted rail joints /
Doctor of Philosophy, The Ohio State University, 1978, Graduate School

Committee:

Not Provided (Other)

Subjects:

Engineering

Keywords:

Railroad engineering;Bolted joints

Laubach, Lloyd LutherCharacteristics of the range of joint motion and its relationship to selected anthropometric dimensions and somatotype components /
Doctor of Philosophy, The Ohio State University, 1969, Graduate School

Committee:

Not Provided (Other)

Subjects:

Education

Keywords:

Joints

Hansen, Matthew Martin KennethOptimization of Conformal Joints in Axial Tension
Master of Science, The Ohio State University, 2012, Mechanical Engineering

Electromagnetic forming uses high current to form conductive material. It has been a possible manufacturing technique for joining materials since the 1960s. In the past decade the process has seen a resurgence due to the desire for lightweight manufacturing. The process provides a means to join dissimilar metals, reduce material costs, and the potential for energy savings in manufacturing. One issue that the process faces is the lack of a model to predict the forming process and effectiveness of resulting joints. There has been work done to characterize high strain rate deformation and to couple electro-mechanical systems, but there are still opportunities to provide better and more specific models of joint formation and behavior. A model was developed to describe the process of electromagnetically compressing aluminum tubes onto a steel mandrel. The model was then used to assess potential mandrel geometries for a tensile joint.

The process of characterizing the joint formation uses a combination of a numerical code to describe the tube compression pressure and an LS-DYNA computer model to describe the tube compression. The resulting conformal joint predicted by the model was experimentally verified and compared to three purposed mandrel geometries. The purposed mandrel designs were an attempt to evenly distribute the tensile load using three gradually increasing groove depths. The simulation then tested the tensile strength of the joints, verified with physical testing, and identified possible improvements in groove design. A test matrix was used to assess the effect of groove radius and groove depth on joint strength. The results showed that, in terms of strength, the groove depth is the most critical dimension and that the groove entry radius had little effect. The final optimized joint had a rectangular groove profile, with a groove entry radius the same size as the depth. The joint evenly distributed the tensile load and was shown to be more resistant to a reduction in friction than previously purposed geometries.

Committee:

Anthony Luscher, PhD (Advisor); Gary Kinzel, PhD (Committee Member); Glenn Daehn, PhD (Committee Member)

Subjects:

Automotive Engineering; Electromagnetism; Engineering; Materials Science; Mechanical Engineering; Mechanics

Keywords:

electromagnetic forming; EMF; LS-DYNA; mechanical joints; lightweight structures; joining methods;

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