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Mechanical Engineering

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Cleveland State University

2013

Articles 1 - 11 of 11

Full-Text Articles in Engineering

On The Uniqueness And Sensitivity Of Indentation Testing Of Isotropic Materials, J. K. Phadikar, T. A. Bogetti, Anette M. Karlsson Oct 2013

On The Uniqueness And Sensitivity Of Indentation Testing Of Isotropic Materials, J. K. Phadikar, T. A. Bogetti, Anette M. Karlsson

Mechanical Engineering Faculty Publications

Instrumented indentation is a popular technique to extract the material properties of small scale structures. The uniqueness and sensitivity to experimental errors determine the practical usefulness of such experiments. Here, a method to identify test techniques that minimizes sensitivity to experimental erros is in indentation experiments developed. The methods are based on considering “shape functions,” which are sets of functions that describe the force–displacement relationship obtained during the indentation test. The concept of condition number is used to investigate the relative reliability of various possible dual indentation techniques. Interestingly, it was found that many dual indentation techniques can be as …

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Implementation Of A Plastically Dissipated Energy Criterion For Three Dimensional Modeling Of Fatigue Crack Growth, Parag G. Nittur, Anette M. Karlsson, Leif A. Carlsson Sep 2013

Implementation Of A Plastically Dissipated Energy Criterion For Three Dimensional Modeling Of Fatigue Crack Growth, Parag G. Nittur, Anette M. Karlsson, Leif A. Carlsson

Mechanical Engineering Faculty Publications

Fatigue crack growth is simulated using three dimensional elastic-plastic finite element analysis. The crack extension per load cycle, da/dN, as well as crack front profile changes (crack tunneling) under cyclic loading is not specified as an input but evaluated based on a condition that relates plastically dissipated energy to a critical value. Simulation of cyclic crack propagation in a middle-crack tension M(T) specimen using this implementation captures the well established, experimentally obtained crack growth rate reduction accompanying a single overload event. The analysis predicts that the single overload also affects the crack front profile, where a tunneling crack propagates with …

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Conical Indentation Of A Viscoelastic Sphere, J. K. Phadikar, T. A. Bogetti, V. N. Kaliakin, Anette M. Karlsson Jun 2013

Conical Indentation Of A Viscoelastic Sphere, J. K. Phadikar, T. A. Bogetti, V. N. Kaliakin, Anette M. Karlsson

Mechanical Engineering Faculty Publications

Instrumented indentation is commonly used for determining mechanical properties of a range of materials, including viscoelastic materials. However, most—if not all—studies are limited to a flat substrate being indented by various shaped indenters (e.g., conical or spherical). This work investigates the possibility of extending instrumented indentation to nonflat viscoelastic substrates. In particular, conical indentation of a sphere is investigated where a semi-analytical approach based on “the method of functional equations” has been developed to obtain the force–displacement relationship. To verify the accuracy of the proposed methodology selected numerical experiments have been performed and good agreement was obtained. Since it takes …

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Time-Dependent Mechanical Response Of A Composite Pfsa Membrane, Narinder S. Khattra, Zongwen Lu, Anette M. Karlsson, Michael H. Santare, F. Colin Busby, Thomas Schmiedel Apr 2013

Time-Dependent Mechanical Response Of A Composite Pfsa Membrane, Narinder S. Khattra, Zongwen Lu, Anette M. Karlsson, Michael H. Santare, F. Colin Busby, Thomas Schmiedel

Mechanical Engineering Faculty Publications

The mechanical response of a composite fuel cell membrane, made from layers of reinforced and unreinforced PFSA material, is investigated via both experimental and numerical means. First, the time-dependent mechanical properties for the reinforced layers are measured for a range of environmental and loading conditions. A three-network, viscoelastic-plastic constitutive model is developed to characterize the mechanical response of this reinforced membrane material. This constitutive model is then used in finite element simulations of a fuel cell unit (consisting of composite membrane, electrodes, gas diffusion layer and bipolar plates) where the effect of relative humidity (RH) cycling on the stress response …

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In Situ Analysis Of Fatigue Crack Propagation In Polymer Foams, Elio E. Saenza, Leif A. Carlsson, Anette M. Karlsson Mar 2013

In Situ Analysis Of Fatigue Crack Propagation In Polymer Foams, Elio E. Saenza, Leif A. Carlsson, Anette M. Karlsson

Mechanical Engineering Faculty Publications

This paper presents an in situ SEM experimental study on cyclic crack propagation in closed-cell polymer foams. The microscopic failure mechanisms in precracked PVC and PES specimens of 60 and 90 kg/m3 densities were examined under low-cycle fatigue loading. In the PVC foam, crack propagation occurred incrementally by successive failure of cell boundaries in front of the crack tip. The crack occasionally jumped to cell boundaries above or below the main crack resulting in non-self similar growth. Crack propagation in the PES foam occurred incrementally by extensive plastic tearing and subsequent tensile failure of the cell edge in front …

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Determining The Mechanical Properties Of Lattice Block Structures, Nathan Wilmoth Jan 2013

Determining The Mechanical Properties Of Lattice Block Structures, Nathan Wilmoth

ETD Archive

Lattice block structures and shape memory alloys possess several traits ideal for solving intriguing new engineering problems in industries such as aerospace, military, and transportation. Recent testing at the NASA Glenn Research Center has investigated the material properties of lattice block structures cast from a conventional aerospace titanium alloy as well as lattice block structures cast from nickel-titanium shape memory alloy. The lattice block structures for both materials were sectioned into smaller subelements for tension and compression testing. The results from the cast conventional titanium material showed that the expected mechanical properties were maintained. The shape memory alloy material was …

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Hybrid Position And Impedance Control Of A Forging Process, Derek Stake Jan 2013

Hybrid Position And Impedance Control Of A Forging Process, Derek Stake

ETD Archive

"Pick and place" robotic material handling has been a key to increase piece rates and reduced variability in forging processes. One of the drawbacks to current "pick and place" robotic material handling methods is the inability to locate the part after a forging operation and move it to the next position in a timely manner. If the billet changes position during the forging process, the manipulator will take longer to find the part and transfer it to the next station or the manipulator will be unable to move the part to the next position correctly which may cause scrap. Another …

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Vibration Analysis Of Anisotropic Plates, Special Case: Violin, Chaitanya J. Lomte Jan 2013

Vibration Analysis Of Anisotropic Plates, Special Case: Violin, Chaitanya J. Lomte

ETD Archive

This thesis presents vibration analysis of the top plate of Stradivari violin by creating a 3D model using SolidWorks and finding mode shapes and natural frequencies using SolidWorks simulation. The top plate was affixed to the bottom plate via a side wall following the contour of the violin plates. Assuming the input excitation is sinusoidal, it was applied at the location of bridge where the strings rest on it.. The static component of the force was calculated to be 83.17 N. The first five natural frequencies of the violin top plate are in the range of 150 to 450 Hertz. …

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Computational Study Of Savonius Wind Turbine, Asmita C. Chinchore Jan 2013

Computational Study Of Savonius Wind Turbine, Asmita C. Chinchore

ETD Archive

This project involves study of 2-Blade and 3-Blade Savonius vertical wind turbines positioned at different orientations. For a 2-Blade turbine the orientations considered were 0 degree, 45 degree, 90 degree and 135 degree in reference to the direction of the prevailing wind and for the 3-Blade turbine the orientations taken into account were 0 degree, 30 degree, 60 degree and 90 degree in reference to the direction of the prevailing wind. The basic aim of this thesis was to study how the two designs are different from each other and which design produces more power when applied with constant wind …

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Aerodynamic Measurements Of A Variable-Speed Power-Turbine Blade Section In A Transonic Turbine Cascade, Ashlie B. Flegel Jan 2013

Aerodynamic Measurements Of A Variable-Speed Power-Turbine Blade Section In A Transonic Turbine Cascade, Ashlie B. Flegel

ETD Archive

The purpose of this thesis is to document the impact of incidence angle and Reynolds number variations on the 3-D flow field and midspan loss and turning of a 2-D section of a variable-speed power-turbine (VSPT) rotor blade. Aerodynamic measurements were obtained in a transonic linear cascade at NASA Glenn Research Center in Cleveland, OH. Steady-state data were obtained for ten incidence angles ranging from +15.8° to -51.0°. At each angle, data were acquired at five flow conditions with the exit Reynolds number (based on axial chord) varying over an order-of-magnitude from 2.12 ₉ 105 to 2.12 ₉ 106. Data …

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Biogeography-Based Optimization For Hydraulic Prosthetic Knee Control, Tim Wilmot, George Thomas, Berney Montavon, Rick Rarick, Antonie J. Van Den Bogert, Steve Szatmary, Daniel J. Simon, William Smith, Sergey Samorezov Jan 2013

Biogeography-Based Optimization For Hydraulic Prosthetic Knee Control, Tim Wilmot, George Thomas, Berney Montavon, Rick Rarick, Antonie J. Van Den Bogert, Steve Szatmary, Daniel J. Simon, William Smith, Sergey Samorezov

Electrical and Computer Engineering Faculty Publications

We discuss open-loop control development and simulation results for a newly-developed cyber-physical system (CPS) used as a semi-active, above-knee prosthesis. The control signal of our CPS consists of two hydraulic valve settings that control a linear cylinder actuator and provide torque to the prosthetic knee. We develop open-loop control using biogeography-based optimization (BBO), which is a recently developed evolutionary algorithm. The research contributes to the field of cyber-physical systems by showing that it is possible to find effective open-loop control signals for our newly proposed semi-active hydraulic knee prosthesis through a dual-system optimization process which includes both human and robot …

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