Engineering Mechanics Commons^™

Topology And Free-Size Optimization With Multiple Loading Conditions For Light Weight Design Of Die Cast Automotive Backrest Frame, Sreeram Polavarapu

All Theses

Automotive seats provide comfort and safety to the occupant travelling in the vehicle. An optimized seat design should be aesthetically pleasing, lightweight and meet the safety requirements. An automotive seat with occupant is subjected to various kinds of forces in the event of crash and should be designed for strength and stiffness as measured by stress and strain, and deflection. In this work, finite element analysis, together with topology and free-size optimization is used to design a lightweight die cast automotive front seat backrest frame when subjected to loads prescribed by ECE R17 European government regulations and additional loads which …

Computational Analysis Of Feasibility And Utility Of Direct-Adhesion Polymer-To-Metal Hybrid Technologies For Use In Load Bearing Body-In-White Automotive Components, Vijay Sellappan

All Theses

Traditionally, metals and plastics are fierce competitors in many automotive engineering applications. This paradigm is gradually being abolished as the polymer-metal-hybrid (PMH) technologies, developed over the last decade, are finding ways to take full advantage of the two classes of materials by combining them into a singular component/sub-assembly. By employing one of the several patented PMH technologies, automotive original equipment manufacturers (OEMs) have succeeded in engaging flexible assembly strategies, decreasing capital expenditures and reducing labor required for vehicle manufacture. The basic concept utilized in all PMH technologies is based on the fact that while an open-channel thin-wall sheet-metal component can …

Compliant Multi-Link Vehicle Suspensions, Souharda Raghavendra

All Theses

One of the goals of automotive lightweight engineering is to achieve reduction in mass, cost, and complexity of vehicle components, subsystems and systems without sacrificing functionality and expected performance. This thesis addresses functionally integrated suspension systems that could lead to reduction in part count and mass and save packaging space. It deals with the analysis of multi-link suspensions that combine the function of energy storage and the mechanism of wheel location and guidance within individual compliant links and members.
To explore possibilities, a generic kinematic model of an independent five-link suspension was built in the MSC.ADAMS multi-body dynamics simulation environment. …

Real-Time Power Management Of A Fuel Cell/Ultracapacitor Hybrid, Wesley Greenwell

All Theses

This thesis presents the system architecture design, system integration methodology, and real-time control of a fuel cell/ultracapacitor hybrid power system. The main objective is for the hybrid system to respond to real-world fluctuations in power without negatively impacting fuel cell life.
A Proton Exchange Membrane (PEM) Fuel Cell is an electrochemical device which converts the chemical energy of pure hydrogen into electricity through a chemical reaction with oxygen. The high conversion efficiency, zero harmful emissions, high power-to-weight ratio, scalability, and low temperature operation make PEM fuel cells very attractive for stationary and portable power applications. However, fuel cells are limited …

Computational Method For Solving Spoke Dynamics On High Speed Rolling Tweel, Kranti Kiran Manga

All Theses

Extensive studies have been conducted in the past to show that the characteristics of a non-pneumatic structure, the TweelTM are the same as the pneumatic tires. These characteristics include low contact pressure, low stiffness, low energy loss from obstacle impacts, low mass, and high load-carrying capacity. The TweelTM consists of a ring shaped shear beam comprised of two inextensible membranes separated by a relatively low modulus elastic material. This shear beam is connected to the hub by thin elastic spokes.
When used for high speed rolling applications, the TweelTM produces unacceptably high levels of acoustic noise. It has been suggested …

Random Road Analysis And Improved Gear Ratio Selection Of A Front Wheel Drive Drag Racing Car, Thomas New

All Theses

Drag racing has been around since the 1950's and has become a very popular and very competitive sport. The difference between winning and losing can be hundredths and even thousandths of a second. Drag racing teams need every advantage they can get in order to excel in their field. On-track testing is very expensive and can consume large amounts of time and resources that a race team may not be able to afford.
One way to address this potential problem of high cost is by using computer simulation to show how your drag race car may perform at different tracks …

Ductile-Regime Machining Of Glass Using The Micromilling Process, Kevin Foy

All Theses

Glass is a homogeneous material with amorphous crystal structure that is produced through the rapid cooling of its molten state below the glass transition temperature. Glass exhibits many excellent mechanical and physical properties, and it is widely used in automotive, communications, optics, electronics, architectural, and biomedical industries. For certain applications such as DNA microarrays, glass components with microfeatures are typically produced using a combination of photolithography and etching processes, which is generally time consuming and can involve hazardous chemicals. It would be ideal to fabricate some glass devices through mechanical micromachining for some rapid prototyping applications of glass-based devices, but …

Investigating The Role Of Prototyping In Mechanical Design Using Case Study Validation, David Stowe

All Theses

The purpose of this research is to explore the application of prototyping in the design process through a case study analysis using structured interviews, an ethnographic study, and documents analysis, to determine what factors and practices result in successful prototyping. In doing so, research questions are established, a prototyping process is developed to assist the investigation, and classification systems are created to organize data collected in the study. As part of the case study, an interview is formulated to answer the proposed research questions and a literature survey of prototyping in design is used to create a larger analytical foundation. …

On New Applications And Sensitivity Enhancement Of Cantilever-Based Sensing Systems, Calvin Bradley

All Theses

Cantilever-based Sensing Systems (CSS) have become a focal area for research with the rise of micro- and nanotechnology. History has led us to use cantilever beams as one of the foremost sensing devices for small scale applications, beginning with the atomic force microscopy, and then being expanded into numerous sensor devices. The CSS include such applications as accelerometers, thermal and chemical sensors which are expanding into the applications of mass sensing and material characterization. Soon, this technology may be used in 'lab on chip' biosensing applications.
This study covers the experimentation into new CSS applications and sensitivity enhancement. In order …

Modeling Of The Effect Of Tool Wear On Cutting Forces In Turning, Yu Long

All Dissertations

Machining is the most widely used and efficient material removal process, and tool wear in machining is usually of great interest in order to improve machining efficiency and effectiveness. Cutting tool wear patterns such as the flank and crater wear and the dead metal zone (DMZ) may induce the cutting tool geometry variation in machining. As a result, cutting forces may increase or decrease due to the change of tool effective cutting geometry during machining operations. A quantitative understanding of and the ability to predict cutting forces in relation to tool wear are important to the tool life estimation, chatter …

Physics-Based Shape Morphing And Packing For Layout Design, Hong Dong

All Dissertations

The packing problem, also named layout design, has found wide applications in the mechanical engineering field. In most cases, the shapes of the objects do not change during the packing process. However, in some applications such as vehicle layout design, shape morphing may be required for some specific components (such as water and fuel reservoirs). The challenge is to fit a component of sufficient size in the available space in a crowded environment (such as the vehicle under-hood) while optimizing the overall performance objectives of the vehicle and improving design efficiency. This work is focused on incorporating component shape design …

Vibration Analysis Of Piezoelectric Microcantilever Sensors, Amin Salehi-Khojin

All Dissertations

The main objective of this dissertation is to comprehensively analyze vibration characteristics of microcantilever-based sensors with application to ultra small mass detection and low dimensional materials characterization. The first part of this work focuses on theoretical developments and experimental verification of piezoelectric microcantilevers, commercially named Active Probes, which are extensively used in most today's advanced Atomic Force Microscopy (AFM) systems. Due to special geometry and configuration of Active Probes, especially multiple jump discontinuities in their cross-section, a general and comprehensive framework is introduced for forced vibration and modal analysis of discontinuous flexible beams. More specifically, a general formulation is obtained …

Me-Em 2008 Annual Report, Department Of Mechanical Engineering-Engineering Mechanics, Michigan Technological University

Department of Mechanical and Aerospace Engineering Annual Reports

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Hypersonic Boundary Layer Receptivity To Acoustic Disturbances Over Cones, Kursat Kara

Mechanical & Aerospace Engineering Theses & Dissertations

The receptivity mechanisms of hypersonic boundary layers to free stream acoustic disturbances are studied using both linear stability theory (LST) and direct numerical simulations (DNS). A computational code is developed for numerical simulation of steady and unsteady hypersonic flow over cones by combining a fifth-order weighted essentially non-oscillatory (WENO) scheme with third-order total-variation-diminishing (TVD) Runge-Kutta method. Hypersonic boundary layer receptivity to free-stream acoustic disturbances in slow and fast modes over 5-degree, half-angle blunt cones and wedges are numerically investigated. The free-stream Mach number is 6.0, and the unit Reynolds number is 7.8×106/ft. Both the steady and unsteady solutions are obtained …

Property Measurements And Evaluation Of Heat Leak, Nathan Race

All Theses

Heat transport in capillary wick structures is an important parameter in loop heat pipe (LHP) design. The purpose of this study was to investigate the conductive heat leak in operating capillary wick structures. The heat leak is the portion of applied heat load conducted through the wick in spite of the convection of working fluid. Four sintered 316 stainless steel wicks were tested for porosity, effective thermal conductivity, pore size, and heat leak. Pore sizes were found to correlate well with the nominal pore size and pores were very narrowly distributed within a size range of approximately 1-10μm. Effective thermal …

The Role Of Computer Aided Engineering In Developing A Combined Trash And Recycling Truck : A Case Study, Peter Johnston

All Theses

This work will illustrate how Environmental America Inc., EAI, and the Clemson University design team utilized lean manufacturing principles to revolutionize the curbside waste collection process. Through the application of lean manufacturing principles the number of non-value added steps was significantly reduced and the information gathered from the lean process tree acted as a framework to develop initial constraints and criteria for the vehicle's development. The design team was asked to construct the fifth iteration of the prototype collection vehicle in an effort to minimize vehicle cost, size and weight. An extensive case study will be presented which illustrates how …

Thermal Diffusion Coefficient Modeling For High Pressure Combustion Simulations, Soundararaghavan Vasudevan

All Theses

The effects of Soret and Dufour diffusion on the behavior of high pressure laminar diffusion flames relevant to modern combustion devices are investigated. A novel model for thermal diffusion coefficients is developed based on experimental data found in the literature and the principle of corresponding states. The new model is first compared with existing models and experimental data and is shown to be more accurate and to exhibit correct behavior in the limit of high temperature relevant to combustion. The model furthermore does not exhibit sensitivity to the equation of state, its mixing rules, or unphysical sign changes observed in …

Least Squares Fitting Of Analytic Primitives On A Gpu, Meghashyam Panyam Mohan Ram

All Theses

Metrology systems take coordinate information directly from the surface of a manufactured part and generate millions of (X, Y, Z) data points. The inspection process often involves fitting analytic primitives such as sphere, cone, torus, cylinder and plane to these points which represent an object with the corresponding shape. Typically, a least squares fit of the parameters of the shape to the point set is performed. The least squares fit attempts to minimize the sum of the squares of the distances between the points and the primitive. The objective function however, cannot be solved in the closed form and numerical …

A Case Study Investigating Rule Based Design In An Industrial Setting, Siva Chavali

All Theses

This thesis presents a case study on the implementation of a rule based design (RBD) process for an engineer-to-order (ETO) company. The time taken for programming and challenges associated with this process are documented in order to understand the benefits and limitations of RBD. These times are obtained while developing RBD programs for grid assemblies of bottle packaging machines that are designed and manufactured by Hartness International (HI). In this project, commercially available computer-aided design (CAD) and RBD software are integrated to capture the design and manufacturing knowledge used to automate the grid design process of HI. The stages involved …

An Investigation Of Cavity Pressure As A Process And Quality Indicator In The Micro-Injection Molding Process, Soon-Chun Kuek

All Theses

Increased demand for micro-scale parts and devices is being met in many cases by micro-injection molding of polymer parts. However, part inspection is difficult due to the micro-scale dimension in the micro-injection molding process. In addition, process control also becomes challenging since the process is susceptible to slight changes in process parameters such as mold temperature, injection velocity, and packing pressure. To address these issues, a suitable process monitoring method such as cavity pressure monitoring can be employed to detect any process deviation that may cause defects in part quality. Cavity pressure has been found to be a reliable process …

A Case Study On The Use Of Design Exemplar As A Search And Retrieval Tool, Narasimha Murty Srirangam

All Theses

This thesis presents a case study examining the suitability of design exemplar technology as a CAD query tool for an industrial scenario. The search and retrieval of geometrically similar mold inserts to save tooling cost for a tire manufacturing company is taken as the case study. During the implementation of the design exemplar as a CAD search and retrieval tool, several limitations of it are identified, such as the difficulty and tediousness in authoring exemplars for real world problems. To overcome these limitations, a new mathematical-based exemplar approach (mathematical model) is developed for tire mold insert retrieval. This approach calculates …

Effects Of Support Grid Vane Angles On Single Phase Heat Transfer Within Rod Bundle Subchannels, Michael Cosby

All Theses

The main goal of this project is to investigate how changes in support grid mixing vane angles affect the single phase heat transfer coefficient for rod bundle flows. Since other studies have been done on these types of flows, the present study also serves the purpose of further solidifying conclusions made in those works. A split-pair mixing vane support grid without weld nugget cutouts is thought to have optimum flow characteristics at a vane angle of 29 degrees. Results obtained from this work have shown this to be true. Vane angles were modified to angles of 37 ¡, 33¡ and …

Surface Finish Control Of 3d Printed Metal Tooling, Brady Godbey

All Theses

Solid freeform fabrication (SFF) technology has shown a great deal of promise for the plastic injection molding industry due to its ability to produce complex geometry tooling relatively quickly. However, one shortcoming of metal-based SFF processes is that they have difficulty producing parts with acceptable surface quality. As such, secondary operations, such as machining, are frequently required thereby increasing fabrication time and cost. In addition, there is variation in the surface quality that is dependent upon the surface orientation during the build process. For example, parts produced using the metal-based 3-D printing process have vertical faces with a typical roughness …

Development Of A Design Enabler Tool For Frame Analysis For A Small Enterprise: A Case Study, Madhusudan Kayyar

All Theses

This case study investigates the design process followed by a small to medium scale enterprise (SME) that primarily depends on special expertise in the form of a few key individuals. These individuals design products mainly based on past experience, augmented by trial and error. This is an inefficient, time consuming, and expensive way of designing products and evaluating their performance. This study critiques the different steps in the current design process, identifying areas of potential improvement and enhancement through application of formal design methods and innovative design enablers. The 'Design Enablers' are design tools that assist the designer at various …

Morphological Charts: A Systematic Exploration Of Qualitative Design Space, Gregory Smith

All Theses

A morphological chart is a tool that represents a large qualitative design space. These charts list the functions identified for the design problem, and the means (solutions) that can perform each function. Combining one means for each function will produce a potential integrated conceptual design solution. Repeating this process with every possible combination contained in the morphological chart will generate a long list of conceptual design solutions. Not all of these solutions will be practical, or even physically possible.
As it is difficult to analyze a long list of design solutions and as at present, there are no systematic design …

Mixed Convective Heat Transfer And Evaporation At The Air-Water Interface, Prasad Gokhale

All Theses

Functional forms for mixed convective heat transfer and evaporation from an air-water interface were obtained. To obtain these functions, heat transfer and evaporation rates from the air-water interface of an evaporating body of water were quantified in a wind/water tunnel in the presence of an oleyl alcohol monolayer on the water surface. The Nusselt (Nu) and Sherwood (Sh) numbers, parameterizing the dimensionless heat and mass transfer respectively, for transport from the water bulk to air were expressed as functions of the air side Rayleigh (Ra) and Reynolds (Re) numbers. The Nu and Sh were calculated for a range of Ra …

A Comparative Fault Diagnosis Methodology Based On Time Series Analysis Of System's Signals, Hany Bassily

All Dissertations

The detection of system anomalies represents an important task in safety critical systems. Over the past two decades, advances in data manipulation techniques and sensor technology have contributed to the widespread application of signal processing concepts for fault diagnosis. However, the majority of these signal processing, or data driven, diagnostics do not possess the redundancy level exhibited in conventional model-based methods. Among signal processing methods, time series analysis is advantageous since it offers insight into the underlying dynamics and forecasts system behavior. Furthermore, the data driven method allows the depiction of system dynamics with an increased level of redundancy. This …

Exact Solution Of Time History Response For Dynamic Systems With Coupled Damping Using Complex Mode Superposition, Manoj Kumar Chinnakonda

All Theses

An exact solution method for general, non-proportional damping time history response for piece-wise linear loading proposed by Dickens is generalized to piece-wise quadratic loading. Comparisons are made to Trapezoidal and Simpson's quadrature rules for approximating the time integral of the weighted generalized forcing function in the exact solution to the decoupled modal equations arising from state-space modal analysis of linear dynamic systems. The time integral of the forcing function is recognized as a weighted integral with complex exponential and the general update formulas are derived using polynomial interpolation to the forcing function. Closed-form expressions for the weighting parameters in the …

A Hydraulic Actuated Thermal Management System For Large Displacement Engine Cooling Systems, Peyton Frick

All Theses

The performance of automotive cooling systems can be improved by replacing the traditional mechanically driven radiator fan and water pump assemblies with computer controlled components. The introduction of electric servo-motors to drive the cooling components can improve temperature tracking, which should increase fuel efficiency and decrease tailpipe emissions. However, the power requirement for these electric motors increases with greater cooling demands if the radiator surface area remains constrained. For heavy-duty applications, where engines are subjected to significant cooling loads, electric motors may become impractical due to their increased size and power requirements; in these situations, hydraulic-based components are advantageous due …

Registration Using Graphics Processor Unit, Koushik Aravalli

All Theses

Data point set registration is an important operation in coordinate metrology. Registration is the operation by which sampled point clouds are aligned with a CAD model by a 4X4 homogeneous transformation (e.g., rotation and translation). This alignment permits validation of the produced artifact's geometry. State-of-the-art metrology systems are now capable of generating thousands, if not millions, of data points during an inspection operation, resulting in increased computational power to fully utilize these larger data sets. The registration process is an iterative nonlinear optimization operation having an execution time directly related to the number of points processed and CAD model complexity. …