Engineering Commons^™

Dyna3d Simulations Of Low-Speed Impact Response Of Laminated Composite Panels, Kenneth William Barlow

Mechanical & Aerospace Engineering Theses & Dissertations

Low-speed impact response of laminated composite panels is simulated without material damage using the DYNA3D finite element analysis code. The DYNA3D code is a nonlinear transient dynamics simulation tool with a contact algorithm for impact. By gaining a more comprehensive understanding of this dynamic impact event, this work is meant to contribute to improving designs for damage tolerance and residual strength by providing modeling and analysis guidelines for the analyst.

Structural modeling of the laminate and the impact event are found to be important factors for the analyst to consider. Since DYNA3D uses an explicit formulation, problem size is constrained …

Computer-Aided Design Of Coupler-Driven Watt I And Tolerance Synthesis For Four-Bar Linkages, Haitao Li

Mechanical & Aerospace Engineering Theses & Dissertations

Theory to rectify circuit defects in rocker-crank and double-rocker at the synthesis level is described based on the angular joint displacements. It complements the crank-rocker and double-crank circuit rectification to complete the circuit rectification of four-bar linkages. The procedure utilizes the algebraic method where special points followed by a line construction procedure are employed to validate the range of the critical angle that can identify the circuit defects as a function of the design positions prior to the completion of the linkage.

A complete procedure of the rectified synthesis of the coupler-driven Watt I six-bar linkage to pass through the …

High-Order Finite-Difference Schemes And Their Application To Computational Acoustics, Joe Leo Manthey

Mathematics & Statistics Theses & Dissertations

The primary focus of this study is upon the numerical stability of high-order finite-difference schemes and their application to duct acoustics. Since acoustic waves are known to be non-dissipative and non-dispersive, high-order schemes are favored for their low dissipation and low dispersion relative to the low-order schemes. The primary obstacle to the the development of explicit high-order finite-difference schemes is the construction of boundary closures which simultaneously maintain the formal order of accuracy and the numerical stability of the overall scheme. In this thesis a hybrid seven-point, fourth-order stencil for computing spatial derivatives is presented and the time stability is …

Photovoltaic System Design Course For Savannah State College: Course Evaluation, Florida Solar Energy Center, Gerard Ventre

FSEC Energy Research Center®

This report describes the evaluation of a course entitles Photovoltaic System Design (PVSD), which was presented by the Florida Solar Energy Center (FSEC) to faculty members of Savannah State University (SSU). This distance education (DE) course was delivered via a two-way audio/video delivery system from FSEC to SSU. This course evaluation report is included as one of the deliverables in a contract awarded to SSU and FSEC as part of the Advanced Communications Technologies Satellite research project sponsored by the NASA Lewis Research Center, Cleveland, Ohio.

Mechatronics Engineering Laboratory Development At San Jose State University, J. Wang, Burford Furman, T. Hsu, P. Hsu, P. Reischl, Freidoon Barez

Faculty Publications, Mechanical Engineering

The Mechanical Engineering Department of San Jose State University has been developing a new mechatronics engineering laboratory since Fall 1995. This laboratory is intended to provide engineering students on the application of electronics, microprocessors and software in designing electro-mechanical systems, mechatronics products and process control systems. The laboratory development is a principal part of an award for “Undergraduate Curriculum Development on Mechatronics System Engineering” by the division of undergraduate education of the National Science Foundation (NSF). Major task of the new laboratory is to support instruction and provide hands-on study of two of the five new courses: ME106 Fundamentals of …

Development Of A Mechatronics Design Studio, Sema E. Alptekin

Industrial and Manufacturing Engineering

Mechatronics is a combination of mechanics, electronics and information technology intended to raise the intelligence level and flexibility of products and devices. There is a need to develop programs and laboratories in Mechatronics to create an understanding of how new technologies influence the traditional methods of designing products and manufacturing systems. A model "Mechatronics Design Studio" has recently been developed to support the Mechatronics and Manufacturing Automation courses offered at Cal Poly's Industrial and Manufacturing Engineering Department. Laboratory experiments have been developed and several student projects have been completed. In this paper, an overview of the design studio and select …

An Experimental Study On Solidification Of Pure Water Or A Dilute Salt Solution In A Horizontal Copper Tube, Hwa-Chong Tien, Sih-Li Chen, Bing-Shiang Yang

Journal of Marine Science and Technology–Taiwan

Solidification of pure water and NaCl-HO solutions in a copper tube is investigated experimentally. The morphology and growth of the two phase region is observed photographically, In the experiments of NaCl-H2O solutions, the salt concentrations in the solutions are smaller than the concentration at the eutectic point. The coolant temperature is higher than the eutectic temperature. The supercooling phenomenon and the effects of the coolant temperature, initial temperature of water or NaCl-HzO solution, and the concentrations of the solutions are studied in detail. In addition to the photographs, results presented also nclude the temperature responses of water and NaCl-H2O solutions …

Limitations Of Methods For Determining The Position Of The Center Of Mass Of A Human Subject Performing A Sit-Up, Terrence Chadwick Smith

Dissertations and Theses

The knowledge of the position of the center of mass of a human subject performing a sit-up could help us understand the coordination of the sit-up motion. This thesis investigates the limits in three methods of determining the center of mass of a human subject. The three methods are the anthropometric method, the dynamic method, and the static torque method. The anthropometric method is a standard method that uses measurements of the subject to estimate the mass properties of individual segments of the body. The center of mass of the body is calculated from the mass and positions of the …

Impact Of Evaporator Coil Air Flow In Residential Air Conditioning Systems, Florida Solar Energy Center, Danny Parker

FSEC Energy Research Center®

The performance of conventional split system residential air conditioners is highly dependent on adequate air flow across the evaporator coil. Sufficient air flow is necessary to achieve a proper balance between sensible and latent cooling capacity. Typical target air flow rates are approximately 350 - 450 cubic feet per minute per ton (581 - 747 L/S per kW) of cooling capacity. The authors have measured the air flow across the coil in 27 installations in Florida. Both flow hood and strip heat resistance methods were used to measure air flow with an established protocol. The installations measured ranged in capacity …

Fuzzy Based Forebody Vortex Flow Controller For The X-29a Aircraft, Jin Suzuki

Masters Theses

This paper demonstrates the development and performance of A Fuzzy Logic based regulator for an aircraft which is equipped with pneumatic forebody Vortex Flow Controller at high angle-of-attack flight condition. The VFC provides the pilot additional control power at flight conditions where conventional effectors such as rudder and differential flaps lose effectiveness.

Fuzzy Logic Control (FLC) is applied to a mixed bang-bang and conventional type control system. This unique configuration ensures robustness of the system and simplifies the controller design. Performance of the FLC based regulator shows a 10.3% reduction in cost function compared to the system controlled by a …

Design And Development Of A User Interface Between Mapics/Db And Factor 5.2, Raghu Pothuri

Masters Theses

An interface program was designed to transfer production data from MAPICS/DB, a MRP II software, to FACTOR 5.2, a Finite Capacity Scheduling software. Since FACTOR 5.2 is designed to be used in a stand-alone mode with its own independent data base, this interface program extracts data from the MRP II System and converts it to formats specified by the Scheduling System. To create a computer model of the manufacturing process, information about manufacturing orders, routings, and production facilities was obtained from MAPICS/DB files. Certain information needed by FACTOR 5.2, which is not available in MAPICS/DB, was supplemented by the program …

Fostering Strong Interactions Between Industry And Academia, T. R. Kurfess, Mark L. Nagurka

Mechanical Engineering Faculty Research and Publications

This paper highlights a number of key issues in the development and execution of joint university-industry engineering projects. Government funding reductions have lead to decreased support of university research and economic forces have driven corporations to reduce or eliminate internal R&D centers. These are two driving factors behind the renewed ties between universities and industries. In developing a plan for a joint research project and when working together towards its solution, both sides need to be cognizant of their respective roles to ensure a successful partnership.

Particle Deposition From Turbulent Flow In A Divergent Channel, Wai-Ting Huang

Dissertations

This dissertation presents a numerical analysis of particle deposition from a dilute gas-solid two-phase suspension in a divergent channel. The Lagrangian governing equations for particle motion include inertia force, viscous force, gravity force and image force from electrostatic charge on the particle. The incompressible two-dimensional turbulent flow field in a divergent channel is solved by employing a Κ-ε modeling technique with FIDAP finite element CFD software. A computational procedure is developed to incorporate the flow field into numerical simulation of particle trajectories from which the fraction of deposition is determined. Several divergent channels (half divergent angles of 0°, 7.5°, 10° …

Modeling Of 3d Swept Volumes Using Sde/Sede Methods And Its Application To Five-Axis Nc Machining, Liping Wang

Dissertations

This research falls in two important areas in solid modeling and manufacturing automation: (1) swept-volume modeling; (2) computer-based NC (Numerically controled) machining simulation and verification. The swept volume is defined as the volume swept by an object undergoing an arbitrary motion. Modeling of 3D swept volumes includes the boundary computation and representation of a swept volume generated by a general object undergoing general motion in three dimensional space. The Sweep Differential Equation (SDE) and Sweep Envelope Differential Equation (SEDE) methods are two of the important swept volume modeling methods employed in this dissertation. They exploit differential equations to obtain the …

The Fatigue Problems Of Cracks Subjected To Obliquely Incident Stress Waves, I-Chung Weng

Dissertations

Catastrophic failure of aircraft and other structures are often caused by undetected cracks. Fracture mechanics has been developed to augment traditional static and fatigue design. In the static theory of fracture mechanics, extensive treatment has been given to the stress distribution around sharp cracks and notches under various loading conditions. Previous works on the problems of dynamic loadings are not accurate in dealing with singularities at high frequencies. The numerical solutions become unrealistic at high frequencies in many practical applications.

To address the need to obtain the stress intensity factor in high frequency dynamic loading situations, we studied the use …

Equivalent Circuit Analysis Of A Seventh Order Bandpass Loudspeaker System, Michael Gunnar Johnson

Theses

A seventh order bandpass loudspeaker system was designed using an equivalent circuit analysis. The electrical, mechanical and acoustic systems were each modeled as separate subcircuits derived by using a Voltage-Force-Pressure or impedance analogy; the interactions between the subcircuits were modeled using coupled controlled-sources. The equivalent circuit was analyzed using SPICE (Simulation Program with Integrated Circuit Emphasis). A technique for modeling port and cavity resonances inside the enclosure using distributed element approximations for the resonant components was developed and verified by measurement.

A complete microcomputer based experimental loudspeaker testing system was designed incorporating a sweep frequency oscillator, a gain-controlled audio power …

Parameters' Analysis Of 3d Random Stacking Palletization, Najeeb Syed

Theses

Palletization is a very important element of production, distribution and warehousing activities. The 3D random stacking palletization method is based on volume utilization instead of surface area optimization. Random stacking provides interlocking among the boxes and hence it improves the stability of the pallet load. Volumetric Pallet Utilization is normally the prime concern of any palletization process, with Work in Process and Palletization time being also important. This research uses data generated from a previous heuristic to establish mathematical relationships between the three mentioned performance indices and also three additional indirect variables, namely: Total Number of Sub Volumes, Partitioned Remaining …

Finite Element Analysis Of Skin Injuries By Water Jet Cutting, Syed Muhammad Arif

Theses

High pressure water jets are used in industry for cleaning and cutting purposes. These devices can generate pressure up to 400 MPa. As high pressure water jets become more widespread in industry, injuries will be seen with great frequency. Penetrating injuries by these devices can produce minimal external evidence of extensive soft tissue injury. To know the extent of injury, it is important to study the relationship between operating parameters of water jet and the skin layers. A computational analysis is carried out using finite element method to find the effects of water jet pressure on the skin layer. Finite …

Heat Transfer Enhancement From A Heat Pipe Immersed Horizontally In Water, Under Natural Convection Conditions, With The Aid Of Gas Injection, Evangelos J. Minakas

Theses

An experimental study has been performed to estimate the degree of heat transfer enhancement from a horizontal heat pipe, immersed in water with the aid of air injection. This thesis investigates the effects of different shroud shapes, shroud distances from the heat pipe, air injection rates, air injection configurations and air injection distances on the augmentation of heat transfer. Water was the experimental fluid and its temperature ranged from 17-60 °C, the surface temperature of the heat pipes varied from 18-75 °C.

It was discovered that the shape of the shrouds is a contributing factor on the heat transfer enhancement. …

Tractor Test Museum Commttee Minutes May 20th, 1997, Tractor Museum

Lester F. Larsen Tractor Museum: Planning and Development Documents

Officer Elections Foundation Funds State Fair Discussions

The Effects Of The Aging Process On The Mechanical Properties In Al-Cu-Li(2195) Alloy, Michael Abernathy

Electronic Dissertations and Theses

The Alumniurn-Copper-Lithi arn (Al-C u-Li) alloy s are used as aero space materi als du e to thei r low den sity , hig h modulus of elasticity, good resistance to fatigue crack propagation , and excelle nt cryogenic properties. In the current experime nt, Al-Cu-L i (2 195) allo y is se lected to study the effect of the ag ing process on mechanical propertie s. The 2 195 all oy in sheet form is supplied by Lockheed-Marti n, New Orleans. The as-received 2 195 alloy sheet is solution-treated at 5 10 ° C for one hour followed by …

Solar Water Heating: A Question And Answer Primer, Florida Solar Energy Center, David L. Block

FSEC Energy Research Center®

Solar water heating is a technology that every homeowner can use to save dollars on utility bills. Questions most frequently addressed to the Florida Solar Energy Center (FSEC) about solar water heating are answered below. Please note that many replies are general and more explanation may be required for those with individual questions. For additional information, contact the FSEC

Solar Water Heating Options In Florida, Florida Solar Energy Center, John Harrison

FSEC Energy Research Center®

This document is intended to acquaint Florida's general public with typical methods of heating household water by means of the sun. The types of solar systems discussed are pumped (both direct and indirect), thermosiphon and integral collector storage.

On-Line Cartesian Trajectory Control Of Mechanisms Along Complex Curves, Edward Red, Zhaoxue Yang

Faculty Publications

New methods have been developed to control a mechanism's realtime Cartesian motion along spatially complex curves such as Non-Uniform Rational B-splines (NURBS). The methods dynamically map the critical trajectory parameters between parameter space, Cartesian space, and joint space. Trajectory models that relate Cartesian tool speeds and accelerations to joint speeds and accelerations have been generalized so that they can be applied to most classes of robots and CNC mechanisms.

Freezing Point Mobile Munitions Assessment Sytem: Thermal Chamber Redesign, Sara Gifford, Preston Harris

Undergraduate Honors Capstone Projects

The Army is actively investigating non-intrusive methods to identify six chemical weapons agents. The chemical munitions in question are often found scattered across military bases and other facilities. These non-stockpile munitions are specifically targeted for identification using the mobile munitions assessment system. This program is being administered by the Idaho National Engineering Laboratory.

Identifying Air Flow Failure Modes In Small Commercial Buildings: Tools And Methodologies For Building Commissioning Diagnostics, Florida Solar Energy Center, James Cummings

FSEC Energy Research Center®

A recent study of small commercial buildings in central Florida found that uncontrolled air flow -- including duct leakage, return air imbalance, and exhaust air/make-up air imbalance -- is widespread. Of 70 buildings studied, only 1 was identified as having no significant uncontrolled air flow. The causes of uncontrolled air flow include failure of design, poor workmanship, O&M problems, HVAC commissioning failures, materials degradation, and building retrofits. This study also found that the consequences of uncontrolled air flow are often quite severe and varied -- including high utility bills, occupant thermal discomfort, high humidity, mold and mildew growth, moisture damage …

Ole Miss Engineer 1997

Ole Miss Engineer

No abstract provided.

Three-Dimensional Aerodynamic Design Optimization Using Discrete Sensitivity Analysis And Parallel Computing, Amidu Olawale Oloso

Mechanical & Aerospace Engineering Theses & Dissertations

A hybrid automatic differentiation/incremental iterative method was implemented in the general purpose advanced computational fluid dynamics code (CFL3D Version 4.1) to yield a new code (CFL3D.ADII) that is capable of computing consistently discrete first order sensitivity derivatives for complex geometries. With the exception of unsteady problems, the new code retains all the useful features and capabilities of the original CFL3D flow analysis code. The superiority of the new code over a carefully applied method of finite-differences is demonstrated.

A coarse grain, scalable, distributed-memory, parallel version of CFL3D.ADII was developed based on "derivative stripmining". In this data-parallel approach, an identical copy …

Analysis And Testing Of Plates With Piezoelectric Sensors And Actuators, Jeffrey S. Bevan

Mechanical & Aerospace Engineering Theses & Dissertations

Piezoelectric material inherently possesses coupling between electrostatics and structural dynamics. Utilizing linear piezoelectric theory results in an intrinsically coupled pair of piezoelectric constitutive equations. One set describes the direct piezoelectric effect, where strains produce an electric field, and the other set describes the converse effect, where an applied electrical field produces strain. The purpose of this study is to compare the finite element analysis and experiments of a thin plate with bonded piezoelectric material.

Since an isotropic plate in combination with a thin piezoelectric layer constitutes a laminated composite, the classical laminate plate theory is used in the formulation to …

Development Of Curved-Plate Elements For The Exact Buckling Analysis Of Composite Plate Assemblies Including Transverse-Shear Effects, David Michael Mcgowan

Mechanical & Aerospace Engineering Theses & Dissertations

The analytical formulation of curved-plate non-linear equilibrium equations including transverse-shear-deformation effects is presented. The formulation uses the principle of virtual work. A unified set of non-linear strains that contains terms from both physical and tensorial strain measures is used. Linearized, perturbed equilibrium equations (stability equations) that describe the response of the plate just after buckling occurs are then derived after the application of several simplifying assumptions. These equations are then modified to allow the reference surface of the plate to be located at a distance z_c, from the centroidal surface. The implementation of the new theory into the …