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Full-Text Articles in Engineering
A Single-Stage Passive Vibration Isolation System For Scanning Tunneling Microscopy, Toan T. Le
A Single-Stage Passive Vibration Isolation System For Scanning Tunneling Microscopy, Toan T. Le
Master's Theses
Scanning Tunneling Microscopy (STM) uses quantum tunneling effect to study the surfaces of materials on an atomic scale. Since the probe of the microscope is on the order of nanometers away from the surface, the device is prone to noises due to vibrations from the surroundings. To minimize the random noises and floor vibrations, passive vibration isolation is a commonly used technique due to its low cost and simpler design compared to active vibration isolation, especially when the entire vibration isolation system (VIS) stays inside an Ultra High Vacuum (UHV) environment. This research aims to analyze and build a single-stage …
Design Of Structural Stand For High-Precision Optics Microscopy, Sara T. Novell
Design Of Structural Stand For High-Precision Optics Microscopy, Sara T. Novell
Master's Theses
Lawrence Livermore National Lab (LLNL) is home to the National Ignition Facility (NIF), the world’s largest and most energetic laser. Each of the 192 beamlines contains dozens of large optics, which require offline damage inspection using large, raster-scanning microscopes. The primary microscope used to measure and characterize the optical damage sites has a precision level of 1 µm. Mounted in a class 100 clean room with a raised tile floor, the microscope is supported by a steel stand that structurally connects the microscope to the concrete ground. Due to ambient vibrations experienced in the system, the microscope is only able …
Manufacture Of Complex Geometry Component For Advanced Material Stiffness, David Russell Bydalek
Manufacture Of Complex Geometry Component For Advanced Material Stiffness, David Russell Bydalek
Master's Theses
The manufacture, laminate design, and modeling of a part with complex geometry are explored. The ultimate goal of the research is to produce a model that accurately predicts part stiffness. This is validated with experimental results of composite parts, which refine material properties for use in a final prototype part model. The secondary goal of this project is to explore manufacturing methods for improved manufacturability of the complex part. The manufacturing portion of the thesis and feedback into material model has incorporated a senior project team to perform research on manufacturing and create composite part to be used for experimental …
Design And Analysis Of The Impact Diffusion Helmet Through A Finite Element Analysis Approach, Steven Paul Warnert
Design And Analysis Of The Impact Diffusion Helmet Through A Finite Element Analysis Approach, Steven Paul Warnert
Master's Theses
By applying the finite element approach to the design and analysis of the impact diffusion helmet, many helmet configurations were able to be analyzed. Initially it was important to determine what design variables had an influence on the impact reducing abilities of the helmet design. The helmet was run through a series of Abaqus simulations that determined that a design with two oval shaped channels running along the length of the helmet was best. Next, these options were optimized to generate the helmet that produced the greatest impact reduction. The optimization simulations determined that a helmet that pushed the channels …
Analysis Of A Carbon Fiber Reinforced Polymer Impact Attenuator For A Formula Sae Vehicle Using Finite Element Analysis, John T. Rappolt
Analysis Of A Carbon Fiber Reinforced Polymer Impact Attenuator For A Formula Sae Vehicle Using Finite Element Analysis, John T. Rappolt
Master's Theses
The Hashin failure criteria and damage evolution model for laminated fiber reinforced polymers are explored. A series of tensile coupon finite element analyses are run to characterize the variables in the physical model as well as modeling techniques for using an explicit dynamic solver for a quasi-static problem. An attempt to validate the model on an axial tube crush is presented. It was found that fiber buckling was not occurring at the impactor-tube interface. Results and speculation as to why the failure initiation is incorrect are discussed. Lessons learned from the tube crush are applied successfully to the quasi-static Formula …
Development Of A Finite Element Model For Predicting The Impact Energy Absorbing Performance Of A Composite Structure, Matthew Lowell Roberts
Development Of A Finite Element Model For Predicting The Impact Energy Absorbing Performance Of A Composite Structure, Matthew Lowell Roberts
Master's Theses
Because of their high strength-to-weight ratio, Fiber Reinforced Composite (FRC) materials are well suited for use in high performance racing applications where weight must be kept to a minimum. Formula SAE (FSAE) race cars are designed and built by college students, roughly following the model of a scaled down Formula One car. Strict regulations are placed on specific components of the car in the interest of equalizing competition and ensuring the safety of the drivers. Students are required to construct a survival cell (the chassis), which can resist large amounts of energy in the event of a crash, with an …
A Prediction Of The Acoustical Output Of A Golf Driver Head Using Finite Elements, Roger Sharpe
A Prediction Of The Acoustical Output Of A Golf Driver Head Using Finite Elements, Roger Sharpe
Master's Theses
A simulation was created using LS-DYNA® to determine the acoustical properties of a golf ball and golf driver head impact. LS-DYNA® has a coupled finite element analysis (FEA) and boundary element method (BEM) solver that uses the integral form of Helmholtz’s acoustic wave equation to deliver predicted sound pressure levels at predetermined acoustic points. Validation of the modeling was done on a simple plate donated by Titleist Golf. The plate was modeled and meshed using TrueGrid and impacted by a three layer golf ball model derived from “Tanka’s” paper on multilayered golf balls. The final converging model consisted of 10,900 …