Mechanics of Materials Commons^™

Simulating Dynamic Failure Of Polymer-Bonded Explosives Under Periodic Excitation, Rachel Kohler, Camilo Duarte Cordon, Marisol Koslowski

The Summer Undergraduate Research Fellowship (SURF) Symposium

Accidental mishandling of explosive materials leads to thousands of injuries in the US every year. Understanding the mechanisms behind the detonation process is crucial to prevent such accidents. In polymer-bonded explosives (PBX), high-frequency mechanical excitation generates thermal energy and can lead to an increase in temperature and vapor pressure, and potentially the initiation of the detonation process. However, the mechanisms behind this energy release, such as the effects of dynamic fracture and friction, are not well understood. Experimental data is difficult to collect due to the different time scales of reactions and vibrations, so research is aided by running simulations ...

A Parametric Study Of The Mechanics Of Different Skin Flap Techniques, Steven J. Meza, Adrián Tepole Buganza

The Summer Undergraduate Research Fellowship (SURF) Symposium

In modern day plastic and reconstructive surgeries numerous skin flap designs have been developed and are used to close open wounds. Skin flaps are developed with the intention of imposing minimal tension in skin closure. Excessive tension can lead to poor blood flow that result in post-surgery complications such as necrosis. Currently there is no standard in choosing a skin flap design and a surgeon's choice is based personal experience. A comparison of the mechanical loading in these various designs has not yet been done. We have developed a parametric study, using finite element analysis, of two advancement skin ...

Development Of The End-Effector Of A Cable-Driven Parallel Manipulator For Automated Crop Sensing, Iman Salafian

Mechanical (and Materials) Engineering -- Dissertations, Theses, and Student Research

A four cable-driven parallel manipulator (4CDPM), consisting of sophisticated spectrometers and imagers, is under development for use in acquiring phenotypic and environmental data over an acre-sized maize field. This thesis presents the design, controls, and testing of two sub-systems in a 4CDPM: a Center of Mass Balance System (CMBS) and a Drop-Down System (DDS).

One of the factors that influences stability is the center of mass (COM) position of the end effector. An offset in COM can cause a pendulum effect or an undesired tilt angle. A center of mass balancing system is presented in this thesis to minimize the ...

Comparing Training Performance With Vibrotactile Hit Alerts Vs. Audio Alerts, Stephen B. Gilbert, Anthony Civitate, Jonathan W. Kelly, Frederick Thompson, Alisha Smith, Ken Kopecky, Eliot Winer, Julio De La Cruz

Jonathan W. Kelly

Live, virtual, and constructive training that integrates dismounted warfighter training with convoy training, pilot training, and other systems has been demonstrated to reduce training time, and studies have shown that a high level of immersion and the illusion of presence in a VR environment contribute to this success. However, current force-on-force training simulators lack one major quality that is needed to impart this strong sense of presence for warfighters: the consequence of getting shot.

Simulated return-fire systems have been developed for different purposes including military, police and entertainment. Some use projectiles, but that approach is usually limited to a shoot ...

Multiple Scattering Theory For Heterogeneous Elastic Continua With Strong Property Fluctuation: Theoretical Fundamentals And Applications, Huijing He

Mechanical & Materials Engineering Faculty Publications

Scattering of elastic waves in heterogeneous media has become one of the most important problems in the field of wave propagation due to its broad applications in seismology, natural resource exploration, ultrasonic nondestructive evaluation and biomedical ultrasound. Nevertheless, it is one of the most challenging problems because of the complicated medium inhomogeneity and the complexity of the elastodynamic equations. A widely accepted model for the propagation and scattering of elastic waves, which properly incorporates the multiple scattering phenomenon and the statistical information of the inhomogeneities is still missing. In this work, the author developed a multiple scattering model for heterogeneous ...

Applied Strength Of Materials For Engineering Technology, Barry Dupen

Manufacturing and Construction Engineering Technology Faculty Publications

No abstract provided.

Development Of 3d Compression Molded Composite Primary Structure, Sean D. Tischler, Jacob H. Goldstein, Alea A. Perez

Mechanical Engineering

The work accomplished by the Black Gold team improved upon the carbon fiber compression molding research and information available on the Cal Poly San Luis Obispo campus. The team used the rear suspension rocker arm off a Ventana Alpino mountain bike as a design goal for this project. This research and body of work includes the methods used to design a compression molded part for complex part loading and shape. This extends to the process of choosing an appropriate layup process, in addition to benefits and drawbacks of the use of chopped fibers in compression molding. The research includes the ...

Deployable Antenna For Cubesat, Mackenzie Thomas Lennon, Caleb Andrew Barber, David Matthew Galves

Mechanical Engineering

This project is a proof-of-concept ground model of a large deployable antenna designed for the small space requirements of CubeSats. This small deployment module is designed to fit a 2 m by 1 m reflective antenna inside a storage volume of with the dimensions 20 cm by 20 cm x 40 cm. The reflector will be deployed to a parabolic shape with the goal of modeling the reflector necessary for high frequency communication. Because this module is designed as a proof-of-concept for the deployable parabolic reflector specifically, no electrical components will be incorporated and will just focus on the deployment ...

Inkjet Printing Of Nano-Silver Conductive Ink On Pet Substrate, Skyler Jiang

Materials Engineering

Printing of conductive ink traditionally uses copper-based ink and was used on high temperature metal substrates due to the high curing and sintering temperature of copper. In this experiment, however, Metalon JS-B25P nano-silver conductive ink was printed using an Epson Stylus C88+ inkjet printer on polyethylene terephthalate (PET) based Novele printing media made for low temperature applications. With silver’s lower sintering temperature, the nano-silver particles in this ink are desired to be able to sinter at a low enough temperature to be used on the PET substrate. The printed ink traces were cured with a temperature-controlled hotplate at 100 ...

Study On The Mechanical Behavior Of Directly Compounded Long Glass Fiber Reinforced Polyamide 6 Composites, Yuchao Liu

Electronic Thesis and Dissertation Repository

With great lightweight potential, high performance-to-cost ratio and mass productivity, direct-compounded long fiber thermoplastics (D-LFT) have drawn great attention from the automotive industry. With better mechanical properties and higher service temperature, polyamide 6 (PA6) was used to replace polypropylene (PP) which is almost the exclusively used matrix for the D-LFT process currently. The investigation was performed on this new material with a focus on the effect of fiber content, processing parameters, temperature and tailored reinforcement on mechanical behavior. The results show that the mechanical properties of this new material are sensitive to the variation of fiber content and service temperature ...

Software For Extracting Deformation Gradient And Stress From Md Simulations: Simulations Using The Charmm Force Field, Mehrdad Negahban, Lili Zhang, Zesheng Zhang, John Jasa, Antoine Jérusalem

Mechanical & Materials Engineering Faculty Publications

Software was developed, and is provided under a general use license, to calculate continuum level deformation gradient and stress for any group of atoms in an MD simulation that uses the Charmm force fields. This software can also calculate the interaction stress applied by one group of atoms on any other group. To obtain deformation gradient and stress, the user needs to provide the selected group(s) of atoms in an atom group identification file, and provide the associated LAMMPS format files and force field parameter file. An example is included to demonstrate the use of the software.

Primary Blast Waves Induced Brain Dynamics Influenced By Head Orientations, Yi Hua, Yugang Wang, Linxia Gu

Mechanical & Materials Engineering Faculty Publications

There is controversy regarding the directional dependence of head responses subjected to blast loading. The goal of this work is to characterize the role of head orientation in the mechanics of blast wave-head interactions as well as the load transmitting to the brain. A three-dimensional human head model with anatomical details was reconstructed from computed tomography images. Three different head orientations with respect to the oncoming blast wave, i.e., front-on with head facing blast, back-on with head facing away from blast, and side-on with right side exposed to blast, were considered. The reflected pressure at the blast wave-head interface ...

Negahban Group Report: Saw-Tooth Shear Response Of Aged Poly(Methyl Methacrylate) (Pmma), Mehrdad Negahban

Mechanical & Materials Engineering Faculty Publications

Results for isothermal saw-tooth shear loading experiments conducted on annealed and oven-cooled poly(methyl methacrylate) (PMMA) at temperatures between 50^oC and 140^oC. The experiments were conducted 1996.

Formation Of Mound-Like Multiscale Surface Structures On Titanium By Femtosecond Laser Processing, Edwin Peng, Alfred Tsubaki, Craig A. Zuhlke, Ryan Bell, Meiyu Wang, Dennis R. Alexander, George Gogos, Jeffrey E. Shield

Mechanical (and Materials) Engineering -- Dissertations, Theses, and Student Research

Surface Functionalization Technique • Femtosecond Laser Surface Processing (FLSP) • Utilize high power, femtosecond (10-15 s) laser pulses • Produce self-organized, multiscale surface micro/nanostructures • Diverse range of applicable substrates: semiconductors, metals, polymers, & composites

Why? • What are the different types of FLSP structures on Ti? • Physical evidence needed for FLSP formation models • Optimize FLSP of Ti for biomedical & other applications

How? • Obtain evidence of mound growth processes by examining underlying microstructure • Utilize dual beam Scanning Electron Microscope-Focused Ion Beam instrument to cross section surface structures & fabricate transmission electron microscopy samples

Elastic Wave Scattering By Arbitrarily Shaped Voids, Paul J. Schafbuch`, R. Bruce Thompson, F. J. Rizzo, Thomas J. Rudolphi

Thomas Rudolphi

This work is motivated by the need for realistic ultrasonic probability of detection (POD) models in nondestructive evaluation (NDE). Past POD models have utilized flaw farfield scattering amplitudes along with other system parameters to predict the expected signal in postulated measurement geometries [1]. However, numerical evaluations of scattering amplitudes have generally been restricted to idealized flaw shapes and, to our knowledge, no scheme to calculate scattering amplitudes of arbitrary shape has ever been implemented in 3D. Volumetric shapes with an axis of symmetry have been examined with T-matrix and MOOT [2,3] but the axisyrametric limitation precludes a large portion ...

Hypersingular Integral Equations For Crack Problems, G. Krishnasamy, Lester W. Schmerr Jr., Thomas J. Rudolphi, F. J. Rizzo

Thomas Rudolphi

The investigation of scattering of waves by cracks in an elastic medium and by thin scatterers in an acoustic medium, via analytical and experimental methods, seems to be of continuing importance to nondestructive evaluation. On the analytical side, formulation and numerical solution of crack scattering problems using boundary integral equations is popular and effective because of the very nature of a crack, but this approach still suffers some shortcomings of an analytical nature. That is, the governing equations in their primitive form involve a hypersingular kernel function, and the usual process of regularization to lower the kernel singularity usually introduces ...

Frontal Crash Analysis Of A Conformable Cng Tank Using Finite Element Analysis, Datta Sandesh Manjunath

Dissertations, Master's Theses and Master's Reports

The purpose of this study is to computationally model and analyze a Conformable Compressed Natural Gas (CNG) fuel tank for frontal crashes using Finite Element Analysis. Researchers have developed a CNG fuel tank, which is conformable, non-conventional and non-cylindrical. This tank increases cost efficiency, volumetric efficiency and cargo efficiency in CNG vehicle applications. A lightweight pickup truck (2015 Chevrolet Silverado) has been used to integrate the CNG tanks and field-testing has been conducted to demonstrate the application.

The report mainly focuses on the effective finite element modeling of the chassis, brackets and tanks using HYPERMESH and RADIOSS. The frontal crash ...

Applied Strength Of Materials For Engineering Technology, Barry Dupen

Manufacturing and Construction Engineering Technology Faculty Publications

This edition has been superseded. Please see the current 12th edition (updated June 2017): http://opus.ipfw.edu/mcetid_facpubs/55/.

Tensile Specimen Punch, John Allen

All Undergraduate Projects

This project comes from a need to have tensile specimens made for the MET 351, Metallurgy/Materials and Processes, and 426, Applied Strengths of Materials, labs. This punch is designed to be used with an arbor press to create the desired tensile specimen shape out of plastic blanks. The initial concept was suggested by Dr. Craig Johnson. The designs went through many changes, for example getting rid of the sides originally proposed to hold the specimen in place, and modifications to other parts to make them more efficient. Additional parts were also added to the design with the help and ...

Asme Baja Rc Car Drivetrain, Walter Lackey

All Undergraduate Projects

The ASME Baja car is a student built radio controlled car, which will compete with other schools in a variety races. The drivetrain aspect of the car must smoothly transfer power from the motor to the rear wheels of the car. The drivetrain must be designed in collaboration with the other team member’s suspension system to avoid interference. The majority of the parts in the drivetrain are purchased parts intended for various applications. These parts were chosen based on their proximity to the optimal calculated values. Power flows from the electric motor through a single gear reduction, then through ...