Engineering Commons^™

Comprehensive Numerical Modeling Of Prestressed Girder Bridges Under Low-Velocity Impact, Mohamed T. Elshazli, Mohanad M. Abdulazeez, Mohamed Elgawady, Ahmed Ibrahim

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Accidental Collisions Involving Over-Height Trucks That Exceed Vertical Clearance Limits And Bridge Superstructures Frequently Happen, Resulting In Compromised Girders And Potential Threats To Structural Safety And Performance. The Numerical Simulation Of Large-Scale Prestressed Girder Bridge Collisions Poses Challenges Due To The Associated Nonlinearities, As Well As The Limited Availability Of Large-Scale Experimental Testing Data In The Literature Due To Cost And Complexity Constraints. This Study Introduces A Numerical Modeling Approach To Efficiently Capture The Response Of Prestressed Girder Bridges Under Lateral Impact Loads. A Finite Element (FE) Model Was Developed Using LS-DYNA And Meticulously Validated Against Experimental Data From The …

The Interaction Of The Cotton Piece With The Piles Of The Scrabble Cotton Drum, Fazliddin Egamberdiev, Ilkhom Abbazov, Oybek Kholmuratov, Rashid Kaldybaev

Technical science and innovation

This article presents the results of an analytical study of the process of loosening and cleaning raw cotton from small debris by pileging working bodies of purifiers, on the basis of which directions for further research were chosen to optimize the parameters of the developed pile drum with spherical piles and rubber strips. Cotton entering production contains impurities. The processes of loosening and cleaning the fiber shreds are key in the initial stages of ginning, as they prepare the raw cotton for ginning and directly affect the reliability, productivity of these processes and the quality of the resulting fiber. Weed …

Comicir- Commercialization Of Innovative Challenges From Industry And Research (Practice), Charlotte Norrman, Ali Moshfegh, Jeanette Engzell

Research Papers

At Linköping university, a model to facilitate impact and bridge the gap between research, education, and business creation, has been developed. It is named “ComICIR”, which stands for Commercialization of Innovative Challenges from Industry and Research. The model allows researchers, firms, and students to work in a co-creation process that are built on the following five steps: (1) research validation, (2) idea generation, (3) idea validation, (4) idea evaluation and, (5) innovation strategy. In the paper, we describe the model and analyse how challenges and ideas could be developed and experientially based pedagogical approaches could be adjusted in order to …

Laboratory Measurements At The Impact Point Of A Falling Jet, Garrett Richins

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Dams and spillways play a vital role in managing water resources. Many of these hydraulic structures feature a falling jet when discharging downstream. Engineers design plunge pools to receive jets with enough water depth or a protective liner to protect the river bottom so that scour is avoided. Quantifying the pressures at the bottom of the falling jet is a key component to determining the potential for scour and the need for mitigation techniques.

In the laboratory setting, significant discrepancies have been observed between different measurement methods to measure mean and fluctuating pressures of a falling jet intercepting a solid …

Drop Impact On Dry And Liquid Infused Substrates With Micro-Wells., Ahmed Nazrul Islam

Electronic Theses and Dissertations

Drop impact on different types of surfaces are important physical concepts that are routinely found in day-to-day life and such studies have immense application for various types of industries. One such important application of drop dynamics is in the field of aviation science which is concerned of very large freezing drizzle drops impacting on airplane wings. Such drops are known as supercooled large droplets (SLD), and they pose a great risk and have been long known to have caused notable accidents in the past. SLDs are liquid drops that can remain in the state of liquid phase and grow into …

Assessment Of Bridge Pier Response To Fire, Vehicle Impact, And Air Blast, Chen Fang, Qusai Alomari, Daniel G. Linzell

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Highway bridges exposed to intentional or unintentional fire followed by combined vehicle impact and air blast are at risk of significant damage and, possibly, collapse. Limited studies examining the complex effects of these extreme demands on bridge support elements and parametrizing their response and damage are found in the open literature. Research that is presented is part of an ongoing numerical investigation examining round, multi-column, reinforced concrete (RC), bridge pier behavior subject to multi-hazard scenarios involving fire, vehicle impact, and air blast. Detailed nonlinear finite element analysis models of single columns and multi-column piers supported by a pile foundation system …

Correlation Of And Development Of Procedure To Use A Resonant Plate With Mechanical Excitation For Shock Testing Small-To-Medium Size Spacecraft And Provide Aerospace Shock Analysis And Testing Guidelines, Monty Kennedy

Dissertations, Master's Theses and Master's Reports

In the aerospace industry it is known that performing shock analysis and testing on spacecraft is difficult to do mostly because shock loads create a very short duration shock wave transient that can have high acceleration peak levels (1,000-5,000 g) and wide frequency content (100-10,000 Hz). FE (finite-element) shock analysis is difficult because implicit linear FE software commonly used for most vibration analysis in aerospace does not account for shock wave propagation, reflection, and attenuation that occurs based upon the distance from the shock source at the base of the spacecraft and the attenuations that occurs through mechanical joints. Spacecraft …

Predicting Engineering Integration In K-12 From The Perspective Of Pre-Service Teachers, Pilar Pazos, Francisco Cima, Jennifer Kidd, Kristie Gutierrez, Dorothy Faulkner, Minjung Lee, Krishna Kaipa, Orlando Ayala

Engineering Management & Systems Engineering Faculty Publications

The integration of engineering content at the pre-college level is gaining global traction as a strategy to improve learning outcomes and to promote inclusion and diversity in STEM (Science, Technology, Engineering, and Mathematics). Preservice teacher (PST) programs have become natural insertion points for integration efforts by providing future K-12 teachers with the resources and preparation to teach engineering as part of their academic preparation. There is a need to understand the socio-cognitive mechanisms by which teacher preparation programs can help teachers to integrate engineering in their future classrooms. This work examines how an innovative cross-disciplinary program impacted important social-cognitive drivers …

Transient Nonlinear Vibration Characterization Of Building Materials In Sequential Impact Scale Experiments, James Bittner, John S. Popovics

Michigan Tech Publications

Characterizing standard building materials such as concrete is challenging primarily because of the broad range of constituent component sizes within the material itself. Concrete, the most ubiquitous building material, contains critical components that span at least three orders of magnitude of physical size. This work introduces a nondestructive sequential impact test to extract transient nonlinear vibration behaviors that provide statistically significant holistic characterization of a heterogeneous building material, neat cement paste, on a centimeter scale sample. The sensitivity of the single impact vibration combined with the repeatability of the new sequential apparatus enables the extraction of statistically distinct transient nonlinear …

Experimental Investigations Of Yarn Pull-Out Behavior In Kevlar®: Influence Of Applied Metallic Coatings And Effect Of Dynamic Loading, Julie Ann Roark

Theses and Dissertations

Flexible woven Kevlar® textile fabrics are widely used in protective armor applications. Yarn pull-out, comprised of yarn uncrimping (i.e., straightening) and yarn translation, is a major energy absorption mechanism during ballistic impact onto these fabrics, especially for impact velocities below the ballistic limit. Yarn pull-out is influenced by various parameters including inter-yarn friction, pull-out distance, pull-out velocity, transverse pre-tension, fiber diameter, fabric architecture, fabric waviness, fabric count and yarn modulus.

The first part of this thesis investigates yarn pull-out behavior of commercially available Kevlar® KM2+ individual yarns coated with metallic layers (copper, aluminum, aluminum nitride, silver) via a directed vapor …

The Development And Analysis Of Methods Used To Evaluate American Football Facemasks, Alexander Bina

All Dissertations

The motivation for this Ph.D. dissertation is to provide football equipment managers, coaches, parents, athletes, and relevant industry personnel with an understanding of the implication a chosen football facemask design will have on the safety of the athlete. As athletes have increased their capacity for speed, size, and strength, so too has the head injury risk increased in American football. To align with the increase in head impact injury in American football, the protective head impact community must expand its capacity to evaluate protective equipment systems. This dissertation focuses specifically on one helmet system component: the football facemask. This dissertation …

Comparison Of Three-Dimensional Dynamic Models For Golf Clubhead-Ball Impacts, Adam Caldwell, John Mcphee

International Sports Engineering Association – Engineering of Sport

No abstract provided.

Simulation Of Debris Flow Impacting Bridge Pier Tests Based On Smooth Particle Hydromechanics Method, Heng Liang, Ji-Lin Li, Fa-Ming Liu, Lun Zhang, Gang Fu, Ming-Qing Li, Si-Ming He

Rock and Soil Mechanics

In this paper, a three-dimensional numerical simulation model is established based on smooth particle hydrodynamics (SPH) method. In this model, the dynamic behavior of debris flow is described by using the Bingham fluid model, and the bridge pier is regarded as the terrain condition. The repulsive force at the boundary is introduced to improve the boundary condition. Based on flume experiments, the accumulation processes of debris flow impacting the bridge pier with various viscosities and characteristics of the impact force-time curves are analyzed. The physical models are established, and the simulation of three-dimensional dynamic evolution processes of debris flow impacting …

Network Modeling Of Hurricane Evacuation Using Data-Driven Demand And Incident-Induced Capacity Loss Models, Yuan Zhu, Kaan Ozbay, Kun Xie, Hong Yang, Ender Foruk Morgul

Civil & Environmental Engineering Faculty Publications

The development of a hurricane evacuation simulation model is a crucial task in emergency management and planning. Two major issues affect the reliability of an evacuation model: one is estimations of evacuation traffic based on socioeconomic characteristics, and the other is capacity change and its influence on evacuation outcome due to traffic incidents in the context of hurricanes. Both issues can impact the effectiveness of emergency planning in terms of evacuation order issuance, and evacuation route planning. The proposed research aims to investigate the demand and supply modeling in the context of hurricane evacuations. This methodology created three scenarios for …

Inhomogeneous Composite Design For High Energy Impact Resistance Through Computational Design, Physical Testing And Analysis, And Mathematical Modeling, Trenin Bayless

Graduate Theses & Non-Theses

Research in the development of impact resistant materials has been an expanding field for the better part of a hundred years. The development of a light penetration resistant and man-portable system that can resist extreme quantities of kinetic energy has been a subject of substantial study. In particular, the use of composite materials, polymers, ceramics, and metals has been critical to the development of the field. With the advent of complex computational programs for defining material properties, it has become possible to use simulations as a starting point for the development of next generation armored systems. To that end, it …

Development Of Hybrid Ultra-High Performance Concrete Thermoplastic Composite Panels For Blast And Ballistic Protection, Alyssa M. Libby

Electronic Theses and Dissertations

In recent years, ultra-high performance concrete (UHPC) has become a material of interest for structures needing resistance to impact and blast loadings. These types of loadings have induced brittle flexural failure in UHPC due to punching shear from the impactor. One way to improve the impact resistance, energy absorption, and ductility of UHPC is by adding fiber-reinforced polymer (FRP) skins to the front and rear faces of the concrete, resulting in a sandwich configuration. In this study, E-glass fiber-reinforced thermoplastic laminates were bonded to UHPC panels using a heated consolidation process known as stamp thermoforming. The bond between the UHPC …

Are Entrepreneurial Capabilities And Prior Knowledge The Silver Bullet For The Generation Of New Digital Venture Ideas In A Digital Context?, Meifang Yao, Dan Ye, Gao Yang, Hui Shi, Xianrong Zheng

Information Technology & Decision Sciences Faculty Publications

Digital technology has had an important impact on entrepreneurship. It has changed the uncertain nature of the process of new venture idea generation, and it has also brought unprecedented opportunities for the generation of new digital venture ideas. In order to explore how startups can deal with major challenges brought by digital technology and create new digital venture ideas, this paper focuses on micro level entrepreneurial actions and constructs a theoretical model of the relationship among networking capabilities, IT capabilities, prior knowledge, and new digital venture ideas. Furthermore, through the hierarchical linear regression analysis of 278 sample data, the paper …

Projectile Generator Design For Underground Coal Mine Seal Testing, Ethan Allan Steward

Masters Theses

"Underground coal mines have several dangers, one of the most hazardous of which is the possibility of an explosion caused by the ignition of methane gas. To reduce ventilation costs, coal mines have the option to close off abandoned areas that are no longer active with structural seals to keep an explosion from propagating into working areas of the mine. Though seals have been designed to resist the overpressure, none have been evaluated for their resistance to the impact of heavy objects. Underground explosions produce high velocity gasses that, traveling through mine openings, may propel objects in the mine at …

Lessons Learned From Six Different Structural Health Monitoring Systems On Highway Bridges, Abheetha Peiris, Charlie Sun, Issam E. Harik

Kentucky Transportation Center Faculty and Researcher Publications

Structural health monitoring has been utilized in numerous ways to investigate the performance and integrity of highway bridges. This paper highlights the use of six structural health monitoring systems, which were deployed to monitor distinct behaviors on six bridges in Kentucky. The structural health monitoring systems are as follows: (1) Over-height truck impact detection and monitoring on the I-64 over US 60 bridge, (2) Barge impact detection and monitoring on northbound US 41 over the Ohio River, (3) effectiveness of carbon fiber-reinforced polymer retrofit evaluation based on prestressed concrete I-girder crack movement on the I-65 elevated expressway in Louisville, (4) …

Force/Position Control For Dual-Arm Space Robot Capturing Object, Qiuhuang Dong, Chen Li, Haiyun Li, Zhiyong Chen

Journal of System Simulation

Abstract: The dynamics control and simulation of dual-arm space robot capture object was studied. The dynamics model of space robot was derived by the second Lagrange equation, for the object capture process, the impact influence on space robot base and arm was calculated by momentum theory. For the space robot and object close-chain system after capturing, a force/position coordinate control algorithm was designed to control the system motion and object clamp force; the stability, reliability and safety of capture process would be ensured by the control algorithm. The simulation result based on the dynamics model and control algorithm was carried …

A Post-Impact Behavior Of Platelet-Based Composites Produced By Compression Molding, Christopher Eugene Ervin Volle

Mechanical & Aerospace Engineering Theses & Dissertations

Prepreg-based Platelet Molded Compounds (PPMCs) are quickly becoming a widely used method for creating structural components in the aerospace and automotive industries. The discontinuous nature of the platelets used allow good formability of both complex and basic structural components; from seats on commercial airplanes to outer panels of vehicles.

This thesis will look at an important research question of these composites: how PPMCs behave under dynamic loading, e.g. impact and post-impact behavior. Impact is analyzed using recorded force and velocity data to find the absorbed energy. Digital image correlation is used with compression after impact testing to study the propagation …

Low Velocity Impact Of Hybrid Stacked Steel Plates, H. Hadidi, R. Q. Feng, M. P. Sealy

Department of Mechanical and Materials Engineering: Faculty Publications

Designing and manufacturing high-strength, low-weight parts with enhanced impact resistance is highly sought after in the transportation industry. The most common methods to improve strength-to-weight ratios of impact targets is a composite material composition or a favorable geometric design. An alternative method to improve impact performance is functionally gradient mechanical properties in a single material by hybrid additive stacking. In this study, low-velocity impact tests were conducted on hybrid stacked 1070 steel plates where individual layers were subjected to shot peening (SP) to functionally grade mechanical properties. Hybrid additive stacking refers to secondarily processing preferential layers within a stacked build …

Peridynamic Approaches For Damage Prediction In Carbon Fiber And Carbon Nanotube Yarn Reinforced Polymer Composites, Forrest E. Baber

Theses and Dissertations

Aerospace structures are increasingly utilizing advanced composites because of their high specific modulus and specific strength. While the introduction of these material systems can dramatically decrease weight, they pose unique certification challenges, often requiring extensive experimental testing in each stage of the design cycle. The expensive and time-consuming nature of experimental testing necessitates the advancement of simulation methodologies to both aid in the certification process and assist in the exploration of the microstructure design space.

Peridynamic (PD) theory, originating from Sandia National Lab’s in the early 2000’s, is a nonlocal continuum-based method that reformulates the equation of motion into an …

Impact Of Increased Precipitation On Midwestern Construction, Monica Feltman

Williams Honors College, Honors Research Projects

This paper presents the current impact of increased precipitation in the Midwest on the construction industry. Mainly, the impact on jobsite safety, increasing insurance rates, and the resulting changes in design codes, or lack thereof. The goal of this independent research is to gather a better understanding of the influence of these changes, because only then can one accurately seek to combat their harmful effects. As a vital element of the global economy, the construction industry must be conscious of their changing relationship with the environment around them. Therefore, understanding the affects of harmful climate change, will increase awareness of …

Formulación De Alternativas Sostenibles Para El Sector Viverista De La Sabana De Bogotá Registrado Ante El Ica, Rosa Alexandra Martínez Simbaqueva, Mateo Palacios Hermann

Ingeniería Ambiental y Sanitaria

El proyecto se desarrolló específicamente en cinco empresas del sector de plantas ornamentales en Bogotá D.C., inicialmente se había propuesto el trabajo en once empresas representativas del sector, siendo estas: Cid Ambientes Naturales, Garden Center, David Plantas, El Otoño, Jardines Tropicales, Las Palmas Y Jardines De Manuel, Orquídeas Del Llano, Paisajismo Y Diseño S.A.S, Pérez Plantas, Plantaciones Moreno y Platicelo. Cada una de esta cuenta con un registro vigente frente al Instituto Colombiano Agropecuario (ICA), pero debido a restricciones de las empresas o fallos de actualización de la base de datos, los participantes fueron limitados a cinco empresas. Las fases …

Damage Resistance And Tolerance Of 3d Woven Composites, Justin T. Mcdermott

Electronic Theses and Dissertations

Composite materials have been adopted into primary aircraft structures by virtue of their great strength-to-weight and stiffness-to-weight ratios, fatigue insensitivity, and corrosion resistance. These characteristics are leveraged by aircraft designers to deliver improved fuel effciency and reduced scheduled maintenance burdens for their customers. These benefits have been impressively realized in the Boeing 787 and Airbus A350 XWB, with airframes utilizing about 50% composites by weight. Tempering these successes, however, are the inherent vulnerabilities of carbon-fiber reinforced composites. When compared to conventional metallic structure, composite laminates are more sensitive to stress concentrations at mechanical fastenings and damage due to low-velocity impact. …

Double-Sided Corrugated Composite Tube And Axle Protective Mechanism For Railway Vehicles, Hozhabr Mozafari

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Structural elements in transportation vehicles are exposed to different types of dynamic loadings and impact scenarios. Protecting passengers against injury and providing mechanisms to avoid impact induced damages to the critical components are the two hot topics in crashworthiness engineering. The presented research work includes two parts. The first part is about designing a novel double-sided composite corrugated tube that can be implemented in front chassis rail of ground vehicles to improve their crashworthiness against collision and car accidents. To maximize the controllable energy absorption of corrugation troughs as observed in the single sided corrugated (SSC) tube, we proposed and …

Extreme Dynamics Of Nanomaterials Under High-Rate Mechanical Stimuli, Wanting Xie

Doctoral Dissertations

Nanomaterials demonstrate novel mechanical properties attributed to the extremely large interfacial area. At quasi-static rates, the interfacial interactions are crucial in mechanical behaviors, however, materials under extreme mechanical stimuli are rarely studied at nanoscale. With an advanced laser-induced projectile impact test, we perform supersonic impact of micro-projectiles on polymer films, multilayer graphene, carbon- based nanocomposites membranes as well as individual micro-fibers, to study the interface interactions in the high-rate regime, and develop a simplified model to characterize the ballistic performance of materials.

Take Off To Superiority: The Evolution & Impact Of U.S. Aircraft In War, Lane Weidner

Honors Theses

Military aviation has become a staple in the way wars are fought, and ultimately, won. This research paper takes a look at the ways that aviation has evolved and impacted wars across the U.S. history timeline. With a brief introduction of early flight and the modern concept of an aircraft, this article then delves into World Wars I and II, along with the Cold, Korean, Vietnam, and Gulf Wars. The current War on Terrorism is then investigated, and finally, a look toward the future. Topics covered include the newest aircraft of each era, technological advancements, and how strategy and war …

Single Particle Impact Electrochemistry: Analyses Of Nanoparticles And Biomolecules, Jian-Hua Zhang, Yi-Ge Zhou

Journal of Electrochemistry

Single particle impact electrochemistry (SPIEC) has grown rapidly in recent years and shown great promise in the analysis of nanoparticle properties as well as the detection of biomolecules including DNA, RNA, protein, enzyme, bacteria, virus, vesicles and others. This minireview summarizes recent advances in electroanalytical applications of SPIEC according to different analytical methods, i.e., direct electrolysis of nanoparticles or labeled nanoparticles, direct electrolysis of soft particles encapsulated redox molecule, indirect electrochemistry of particles, area and diffusion blocking, and changes in current magnitude and collision frequency.