Engineering Commons^™

Numerical And Experimental Investigation Of Negative Stiffness Beams And Honeycomb Structures, Yasser Darwish, Mohamed A. Elgawady

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Metamaterial structures that exhibit negative stiffness (MSNS) behavior have shown the potential to be used as energy dissipation systems in different applications. Negative stiffness honeycomb structures consist of multiple pre-buckled beams that snapping through from one pre-buckled mode to another buckled mode, when subjected to transverse loads, displaying negative stiffness, and dissipating a significant portion of the input energy. This paper presents finite element models (FEMs) developed to investigate the performance of negative stiffness pre-buckled beams and honeycombs. The FEMs were validated using experimental results of single pre-buckled beams and honeycomb structures. The experimental testing of the pre-buckled beams was …

Investigation Into The Load Transfer Mechanism Of Trees To Develop An Innovative Foundation Configuration Using 3d Finite Element Modeling, Kaleb Boland

All Theses

This study was inspired by a tree’s reliance on its root system that enables it to withstand a natural disaster, such as an extreme hydroclimatic event or hurricane. This curiosity has led to an investigation into what makes this possible, developing a new and innovative foundation configuration for infrastructure systems, and a new possible construction material and method. This study provides results on a material that does not have conventional testing procedures or standards: a tree root. The trees studied are common to the upstate of South Carolina, which are Pine, Sweetgum, and White Oak. According to the results, on …

Improved Vehicle-Bridge Interaction Modeling And Automation Of Bridge System Identification Techniques, Omar Abuodeh

All Dissertations

The Federal Highway Administration (FHWA) recognizes the necessity for cost-effective and practical system identification (SI) techniques within structural health monitoring (SHM) frameworks for asset management applications. Indirect health monitoring (IHM), a promising SHM approach, utilizes accelerometer-equipped vehicles to measure bridge modal properties (e.g., natural frequencies, damping ratios, mode shapes) through bridge vibration data to assess the bridge's condition. However, engineers and researchers often encounter noise from road roughness, environmental factors, and vehicular components in collected vehicle signals. This noise contaminates the vehicle signal with spurious modes corresponding to stochastic frequencies, impacting damage monitoring assessments. Thus, an efficient and reliable SI …

Aerostructural Predictions Combining Fenics And A Viscous Vortex Particle Method, Ryan Anderson, Andrew Ning, Ru Xiang, Sebastiaan P. C. Van Schie, Mark Sperry, Darshan Sarojini, David Kamensky, John T. Hwang

Faculty Publications

Electric Vertical Takeoff and Landing (eVTOL) aircraft experience complex, unsteady aerodynamic interactions between rotors, wings, and fuselage that can make design difficult. We introduce a new framework for predicting aerostructural interactions. Specifically, we demonstrate the coupling of a finite element solver with Reissner-Mindlin shell theory for computing deflections and a viscous vortex particle for capturing wakes. We perform convergence studies of the aerodynamics and the coupled aerostructural model. Finally, we share some preliminary results of the dynamic aeroelastic response of Uber’s eCRM-002 main wing, and share some qualitative observations.

Modeling, Analysis, And Simulation To Reveal The Mechanisms Of Ciliary Beating, Louis Woodhams

McKelvey School of Engineering Theses & Dissertations

Cilia are microscopic cellular appendages that help us breathe by clearing our airways, maintain the health of our central nervous system by circulating cerebrospinal fluid, and allow us to reproduce by transporting eggs and propelling sperm cells. Cilia even determine the asymmetry of our internal organs during embryonic development. However, the mechanisms underlying ciliary beating are not fully understood. Questions remain as to how arrays of the motor protein dynein generate the propulsive waveforms observed in cilia and how structural elements within the cilium and its connection to the cell deform during beating. In the current work, mathematical modeling, analysis, …

Integrated Neuromusculoskeletal Modeling Within A Finite Element Framework To Investigate Mechanisms And Treatment Of Neurodegenerative Conditions, Victoria L. Volk

Boise State University Theses and Dissertations

Neurodegenerative and neurodevelopmental disorders are a group of conditions that stem from irregularities in the nervous system that lead to complications in function and movement. The goal of this work is to develop computational tools that: (1) measure the accuracy of surgical interventions in neurodegenerative and neurodevelopmental conditions, and (2) integrate neural and musculoskeletal frameworks to provide a platform to better investigate neurodegenerative and neurodevelopmental disorders. Parkinson’s disease (PD) is a neurodegenerative condition projected to affect over 1.2 million people by 2030 in the US. It is caused by atypical firing patterns in the basal ganglia region of the brain …

Triangular Mesh Boolean Operation Method For Finite Element Analysis, Yufei Guo, Kang Zhao, Yongqing Hai

Journal of System Simulation

Abstract: To shorten the cycle of finite element analysis (FEA), an adaptive triangular mesh Boolean operation method for finite element analysis is proposed. The ADT (alternating digital tree) data structure is applied to the intersection calculation of triangular meshes, which improves the efficiency of the intersection calculation of Boolean operations. A sphere packing algorithm and a node addition/deletion algorithm are used to remesh some remeshing regions, which ensures the efficiency of the method and the high-quality of remeshed meshes. An improved octree background grid is used to record and smooth the size field, which can generate size-adaptive meshes. The size …

A New Generation Of Open-Graded Friction Course For Enhanced Durability And Functionality, Hossam Abohamer

LSU Doctoral Dissertations

This study aims at (1) enhancing Open Graded Friction Course (OGFC) mixes durability using additives and other by-products; (2) investigating the impacts of selected factors on OGFC pavements seepage characteristics; (3) developing a quantitative tool to model the deterioration in OGFC pavements functional performance; and (4) developing new guidelines of Air Void (AV) content for OGFC for optimum functionality and durability. For the durability objective, eight mixes were prepared with a PG 76-22 binder and two sources of aggregate (i.e., # 78 limestone and # 67 sandstone). Three Warm Mix Additives (WMA), one by-product (i.e., crumb rubber [CR]), and two …

The Influence Of Frontal And Axial Plane Deformities On Contact Mechanics During Squatting: A Finite Element Study, Yidan Xu

Electronic Thesis and Dissertation Repository

Knee Osteoarthritis (KOA) is a degenerative joint disease and a leading cause of disability worldwide. Lower limb malalignment was a risky factor leading to KOA, altering the load distributions. This study aimed to study the influence of knee deformities on knee contact mechanics and knee kinematics during squatting. A full-leg squat FE model was developed based on general open-source models and validated with in vivo studies to investigate the outputs under frontal malalignment (valgus 8° to varus 8°) and axial malalignment (miserable malalignment 30°). As a result, Varus-aligned and miserable aligned models increased medial tibiofemoral force and lateral patellar contact …

Numerical Analysis On Dynamic Response Characteristics Of Geosynthetic Reinforced Embankment Under Moving Load, Ling Zhang, Qiang Ou, Ming-Hua Zhao, Xuan-Ming Ding, Jian-Fei Liu

Rock and Soil Mechanics

The dynamic response of geosynthetic reinforced embankment under traffic moving load has attracted increasing attentions in the engineering field. A 3D model of geosynthetic reinforced embankment was established by using the ABAQUS finite element software in this paper, which was used to analyze the dynamic stress and deformation of geosynthetic reinforced embankment under moving load. The traffic load was simulated by two moving rectangular plane loads. Fortran subroutine was developed to control the amplitude, range, and speed of the moving load. The equivalent linear viscoelastic model was developed to simulate embankment fill to reflect the viscoelasticity of embankment fill. The …

Atomistic-Continuum Membrane And Machine Learning Models For Two-Dimensional Materials, Upenda Yadav

Dissertations, Master's Theses and Master's Reports

“What could we do with layered structures with just the right layers?” asked Richard Feynman in his famous 1959 lecture, “There’s plenty of room at the bottom.” With the help of the amazing developments of the past several years, we are coming close to answering that question. In 2004, graphene was first isolated from graphite and only six short years later it won the Nobel Prize in Physics. Graphene is one atomic layer of Carbon, it is the thinnest and yet the strongest materials we have ever seen. It is 200 times stronger than its equivalent weight in steel and …

Behaviour Of Transmission Lines Subjected To Tornadoes Through Aeroelastic Testing And Numerical Modeling, Nima Ezami

Electronic Thesis and Dissertation Repository

Tornadoes, as a form of high intensity wind (HIW) events, represent major threats to transmission line systems in many regions around the globe. Transmission line systems are among the most vulnerable structures to tornadoes due to their expansion over hundreds of kilometers and, therefore, increased exposure to such localized wind events. A comprehensive research project has been developed over the past two decades at Western University to study this problem. The research conducted in this thesis provides a significant development to the advancement of knowledge in this area through achieving three main objectives. The first objective is to assess and …

Using Differential Shear Strain Measurements To Monitor Crosstie Support Conditions In Railroad Tracks, D. Kody Johnson

Boise State University Theses and Dissertations

This thesis details a comprehensive numerical analysis of load determination, and crosstie support assessment and monitoring using strain gauges to measure differential rail shear strain in ballasted railroad tracks due to applied railcar wheel loads. These differential shear strain measurements can be related to applied wheel loading and crosstie support reactions through the geometric and constitutive properties of a given rail section. The basic theory behind the measurement technique was reviewed and investigated using finite element models of varying complexity. The impact of field conditions such as differential ballast and subgrade support, track stiffness, crosstie spacing, gauge installation location, and …

Musculoskeletal Adaptation Of Young And Older Adults In Response To Environmental, Physical, And Cognitive Conditions, Amy E. Holcomb

Boise State University Theses and Dissertations

Accidental falls present a large functional and financial burden among people aged 65 years and older. Falls, injuries associated with falls, and the fear of falling decrease quality of life, physical function, and independence for older adults. To prevent falls, improve stability, and protect joints from damage or injury, the typical response to "challenging" conditions include cautious gait, increase muscle co-contraction, and decreased range of motion. These compensatory strategies are more pronounced in the older adult population with apprehensive "cautious" gait at slower speeds, decreased knee flexion, and increased muscle activation around the knee and ankle. The underlying mechanisms and …

Investigating A Finite Element Model Updating Methodology For Characterizing Mechanical Properties Of Ncf Composites, Pasworn Chanchai

Mechanical and Aerospace Engineering Theses

Composite materials have been a key breakthrough in developing aircraft structures. Their superior strength and stiffness-to-density ratio, which are unmatched by no other materials, allow engineers to create high strength and ultra-lightweight aircraft structures. Recently, non-Crimp Fabric (NCF) composites have emerged as attractive alternatives to traditional autoclave pre-impregnated composites allowing for lower production costs, better handling and improved shelf life while maintaining excellent in-plane mechanical properties compared to other types of textile composites. NCF out-of-plane mechanical properties can also be enhanced by stitching a high tensile strength yarn throughout their entire laminate thickness, improving the resistance to delamination. However, stitch-reinforced …

3d Printable And Computational Models Of The Bone Marrow Mechanical Environment, Alexander Regner

Boise State University Theses and Dissertations

Aged individuals and astronauts experience bone loss despite rigorous physical activity. Bone mechanoresponse is in part regulated by mesenchymal stem cells (MSCs). We reported that daily low intensity vibration (LIV) restores MSC proliferation in senescence and simulated microgravity models, suggesting reduced mechanical signal delivery to MSCs likely contributes to declining bone mechanoresponse. To this end, we have developed a 3D bone marrow analog which controls trabecular geometry, marrow mechanics and external stimuli.

Finite element (FE) models of hydrogels, representing bone marrow, were generated using instantaneous compression (1000% strain/s, 20% strain) and relaxation experiments (100s) of both gelatin and hyaluronin-based hydrogels. …

Visualization Of Finite Element Analysis Deformation Results Based On Hololens, Jinli Xu, Zhou Zheng

Journal of System Simulation

Abstract: An UWP application of virtual review of the finite element analysis based on Microsoft HoloLens is developed by using Unity3D software. A set of programs are completed to realize three-dimensional solid static finite element analysis in Matlab. To realize the visualization of the deformation effect, the useful information of the finite element analysis result is extracted and exported to VTK file, then converted into DAE file. A vertex shader is written in Unity3D software to realize the color display and the visualization of deformation effect of one-sided model, and finally the UWP application is released to HoloLens. The test …

Impact Analysis Of Gun-On Target Parameters On The Blunting Effect Of The Soft Protective Human Body, Sun Fei, Wenmin Yan, Junbin Zhang, Yongjuan Wang, Xu Cheng

Journal of System Simulation

Abstract: In order to research the blunt impact effect of target-entry parameters of pistol bullets, the finite element models of the soft upper body of the pistol blunt with a soft-protected human body are developed. By hitting the heart, lung, liver and stomach at three target-entry velocities, the impact response of pistol bullet impacting on human torso with soft armor is numerically calculated by finite element method. The simulation results quantitatively reveal the pressure transmission mechanism of the human body with blunt body armor at different target speeds and positions and the law of blunt impact response at different target …

Optimized Analysis Of Milling Thin-Wall Parts Based On Shell Element Models, Yusong Liao, Han Jiang

Journal of System Simulation

Abstract: As to milling the thin-wall part accurately, here with the finite element model composed of SHELL elements, the effects of lowering position, size of the part and cutting parameters to the deformations of the thin-wall part were analyzed and compared, and the corresponding theoretical analysis was provided. The conclusions can be got as; the model composed of SHELL elements can analyze the factors causing the deforroations of the thin-wall part and optimize the cutting method and cutting parameters effectively to improve the machining accuracy and efficiency.

3d Acoustic Pipe Locator Imaging Based On Finite Element Analysis, Yi Liu

Graduate College Dissertations and Theses

A more complex underground pipe system is growing with the expansion of cities. However, there is no comprehensive database of underground pipes. Thus, it is urgent to build database with materials, positions, diameters, and etc. To locate the pipes is the first step. There are many ways to find pipes such as metal detector, ground penetrating radar, and acoustic method. Metal detectors are becoming increasing ineffective with more and more nonmetal is using in pipes. Ground penetrating radar is a precise way to find pipes but it is only works well under low moisture environment. Additionally, ground penetrating radar is …

Estimation And Mitigation Of Stresses In Mass Concrete Structures Containing Ground Granulated Blast Furnaceslag And Fly Ash, Guadalupe Leon

Graduate Theses, Dissertations, and Problem Reports

In large concrete structures, due to concrete’s low thermal conductivity, the interior temperature rise can approach the concrete’s adiabatic temperature rise. As the concrete’s surface losses heat to the environment and cools rapidly, the interior of the concrete attempts to expand while the exterior provides an internal restraint. The phenomenon causes thermal stresses at the concrete’s surface. If the thermal stresses exceed the concrete’s tensile strength, there is a high probability of cracking. The cracks usually appear during the first few days after construction while the concrete’s tensile strength is low. These early-age cracks can reduce the service life of …

Tibial Strains And Tray-Bone Micromotions After Total Knee Arthroplasty: Computational Studies Evaluating The Tibial Fixation, Huizhou Yang

Electronic Theses and Dissertations

Cemented and cementless fixation in total knee arthroplasty (TKA) have been successfully used for decades. As the number of younger and more active patients treated with TKA continues to increase, long-term implant survivorship is of increasing importance. One of the most common complications and hence the reason for revision is mechanical loosening (23.1% of all revised TKA). The loosening mechanisms have been proposed for different fixation types. For cemented fixation, bone remodeling after surgery is regulated by the changes in strain energy density (SED). The recruitment of osteoclasts and osteoblasts is controlled by SED-related signals. Insufficient stimuli can promote bone …

Hydration, Shrinkage, Cracking, And Mechanical Properties Of Cementitious Materials With Lignocellulosic Biomass Wastes., Aofei Guo

Electronic Theses and Dissertations

The disposal of lignocellulosic biomass wastes imposes a huge economic and environmental burden on this society. Recycling lignocellulosic biomass wastes and applying them to cementitious materials provides a sustainable and value-added way for both agriculture and concrete industries. To comprehensively identify the effect of lignocellulosic biomass wastes at different scales on cementitious materials, the hydration, shrinkage, cracking, and mechanical properties of cementitious materials with lignocellulosic biomass wastes were studied. Given the three different forms (powders, chips, and fibers) of lignocellulosic biomass wastes in this study, the research was implemented in three stages. In the first stage, hemp powders were collected …

Modal Analysis Of Iced Conductor Galloping For Continuous Spans, Xiaohui Liu, Lufei Zhang, Yan Bo, Xiaoyan Zhang

Journal of System Simulation

Abstract: The parameter analysis was presented for continuous spans vibration induced by single-span conductor galloping. The fine finite element model of continous spans and insulator strings was set up by ABAQUS softwart, the aerodynamic load was defined by UEL. So the dynamic response of continuous spans induced by single-span conductor galloping were numerically simulated in ABAQUS. The numerical simulation results show that the structure parameters have obvious effect on the vibration amplitude of the displacements and tention, low order modes have great influence on the vibration amplitede of the displacements, high order modes have great influence on the vibration amplitude …

A Computational Framework To Model Mesenchymal Stem Cell Nucleus Mechanics Using Confocal Microscopy, Zeke Kennedy

Boise State University Theses and Dissertations

The mechanical properties of the cell nucleus are emerging as a key component in genetic transcription. It has been shown that the stiffness of the nucleus in part regulates the transcription of genes in response to external mechanical stimuli. The stiffness has been shown to change as a result of both disease and changes to the external environment. While the mechanical structure of the nucleus can be visually documented using a confocal microscope, it is currently impossible to test the stiffness of the nucleus without a mechanical testing apparatus such as an atomic force microscope. This is problematic in that …

Finite Element Simulation Of Machining 7075 Aluminum Alloy Based On Advantedge And Corresponding Experimental Study, Yusong Liao, Han Jiang

Journal of System Simulation

Abstract: Abstract: The finite element simulation of cutting 7050 aluminum alloy was carried out based on the software of AdvantEdge, and Johnson-Cook constitutive model was chosen for the workpiece material in the model. The parameters for the constitutive model were obtained through the Hopkinson experiment. The cutting forces and surface qualities were observed through different cutting velocities and cutting depths. The cutting velocity and cutting depth were optimized, and the experiment was carried out with the guidance of the simulation results. The machined workpiece obtained from the experiment shows that the optimized cutting parameters can improve the machined surface property …

Numerical Investigation Of Concrete Breakout Strength Of Anchors In Shear Within Fiber Reinforced Concrete, Yash Hitendrakumar Patel

Civil Engineering Theses

This study investigates the numerical analysis of concrete breakout strength of cast in place anchors in shear within synthetic fiber reinforced concrete (SYN-FRC). A three dimensional, full-scale model was developed using the ABAQUS 6.14 software. The 3D solid elements with consideration of material nonlinearities were chosen to stimulate the SYN-FRC beam anchorage. The numerical analysis was conducted with a fixed loading rate of 300lb per step to obtain the behavior of fiber-reinforced concrete breakout with design-mix compressive strength of 4,000 psi and fiber volume fraction of 0%, 0.5%, 1.0%, and 1.5%. An inverse analysis was used to calibrate the material …

Computational Approach To Correcting Joint Instability In Patients With Recurrent Patellar Dislocation, Oliver Alvarez, Robert N. Steensen, Paul J. Rullkoetter, Clare K. Fitzpatrick

Mechanical and Biomedical Engineering Faculty Publications and Presentations

Patellar dislocation is a debilitating injury common in active adolescents and young adults. Conservative treatment after initial dislocation is often recommended, but almost half of these patients continue to suffer from recurrent dislocation. The objective of this study was to compare preoperative patellofemoral joint stability with stability after a series of simulated procedures, including restorative surgery to correct to pre-injury state, generic tibial tubercle osteotomy, patient-specific reconstructive surgery to correct anatomic abnormality, less invasive patient-specific surgery, and equivalent healthy controls. Three-dimensional, subject-specific finite element models of the patellofemoral joint were developed for 28 patients with recurrent patellar dislocation. A …

Biomechanical Behavior Of A Variable Angle Locked Tibiotalocalcaneal Construct, Farah Hamandi, Gerard Simon, Richard T. Laughlin, Tarun Goswami

Biomedical, Industrial & Human Factors Engineering Faculty Publications

This paper examines the mechanics of the tibiotalocalcaneal construct made with a PHILOS plating system. A failed device consisting of the LCP plate and cortical, locking, and cannulated screws was used to perform the analysis. Visual, microstructure, and fractographic examinations were carried out to characterize the fracture surface topology. These examinations revealed the presence of surface scratching, inclusions, discoloration, corrosion pits, beach marks, and cleavage and striations on the fracture surface. Further examination of the material crystallography and texture revealed an interaction of S, Ni, and Mo-based inclusions that may have raised pitting susceptibility of the device made with Stainless …

Computational Modeling Of Laminated Veneer Bamboo (Lvb) Dowel Joints, Niloufar Khoshbakht

Doctoral Dissertations

Laminated veneer bamboo (LVB) is a sustainable building material that has been gaining interest in the construction industry of late. As a relatively new product, little is known about its connection performance, specifically, its failure behavior in dowel type joints and possible similarities it may have to engineered wood products in terms of failure mechanisms. Research is needed to aid in the understanding of LVB dowel connection failure behavior and to quantify the failure mechanism and key factors associated with LVB dowel connection strength. Modeling, as conducted in this research, is a valuable tool to help devise safe standards and …