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Michigan Technological University

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Articles 211 - 240 of 839

Full-Text Articles in Mechanical Engineering

Evolution Of Glassy Carbon Derived From Pyrolysis Of Furan Resin, Josh Kemppainen, Ivan Gallegos, Aaron Krieg, Jacob R. Gissinger, Kristopher E. Wise, Margaret Kowalik, Julia A. King, S. Gowtham, Adri Van Duin, Gregory Odegard Oct 2023

Evolution Of Glassy Carbon Derived From Pyrolysis Of Furan Resin, Josh Kemppainen, Ivan Gallegos, Aaron Krieg, Jacob R. Gissinger, Kristopher E. Wise, Margaret Kowalik, Julia A. King, S. Gowtham, Adri Van Duin, Gregory Odegard

Michigan Tech Publications

Glassy carbon (GC) material derived from pyrolyzed furan resin was modeled by using reactive molecular dynamics (MD) simulations. The MD polymerization simulation protocols to cure the furan resin precursor material are validated via comparison of the predicted density and Young's modulus with experimental values. The MD pyrolysis simulations protocols to pyrolyze the furan resin precursor is validated by comparison of calculated density, Young's modulus, carbon content, sp carbon content, the in-plane crystallite size, out-of-plane crystallite stacking height, and interplanar crystallite spacing with experimental results from the literature for furan resin derived GC. The modeling methodology established in this work can …


Me-Em Enewsbrief, September 2023, Department Of Mechanical Engineering-Engineering Mechanics, Michigan Technological University Oct 2023

Me-Em Enewsbrief, September 2023, Department Of Mechanical Engineering-Engineering Mechanics, Michigan Technological University

Department of Mechanical and Aerospace Engineering eNewsBrief

No abstract provided.


Electric Motor And Transmission Integration For Light-Duty Electric Vehicles: A 2023 Benchmarking Perspective And Component Sizing For A Fleet Approach, Darrell Robinette Sep 2023

Electric Motor And Transmission Integration For Light-Duty Electric Vehicles: A 2023 Benchmarking Perspective And Component Sizing For A Fleet Approach, Darrell Robinette

Michigan Tech Publications

A review of past, current, and emerging electric vehicle (EV) propulsion system technologies and their integration is the focus of this paper, namely, the matching of electric motor (EM) and transmission (TRM) to meet basic requirements and performance targets. The fundaments of EM and TRM matching from a tractive effort and a vehicle dynamics perspective are provided as an introductory context to available or near-production propulsion system products available from OEM and Tier 1 suppliers. Engineering data and details regarding EM and TRM combinations are detailed with a specific focus on volumetric and mass density. Evolutionary trends in EM and …


Me-Em Enewsbrief, June 2023, Department Of Mechanical Engineering-Engineering Mechanics, Michigan Technological University Sep 2023

Me-Em Enewsbrief, June 2023, Department Of Mechanical Engineering-Engineering Mechanics, Michigan Technological University

Department of Mechanical and Aerospace Engineering eNewsBrief

No abstract provided.


Establishing Physical And Chemical Mechanisms Of Polymerization And Pyrolysis Of Phenolic Resins For Carbon-Carbon Composites, Ivan Gallegos, Josh Kemppainen, Jacob R. Gissinger, Malgorzata Kowalik, Adri Van Duin, Kristopher E. Wise, S. Gowtham, Gregory Odegard Sep 2023

Establishing Physical And Chemical Mechanisms Of Polymerization And Pyrolysis Of Phenolic Resins For Carbon-Carbon Composites, Ivan Gallegos, Josh Kemppainen, Jacob R. Gissinger, Malgorzata Kowalik, Adri Van Duin, Kristopher E. Wise, S. Gowtham, Gregory Odegard

Michigan Tech Publications

The complex structural and chemical changes that occur during polymerization and pyrolysis critically affect material properties but are difficult to characterize in situ. This work presents a novel, experimentally validated methodology for modeling the complete polymerization and pyrolysis processes for phenolic resin using reactive molecular dynamics. The polymerization simulations produced polymerized structures with mass densities of 1.24 ± 0.01 g/cm3 and Young's moduli of 3.50 ± 0.64 GPa, which are in good agreement with experimental values. The structural properties of the subsequently pyrolyzed structures were also found to be in good agreement with experimental X-ray data for the phenolic-derived carbon …


Explainable Ai For Tool Wear Prediction In Turning, Saleh Valizadeh Sotubadi, Rui Liu, Vinh Nguyen Aug 2023

Explainable Ai For Tool Wear Prediction In Turning, Saleh Valizadeh Sotubadi, Rui Liu, Vinh Nguyen

Michigan Tech Publications

This research aims develop an Explainable Artificial Intelligence (XAI) framework to facilitate human-understandable solutions for tool wear prediction during turning. A random forest algorithm was used as the supervised Machine Learning (ML) classifier for training and binary classification using acceleration, acoustics, temperature, and spindle speed during the orthogonal tube turning process as input features. The ML classifier was used to predict the condition of the tool after the cutting process, which was determined in a binary class form indicating if the cutting tool was available or failed. After the training process, the Shapley criterion was used to explain the predictions …


Power Packet Networks For Wave Energy Converter Arrays, David G. Wilson, Raymond H. Byrne, Steven F. Glover, Tu Anh Nguyen, Rush Robinett, Wayne Weaver, Et. Al Aug 2023

Power Packet Networks For Wave Energy Converter Arrays, David G. Wilson, Raymond H. Byrne, Steven F. Glover, Tu Anh Nguyen, Rush Robinett, Wayne Weaver, Et. Al

Michigan Tech Patents

One of the biggest challenges for all renewable energy sources (RES) is that they are variable power generators which will require reactive power or energy storage systems (ESS) to provide reliable power quality (ideally power factor of one) at the power grid generation side. The present invention is directed to a power packet network (PPN) for integrating wave energy converter (WEC) arrays into microgrids. Specifically, an array of WECs can be physically positioned such that the incoming regular waves will produce an output emulating an N-phase AC system such that the PPN output power is constant. ESS requirements are thereby …


The Intertwined Renewable Energy–Water–Environment (Rewe) Nexus Challenges And Opportunities: A Case Study Of California, Shahryar Jafarinejad, Rebecca R. Hernandez, Sajjad Bigham, Bryan S. Beckingham Jul 2023

The Intertwined Renewable Energy–Water–Environment (Rewe) Nexus Challenges And Opportunities: A Case Study Of California, Shahryar Jafarinejad, Rebecca R. Hernandez, Sajjad Bigham, Bryan S. Beckingham

Michigan Tech Publications, Part 1

In our built environment, societal production of energy and clean water is inextricably linked to the natural resources from which they are derived. Acknowledgement and consideration of the coupling of energy, water, and the environment (the energy–water–environment nexus) will be critical to a sustainable future. This is particularly true as we transition away from historical energy sources (e.g., coal, petroleum, natural gas) and into the widespread adaptation of renewable energy (RE) sources (e.g., solar, wind, geothermal, hydro, bioenergy) as a strategy to decrease greenhouse gas emissions and consequently slow global climate change. This transition is fraught with both challenges and …


Coordinating Tethered Autonomous Underwater Vehicles Towards Entanglement-Free Navigation, Abhishek Patil, Myoungkuk Park, Jungyun Bae Jun 2023

Coordinating Tethered Autonomous Underwater Vehicles Towards Entanglement-Free Navigation, Abhishek Patil, Myoungkuk Park, Jungyun Bae

Michigan Tech Publications, Part 1

This paper proposes an algorithm that provides operational strategies for multiple tethered autonomous underwater vehicle (T-AUV) systems for entanglement-free navigation. T-AUVs can perform underwater tasks under reliable communication and power supply, which is the most substantial benefit of their operation. Thus, if one can overcome the entanglement issues while utilizing multiple tethered vehicles, the potential applications of the system increase including ecosystem exploration, infrastructure inspection, maintenance, search and rescue, underwater construction, and surveillance. In this study, we focus on developing strategies for task allocation, path planning, and scheduling that ensure entanglement-free operations while considering workload balancing among the vehicles. We …


Unmanned Aerial Vehicle-Based Computer Vision For Structural Vibration Measurement And Condition Assessment: A Concise Survey, Kai Zhou, Zequn Wang, Yi Qing Ni, Yang Zhang, Jiong Tang Jun 2023

Unmanned Aerial Vehicle-Based Computer Vision For Structural Vibration Measurement And Condition Assessment: A Concise Survey, Kai Zhou, Zequn Wang, Yi Qing Ni, Yang Zhang, Jiong Tang

Michigan Tech Publications

With the rapid advance in camera sensor technology, the acquisition of high-resolution images or videos has become extremely convenient and cost-effective. Computer vision that extracts semantic knowledge directly from digital images or videos, offers a promising solution for non-contact and full-field structural vibration measurement and condition assessment. Unmanned aerial vehicles (UAVs), also known as flying robots or drones, are being actively developed to suit a wide range of applications. Taking advantage of its excellent mobility and flexibility, camera-equipped UAV systems can facilitate the use of computer vision, thus enhancing the capacity of the structural condition assessment. The current article aims …


Neuroevolution Application To Collaborative And Heuristics-Based Connected And Autonomous Vehicle Cohort Simulation At Uncontrolled Intersection, Frederic Jacquelin, Jungyun Bae, Bo Chen, Darrell Robinette Jun 2023

Neuroevolution Application To Collaborative And Heuristics-Based Connected And Autonomous Vehicle Cohort Simulation At Uncontrolled Intersection, Frederic Jacquelin, Jungyun Bae, Bo Chen, Darrell Robinette

Michigan Tech Publications

Artificial intelligence is gaining tremendous attractiveness and showing great success in solving various problems, such as simplifying optimal control derivation. This work focuses on the application of Neuroevolution to the control of Connected and Autonomous Vehicle (CAV) cohorts operating at uncontrolled intersections. The proposed method implementation’s simplicity, thanks to the inclusion of heuristics and effective real-time performance are demonstrated. The resulting architecture achieves nearly ideal operating conditions in keeping the average speeds close to the speed limit. It achieves twice as high mean speed throughput as a controlled intersection, hence enabling lower travel time and mitigating energy inefficiencies from stop-and-go …


Real-Time Suitable Predictive Control Using Spat Information From Automated Traffic Lights, Pradeep Bhat, Bo Chen May 2023

Real-Time Suitable Predictive Control Using Spat Information From Automated Traffic Lights, Pradeep Bhat, Bo Chen

Michigan Tech Publications

Traffic intersections throughout the United States combine fixed, semi-actuated, and fully actuated intersections. In the case of the semi-actuated and actuated intersections, uncertainties are considered in phase duration. These uncertainties are due to car waiting queues and pedestrian crossing. Intelligent transportation systems deployed in traffic infrastructure can communicate Signal and Phase Timing messages (SPaT) to vehicles approaching intersections. In the connected and automated vehicle ecosystem, the fuel savings potential has been explored. Prior studies have predominantly focused on fixed time control for the driver. However, in the case of actuated signals, there is a different and significant challenge due to …


Me-Em Enewsbrief, March 2023, Department Of Mechanical Engineering-Engineering Mechanics, Michigan Technological University May 2023

Me-Em Enewsbrief, March 2023, Department Of Mechanical Engineering-Engineering Mechanics, Michigan Technological University

Department of Mechanical and Aerospace Engineering eNewsBrief

No abstract provided.


Base Vibration Effects On Additive Manufactured Part Quality, N. J. Jensen, G. G. Parker, J. R. Blough Apr 2023

Base Vibration Effects On Additive Manufactured Part Quality, N. J. Jensen, G. G. Parker, J. R. Blough

Michigan Tech Publications, Part 1

Additive Manufacturing (AM) has opened the door for portable and self-sufficient fabrication. However, environments with base vibration degrade part quality during production. This work focuses on investigating and mitigating the effects of base vibration on AM part quality. Factors influencing part quality initiated the approach, followed by experiments on an extrusion-type printer to inspect and minimize vibration effects. Part roughness was used as the part quality metric based on preliminary experimental observations. A modal impact test identified the print bed and print head gantry as vibration-sensitive components at ≈ 40 Hz. These vibration modes were targeted with experiments to evaluate …


Adaptation Of High Spatio-Temporal Resolution Weather/Load Forecast In Real-World Distributed Energy-System Operation, Amir Ali Safaei Pirooz, Mohammad J. Sanjari, Young Jin Kim, Stuart Moore, Richard Turner, Wayne Weaver, Dipti Srinivasan, Josep M. Guerrero, Mohammad Shahidehpour Apr 2023

Adaptation Of High Spatio-Temporal Resolution Weather/Load Forecast In Real-World Distributed Energy-System Operation, Amir Ali Safaei Pirooz, Mohammad J. Sanjari, Young Jin Kim, Stuart Moore, Richard Turner, Wayne Weaver, Dipti Srinivasan, Josep M. Guerrero, Mohammad Shahidehpour

Michigan Tech Publications, Part 1

Despite significant advances in distributed renewable energy systems (DRES), the technology still faces several substantial challenges that prevent the large-scale adoption of these systems into a country’s energy sector. The intermittency of renewables, uncertainties associated with real-time multi-horizon weather and load forecasts, and lack of comprehensive control systems are among the main technical and regulatory challenges for the real-world adoption of DRES. This paper outlines the current state of knowledge in the real-world operation of DRES and also describes pathways and methodologies that enable and facilitate the uptake of DRES in a country’s energy sector.


Effect Of The Dynamic Froude–Krylov Force On Energy Extraction From A Point Absorber Wave Energy Converter With An Hourglass-Shaped Buoy, Houssein Yassin, Tania Demonte Gonzalez, Gordon Parker, David Wilson Mar 2023

Effect Of The Dynamic Froude–Krylov Force On Energy Extraction From A Point Absorber Wave Energy Converter With An Hourglass-Shaped Buoy, Houssein Yassin, Tania Demonte Gonzalez, Gordon Parker, David Wilson

Michigan Tech Publications, Part 1

Point absorber wave energy converter (WEC) control strategies often require accurate models for maximum energy extraction. While linear models are suitable for small motions, the focus is on the nonlinear model of an hour-glass shaped buoy undergoing large vertical displacements. Closed-form expressions for the static and dynamic Froude–Krylov forces are developed. It is shown that, in general, the dynamic and static forces are of similar magnitude, which is not the case for a spherical buoy. While the dynamic force reduces the amplitude of the net buoy force, its shape predicts a larger buoy response than if neglected, causing the nonlinear …


Optimal Configuration Of Extreme Fast Charging Stations Integrated With Energy Storage System And Photovoltaic Panels In Distribution Networks, Zhouquan Wu, Pradeep Bhat, Bo Chen Mar 2023

Optimal Configuration Of Extreme Fast Charging Stations Integrated With Energy Storage System And Photovoltaic Panels In Distribution Networks, Zhouquan Wu, Pradeep Bhat, Bo Chen

Michigan Tech Publications, Part 1

Extreme fast charging (XFC) for electric vehicles (EVs) has emerged recently because of the short charging period. However, the extreme high charging power of EVs at XFC stations may severely impact distribution networks. This paper addresses the estimation of the charging power demand of XFC stations and the design of multiple XFC stations with renewable energy resources in current distribution networks. First, a Monte Carlo (MC) simulation tool was created utilizing the EV arrival time and state-of-charge (SOC) distributions obtained from the dataset of vehicle travel surveys. Various impact factors are considered to obtain a realistic estimation of the charging …


Boron Nitride Nanotubes: Force Field Parameterization, Epoxy Interactions, And Comparison With Carbon Nanotubes For High-Performance Composite Materials, Swapnil S. Bamane, Michael B. Jakubinek, Krishan Kanhaiya, Behnam Ashrafi, Hendrik Heinz, Gregory Odegard Feb 2023

Boron Nitride Nanotubes: Force Field Parameterization, Epoxy Interactions, And Comparison With Carbon Nanotubes For High-Performance Composite Materials, Swapnil S. Bamane, Michael B. Jakubinek, Krishan Kanhaiya, Behnam Ashrafi, Hendrik Heinz, Gregory Odegard

Michigan Tech Publications, Part 1

Boron nitride nanotubes (BNNTs) are a very promising reinforcement for future high-performance composites because of their excellent thermo-mechanical properties. To take full advantage of BNNTs in composite materials, it is necessary to have a comprehensive understanding of the wetting characteristics of various high-performance resins. Molecular dynamics (MD) simulations provide an accurate and efficient approach to establish the contact angle values of engineering polymers on reinforcement surfaces, which offers a measure for the interaction between the polymer and reinforcement. In this research, MD simulations and experiments are used to determine the wettability of various epoxy systems on BNNT surfaces. The reactive …


Utilization Of Mechanically Recycled Carbon Fibers In Vinyl Ester Composites, Khaled Alharmoodi, Amir Hussain Idrisi, Abdel Hamid Ismail Mourad, Basim Abu-Jdayil Feb 2023

Utilization Of Mechanically Recycled Carbon Fibers In Vinyl Ester Composites, Khaled Alharmoodi, Amir Hussain Idrisi, Abdel Hamid Ismail Mourad, Basim Abu-Jdayil

Michigan Tech Publications, Part 1

As we enter the twenty-first century, the aviation sector is expected to thrive as flying becomes the primary mode of transportation between states or nations. With such a demand, there is a corresponding need to manufacture aircraft components. The study focused on recycling carbon fiber composites received from the STRATA company, which were cut-off/waste material generated during the manufacture of airplane components. The cut-offs were then reduced to powder form using a standard face milling machine in three sizes (90, 150, and 250 µm). After, the powder was utilized to fabricate vinyl ester composites with four weight percentages (10%, 20%, …


Dsrc Versus Lte-V2x: Empirical Performance Analysis Of Direct Vehicular Communication Technologies, Ehsan Moradi-Pari, Danyang Tian, Mojtaba Bahramgiri, Samer Rajab, Sue Bai Feb 2023

Dsrc Versus Lte-V2x: Empirical Performance Analysis Of Direct Vehicular Communication Technologies, Ehsan Moradi-Pari, Danyang Tian, Mojtaba Bahramgiri, Samer Rajab, Sue Bai

Michigan Tech Publications, Part 1

Vehicle-to-Vehicle (V2V) communication systems have an eminence potential to improve road safety and optimize traffic flow by broadcasting Basic Safety Messages (BSMs). Dedicated Short-Range Communication (DSRC) and LTE Vehicle-to-Everything (V2X) are two candidate technologies to enable V2V communication. DSRC relies on the IEEE 802.11p standard for its PHY and MAC layer while LTE-V2X is based on 3GPP’s Release 14 and operates in a distributed manner in the absence of cellular infrastructure. There has been considerable debate over the relative advantages and disadvantages of DSRC and LTE-V2X, aiming to answer the fundamental question of which technology is most effective in real-world …


Me-Em Enewsbrief, December 2022, Department Of Mechanical Engineering-Engineering Mechanics, Michigan Technological University Feb 2023

Me-Em Enewsbrief, December 2022, Department Of Mechanical Engineering-Engineering Mechanics, Michigan Technological University

Department of Mechanical and Aerospace Engineering eNewsBrief

No abstract provided.


Probing The Influence Of Surface Chemical Functionalization On Graphene Nanoplatelets-Epoxy Interfacial Shear Strength Using Molecular Dynamics, Hashim Al Mahmud, Sagar Patil, Matthew Radue, Gregory Odegard Jan 2023

Probing The Influence Of Surface Chemical Functionalization On Graphene Nanoplatelets-Epoxy Interfacial Shear Strength Using Molecular Dynamics, Hashim Al Mahmud, Sagar Patil, Matthew Radue, Gregory Odegard

Michigan Tech Publications, Part 1

In this work, a characterization study of the interfacial interaction between different types of graphene nanoplatelets and an epoxy matrix is computationally performed. To quantify the discrete mutual graphene–epoxy “interfacial interaction energy” (IIE) within the nanocomposite, molecular dynamics simulations with a reactive force field are performed on a localized model of the suggested nanocomposite. Pull-out molecular dynamics simulations are also performed to predict the interfacial shear strength between the two constituents. The results indicate a significant increase in interfacial adhesion of functionalized nanoplatelets with the hosting epoxy matrix relative to virgin graphene nanoplatelets. The obtained results also demonstrate a dramatic …


An Experimentally Validated Computational Model For The Degradation And Fracture Of Magnesium-Based Implants In A Chemically Corrosive Environment, Mark M. Ousdigian Jan 2023

An Experimentally Validated Computational Model For The Degradation And Fracture Of Magnesium-Based Implants In A Chemically Corrosive Environment, Mark M. Ousdigian

Dissertations, Master's Theses and Master's Reports

In the orthopedic and cardiovascular fields there is a growing interest for biodegradable implants, which can be naturally degraded in the body environment over time so that no extraction surgery is required. These implants must be designed to maintain their strength until the fracture has healed in the body, which could be influenced by many factors such as -the patient’s age, activities, body weight, pre-existing conditions etc. Hence, an ideal implant design should be done on a patient-by-patient basis. In the present work, a computational model is developed to predict the degradation and fracture of magnesium-based implants in a stress-coupled …


Capturing Microstructural Heterogeneity And Predicting Local Transport Phenomena In Pemfc Catalyst Layers: A Comprehensive Network Modeling Approach, Shahriar Alam Jan 2023

Capturing Microstructural Heterogeneity And Predicting Local Transport Phenomena In Pemfc Catalyst Layers: A Comprehensive Network Modeling Approach, Shahriar Alam

Dissertations, Master's Theses and Master's Reports

A unique network architecture that captures the microstructural heterogeneity and predicts the local transport properties of PEMFC catalyst layers is proposed. Separate networks containing numerous cylindrical elements and nodes are generated that represent the solid and pore phase of the catalyst layer. Transport resistances are assigned to the elements while the nodes are volumeless. The networks are interlinked through nodes where local properties are stored. The generated computational grid's macroscopic behaviors (percolation behavior, gas diffusivity, and ion conductivity) will be matched against the experimental data for validation. Diffusion-like transport equations are applied to the networks that provide local water balance, …


An Active Voice Coil Negative Stiffness Vibration Isolator With Application To Mobile 3d Printing, Lucas M. Schloemp Jan 2023

An Active Voice Coil Negative Stiffness Vibration Isolator With Application To Mobile 3d Printing, Lucas M. Schloemp

Dissertations, Master's Theses and Master's Reports

Equipment whose performance degrades when exposed to base vibration is often deployed in vibration-rich environments. Using 3D printers in mobile applications, such as vehicles and ships, are typical examples where the extruder and bedplate are easily excited by base vibration. A versatile active vibration isolator is considered in this thesis constructed using a voice coil actuator and a laser displacement feedback sensor to achieve a wide range of dynamic response characteristics, including negative stiffness. This approach permits transmissibility shaping to meet band-limited base isolation requirements without active damping vibration control. A combination of simulation and hardware validation is used to …


Programming The Bistable Dynamic Vibration Absorbers Of A 1d-Metastructure For Adaptive Broadband Vibration Absorption, Shantanu H. Chavan Jan 2023

Programming The Bistable Dynamic Vibration Absorbers Of A 1d-Metastructure For Adaptive Broadband Vibration Absorption, Shantanu H. Chavan

Dissertations, Master's Theses and Master's Reports

This research addresses a critical challenge in structural engineering—achieving comprehensive vibration control and energy dissipation in meta-structures. Departing from the limitations of passive structures with fixed bandgaps, we propose an innovative approach utilizing active meta-structures capable of dynamically tuning their bandgaps. The primary goal is to introduce an efficient method for programming meta-structures with multiple variable bandgaps, thereby enabling effective vibration attenuation across a broad frequency spectrum.

The methodology involves transforming passive resonators into bistable adaptable Dynamic Vibration Regulators (DVRs) through a sophisticated switching mechanism. This adaptation sets the stage for numerous unique combinations by independently switching each resonator. A …


Study Of Eco-Driving And Charging Planning In Connected And Automated Vehicles Environment, Pradeep Bhat Jan 2023

Study Of Eco-Driving And Charging Planning In Connected And Automated Vehicles Environment, Pradeep Bhat

Dissertations, Master's Theses and Master's Reports

In this dissertation, the development of eco-driving and charging planning algorithms in the connected and automated vehicle environment (CAV) are presented. CAV technologies provide opportunities for potential energy savings and efficiency improvement of transportation networks, which are explored through multiple research tasks in this study.

The objective of the first study presented in Chapter 2 is to reduce vehicle dynamic losses and required tractive force while completing trip distance within a given travel time. Sequential Quadratic Programming method is employed for this nonlinearly constrained optimization problem. The validation result illustrates the benefits of optimal velocity trajectories. The objective of the …


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 Jan 2023

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 …


Alternative Method For Low Frequency Impact Sound Measurement For Building Field Tests, Sunit Girdhar Jan 2023

Alternative Method For Low Frequency Impact Sound Measurement For Building Field Tests, Sunit Girdhar

Dissertations, Master's Theses and Master's Reports

What do high heels, dog nails, and dragging furniture have in common? They are all frequent sources of noise pollution and annoyance in multi-story buildings. Building codes exist to control and mitigate such noise, but these codes are outdated and fail to protect the residents against noise annoyance. Footstep noise is still the number one cause of complaints among the residents. The impact performance of floor-ceiling assemblies is characterized using a single-number rating called the Impact Sound Rating (ISR). A standard tapping machine is used in pre-defined locations on the floor and the radiated Sound Pressure Level (SPL) is measured …


Study Of Nanocomposite Materials Using Molecular Dynamics, Prashik Sunil Gaikwad Jan 2023

Study Of Nanocomposite Materials Using Molecular Dynamics, Prashik Sunil Gaikwad

Dissertations, Master's Theses and Master's Reports

There is an increase in demand for new lightweight structural materials in the aerospace industry for more efficient and affordable human space travel. Polymer matrix composites (PMCs) with reinforcement material as carbon nanotubes (CNTs) have shown exceptional increase in the mechanical properties. Flattened carbon nanotubes (flCNTs) are a primary component of many carbon nanotube (CNT) yarn and sheet materials, which are promising reinforcements for the next generation of ultra-strong composites for aerospace applications. These flCNT/polymer materials are subjected to extreme pressure and temperature during curing process. Therefore there is a need to investigate the evolution of properties during the curing …