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Articles 6211 - 6240 of 30103

Full-Text Articles in Engineering

Computational Based Investigation Of Lattice Cell Optimization Under Uniaxial Compression Load, Derek G. Spear, Jeremiah S. Lane, Anthony N. Palazotto, Ryan A. Kemnitz Mar 2022

Computational Based Investigation Of Lattice Cell Optimization Under Uniaxial Compression Load, Derek G. Spear, Jeremiah S. Lane, Anthony N. Palazotto, Ryan A. Kemnitz

Faculty Publications

Structural optimization is a methodology used to generate novel structures within a design space by finding a maximum or minimum point within a set of constraints. Topology optimization, as a subset of structural optimization, is often used as a means for light-weighting a structure while maintaining mechanical performance. This article presents the mathematical basis for topology optimization, focused primarily on the Bi-directional Evolutionary Structural Optimization (BESO) and Solid Isotropic Material with Penalization (SIMP) methodologies, then applying the SIMP methodology to a case study of additively manufactured lattice cells. Three lattice designs were used: the Diamond, I-WP, and Primitive cells. These …

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Multisector Dynamics: Advancing The Science Of Complex Adaptive Human-Earth Systems, Patrick M. Reed, Antonia Hadjimichael, Richard H. Moss, Christa Brelsford, Casey D. Burleyson, Stuart Cohen, Ana Dyreson, David F. Gold, Rohini S. Gupta, Klaus Keller, Megan Konar, Erwan Monier Mar 2022

Multisector Dynamics: Advancing The Science Of Complex Adaptive Human-Earth Systems, Patrick M. Reed, Antonia Hadjimichael, Richard H. Moss, Christa Brelsford, Casey D. Burleyson, Stuart Cohen, Ana Dyreson, David F. Gold, Rohini S. Gupta, Klaus Keller, Megan Konar, Erwan Monier

Michigan Tech Publications, Part 1

The field of MultiSector Dynamics (MSD) explores the dynamics and co-evolutionary pathways of human and Earth systems with a focus on critical goods, services, and amenities delivered to people through interdependent sectors. This commentary lays out core definitions and concepts, identifies MSD science questions in the context of the current state of knowledge, and describes ongoing activities to expand capacities for open science, leverage revolutions in data and computing, and grow and diversify the MSD workforce. Central to our vision is the ambition of advancing the next generation of complex adaptive human-Earth systems science to better address interconnected risks, increase …

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Investigation Of Mechanical Properties Of Parts Fabricated With Gas- And Water-Atomized 304l Stainless Steel Powder In The Laser Powder Bed Fusion Process, M. Hossein Sehhat, Austin T. Sutton, Chia Hung Hung, Joseph William Newkirk, Ming-Chuan Leu Mar 2022

Investigation Of Mechanical Properties Of Parts Fabricated With Gas- And Water-Atomized 304l Stainless Steel Powder In The Laser Powder Bed Fusion Process, M. Hossein Sehhat, Austin T. Sutton, Chia Hung Hung, Joseph William Newkirk, Ming-Chuan Leu

Materials Science and Engineering Faculty Research & Creative Works

The use of gas-atomized powder as the feedstock material for the laser powder bed fusion (LPBF) process is common in the additive manufacturing (AM) community. Although gas-atomization produces powder with high sphericity, its relatively expensive production cost is a downside for application in AM processes. Water atomization of powder may overcome this limitation due to its low-cost relative to the gas-atomization process. In this work, gas- and water-atomized 304L stainless steel powders were morphologically characterized through scanning electron microscopy (SEM). The water-atomized powder had a wider particle size distribution and exhibited less sphericity. Measuring powder flowability using the Revolution Powder …

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Simultaneous Actuation And Sensing Of Electrostatic Mems, Jacob E. Song Mar 2022

Simultaneous Actuation And Sensing Of Electrostatic Mems, Jacob E. Song

Theses and Dissertations

Micro-Electro-Mechanical Systems (MEMS) are devices that play important roles of sensing and actuation in many different industries including automation, electronics, medical, communications, and defense. In order to make full use of these devices, it is important to understand the peripherals that enable these devices. Simultaneous actuation and control of MEMS devices is an important area of research as it enables feedback control of these device and allows devices to maintain performance as devices depreciate over their lifetime. The aim of this thesis is to perform a design space analysis on an electrostatic MEMS simultaneous actuation and sensing circuit that is …

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Amplitude And Wavelength Scaling Of Sinusoidal Roughness Effects In Turbulent Channel Flow At Fixed ReΤ, Sparsh Ganju, Sean C. C. Bailey, Christoph Brehm Feb 2022

Amplitude And Wavelength Scaling Of Sinusoidal Roughness Effects In Turbulent Channel Flow At Fixed ReΤ, Sparsh Ganju, Sean C. C. Bailey, Christoph Brehm

Mechanical Engineering Faculty Publications

Direct numerical simulations are performed for incompressible, turbulent channel flow over a smooth wall and different sinusoidal wall roughness configurations at a constant Reτ = 720. Sinusoidal walls are used to study the effects of well-defined geometric features of roughness-amplitude, a, and wavelength, λ, on the flow. The flow in the near-wall region is strongly influenced by both a and λ. Establishing appropriate scaling laws will aid in understanding the effects of roughness and identifying the relevant physical mechanisms. Using inner variables and the roughness function to scale the flow quantities provides support for Townsend’s hypothesis, …

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A Continuum Damage Approach To Spallation And The Role Of Microinertia, S. B. Qamar, John A. Moore, Nathan R. Barton Feb 2022

A Continuum Damage Approach To Spallation And The Role Of Microinertia, S. B. Qamar, John A. Moore, Nathan R. Barton

Mechanical Engineering Faculty Research and Publications

Spall failure is of interest due to its prevalence in high strain rate problems in which the spallation is driven by the interaction of release waves. In this article, a porosity-based damage model that includes microinertial effects is used to examine spall failure. The model is successfully calibrated to plate impact-driven experiments and then used to evaluate experimental conditions producing more extreme strain rate conditions, such as those in laser-driven experiments. The incorporation of microinertia allows us to better understand the increase in apparent macroscopic spall strength seen at high strain rates. Correspondingly, we conclude that the incorporation of microinertial …

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Decellularized Articular Cartilage Microgels As Microcarriers For Expansion Of Mesenchymal Stem Cells, Esmaiel Jabbari, Azadeh Sepahvandi Feb 2022

Decellularized Articular Cartilage Microgels As Microcarriers For Expansion Of Mesenchymal Stem Cells, Esmaiel Jabbari, Azadeh Sepahvandi

Faculty Publications

Conventional microcarriers used for expansion of human mesenchymal stem cells (hMSCs) require detachment and separation of the cells from the carrier prior to use in clinical applications for regeneration of articular cartilage, and the carrier can cause undesirable phenotypic changes in the expanded cells. This work describes a novel approach to expand hMSCs on biomimetic carriers based on adult or fetal decellularized bovine articular cartilage that supports tissue regeneration without the need to detach the expanded cells from the carrier. In this approach, the fetal or adult bovine articular cartilage was minced, decellularized, freeze-dried, ground, and sieved to produce articular …

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Decellularized Articular Cartilage Microgels As Microcarriers For Expansion Of Mesenchymal Stem Cells, Esmaiel Jabbari, Azadeh Sepahvandi Feb 2022

Decellularized Articular Cartilage Microgels As Microcarriers For Expansion Of Mesenchymal Stem Cells, Esmaiel Jabbari, Azadeh Sepahvandi

Faculty Publications

Conventional microcarriers used for expansion of human mesenchymal stem cells (hMSCs) require detachment and separation of the cells from the carrier prior to use in clinical applications for regeneration of articular cartilage, and the carrier can cause undesirable phenotypic changes in the expanded cells. This work describes a novel approach to expand hMSCs on biomimetic carriers based on adult or fetal decellularized bovine articular cartilage that supports tissue regeneration without the need to detach the expanded cells from the carrier. In this approach, the fetal or adult bovine articular cartilage was minced, decellularized, freeze-dried, ground, and sieved to produce articular …

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Fourth-Order Comprehensive Adjoint Sensitivity Analysis Methodology For Nonlinear Systems (4th-Casam-N): I. Mathematical Framework, Dan Gabriel Cacuci Feb 2022

Fourth-Order Comprehensive Adjoint Sensitivity Analysis Methodology For Nonlinear Systems (4th-Casam-N): I. Mathematical Framework, Dan Gabriel Cacuci

Faculty Publications

This work presents the fourth-order comprehensive sensitivity analysis methodology for nonlinear systems (abbreviated as “4th-CASAM-N”) for exactly and efficiently computing the first-, second-, third-, and fourth-order functional derivatives (customarily called “sensitivities”) of physical system responses (i.e., “system performance parameters”) to the system’s (or model) parameters. The qualifier “comprehensive” indicates that the 4th-CASAM-N methodology enables the exact and efficient computation not only of response sensitivities with respect to the customary model parameters (including computational input data, correlations, initial and/or boundary conditions) but also with respect to imprecisely known material boundaries, caused by manufacturing tolerances, of the system under consideration. The 4th-CASAM-N …

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Comparative Study Of Decision Tree Models For Bearing Fault Detection And Classification, Armin Moghadam, Fatemeh Davoudi Kakhki Feb 2022

Comparative Study Of Decision Tree Models For Bearing Fault Detection And Classification, Armin Moghadam, Fatemeh Davoudi Kakhki

Faculty Research, Scholarly, and Creative Activity

Fault diagnosis of bearings is essential in reducing failures and improving functionality and reliability of rotating machines. As vibration signals are non-linear and non-stationary, extracting features for dimension reduction and efficient fault detection is challenging. This study aims at evaluating performance of decision tree-based machine learning models in detection and classification of bearing fault data. A machine learning approach combining the tree-based classifiers with de-rived statistical features is proposed for localized fault classification. Statistical features are extracted from normal and faulty vibration signals though time do-main analysis to develop tree-based models of AdaBoost (AD), classification and regression trees (CART), LogitBoost …

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Large Scale Dataset Of Real Space Electronic Charge Density Of Cubic Inorganic Materials From Density Functional Theory (Dft) Calculations, Fancy Qian Wang, Kamal Choudhary, Jianjun Hu, Ming Hu Feb 2022

Large Scale Dataset Of Real Space Electronic Charge Density Of Cubic Inorganic Materials From Density Functional Theory (Dft) Calculations, Fancy Qian Wang, Kamal Choudhary, Jianjun Hu, Ming Hu

Faculty Publications

Driven by the big data science, material informatics has attracted enormous research interests recently along with many recognized achievements. To acquire knowledge of materials by previous experience, both feature descriptors and databases are essential for training machine learning (ML) models with high accuracy. In this regard, the electronic charge density ρ(r), which in principle determines the properties of materials at their ground state, can be considered as one of the most appropriate descriptors. However, the systematic electronic charge density ρ(r) database of inorganic materials is still in its infancy due to the difficulties in …

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Auto-Ethnographic Reflections: Lessons From Leading A Stem Initiative For Girls In School While We Ourselves Were In School, Kayli Heather Battel, Kritin Mandala, Sreyoshi Bhaduri, Natalie Anna Foster, Lilianny Virguez, Lissa Erickson, Krishna Pakala Feb 2022

Auto-Ethnographic Reflections: Lessons From Leading A Stem Initiative For Girls In School While We Ourselves Were In School, Kayli Heather Battel, Kritin Mandala, Sreyoshi Bhaduri, Natalie Anna Foster, Lilianny Virguez, Lissa Erickson, Krishna Pakala

Mechanical and Biomedical Engineering Faculty Publications and Presentations

In this paper, we use an auto-ethnographic approach to describe first-hand the reflections and learnings from leading an organization to help school children, especially girls, familiarize themselves with STEM and Cyber Security. The primary authors and ethnographers are founders of STEM initiatives for young learners. The primary author is a recent high school graduate who has taken up an engineering field, and two other contributing authors are high-schoolers currently leading these initiatives. With help from the three engineering educators on our authorship team, we use our individual self-narratives to develop a set of recommendations for other young engineering educators across …

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Opportunities From Disruption: How Lifelong Learning Helped Create More Connected Classrooms, Krishna Pakala, Sreyoshi Bhaduri Feb 2022

Opportunities From Disruption: How Lifelong Learning Helped Create More Connected Classrooms, Krishna Pakala, Sreyoshi Bhaduri

Mechanical and Biomedical Engineering Faculty Publications and Presentations

The coronavirus pandemic has led to instructors worldwide seeking ways to engage students better through virtual platforms. As the world interacts online, more than ever before, this paper reflects on an educator’s experience with the virtual teaching and learning spaces pre and during the ongoing pandemic. Autoethnography is a research methodology that analyzes a phenomenon through the use of self-narratives, which would otherwise remain private or buried. This paper uses an autoethnographic approach to describe first-hand. the experiences and learnings of an educator at a Western US Public University. This paper describes how first as an international student, a first …

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Real-Time Complex Hand Gestures Recognition Based On Multi- Dimensional Features, Isack Bulugu Feb 2022

Real-Time Complex Hand Gestures Recognition Based On Multi- Dimensional Features, Isack Bulugu

Tanzania Journal of Engineering and Technology (TJET)

Gesture recognition is broadly utilized within the field of sensing. There are basically three gesture recognition methods based on computer vision, depth sensor and motion sensor. Motion sensor-based gesture recognition has few input data, fast speed, and direct access to three- dimensional information of the hand. The advantages of traditional motion sensor-based gesture recognition have gradually become a current research hotspot. The essence of traditional motion sensor-based gesture recognition is a pattern recognition problem, and its accuracy depends heavily on the feature dataset extracted from prior experience. Unlike traditional pattern recognition methods, deep learning can be used to a large …

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Economic Analysis Of Islanded Microgrid: A Case Study Of Kisiju Village - Coastal Region, Jackson Justo Feb 2022

Economic Analysis Of Islanded Microgrid: A Case Study Of Kisiju Village - Coastal Region, Jackson Justo

Tanzania Journal of Engineering and Technology (TJET)

The concept of Microgrid (MG) has gained significant attention of researchers and projects on the business side of electrical power generation and utilization, particularly in electrification of islanded areas such as villages. Most of these microgrids are powered by renewable energy resources (RERs) and they distribute power in low voltage distribution networks. Hence, these systems are faced with reliability problems due to the intermittency nature of RERs which affect the technical as well as the return on Investment of specific projects. In the latter context, reliability and economic analysis of the MG systems is an inevitable choice. This paper presents …

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Complete Neighbourhood Search Heuristic Algorithm For Portfolio Optimization, Collether John Feb 2022

Complete Neighbourhood Search Heuristic Algorithm For Portfolio Optimization, Collether John

Tanzania Journal of Engineering and Technology (TJET)

In portfolio optimization, the fundamental goal of an investor is to optimally allocate investments between different assets. Mean-variance optimization methods make unrealistic assumptions to solve the problem of optimal allocation. On the other hand, when realistic constraints like holding size and cardinality are introduced it leads to optimal asset allocation which differ from the mean variance optimization. The resulting optimization problem become quite complex as it exhibits multiple local extrema and discontinuities. Heuristic algorithms work well for the complex problem. Therefore, a heuristic algorithm is developed which is based on hill climbing complete (HC-C). It is utilized to solve the …

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State Of Industry 5.0—Analysis And Identification Of Current Research Trends, Aditya Akundi, Daniel Euresti, Sergio Luna, Wilma Ankobiah, Amit Lopes, Immanuel Edinbarough Feb 2022

State Of Industry 5.0—Analysis And Identification Of Current Research Trends, Aditya Akundi, Daniel Euresti, Sergio Luna, Wilma Ankobiah, Amit Lopes, Immanuel Edinbarough

Manufacturing & Industrial Engineering Faculty Publications

The term Industry 4.0, coined to be the fourth industrial revolution, refers to a higher level of automation for operational productivity and efficiency by connecting virtual and physical worlds in an industry. With Industry 4.0 being unable to address and meet increased drive of personalization, the term Industry 5.0 was coined for addressing personalized manufacturing and empowering humans in manufacturing processes. The onset of the term Industry 5.0 is observed to have various views of how it is defined and what constitutes the reconciliation between humans and machines. This serves as the motivation of this paper in identifying and analyzing …

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Effect Of Processing Parameters And Build Orientation On Microstructure And Performance Of Aisi Stainless Steel 304l Made With Selective Laser Melting Under Different Strain Rates, Tan Pan, Xinchang Zhang, Aaron Flood, Sreekar Karnati, Wei Li, Joseph William Newkirk, Frank W. Liou Feb 2022

Effect Of Processing Parameters And Build Orientation On Microstructure And Performance Of Aisi Stainless Steel 304l Made With Selective Laser Melting Under Different Strain Rates, Tan Pan, Xinchang Zhang, Aaron Flood, Sreekar Karnati, Wei Li, Joseph William Newkirk, Frank W. Liou

Materials Science and Engineering Faculty Research & Creative Works

Selective laser melting (SLM) process allows greater geometry flexibility; therefore, it has become more widespread in its deployment in the industry for fabricating metal alloys. However, a material characterization study is needed in order to understand better the correlation between the process, microstructure, and performance. In the current study, the raw SLM fabricated AISI stainless steel 304 L was fabricated with different processing parameters and build orientations (horizontal, inclined, and vertical). The tensile behavior was evaluated under different strain rates (0.0001/s, 0.001/s, 0.01/s, and 0.1/s) and then compared to commercial cold-rolled and annealed counterparts. Grain structures, tensile strength, elongation-to-failure, strain …

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Open-Loop Control Of Electrostatic Levitation Actuators To Enhance The Travel-Range Of Optical Switches, Mohammad Mousavi, Mohammad Alzgool, Daniel Lopez, Shahrzad Towfighian Feb 2022

Open-Loop Control Of Electrostatic Levitation Actuators To Enhance The Travel-Range Of Optical Switches, Mohammad Mousavi, Mohammad Alzgool, Daniel Lopez, Shahrzad Towfighian

Mechanical Engineering Faculty Scholarship

Command shaping is a driving technique for handling the large settling time of the high-Q-MEMS actuators. The strong nonlinearity due to the electrostatic actuation limits the linear operation range in cantilevered or torsional micro-mirrors where command shaping techniques can be applied for positioning. Experimental and simulation results of this research demonstrate the effectiveness of using electrostatic levitation to overcome the actuation nonlinearities and a significant increase in the operation range. The motivation for this research is that applying the nonlinear command shaping causes complexity in command manipulation and requires an accurate knowledge of the nonlinear terms involved in the system …

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Modification Of Superabsorbent Hydrogels For Industrial Wastewater Treatment, Md. Owaleur Rahman, Md. Abdul Halim, Anjan Deb, Shafi Ahmed, Md. Wasikur Rahman, N. C. Dafader, S. M. Nur Alam, Shahjalal Khandaker, Md. Jahangir Alam Feb 2022

Modification Of Superabsorbent Hydrogels For Industrial Wastewater Treatment, Md. Owaleur Rahman, Md. Abdul Halim, Anjan Deb, Shafi Ahmed, Md. Wasikur Rahman, N. C. Dafader, S. M. Nur Alam, Shahjalal Khandaker, Md. Jahangir Alam

Mechanical Engineering Faculty Publications

A breakthrough in superabsorbent hydrogel (SAH) preparation was studied in the current issue by blending potato starch and acrylic acid for wastewater treatment. Gamma irradiation source (60Co irradiation) was used to irradiate SAH from 1 to 10 kGy dose at room temperature (~27°C). The swelling ratio, water absorption, equilibrium water content, and gel fraction properties of the hydrogel were investigated. The as-prepared hydrogel treated with KOH (THG) showed excellent absorption capacity but less mechanical stability compared to untreated hydrogel (UHG). The gel fraction of treated SAH was slightly lower in methanol, but the utmost in water at 5 kGy infers …

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Six-Bar Linkage Models Of A Recumbent Tricycle Mechanism To Increase Power Throughput In Fes Cycling, Nicholas A. Lanese, David H. Myszka, Anthony L. Bazler, Andrew P. Murray Feb 2022

Six-Bar Linkage Models Of A Recumbent Tricycle Mechanism To Increase Power Throughput In Fes Cycling, Nicholas A. Lanese, David H. Myszka, Anthony L. Bazler, Andrew P. Murray

Mechanical and Aerospace Engineering Faculty Publications

This paper presents the kinematic and static analysis of two mechanisms to improve power throughput for persons with tetra- or paraplegia pedaling a performance tricycle via FES. FES, or functional electrical stimulation, activates muscles by passing small electrical currents through the muscle creating a contraction. The use of FES can build muscle in patients, relieve soreness, and promote cardiovascular health. Compared to an able-bodied rider, a cyclist stimulated via FES produces an order of magnitude less power creating some notable pedaling difficulties especially pertaining to inactive zones. An inactive zone occurs when the leg position is unable to produce enough …

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Strong Laser Polarization Control Of Coherent Phonon Excitation In Van Der Waals Material Fe3Gete2, Yu Gong, Ming Hu, Nico Harris, Zhonghua Yang, Ti Xie, Alem Teklu, Narayanan Kuthirummal, Jacob Koenemann, Xianghan Xu, Sang-Wook Cheong, Will Mcloud, Cheng Gong Feb 2022

Strong Laser Polarization Control Of Coherent Phonon Excitation In Van Der Waals Material Fe3Gete2, Yu Gong, Ming Hu, Nico Harris, Zhonghua Yang, Ti Xie, Alem Teklu, Narayanan Kuthirummal, Jacob Koenemann, Xianghan Xu, Sang-Wook Cheong, Will Mcloud, Cheng Gong

Faculty Publications

Optical manipulation of coherent phonon frequency in two-dimensional (2D) materials could advance the development of ultrafast phononics in atomic-thin platforms. However, conventional approaches for such control are limited to doping, strain, structural or thermal engineering. Here, we report the experimental observation of strong laser-polarization control of coherent phonon frequency through time-resolved pump-probe spectroscopic study of van der Waals (vdW) materials Fe3GeTe2. When the polarization of the pumping laser with tilted incidence is swept between in-plane and out-of-plane orientations, the frequencies of excited phonons can be monotonically tuned by as large as 3% (~100 GHz). Our first-principles …

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Per-Person And Whole-Building Voc Emission Factors In An Occupied School With Gas-Phase Air Cleaning., Brett W. Stinson, Aurélie Laguerre, Elliott T. Gall Feb 2022

Per-Person And Whole-Building Voc Emission Factors In An Occupied School With Gas-Phase Air Cleaning., Brett W. Stinson, Aurélie Laguerre, Elliott T. Gall

Mechanical and Materials Engineering Faculty Publications and Presentations

Using real-time measurements of CO and volatile organic compounds (VOCs) in the air handler of an occupied middle school, we quantified source strengths for 249 VOCs and apportioned the source to the building, occupants and their activities, outdoor air, or recirculation air. For VOCs quantified in this study, there is a source to the outdoors of 8.6 ± 1.8 g/h in building exhaust air, of which 5.9 ± 1.7 g/h can be attributed to indoor sources (the building and occupants and their activities). The corresponding whole-building area emission factor from indoor sources is 1020 ± 300 μg/(m h), including reactive …

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A Tale Of Two Sides: Modeling Great Salt Lake Flows To Help Balance Current Ecosystem Influences, Eric Larsen Feb 2022

A Tale Of Two Sides: Modeling Great Salt Lake Flows To Help Balance Current Ecosystem Influences, Eric Larsen

Research on Capitol Hill

USU senior Eric, hailing from Spanish Fork, studies mechanical engineering and funded this project through an engineering student grant. While there are several sampling stations that measure the waterflow of the Great Salt Lake, there are gaps in the data they collect that limit our ability to predict how water moves between the north and south sides of the lake. Eric has been developing machine learning models that more accurately portray the flows. This has applications for both GSL ecological preservation and the brine shrimp and salt industries. Eric loved how hands-on this project was, seeing the phenomenon that his …

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Storage Minimization Of Marine Energy Grids Using Polyphase Power, Salman Husain, Gordon Parker, Wayne W. Weaver Feb 2022

Storage Minimization Of Marine Energy Grids Using Polyphase Power, Salman Husain, Gordon Parker, Wayne W. Weaver

Michigan Tech Publications, Part 1

Multiple wave energy converter (WEC) buoys can be used to establish a WEC array-powered microgrid collectively forming a Marine Energy Grid (MEG). An oceanic domain with gravity waves will have significant spatial variability in phase, causing the power produced by a WEC array to have high peak-to-average ratios. Minimizing these power fluctuations reduces the demand for large energy storage by WEC array-powered DC microgrids while also reducing losses in the undersea cable to the shore. Designs that reduce energy storage requirements are desirable to reduce deployment and maintenance costs. This work demonstrates that polyphase power in conjunction with an energy …

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Flexible Planar Metamaterials With Tunable Poisson’S Ratios, Nicholas Pagliocca, Kazi Zahir Uddin, Ibnaj Anamika Anni, Chen Shen, George Youssef, Behrad Koohbor Feb 2022

Flexible Planar Metamaterials With Tunable Poisson’S Ratios, Nicholas Pagliocca, Kazi Zahir Uddin, Ibnaj Anamika Anni, Chen Shen, George Youssef, Behrad Koohbor

Henry M. Rowan College of Engineering Departmental Research

This research reports on the design, fabrication, and multiscale mechanical characterization of flexible, planar mechanical metamaterials with tailorable mechanical properties. The tunable mechanical behavior of the structures is realized through the introduction of orthogonal perforations with different geometric features. Various configurations of the perforations lead to a wide range of Poisson’s ratios (from −0.8 to 0.4), load-bearing properties, and energy absorption capacities. The correlations between the configuration of the perforations and the auxetic response of the structures are highlighted through computational and experimental characterizations performed at multiple length scales. It is demonstrated that the local in-plane rotation of the solid …

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Computational Investigation Of The Post-Yielding Behavior Of 3d-Printed Polymer Lattice Structures, Abdalsalam Fadeel, Hasanain Abdulhadi, Golam Newaz, Raghavan Srinivasan, Ahsan Mian Feb 2022

Computational Investigation Of The Post-Yielding Behavior Of 3d-Printed Polymer Lattice Structures, Abdalsalam Fadeel, Hasanain Abdulhadi, Golam Newaz, Raghavan Srinivasan, Ahsan Mian

Mechanical and Materials Engineering Faculty Publications

Sandwich structures are widely used due to their light weight, high specific strength, and high specific energy absorption. Three-dimensional (3D) printing has recently been explored for creating the lattice cores of these sandwich structures. Experimental evaluation of the mechanical response of lattice cell structures (LCSs) is expensive in time and materials. As such, the finite element analysis (FEA) can be used to predict the mechanical behavior of LCSs with many different design variations more economically. Though there have been several reports on the use of FEA to develop models for predicting the post-yielding stages of 3D-printed LCSs, they are still …

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Color Tunable Aerogels/Sponge-Like Structures Developed From Fine Fiber Membranes, Alexa Villarreal, Raul Barbosa, Saptasree Bose, Bhupendra B. Srivastava, Victoria Padilla-Gainza, Karen Lozano Feb 2022

Color Tunable Aerogels/Sponge-Like Structures Developed From Fine Fiber Membranes, Alexa Villarreal, Raul Barbosa, Saptasree Bose, Bhupendra B. Srivastava, Victoria Padilla-Gainza, Karen Lozano

Mechanical Engineering Faculty Publications

The development of macroscopic aerogels from 1D systems, such as nanofibers, has resulted in a novel pathway to obtain porous and lightweight architectures. In this work, bright green, red, and tunable color emitting aerogels were obtained with luminescent nanofibers as the precursor system. A simple, low cost, and environmentally friendly process is followed where luminescent fillers are encapsulated within fibers which were subsequently freeze-dried to form 3D aerogels and sponge-like structures. Moreover, the aerogels/sponge-like structures show higher photoluminescence intensity than the fiber mats due to an increase of porosity which provides higher and direct interaction with the fillers and therefore …

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A Note On Gradient/Fractional One-Dimensional Elasticity And Viscoelasticity, Kostas Parisis, Vlasis Dimosthenis, Leonidas Kouris, Avraam Konstantinidis, Elias C. Aifantis Feb 2022

A Note On Gradient/Fractional One-Dimensional Elasticity And Viscoelasticity, Kostas Parisis, Vlasis Dimosthenis, Leonidas Kouris, Avraam Konstantinidis, Elias C. Aifantis

Michigan Tech Publications, Part 1

An introductory discussion on a (weakly non-local) gradient generalization of some one-dimensional elastic and viscoelastic models, and their fractional extension is provided. Emphasis is placed on the possible implications of micro-and nano-engineering problems, including small-scale structural mechanics and composite materials, as well as collagen biomechanics and nanomaterials.

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Implementation Of Multiscale Mechanisms In Finite Element Analysis Of Active Composite Structures, Amany G. Micheal Prof., Yehia Bahei El Din Prof. Feb 2022

Implementation Of Multiscale Mechanisms In Finite Element Analysis Of Active Composite Structures, Amany G. Micheal Prof., Yehia Bahei El Din Prof.

Centre for Advanced Materials

Composite structures reinforced with electrically active filaments are modeled with the finite element method while the underlying thermo-electromechanical coupling phenomena and damage are taken into consideration. At the outset, structural analysis is performed with a general-purpose finite element code and a special material routine, which propagates local phenomena to the overall scale is utilized. The material routine implements an interactive, multiscale analysis, which provides seamless integration of the mechanics at the composite’s micro, macro, and structural length scales. The interface between the multiscale material routine and the finite element code is made through nonmechanical strains caused by damage, and piezo/pyro-electric …

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