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Full-Text Articles in Engineering

Mechanics Of Pure Bending And Eccentric Buckling In High-Strain Composite Structures, Jimesh D. Bhagatji, Oleksandr G. Kravchenko, Sharanabasaweshwara Asundi Jan 2024

Mechanics Of Pure Bending And Eccentric Buckling In High-Strain Composite Structures, Jimesh D. Bhagatji, Oleksandr G. Kravchenko, Sharanabasaweshwara Asundi

Mechanical & Aerospace Engineering Faculty Publications

To maximize the capabilities of nano- and micro-class satellites, which are limited by their size, weight, and power, advancements in deployable mechanisms with a high deployable surface area to packaging volume ratio are necessary. Without progress in understanding the mechanics of high-strain materials and structures, the development of compact deployable mechanisms for this class of satellites would be difficult. This paper presents fabrication, experimental testing, and progressive failure modeling to study the deformation of an ultra-thin composite beam. The research study examines the deformation modes of a post-deployed boom under repetitive pure bending loads using a four-point bending setup and …


Advancements And Challenges In Additively Manufactured Functionally Graded Materials: A Comprehensive Review, Suhas Alkunte, Ismail Fidan, Vivekanand Naikwadi, Shamil Gudavasov, Mohammad Alshaikh Ali, Mushfig Mahmudov, Seymur Hasanov, Muralimohan Cheepu Jan 2024

Advancements And Challenges In Additively Manufactured Functionally Graded Materials: A Comprehensive Review, Suhas Alkunte, Ismail Fidan, Vivekanand Naikwadi, Shamil Gudavasov, Mohammad Alshaikh Ali, Mushfig Mahmudov, Seymur Hasanov, Muralimohan Cheepu

Engineering Technology Faculty Publications

This paper thoroughly examines the advancements and challenges in the field of additively manufactured Functionally Graded Materials (FGMs). It delves into conceptual approaches for FGM design, various manufacturing techniques, and the materials employed in their fabrication using additive manufacturing (AM) technologies. This paper explores the applications of FGMs in diverse fields, including structural engineering, automotive, biomedical engineering, soft robotics, electronics, 4D printing, and metamaterials. Critical issues and challenges associated with FGMs are meticulously analyzed, addressing concerns related to production and performance. Moreover, this paper forecasts future trends in FGM development, highlighting potential impacts on diverse industries. The concluding section summarizes …


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

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 …


Non-Destructive Infrared Thermographic Curing Analysis Of Polymer Composites, Md Ashiqur Rahman, Javier Becerril, Dipannita Ghosh, Nazmul Islam, Ali Ashraf Feb 2023

Non-Destructive Infrared Thermographic Curing Analysis Of Polymer Composites, Md Ashiqur Rahman, Javier Becerril, Dipannita Ghosh, Nazmul Islam, Ali Ashraf

Mechanical Engineering Faculty Publications and Presentations

Infrared (IR) thermography is a non-contact method of measuring temperature that analyzes the infrared radiation emitted by an object. Properties of polymer composites are heavily influenced by the filler material, filler size, and filler dispersion, and thus thermographic analysis can be a useful tool to determine the curing and filler dispersion. In this study, we investigated the curing mechanisms of polymer composites at the microscale by capturing real-time temperature using an IR Thermal Camera. Silicone polymers with fillers of Graphene, Graphite powder, Graphite flake, and Molybdenum disulfide (MoS2) were subsequently poured into a customized 3D printed mold for …


Impact Behavior Of Laminated Composites Built With Fique Fibers And Epoxy Resin: A Mechanical Analysis Using Impact And Flexural Behavior, Julian Rua, Mario F. Buchely, Sergio Neves Monteiro, Gloria I. Echeverri, Henry A. Colorado Sep 2021

Impact Behavior Of Laminated Composites Built With Fique Fibers And Epoxy Resin: A Mechanical Analysis Using Impact And Flexural Behavior, Julian Rua, Mario F. Buchely, Sergio Neves Monteiro, Gloria I. Echeverri, Henry A. Colorado

Materials Science and Engineering Faculty Research & Creative Works

This research analyzes the behavior of natural fiber reinforced laminated polymer composites (NFRPC) under mechanical solicitations. Samples were fabricated with epoxy resin matrix reinforced with a multilayer natural fique fiber in a bi-directional commercial fabric configuration. Different reinforcement contents without additives were prepared taking in the account the simplicity in processing, fabrication cost, and applications in which this material might be used with high performance standards. Charpy notched impact and 3-point bending test were carried out to evaluate the mechanical behavior and the work of fracture, which was improved significatively with the fibers, showing an increase from 5 to 30 …


Exploring The Impact Of Composite Material Fires And Associated Response Protocol On The Material Analysis During An Aircraft Accident Investigation, Flavio A. C. Mendonca, Natalie Zimmermann, Peng Hao Wang, Julius Keller Jan 2021

Exploring The Impact Of Composite Material Fires And Associated Response Protocol On The Material Analysis During An Aircraft Accident Investigation, Flavio A. C. Mendonca, Natalie Zimmermann, Peng Hao Wang, Julius Keller

Publications

Metals, beginning in the 1930s, have been frequently used as the material of choice for aircraft construction (Hallion, 1978; Jakab, 1999). Common metals used in the aviation industry range from alloyed and heat-treated aluminum to titanium, magnesium, and superalloys, the latter used in specialized applications (Hallion, 1978; Mouritz, 2012). Nevertheless, a shift in aircraft construction – specifically in terms of the materials used – began in the 1970s, as composite materials were introduced into commercial aircraft (Mouritz, 2012). Among others, the increased use of composited materials was – and still is – propelled by the ability to manufacture comparative lightweight …


Properties And Performance Of The Basalt-Fiber Reinforced Texture Roof Tiles, Parinya Chakartnarodom, Wichit Prakaypan, Pitcharat Ineure, Nutthita Chuankrerkkul, Edward A. Laitila, Nuntaporn Kongkajun Dec 2020

Properties And Performance Of The Basalt-Fiber Reinforced Texture Roof Tiles, Parinya Chakartnarodom, Wichit Prakaypan, Pitcharat Ineure, Nutthita Chuankrerkkul, Edward A. Laitila, Nuntaporn Kongkajun

Michigan Tech Publications

The mechanical and the physical properties, and the performance of texture roof tiles reinforced with the basalt fibers were observed. The samples of the basalt-fiber reinforced texture roof tiles were produced on the industrial scale by using filter pressing method. After forming, the as-molded samples were air cured and characterized based on ASTM C1185 standard for their mechanical properties and physical properties. In addition, the roof-tile installation test was also performed. The results showed that the samples of the basalt-fiber reinforced texture roof tile (BFRT) could be produced on the industrial scale by using the common setting of the forming …


Composite Materials Based On Twaron And Nano Materials, Omnia Hamdy, Remon A. Mankarious, M. A. Radwan, M. A. Sadek, Hany A. Elazab Nov 2019

Composite Materials Based On Twaron And Nano Materials, Omnia Hamdy, Remon A. Mankarious, M. A. Radwan, M. A. Sadek, Hany A. Elazab

Chemical Engineering

This research aims to participate in producing body shield that can overcome pervious drawbacks using behaviour of shear thickening fluid. Initially, the rheological behaviour of silica-polyethylene glycol shear thickening fluid is examined at different concentrations. Then, ballistic fabric samples are impregnated into silica-polyethylene glycol shear thickening fluid at various concentrations of silica and tested using gas gun simulating real ballistic threat. After that, the impact of rubbery hot water pack filled with around 66.67 wt% starch in water is tested using gas gun. Results showed as the concentration of silica increases, the indentation depth in the impregnated fabric decreases which …


Composite Materials Based On Twaron And Nano Materials, Omnia Hamdy, Remon A. Mankarious, M. A. Radwan, M. A. Sadek, Hany A. Elazab Nov 2019

Composite Materials Based On Twaron And Nano Materials, Omnia Hamdy, Remon A. Mankarious, M. A. Radwan, M. A. Sadek, Hany A. Elazab

Chemical and Biochemical Engineering Faculty Research & Creative Works

This research aims to participate in producing body shield that can overcome pervious drawbacks using behavior of shear thickening fluid. Initially, the rheological behavior of silica-polyethylene glycol shear thickening fluid is examined at different concentrations. Then, ballistic fabric samples are impregnated into silica-polyethylene glycol shear thickening fluid at various concentrations of silica and tested using gas gun simulating real ballistic threat. After that, the impact of rubbery hot water pack filled with around 66.67 wt% starch in water is tested using gas gun. Results showed as the concentration of silica increases, the indentation depth in the impregnated fabric decreases which …


Prototyping A Conductive Polymer Steering Pad For Rail Freight Service, Anthony A. Villarreal, Constantine Tarawneh, Miguel Ontiveros, James Aranda, Robert Jones Jul 2019

Prototyping A Conductive Polymer Steering Pad For Rail Freight Service, Anthony A. Villarreal, Constantine Tarawneh, Miguel Ontiveros, James Aranda, Robert Jones

Mechanical Engineering Faculty Publications and Presentations

The AdapterPlus™ steering pad is a polymer component on a railcar that helps to reduce stresses on the axle as a railcar rounds a curve. One railway application requires a minimum of 240 mA to be passed through the steering pad to the rail, which activates air valves that control automated cargo gates. Currently, two copper studs are inserted into the pad to provide a conductive path. However, after continuous cyclic loading caused by normal service operation, the copper studs deform, wear, and eventually lose contact between the two surfaces rendering the pad nonconductive. One proposed solution to this problem …


A New Thickness-Based Accelerated Aging Test Methodology For Resin Materials: Theory And Preliminary Experimental Study, Yanlei Wang, Xue Zhang, Gaochuang Cai, Baolin Wan, Danièle Waldmann, Yuan Qu Oct 2018

A New Thickness-Based Accelerated Aging Test Methodology For Resin Materials: Theory And Preliminary Experimental Study, Yanlei Wang, Xue Zhang, Gaochuang Cai, Baolin Wan, Danièle Waldmann, Yuan Qu

Civil and Environmental Engineering Faculty Research and Publications

This paper proposes a novel accelerated test method based on the thickness of resin materials. This method is to overcome the adverse influence of high temperature on the reliability of experimental results of the accelerated tests widely adopted in the current practice. To verify the proposed thickness-based accelerated method (ThAM), an experimental investigation was conducted focusing on the water absorption and tensile properties of epoxy resin. The results suggest that the existing temperature-based accelerated method (TAM) cannot be applied when the test temperature is high as in this case the degradation mechanism of materials is probably changed. The acceleration factor …


Experimental Investigation Of Impact Localization In Composite Plate Using Newly Developed Imaging Method, Mohammad Faisal Haider, Asaad Migot, Md Yeasin Bhuiyan, Victor Giurgiutiu Aug 2018

Experimental Investigation Of Impact Localization In Composite Plate Using Newly Developed Imaging Method, Mohammad Faisal Haider, Asaad Migot, Md Yeasin Bhuiyan, Victor Giurgiutiu

Faculty Publications

This paper focuses on impact localization of composite structures, which possess more complexity in the guided wave propagation due to the anisotropic behavior of composite materials. In this work, a composite plate was manufactured by using a compression molding process with proper pressure and temperature cycle. Eight layers of woven composite prepreg were used to manufacture the composite plate. A structural health monitoring (SHM) technique was implemented with piezoelectric wafer active sensors (PWAS) to detect and localize the impact on the plate. There were two types of impact event that were considered in this paper (a) low energy impact event …


Torsional Behaviour And Finite Element Analysis Of The Hybrid Laminated Composite Shafts: Comparison Of Vartm With Vacuum Bagging Manufacturing Method, Mehmet Emin Taşdelen, Mehmet Halidun Keleştemur, Ercan Şevkat Jan 2016

Torsional Behaviour And Finite Element Analysis Of The Hybrid Laminated Composite Shafts: Comparison Of Vartm With Vacuum Bagging Manufacturing Method, Mehmet Emin Taşdelen, Mehmet Halidun Keleştemur, Ercan Şevkat

Faculty Publications - Mechanical Engineering

Braided sleeve composite shafts are produced and their torsional behavior is investigated. The braided sleeves are slid over an Al tube to create very strong and rigid tubular form shafts and they are in the form of 2/2 twill biaxial fiber fabric that has been woven into a continuous sleeve. Carbon and glass fibers braided sleeves are used for the fabrication of the composite shafts. VARTM (vacuum assisted resin transfer molding) and Vacuum Bagging are the two different types of manufacturing methods used in the study. Torsional behaviors of the shafts are investigated experimentally in terms of fabrication methods and …


Processing Of Al-12si-Tnm Composites By Selective Laser Melting And Evaluation Of Compressive And Wear Properties, Konda Prashanth, Sergio Scudino, Anil Chaubey, Lukas Löber, Pei Wang, Hooyar Attar, Frank Schimansky, Florian Pyczak, Jürgen Eckert Jan 2016

Processing Of Al-12si-Tnm Composites By Selective Laser Melting And Evaluation Of Compressive And Wear Properties, Konda Prashanth, Sergio Scudino, Anil Chaubey, Lukas Löber, Pei Wang, Hooyar Attar, Frank Schimansky, Florian Pyczak, Jürgen Eckert

Research outputs 2014 to 2021

Al-12Si (80 vol%)-Ti52.4Al42.2Nb4.4Mo0.9B0.06 (at.%) (TNM) composites were successfully produced by the selective laser melting (SLM). Detailed structural and microstructural analysis shows the formation of the Al6MoTi intermetallic phase due to the reaction of the TNM reinforcement with the Al-12Si matrix during SLM. Compression tests reveal that the composites exhibit significantly improved properties (∼140 and ∼160 MPa higher yield and ultimate compressive strengths, respectively) compared with the Al-12Si matrix. However, the samples break at ∼6% total strain under compression, thus showing a reduced plasticity of the composites. Sliding wear tests were carried out for both the Al-12Si matrix and the Al-12Si-TNM …


Optical Fiber Sensors For Smart Composite Materials And Structures, Manjusha Ramakrishnan, Yuliya Semenova, Gerald Farrell, Ginu Rajan Jan 2015

Optical Fiber Sensors For Smart Composite Materials And Structures, Manjusha Ramakrishnan, Yuliya Semenova, Gerald Farrell, Ginu Rajan

Books/Book chapters

Composite material structures are widely used in the aerospace, marine, aviation, transport, sport/leisure and civil engineering industries. Such composite material structures are frequently subjected to external perturbations and varying environmental conditions, which may cause the structures to suffer from fatique damage and/or failure, and thus require real-time structural health monitoring (SHM). Of necessity, the diagnosis process and condition monitoring of composite structures are usually carried out during their working life. The goal of such diagnosis is to detect, identify, locate, and assess the defects that my affect the safety or performance of a structure.


Thermoelectric Properties Of Wsi2–Sixge1−X Composites, F. W. Dynys, A. Sayir, Jonathan Mackey, A Sehirlioglu Aug 2014

Thermoelectric Properties Of Wsi2–Sixge1−X Composites, F. W. Dynys, A. Sayir, Jonathan Mackey, A Sehirlioglu

Mechanical Engineering Faculty Research

Thermoelectric properties of the W/Si/Ge alloy system have been investigated with varying concentration levels of germanium and tungsten. The alloys were fabricated by directional solidification with the Bridgman method using boron nitride and fused silica crucibles. The effect of crucible contamination was investigated and found to result in doping the system to suitable levels for thermoelectric applications. The system has been demonstrated as a suitable high temperature p-type thermoelectric material exhibiting high power factors, >3000 μW/m K2. Seebeck coefficients of the system are on the order of +300 μV/K and electrical conductivities of 2.8 × 104 S/m …


A Photonic Crystal Fiber Based Polarimetric Sensor For Cure Monitoring Of Magneto-Rheological Smart Composite Material, Manjusha Ramakrishnan, Ginu Rajan, Yuliya Semenova, Y. Zhou, Stephen Jerrams, Gerald Farrell Jan 2014

A Photonic Crystal Fiber Based Polarimetric Sensor For Cure Monitoring Of Magneto-Rheological Smart Composite Material, Manjusha Ramakrishnan, Ginu Rajan, Yuliya Semenova, Y. Zhou, Stephen Jerrams, Gerald Farrell

Articles

A buffer stripped high birefringent photonic crystal fibre based polarimetric sensor is developed for monitoring the curing process of magnetorheological elastomer (MRE) smart composite material. Using the developed sensor, different phases of the MRE curing process are clearly visible from the phase shift variation of the embedded polarisation maintaining photonic crystal fibre (PM-PCF) sensor. During the curing process, the buffer stripped PM-PCF exhibits a stress/strain induced phase shift variation from 0 to 1.98 rad. This is a significantly large phase change, which can be used to very clearly identify the different stages in the curing process. For comparison, a fibre …


Experimental Study And Analysis Of A Polymer Fiber Bragg Grating Embedded In A Composite Material, Ginu Rajan, Manjusha Ramakrishnan, Yuliya Semenova, Eliathamby Ambikairajah, Gerald Farrell, Gang-Ding Peng Jan 2014

Experimental Study And Analysis Of A Polymer Fiber Bragg Grating Embedded In A Composite Material, Ginu Rajan, Manjusha Ramakrishnan, Yuliya Semenova, Eliathamby Ambikairajah, Gerald Farrell, Gang-Ding Peng

Articles

The characteristics of polymer fiber Bragg gratings (FBGs) embedded in composite materials are studied in this paper and are compared with characteristics of their silica counterparts. A polymer FBG of 10 mm length which exhibits a peak reflected wavelength circa 1530 nm is fabricated and characterized for this purpose. A silica FBG with a peak reflected wavelength circa 1553 nm is also embedded in the composite material for a comparison study. The fabricated composite material sample with embedded sensors is subjected to temperature and strain changes and the corresponding effects on the embedded polymer and silica FBGs are studied. The …


New Class Of Garnet Nanocomposites For Use In Magnetic Photonic Crystals Prepared By Rf Magnetron Co-Sputtering, Mohammad Nur E Alam, Mikhail Vasiliev, Kamal Alameh Jan 2012

New Class Of Garnet Nanocomposites For Use In Magnetic Photonic Crystals Prepared By Rf Magnetron Co-Sputtering, Mohammad Nur E Alam, Mikhail Vasiliev, Kamal Alameh

Research outputs 2012

A new class of magneto-optic garnet nanocomposite materials is prepared using two Bi-substituted iron garnet materials of composition types (Bi,Dy) 3(Fe,Ga)5O12 and Bi3Fe 5O12. A composition adjustment approach is applied by varying the radio frequency (RF) powers driving each sputtering target during the deposition process. This new class of nanocomposite materials exhibits simultaneously high specific Faraday rotation, MO figure of merit, and effective uniaxial magnetic anisotropy after being crystallized through optimized annealing processes. We demonstrate experimentally that the excellent combination of materials' properties obtained in this garnet nanocomposite is particularly advantageous for developing magneto-photonic crystals as well as optical sensors …


Full-Wave Emc Simulations Using Maxwell Garnett Model For Composites With Cylindrical Inclusions, M. H. Nisanci, F. De Paulis, Marina Koledintseva, A. Orlandi Oct 2011

Full-Wave Emc Simulations Using Maxwell Garnett Model For Composites With Cylindrical Inclusions, M. H. Nisanci, F. De Paulis, Marina Koledintseva, A. Orlandi

Electrical and Computer Engineering Faculty Research & Creative Works

Four different models for effective dielectric properties of biphasic composite containing random or aligned cylindrical inclusions are considered in this paper. These models are based on the Maxwell Garnett (MG) mixing rule. The effects of distribution and orientation of cylindrical inclusions in a composite material is studied. An equivalent averaged material with Debye-like frequency characteristics, suitable for time-domain full-wave numerical electromagnetic simulations is retrieved. This Debye model is derived from the Maxwell Garnett formulation. The numerical model test structure consists of a composite slab inserted in a rectangular waveguide. Simulations are run for the frequency range above the cut-off frequency …


The Influence Of Thermal Expansion Of A Composite Material On Embedded Polarimetric Sensors, Manjusha Ramakrishnan, Ginu Rajan, Yuliya Semenova, Piotr Lesiak, Andrzej Domanski, Tomasz Wolinksi, Anna Boczkowska, Gerald Farrell Jan 2011

The Influence Of Thermal Expansion Of A Composite Material On Embedded Polarimetric Sensors, Manjusha Ramakrishnan, Ginu Rajan, Yuliya Semenova, Piotr Lesiak, Andrzej Domanski, Tomasz Wolinksi, Anna Boczkowska, Gerald Farrell

Articles

Abstract. Some of the most critical issues of the influence of the thermal expansion of composite materials on embedded polarimetric sensors for measurements of strain and temperature are studied in this paper. A composite material sample with polarimetric fiber sensors embedded in two distinct layers of a multi-layer composite structure is fabricated and characterized. The polarimetric fiber sensors used in this study are based on panda type fiber and polarization maintaining photonic crystal fiber (PM-PCF). The temperature sensitivities of polarimetric fiber sensors with acrylate buffer coated and buffer stripped polarization maintaining optical fibers are measured in free space and compared …


High Strength And Light-Weight Materials Inspired By The Exoskeleton Of Arthropods, Anette M. Karlsson May 2010

High Strength And Light-Weight Materials Inspired By The Exoskeleton Of Arthropods, Anette M. Karlsson

Mechanical Engineering Faculty Publications

This work investigates the multiscaled structure and the constitutive behavior of the exoskeleton of arthropods (Japanese beetle) along with the response of biomimicked structures. Image analysis (SEM and TEM) revealed three load-bearing regions comprised of chitin-protein fiber layers orientated parallel to the cuticle surface. The chitin fibers in the exocuticle and mesocuticle are organized in a helicoidal structure (layers stacked with a small rotational angle relative to their adjacent layers). The endocuticle has a distinct pseudo-orthogonal pattern, characterized by a thin transitional helicoidal region inserted between two orthogonal layers. Idealized mechanics based models showed that the pseudo-orthogonal structure redistributes the …


Numerical Investigation Of Mechanical Durability In Polymer Electrolyte Membrane Fuel Cells, Ahmet Kusoglu, Michael H. Santare, Anette M. Karlsson, Simon Cleghorn, William B. Johnson Jan 2010

Numerical Investigation Of Mechanical Durability In Polymer Electrolyte Membrane Fuel Cells, Ahmet Kusoglu, Michael H. Santare, Anette M. Karlsson, Simon Cleghorn, William B. Johnson

Mechanical Engineering Faculty Publications

The relationship between the mechanical behavior and water transport in the membrane electrode assembly (MEA) is numerically investigated. Swelling plays a key role in the mechanical response of the MEA during fuel cell operation because swelling can be directly linked to the development of stresses. Thus, in the model introduced here, the stresses and the water distribution are coupled. Two membranes are studied: unreinforced perfluorosulfonic acid (PFSA) and an experimental reinforced composite membrane. The results suggest that open-circuit voltage operations lead to a uniform distribution of stresses and plastic deformation, whereas under current-load operation, the stresses and the plastic deformation …


Impact Mechanics And High-Energy Absorbing Materials: Review, Pizhong Qiao, Mijia Yang, Florin Bobaru Oct 2008

Impact Mechanics And High-Energy Absorbing Materials: Review, Pizhong Qiao, Mijia Yang, Florin Bobaru

Department of Engineering Mechanics: Faculty Publications

In this paper a review of impact mechanics and high-energy absorbing materials is presented. We review different theoretical models (rigid-body dynamics, elastic, shock, and plastic wave propagation, and nonclassical or nonlocal models. and computational methods (finite-element, finite-difference, and mesh-free methods. used in impact mechanics. Some recent developments in numerical simulation of impact (e.g., peridynamics) and new design concepts proposed as high energy absorbing materials (lattice and truss structures, hybrid sandwich composites, metal foams, magnetorheological fluids, porous shape memory alloys. are discussed. Recent studies on experimental evaluation and constitutive modeling of strain rate-dependent polymer matrix composites are also presented. Impact damage …


Prediction Of Effective Permittivity Of Diphasic Dielectrics Using An Equivalent Capacitance Model, Sandeep K. Patil, Marina Koledintseva, Robert W. Schwartz, Wayne Huebner Oct 2008

Prediction Of Effective Permittivity Of Diphasic Dielectrics Using An Equivalent Capacitance Model, Sandeep K. Patil, Marina Koledintseva, Robert W. Schwartz, Wayne Huebner

Electrical and Computer Engineering Faculty Research & Creative Works

An analytical model based on an equivalent capacitance circuit for expressing a static effective permittivity of a composite dielectric with complex-shaped inclusions is presented. The dielectric constant of 0-3 composites is investigated using this model. The geometry of the capacitor containing a composite dielectric is discretized into partial parallel-plate capacitor elements, and the effective permittivity of the composite is obtained from the equivalent capacitance of the structure. First, an individual cell diphasic dielectric (a high-permittivity spherical inclusion enclosed in a lower permittivity parallelepiped) is considered. The capacitance of this cell is modeled as a function of an inclusion radius/volume fraction. …


Method Of Measuring Permittivity Of Composite Materials With Hexagonal Ferrite Inclusions, Alexander A. Kitaytsev, Gulnur N. Zhumabayeva, Marina Koledintseva Jul 2007

Method Of Measuring Permittivity Of Composite Materials With Hexagonal Ferrite Inclusions, Alexander A. Kitaytsev, Gulnur N. Zhumabayeva, Marina Koledintseva

Electrical and Computer Engineering Faculty Research & Creative Works

A new simple method for measuring complex permittivity of substantially lossy composite materials is presented. In this method, a sample of the material under study should completely fill in the cross-section of the single-mode transmission line (waveguide), and the length of the sample must be an integer of a half-wavelength in the waveguide filled with this material. The oscillator frequency is swept linearly, the minima of the reflection coefficient are measured, and then analytical formulas are used to calculate real and imaginary parts of permittivity. The method was tested on magneto- dielectric samples containing hexagonal ferrite powders, as well on …


Acoustic Emission Detection And Prediction Of Fatigue Crack Propagation In Composite Patch Repairs Using Neural Networks, Navdeep Singh, Navrag Singh, Anthony Chukwujekwu Okafor Jan 2007

Acoustic Emission Detection And Prediction Of Fatigue Crack Propagation In Composite Patch Repairs Using Neural Networks, Navdeep Singh, Navrag Singh, Anthony Chukwujekwu Okafor

Mechanical and Aerospace Engineering Faculty Research & Creative Works

An aircraft is subjected to severe structural and aerodynamic loads during its service life. These loads can cause damage or weakening of the structure especially for aging military and civilian aircraft, thereby affecting its load carrying capabilities. Hence composite patch repairs are increasingly used to repair damaged aircraft metallic structures to restore its structural efficiency. This paper presents the results of Acoustic Emission (AE) monitoring of crack propagation in 2024-T3 Clad aluminum panels repaired with adhesively bonded octagonal, single sided boron/epoxy composite patch under tension-tension fatigue loading. Crack propagation gages were used to monitor crack initiation. The identified AE sensor …


Reliability-Based Optimization Of Fiber-Reinforced Polymer Composite Bridge Deck Panels, Michel D. Thompson, Christopher D. Eamon, Masoud Rais-Rohani Dec 2006

Reliability-Based Optimization Of Fiber-Reinforced Polymer Composite Bridge Deck Panels, Michel D. Thompson, Christopher D. Eamon, Masoud Rais-Rohani

Civil and Environmental Engineering Faculty Research Publications

A reliability-based optimization (RBO) procedure is developed and applied to minimize the weight of eight fiber-reinforced polymer composite bridge deck panel configurations. The method utilizes interlinked finite element, optimization, and reliability analysis procedures to solve the weight minimization problem with a deterministic strength constraint and two probabilistic deflection constraints. Panels are composed of an upper face plate, lower face plate, and a grid of interior stiffeners. Different panel depths and stiffener layouts are considered. Sensitivity analyses are conducted to identify significant design and random variables. Optimization design variables are panel component ply thicknesses while random variables include load and material …


Mechanics Of Composite Materials In Fuel Cell Systems, Kenneth Reifsnider, Xinyu Huang, G. Ju, Matthew Feshler, K. An Jan 2005

Mechanics Of Composite Materials In Fuel Cell Systems, Kenneth Reifsnider, Xinyu Huang, G. Ju, Matthew Feshler, K. An

Faculty Publications

The science and technology that are fundamental to the concept of composite materials are also the foundation for the construction and function of fuel cells and fuel cell systems. The present paper outlines this relationship in the context of the physics and chemistry that are enabled by the specific selection and arrangement of constituents of the “functional composite” fuel cell. General principles of operation are described, and fundamental issues are defined that must be addressed by the composites community if the fuel cell science and engineering is to advance. Examples of several types of functional composite fuel cells are presented, …


Microwave Permeability Of Co₂ Z Composites, Konstantin Rozanov, Marina Koledintseva, Z. W. Li, L. F. Chen Jan 2005

Microwave Permeability Of Co₂ Z Composites, Konstantin Rozanov, Marina Koledintseva, Z. W. Li, L. F. Chen

Physics Faculty Research & Creative Works

The microwave permittivity and permeability of Co2Z barium ferrite composite samples are measured as functions of frequency and volume fraction of the ferrite. Magnetostatic properties of the bulk ferrite are determined. This allows Snoek's law [J. L. Snoek, Physica 14, 204 (1948)] to be verified by comparing the microwave and magnetostatic Snoek's constants. The modification of Snoek's law for hexagonal ferrites suggested recently by Acher et al. [Phys. Rev. B 62, 11324 (2000)] is also verified. Acher's constant is found from microwave measurements to agree with the value calculated from the magnetostatic properties of bulk ferrite, but microwave and magnetostatic …