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Composites

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Full-Text Articles in Engineering Science and Materials

Structural Health Monitoring Of Composite Parts: A Review, Jacob Pessin Jun 2019

Structural Health Monitoring Of Composite Parts: A Review, Jacob Pessin

Honors Theses

Structural health monitoring has the potential to allow composite structures to be more reliable and safer, then by using more traditional damage assessment techniques. Structural health monitoring (SHM) utilizes individual sensor units that are placed throughout the load bearing sections of a structure and gather data that is used for stress analysis and damage detection. Statistical time based algorithms are used to analyze collected data and determine both damage size and probable location from within the structure. While traditional calculations and life span analysis can be done for structures made of isotropic materials such as steel or other metals, composites ...


A Comparison Study Of Composite Laminated Plates With Holes Under Tension, Joun S. Kim Dec 2017

A Comparison Study Of Composite Laminated Plates With Holes Under Tension, Joun S. Kim

Master's Theses and Project Reports

A Comparison Study of Composite Laminated Plates with Holes under Tension

A study was conducted to quantify the accuracy of numerical approximations to deem sufficiency in validating structural composite design, thus minimizing, or even eliminating the need for experimental test. Error values for stress and strain were compared between Finite Element Analysis (FEA) and analytical (Classical Laminated Plate Theory), and FEA and experimental tensile test for two composite plate designs under tension: a cross-ply composite plate design of [(0/90)4]s, and a quasi-isotropic layup design of [02/+45/-45/902]s, each with a single, centered hole of ...


Organic-Inorganic Graphite And Transition Metal Dichalcogenide Based Composites For 3d Printing, Jorge Alfredo Catalan Gonzalez Jan 2017

Organic-Inorganic Graphite And Transition Metal Dichalcogenide Based Composites For 3d Printing, Jorge Alfredo Catalan Gonzalez

Open Access Theses & Dissertations

This project was multipronged to help fuse together topics of additive manufacturing and two-dimensional (2D) layered materials, and studying the mechanical and electrical properties of the composites produced. The composites are made from the thermoplastic polymer acting as a matrix and the graphite and 2D transition metal dichalcogenides (TMDs) serving as the filler or reinforcement. Different concentrations of TMD's were added to the matrix to study the effect of composition on the mechanical and electrical properties. To shed insights into the mechanical properties, test coupons were produced as "dog bone" structures for tensile testing using the ASTM D638 type ...


Controllable Energy Absorption Of Double Sided Corrugated Tubes Under Axial Crushing, Hozhabr Mozafari, Shengmao Lin, Linxia Gu Jan 2017

Controllable Energy Absorption Of Double Sided Corrugated Tubes Under Axial Crushing, Hozhabr Mozafari, Shengmao Lin, Linxia Gu

Mechanical & Materials Engineering Faculty Publications

To maximize the controllable energy absorption of corrugation troughs as observed in the single sided corrugated (SSC) tube, we proposed and tested a new structure design, i.e., double-sided corrugated (DSC) tube made of Al 6060-T6 aluminum alloy or CF1263 carbon/epoxy composite. Finite element models were developed to test the mechanical advantage of the DSC tube in comparison with both SSC and classical straight (S) tubes under axial crushing. Results have shown that the total absorbed energy of the DSC aluminum tube with 14 corrugations was 330% and 32% higher than that of the SSC tube with 14 corrugations ...


Fabrication And Testing Of Cfrp Composites With Embedded Piezoelectric Particles For Temperature Sensing And Energy Harvesting, Emilio Tarango Valles Jan 2016

Fabrication And Testing Of Cfrp Composites With Embedded Piezoelectric Particles For Temperature Sensing And Energy Harvesting, Emilio Tarango Valles

Open Access Theses & Dissertations

As a part of this world's continuous evolution and technological advancements, smart materials and functional composites have become an attractive topic. In many cases, these new functional composites are replacing the traditional engineering material due to their customizable mechanical properties. This Thesis analyzes and demonstrates the signal response, sensing capabilities and structural properties from Carbon/Glass Fiber Reinforced Plastic Composites (CFRP) with embedded Lead Zirconate Titanate Particles (PZT). The added PZT particles function as actuators, giving the composites a functionality. The PZT quantity inside each composite was variated to study better and characterize the mechanical and electrical properties; the ...


Damage Tolerance And Assessment Of Unidirectional Carbon Fiber Composites, Mark David Flores Jan 2016

Damage Tolerance And Assessment Of Unidirectional Carbon Fiber Composites, Mark David Flores

Open Access Theses & Dissertations

Composites are beginning to be used in a variety of different applications throughout industry. However, certification and damage tolerance is a growing concern in many aerospace and marine applications. Although compression-after-impact have been studied thoroughly, determining a damage tolerance methodology that accurately characterizes the failure of composites has not been established. An experimental investigation was performed to study the effect of stacking sequence, low-velocity impact response, and residual strength due to compression and fatigue. Digital Image Correlation (DIC) captured the strains and deformation of the plate due to compression. Computational investigations integrated non-destructive techniques (C-Scan, X-Ray) to determine the extent ...


Resilience-Based Design Of Precast Steel-Concrete Composites For Railway Track Slabs, Sakdirat Kaewunruen, Dane Wp Griffin, Olivia Mirza, Kenny Kwok Jun 2015

Resilience-Based Design Of Precast Steel-Concrete Composites For Railway Track Slabs, Sakdirat Kaewunruen, Dane Wp Griffin, Olivia Mirza, Kenny Kwok

Sakdirat Kaewunruen

The relatively high turnover of timber sleepers (crossties in a plain track), bearers (skeleton ties in a turnout), and transoms (bridge cross beams) is responsible for producing greenhouse gas emissions 6 times greater than an equivalent reinforced concrete counterparts. This paper presents an innovative solution for the replacement of aging timber transoms installed on existing railway bridges along with the incorporation of a continuous walkway platform, which is proven to provide environmental, safety and financial benefits. Recent developments for alternative composite materials to replace timber components in railway infrastructure construction and maintenance demonstrate some compatibility issues with track stiffness as ...


Acoustic Emission Characteristics Of Damage Accumulation In Kevlar® 49 Composites, Eduardo Andrade Jan 2015

Acoustic Emission Characteristics Of Damage Accumulation In Kevlar® 49 Composites, Eduardo Andrade

Open Access Theses & Dissertations

Acoustic emission (AE) data attained during tensile testing of epoxy impregnated Kevlar® 49 (K/Ep) composite strands were reduced and analyzed to monitor progressive damage accumulation during the approach to tensile failure. The K/Ep material tested in this study was chosen due to its similarity to the material-of-construction used in composite overwrapped pressure vessels (COPVs) used on the NASA Space Shuttle Orbiter. Insight into the progressive microstructural degradation of K/Ep strands was gained by monitoring AE event rate and energy. Source location based on energy attenuation and arrival time data was used to differentiate between significant AE attributable ...


Design And Analysis Of A Novel Latch System Implementing Fiber-Reinforced Composite Materials, Francisco Guevara Jan 2015

Design And Analysis Of A Novel Latch System Implementing Fiber-Reinforced Composite Materials, Francisco Guevara

Open Access Theses & Dissertations

The use of fiber-reinforced composite materials have increased in the last four decades in high technology applications due to their exceptional mechanical properties and low weight. In the automotive industry carbon fiber have become popular exclusively in luxury cars because of its high cost. However, Carbon-glass hybrid composites offer an effective alternative to designers to implement fiber-reinforced composites into several conventional applications without a considerable price increase maintaining most of their mechanical properties. A door latch system is a complex mechanism that is under high loading conditions during car accidents such as side impacts and rollovers. Therefore, the Department of ...


Nanoparticle-Shelled Bubbles For Lightweight Materials, Teresa Brugarolas Brufau Jan 2014

Nanoparticle-Shelled Bubbles For Lightweight Materials, Teresa Brugarolas Brufau

Publicly Accessible Penn Dissertations

Lightweight materials that are mechanically robust are of great interest in automotive, aerospace, and construction industries. However due to the nature of materials, it is challenging to obtain materials that have high strength, stiffness and toughness, and light weight simultaneously. One approach that tries to address this limitation is the use of composite materials containing hollow microparticles, also known as syntactic foams. The incorporation of hollow microparticles decreases the density of the material at the same time that increases its specific strength. Conventional methods of fabrication of hollow particles involving bulk reactions result in high heterogeneity in geometry as well ...


Overall Mechanical Response Of Soft Composite Materials With Particulate Microstructure At Finite Strains, Reza Avazmohammadi Jan 2014

Overall Mechanical Response Of Soft Composite Materials With Particulate Microstructure At Finite Strains, Reza Avazmohammadi

Publicly Accessible Penn Dissertations

Many soft, composite materials manufactured or found in nature consist of a homogeneous matrix phase and a random distribution of micron-sized particles in the matrix. Examples among engineering materials include reinforced elastomers, microgel suspensions and polymer-matrix composites, whereas biological tissues and fluids, such as intervertebral disc and blood, provide examples of natural materials. In this thesis, we present homogenization-based models for the overall constitutive behavior of such composite materials when subjected to mechanical loadings. These models account for the constitutive nonlinearities associated with the local behavior of the matrix and particle phases, as well as for the nonlinearities associated with ...


Dielectric Elastomer Composites: Macroscopic Behavior And Instabilities, Morteza Hakimi Siboni Jan 2014

Dielectric Elastomer Composites: Macroscopic Behavior And Instabilities, Morteza Hakimi Siboni

Publicly Accessible Penn Dissertations

Dielectric Elastomers (DEs) are an interesting class of active materials that can exhibit coupled electrical and mechanical behaviors, for example they can respond to an external electric field by changing their shape or size. This unique property is known as electrostriction, and makes such materials promising candidates for a wide range of practical applications, and therefore there is a need for the design of DEs with enhanced electromechanical couplings. In this work we investigate the possibility of enhancing the electrostriction by making composites consisting of one or more family of filler phases in a soft dielectric host.

We use homogenization ...


Study Of Mechanical And Thermal Properties Of Soy Flour Elastomers, Kendra Allen Jan 2014

Study Of Mechanical And Thermal Properties Of Soy Flour Elastomers, Kendra Allen

Graduate Theses and Dissertations

Bio-based plastics are becoming viable alternatives to petroleum-based plastics because they decrease dependence on petroleum derivatives and are more environmentally friendly. Raw materials such as soy flour are widely available, low cost, lightweight, stiffness and have high strength characteristics, but weak interfacial adhesion between the soy flour and the polymer poses a challenge. In this study, soy flour was utilized as a filler in thermoplastic elastomer composites. A surface modification called acetylation was investigated at soy flour concentrations of 10 wt%, 15 wt% and 20 wt%. The mechanical properties of the composites were then compared to that of elastomers without ...


Inherent Acoustic Nonlinearity In Fiber Reinforced Composites, Sunil Kishore Chakrapani Jan 2014

Inherent Acoustic Nonlinearity In Fiber Reinforced Composites, Sunil Kishore Chakrapani

Graduate Theses and Dissertations

Nonlinear elastic wave methods such as nonlinear resonant ultrasound spectroscopy (NRUS) and nonlinear wave modulation spectroscopy have been previously used to detect damages in several materials. It was observed that applying these techniques to composite materials becomes difficult due to the significant inherent baseline nonlinearity, i.e. nonlinearity in the undamaged state. Understanding the non-classical nonlinear nature of the composites plays a vital role in implementing nonlinear acoustic techniques for material characterization as well as qualitative nondestructive testing of composites. There are several factors which can influence the baseline nonlinear response in fiber reinforced composites, but this work is limited ...


An Automated Finite Element Analysis Framework For The Probabilistic Evaluation Of Composite Lamina Properties, Jonathan Phillips Weigand Dec 2013

An Automated Finite Element Analysis Framework For The Probabilistic Evaluation Of Composite Lamina Properties, Jonathan Phillips Weigand

Masters Theses

This thesis outlines the development of computational modeling tools used to predict the elastic properties of composite lamina from representative volume elements (RVE) using numerical methods. The homogenization approach involves the use of Gauss’s Theorem to simply the average volumetric strain integral into a surface integral containing which is defined by surface displacements and their direction. Simulations of RVEs under specific loading conditions (longitudinal tension or shear and transverse tension or shear) are then performed in the software package ABAQUS to obtain the surface displacements. It was found that obtaining quality meshes and applying periodic boundary conditions for each ...


Damage Detection And Characterization Of Fiber-Reinforced Composites Using Ultrasonics, Ajith Subramanian Jan 2013

Damage Detection And Characterization Of Fiber-Reinforced Composites Using Ultrasonics, Ajith Subramanian

Graduate Theses and Dissertations

Due to the prevalence of fiber-reinforced composites in industrial applications, the need for damage-detection and characterization has increased. Ultrasonic nondestructive testing (NDT) is a powerful and non-invasive method of detecting flaws and defects in composite materials. Air-coupled and immersion UT techniques are used to quantify the effect of matrix microcracking and delamination within the composite laminate. Detection of matrix microcracks in the laminate is of primary concern since microcracking is one of the initial damage modes resulting in local stiffness reduction. The techniques considered include pulse-echo in immersion, angle-beam through-transmission Lamb wave time-of-flight shift and velocity measurements, and angle-beam backscatter ...


Finite Element Modeling Of Ballistic Impact On A Glass Fiber Composite Armor, Dan M. Davis Jun 2012

Finite Element Modeling Of Ballistic Impact On A Glass Fiber Composite Armor, Dan M. Davis

Master's Theses and Project Reports

Finite Element Modeling of Ballistic Impact on a Glass Fiber Composite Armor

Dan Davis

Experiments measuring the ballistic performance of a commercially available fiberglass armor plate were used to guide the development of constitutive laws for a finite element model of the impact. The test samples are commercially available armor panels, made from E-glass fiber reinforced polyester rated to NIJ level III. Quasi-static tensile tests were used to establish material properties of the test panels. These properties were then used to create models in the explicit finite element code LSDYNA.

Ballistic impact testing of the panels was conducted using a ...


The Effects Of Damage Arrestment Devices In Composite Plate Sandwiches With Fastener Holes, Mark Anderson, Nancy Hung Choy, Lacey Jones, Rita Kourskaya Jun 2011

The Effects Of Damage Arrestment Devices In Composite Plate Sandwiches With Fastener Holes, Mark Anderson, Nancy Hung Choy, Lacey Jones, Rita Kourskaya

Aerospace Engineering

Composite materials such as a carbon fiber are used in a variety of new technologies including aircraft, spacecraft, and motor vehicles. Carbon fiber has a high strength to weight ratio, a key advantage over other material options. This report discusses the use of composite damage arrestment devices (DADs) in composite sandwich panels with a foam core. There are three different curing cycles tested for the DADs: pressure only, vacuum only, and vacuum with 1000 lbs of pressure. Using a Tetrahedron Heat Press to cure the composite specimen and an Instron Machine to perform tensile testing, data was collected for each ...


Interfacial Modification Of Microcellular Carbon: Influence Of Ceramic And Carbon Nanotube Coatings, Anil Kumar Karumuri Jan 2009

Interfacial Modification Of Microcellular Carbon: Influence Of Ceramic And Carbon Nanotube Coatings, Anil Kumar Karumuri

Browse all Theses and Dissertations

Microcellular carbon is an emerging ultra lightweight and efficient thermal management material, which also has great potential as a reinforcement material for selected composites. However, these porous materials exhibit relatively low mechanical properties, and are susceptible to degradation in oxidizing environment. The scope of this research is to investigate surface modification approaches that can address these issues. Two specific objectives were: (1) to develop ceramic coatings to improve the survivability of carbon foams in high temperature applications, and (2) to develop and test modifications that can improve cellular composites involving carbon foam. It was seen that a mixed layer of ...


Ultrasonic Nondestructive Evaluation Of Fibre-Reinforced Composite Materials - A Review, Vikram K. Kinra, Vinay Dayal Jan 1987

Ultrasonic Nondestructive Evaluation Of Fibre-Reinforced Composite Materials - A Review, Vikram K. Kinra, Vinay Dayal

Vinay Dayal

This paper reviews various ultrasonic nondestructive evaluation techniques applicable to fibre-reinforced composites. The techniques are briefly described and key references are cited. Methods to evaluate the reduced stiffness of composites due to micro-damage are described. Results show that for composites through-the-thickness attenuation increases and stiffness does not change due to transverse cracks, but in-plane stiffness and attenuation changes are substantial and can be measured by the Lamb wave techniques.