Engineering Science and Materials Commons^™

Characterization Of Bamboo Petung Fiber Reinforced Composites With Environmentally Friendly Enzymes, Rudianto Raharjo, Teguh Dwi Widodo, Redi Bintarto, Fikrul Akbar Alamsyah

Journal of Mechanical Engineering Science and Technology (JMEST)

Natural fiber composites are a good choice for many businesses uses because of their better mechanical properties and are friendly environment. Researchers are currently looking into bamboo petung fiber (BPF) and epoxy composites as alternative to synthetic fibers and products made from petroleum. This study's goal is to improve the overall performance of these composites while reducing the need for non-organic materials. This study used the various concentration of bromelain enzyme in BPF to changes the mechanical and physical properties of epoxy composites made from BPF. Composites were characterized the mechanical properties including tensile strength using tensile tester, impact strength …

Fatigue Behavior Of An Advanced Sic/Sic Composite With An Array Of Small Cooling Holes At 1200°C, Tess K. Panchyshyn

Theses and Dissertations

Tension-tension fatigue behavior of an advanced melt-infiltrated (MI) silicon carbide/silicon carbide (SiC/SiC) composite was evaluated, and basic tensile properties measured, at 1200°C in laboratory air.  The composite consists of a melt-infiltrated SiC matrix reinforced with laminated Hi-Nicalon Type-S fibers woven in a 5-harness satin weave. The Hi-Nicalon-S fiber preforms were coated with a boron nitride (BN) fiber coating by chemical vapor infiltration (CVI). The melt-infiltrated matrix was consolidated by combining CVI-SiC with SiC particulate slurry and molten silicon infiltration. The finished ceramic matrix composite (CMC) had a fiber volume fraction of 33%. Additionally, the effect of multiple small holes on …

Friction Modeling Of Composite Brake Pads With Ulin Wood Powder (Eusideroxylon Zwageri), Muhammad Rezki Fitri Putra, Hajar Isworo, Muhamad Noor Yasin, Rachmat Subagyo

Journal of Mechanical Engineering Science and Technology (JMEST)

This study investigates the performance of composite brake pads made of Ulin (Eusideroxylon zwageri) sawdust using simulation modeling, focusing on the pressure distribution, frictional stress, and contact state in five brake pad designs (DS0 to DS4). The brake pad designs used U-shaped grooves to improve cooling efficiency and debris removal. The results show that DS1 and DS2 exhibit the most uniform pressure distribution, with maximum values of 0.045 MPa and 0.048 MPa, respectively. DS1 recorded the highest peak frictional stress at 2.53 × 10-8 MPa, while DS2 showed consistent stress stability, reducing the possibility of uneven wear. DS3 achieved a …

Multiscale Modeling And Gaussian Process Regression For Applications In Composite Materials, Joshua Arp

All Dissertations

An ongoing challenge in advanced materials design is the development of accurate multiscale models that consider uncertainty while establishing a link between knowledge or information about constituent materials to overall composite properties. Successful models can accurately predict composite properties, reducing the high financial and labor costs associated with experimental determination and accelerating material innovation. Whereas early pioneers in micromechanics developed simplistic theoretical models to map these relationships, modern advances in computer technology have enabled detailed simulators capable of accurately predicting complex and multiscale phenomena.

This work advances domain knowledge via two means: firstly, through the development of high-fidelity, physics-based finite …

Mechanical Properties And Performance Of A Novel Nano-Engineered Unitized Composite With Quasi-Isotropic Layup, Brian Matthew Pudlo

Theses and Dissertations

Carbon nanotubes (CNTs) exhibit outstanding mechanical, electrical, and thermal properties, but are a challenge to effectively implement into macroscopic composites for aerospace applications. This research investigates the mechanical properties and performance of a newly developed hybrid NanoStitch composite, alongside a control polymer matrix composite, at room temperature. Both composite material systems investigated in this work have quasi-isotropic layup. Monotonic tension-tofailure, tension-tension fatigue, and creep tests were performed to characterize the performance of the composites under cyclic and sustained loading. Experimental results obtained for the quasi-isotropic NanoStitch composite were compared to those obtained for the quasi-isotropic control composite. The properties and …

Effect Of Variation Of Sic Mass Fraction On Mechanical Properties Of Al-Sic Composite Using Stir Casting Method, Sumarji Sumarji, Naufal Fardio Albajili, Mahros Darsin, Rahma Rei Sakura, Andi Sanata

Journal of Mechanical Engineering Science and Technology (JMEST)

Al-SiC is a composite composed of AA6061 as a matrix and SiC as a reinforcement particle. The variation of mass added will affect the mechanical properties of the composite because Al-SiC is hardenable, which means that its mechanical properties can be improved by adding the reinforcement component. However, an excessive portion of SiC leads to a decrease in mechanical properties. The purpose of this study was to find the optimal composition of the addition of SiC into the aluminium matrix to gain maximum tensile strength and hardness. The mass fraction variation that would be used in this composite was the …

Inhomogeneous Composite Design For High Energy Impact Resistance Through Computational Design, Physical Testing And Analysis, And Mathematical Modeling, Trenin Bayless

Graduate Theses & Non-Theses

Research in the development of impact resistant materials has been an expanding field for the better part of a hundred years. The development of a light penetration resistant and man-portable system that can resist extreme quantities of kinetic energy has been a subject of substantial study. In particular, the use of composite materials, polymers, ceramics, and metals has been critical to the development of the field. With the advent of complex computational programs for defining material properties, it has become possible to use simulations as a starting point for the development of next generation armored systems. To that end, it …

Optimization Of Stir Casting Of Aluminum Matrix Composites (Amcs) With Filler Of Recycled Glass Powder (Rgp) For The Mechanical Properties, Yusup Hendronursito, Tumpal Ojahan, Anang Anshori, Asep Yunanto

Journal of Mechanical Engineering Science and Technology (JMEST)

A study of making Aluminum Matrix Composites (AMCs) uses recycled glass powder (RGP) as a filler has been carried out through the stir casting process. The experimental design uses the Taguchi method of 3^3 orthogonal array L9 with the parameters of powder size (20>x> 80, 80>y> 200, 200>z> 325), percentage of filler vs matrix (2%, 7%, 12%), and stirring time (30 Seconds, 3 Minutes, 12 Minutes). The optimum conditions for the hardness of Al-GRp composites were obtained from specimens with Mesh powder size parameters 200> z> 325, the percentage of glass vs aluminum powder was 12% wt, …

The Effect Of Heat Treatment To The Erosion Rate Of Brass Composite, Aminnudin Aminnudin, Solichin Solichin

Journal of Mechanical Engineering Science and Technology (JMEST)

Brass composites can be improved their mechanical properties by the heat treatment process. The improvement of the mechanical properties of this technique is expected to increase the resistance of the composite to erosion that occurs in the environment of flow water. Brass composites used are compositeswith fly ash 5, 10, 15, and 20%. The heat treatment process was carried out using electric furnace withoutprotective gas. Composite heat up to 350°C and 400°C for 30 min. and quenching with water. Before and after the erosion test, the weight of the test specimen was weighed with analytical scales. The treatment process affects …

Resistance To Helium Bubble Formation In Amorphous Sioc/Crystalline Fe Nanocomposite, Qing Su, Tianyao Wang, Jonathan Gigax, Lin Shao, Michael Nastasi

Department of Mechanical and Materials Engineering: Faculty Publications

The management of radiation defects and insoluble He atoms represent key challenges for structural materials in existing fission reactors and advanced reactor systems. To examine how crystalline/amorphous interface, together with the amorphous constituents affects radiation tolerance and He management, we studied helium bubble formation in helium ion implanted amorphous silicon oxycarbide (SiOC) and crystalline Fe composites by transmission electron microscopy (TEM). The SiOC/Fe composites were grown via magnetron sputtering with controlled length scale on a surface oxidized Si (100) substrate. These composites were subjected to 50 keV He+ implantation with ion doses chosen to produce a 5 at% peak He …

Reinventing The Wheel, Esther K. Unti, Ahmed Z. Shorab, Patrick B. Kragen, Adam M. Menashe

Mechanical Engineering

Reinventing the Wheel selected tires and designed wheels for the 2018 Cal Poly, San Luis Obispo Formula SAE combustion vehicle. Available tire options were evaluated for steady-state and transient performance as well as vehicle integration. A single-piece composite wheel with hollow spokes was designed to meet stiffness, strength, and tolerance requirements. A detailed study of wheel loading and geometric structural efficiency was performed. Finite element analysis was used to iterate the geometry and laminate. A two-piece male mold was designed and machined to manufacture the wheel. Removable silicone inserts were used to create the hollow spokes.

Manufacturing A Composite Wheel Prototype Using 3d Printed Molds, Steven Thuening

All Graduate Theses, Dissertations, and Other Capstone Projects

Throughout the evolution of high performance racing, a large emphasis has been on reducing the weight of the vehicle in order to improve its performance. Over the years, new designs and materials have been introduced reducing weight in a variety of different locations. Comparing weight reduced in different areas has shown that some areas are more valuable to reduce than others are. Perhaps one of the most beneficial locations are the wheels. This is because the mass of the wheel is considered unsprung and rotational. Because of this, large improvements towards the reduction of wheel mass have been developed in …

Characterization Of 3d Printed Polylactic Acid/ Polycaprolactone/Titanium Dioxide Composites For Bone Replacement And Grafting, Sandra Elena Najera Beltran

Open Access Theses & Dissertations

A material that mimics the properties of bones was developed by optimizing the ratio of polymer composites of polylactic acid (PLA) and poly-ε-caprolactone (PCL), containing small amounts of titanium oxide (TiO2). Although titanium-based alloys have commonly been used for bone replacement procedures due to their biocompatibility with the human body and their mechanical properties, stress shielding continues to be a problem. The structure of a bone has a porosity which permits the flow of nutrients, blood, oxygen and minerals, and is an issue at the time of creating bone replacements using conventional methods. PLA and PCL have been used in …

The Inter-Laminar Shearing Effect On Wrinkle Development In Composite Forming Processes, David Sundquist

McKelvey School of Engineering Graduate Student Theses & Dissertations

Composite materials are becoming prevalent in aerospace industries as the uniqueness of the composite structure allows the composite to be tailored specifically for individual applications. Many fabrication techniques produce defects in composite parts such as wrinkles, fiber waviness, fiber misalignment, and porosity. The driving mechanisms behind these defects occurring during forming processes are not fully understood and, thus, characterization formation of these defects in a uncured state is beneficial to optimize composite processing. This work primarily investigated the influence of how uncured pre-impregnated carbon ply properties affect the wrinkling behavior of a composite laminates. Several factors affecting composite ply forming …

Bear Minimum: Ultralight Composite Bear Canister, Rama B. Adajian, Adam C. Eisenbarth

Mechanical Engineering

The ultralight backpacking community needs a strong, easy to use, safe bear canister that is lighter than current market products for trekking in the backcountry. A full design of the lid for the bear canister is to be completed. This includes the locking mechanism to ensure it is bear proof, the interface between the lid and the canister, and the structure of the lid so it passes the strength and weight specifications. The lid, along with the already designed canister body, is to be manufactured with formal documentation. The lid will initially be tested separately and then with the canister …

Development Of 3d Compression Molded Composite Primary Structure, Sean D. Tischler, Jacob H. Goldstein, Alea A. Perez

Mechanical Engineering

The work accomplished by the Black Gold team improved upon the carbon fiber compression molding research and information available on the Cal Poly San Luis Obispo campus. The team used the rear suspension rocker arm off a Ventana Alpino mountain bike as a design goal for this project. This research and body of work includes the methods used to design a compression molded part for complex part loading and shape. This extends to the process of choosing an appropriate layup process, in addition to benefits and drawbacks of the use of chopped fibers in compression molding. The research includes the …

Compression Testing And Failure Modes Of Steel-Concrete Composite (Sc) Structures For Nuclear Containment, Patrick Michael Wanamaker, Amit H. Varma

The Summer Undergraduate Research Fellowship (SURF) Symposium

Although being able to provide much cleaner power than burning coal and other fossil fuels, nuclear power plants are still a tough sell to the general public due to their history of being spontaneously dangerous. The containment structures surrounding these nuclear plants, however, can play a huge role in reducing the risks associated with them. Relatively new designs for these containment assemblies, known as SC (steel-concrete composite) structures, aim to increase the strength and durability of the containment facilities while keeping costs down. By varying the spacing between shear studs, the ratio of concrete to steel, and the ratio of …

Preparation And Electrochemical Performance Of Hollow Carbon Spheres/Sulfur Composite, Jun Zang, Hang Qian, Er-Man Zeng, Juan-Ni Fu, Ming-Sen Zheng, Quan-Feng Dong

Journal of Electrochemistry

Hollow carbon spheres were prepared by the PMMA template. Hollow carbon spheres/sulfur composite was made from sulfur and hollow carbon spheres as a conducting framework. The results of SEM and TEM showed that sulfur was uniformly filled in both of the shell and hollow core of hollow carbon spheres. The electrochemical performance of hollow carbon spheres/sulfur composite was characterized by the charge/discharge method. The results showed the excellent rate and cycle performance of hollow carbon spheres/sulfur composite. The reversible capacities of hollow carbon spheres/sulfur composite are 1145 mAh·g^-1, 824 mAh·g^-1, 702 mAh·g^-1, 586 mAh·g …

Electrochemical Performances Of Layered Polypyrrole/Chemically Reduced Graphene Oxide Nanocomposites As Supercapacitor Electrodes, Si-Zhe Xu, Xue-Jiao Zhou, Kun Wu, Yong-Qiang Yang, Hai-Xia Wu

Journal of Electrochemistry

Nanocomposites of polypyrrole (Ppy) and chemically reduced graphene oxide (CRGO), Ppy/CRGO, have been fabricated through in-situ polymerization of pyrrole on graphene oxide (GO) sheets. The as-synthesized Ppy/CRGO composites were characterized complementarily using scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and Fourier transformed infrared spectroscopy (FT-IR). By controlling the initial ratio of the GO to pyrrole, the layered composites could be obtained and their thickness could be tuned properly. The Ppy/CRGO electrodes were prepared using a mechanical compressing technique and their electrical conductivity and electrochemical properties were characterized systematically. We demonstrated that as electrodes for supercapacitor, the Ppy/CRGO composites with Ppy …

A Resistance Based Structural Health Monitoring System For Composite Structure Applications, Dennis N. Boettcher

Master's Theses

This research effort explored the possibility of using interwoven conductive and nonconductive fibers in a composite laminate for structural health monitoring (SHM). Traditional SHM systems utilize fiber optics, piezoelectrics, or detect defects by nondestructive test methods by use of sonar graphs or x-rays. However, these approaches are often expensive, time consuming and complicated.

The primary objective of this research was to apply a resistance based method of structural health monitoring to a composite structure to determine structural integrity and presence of defects.

The conductive properties of fiber such as carbon, copper, or constantan - a copper-nickel alloy - can be …

Synthesis And Electrochemical Performance Of Xlifepo4·Yli3V2(Po4)3 Composites, Ping-Ping Ma, Zhi-Jian Liu, Jian-Hua Xia, Yu Chen, Pu Hu, Zhi-Chao Lu, Ding-Guo Xia

Journal of Electrochemistry

A series of xLiFePO₄·yLi₃V₂(PO₄)₃ composites were systematically synthesized through solid state reactions by variations in the proportions of LiFePO₄ and Li₃V₂(PO₄)₃. The properties of the prepared compounds were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical measurements. The capacity of 162.7 mAh/g at 0.2 C rate was obtained with the relatively good cycle stability and good conductivity for 0.95LiFePO₄·0.05Li₃V₂(PO₄)₃ due to more uniformed distributed and smaller particle sizes.

The Functionalization And Characterization Of Adherent Carbon Nanotubes With Silver Nanoparticles For Biological Applications, Adam A. Maleszewski

Browse all Theses and Dissertations

The purpose of this project is to form silver nanoparticles (Ag-NP) attached to a hierarchical substrate for possible use in biological applications. The effectiveness of these Ag-NP-containing devices, including biofilters and biosensors, may be dramatically enhanced by the use of hierarchical structures such as carbon nanotubes (CNT), as they offer a high surface area surface suitable for cell-device interactions, while Ag-NP would be a suitable component in many such devices due to its plasmonic surface properties (e.g. in sensor and directed energy applications) and its anti-microbial properties (desirable for fluid filtration due to its low weight. Meaningful control over the …

Natural Fibers And Fiberglass: A Technical And Economic Comparison, Justin Andrew Zsiros

Theses and Dissertations

Natural fibers have received attention in recent years because of their minimal environmental impact, reasonably good properties, and low cost. There is a wide variety of natural fibers suitable for composite applications, the most common of which is flax. Flax has advantages in tensile strength, light weight, and low cost over other natural fibers. As with other natural and synthetic fibers, flax is used to reinforce both thermoset and thermoplastic matrices. When flax is used in thermoplastic matrices, polypropylene and polyethylene are the main resins used. Although at first glance flax may seem to be a cheaper alternative to fiberglass, …

Design, Fabrication, Structural Testing, And Numerical Analysis Of A Small Scale Composite Wing, Jacob David Gaunt, Juan Carlos Flores, Vincent Andrew Perry

Aerospace Engineering

A small scale composite wing based on a design found on an experimental aircraft was designed, constructed, and tested dynamically and statically. The wing was constructed similarly to an experimental aircraft wing. The performed static test was intended to produce pure bending. Strain gages were used to measure strains on the wing structure. The strains were converted to stresses to aid in analysis. The static test results suggested that the wing was actually under torsion. Four structural modes were found from the static test. A finite element analysis model was made to compare experimental results to numerical analytical results. The …

Performance Of Sulfur-Super Conductive Carbon Black Composite In Electrolyte Mixed With Room Temperature Ionic Liquid, Bo Zhang, Si-Ting Chen, Xue-Ping Gao

Journal of Electrochemistry

The sulfur-super conductive carbon black composite was prepared as cathode material of lithium/sulfur battery.The composite was characterized by scanning electron microscopy(SEM),X-ray diffraction(XRD),and electrochemical impedance spectroscopy(EIS).The sulfur composite shows a high discharge capacity and a good cycle performance in electrolyte mixed with 50% of room temperature ionic liquid.In particular,the discharge capacity of the composite was stabilized at 483.6 mAh/g after 50 cycles.

Nano-Sn/Hard Carbon Composite As Anode Material For Lithium Ion Batteries, Bing-Kun Guo, Jie Shu, Kun Tang, Ying Bai, Zhao-Xiang Wang, Li-Quan Chen

Journal of Electrochemistry

The tin(Sn) nano particles were embedded into the mesopores of hard carbon spherules(HCS) to form a composite anode material for lithium ion batteries.The structure of the obtained composite was characterized by X-ray diffraction(XRD) while its electrochemical performances were evaluated with galvanostatic cycling.It is found that the embedding Sn nanoparticles into porous HCS not only result in a composite material with high lithium storage capacity and capacity retention,but also increase the initial coulombic efficiency of the composite.Based on the infrared spectroscopic analysis,the enhanced initial coulombic efficiency is attributed to the inductive decomposition of the ROCO₂Li species in the solid …

Preparations Of Composite Electrodes Of Pt With HXWo3 And Catalytic Activity Toward Oxygen Reduction Reaction, Pan-Pan Guo, You-Ju Huang, Hong-Yan Yang, Wei Li, Qing-Long Zhang, Wei-Shan Li

Journal of Electrochemistry

Three composite electrodes of platinum with hydrogen tungsten bronze(H_xWO₃)were prepared by voltammetry: hydrogen tungsten bronze deposited on platinum(H_xWO₃/Pt);platinum deposited on hydrogen tungsten bronze(Pt/H_xWO₃) and codeposited platinum and hydrogen tungsten bronze(Pt-H_xWO₃).The eletro-catalytic activities of three electrodes toward oxygen reduction reaction were studied.It is found that the catalytic activity of platinum can be improved by introducing with hydrogen tungsten bronze.Among these composite electrodes Pt/H_xWO₃,and the electrode shows the best eletro-catalytic activity toward oxygen reduction reaction,hence,provides a new way for reducing loading of …

Utilization Of Municipal Solid Waste Rejects In The Production Of A Recycled Plastic Waste Composite Material, Mohamed Kamal Abou Khatwa

Archived Theses and Dissertations

The solid waste disposal problem has grown significantly in the last decades imposing a lot of pressure on disposal and treatment acts. In the past, incineration and landfilling were the common methods for disposing of products of municipal solid waste. With the increasing volumes of waste generation and the legislative restrictions of these treatment methods, reuse of bulk waste is foreseen as the best alternative to disposal. Due to the current widespread use of plastic products in daily life, post consumer plastics now contribute significantly to municipal solid waste generation rates with a contradicting low participation in waste minimization practices. …