Mechanical Engineering Commons^™

Ultrasonic-Based Condition Assessment Of Wooden Utility Poles, Yishi Lee

Electronic Theses and Dissertations

More than 300 million utility poles shoulder the utility grid in the United States. However, the ineffectiveness of the current inspection process causes roughly a third of utility poles removed from the service deemed suitable for reuse. Due to the utterly essential role of the power infrastructure, budget shrinkage, and the structural degradation of the modern distribution grid, this Ph.D. dissertation addresses the challenges by proposing a physics-based signal analysis method with a jointly developed ultrasonic UB1000 system c to enhance the objectivity in ultrasonic-based nondestructive evaluation (NDE). The proposed methodology has been deployed commercially in the field and featured …

On Geometric Design Rules And In-Process Build Quality Monitoring Of Thin-Wall Features Made Using Laser Powder Bed Fusion Additive Manufacturing Process, Aniruddha Gaikwad

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

The goal of this thesis is to quantify the link between the design features (geometry), in-process signatures, and build quality of parts made using the laser powder bed fusion (LPBF) additive manufacturing (AM) process. This knowledge is the foundational basis for proposing design rules in AM, as well as for detecting the impending build failures using in-process sensor data.

As a step towards this goal, the objectives of this work are two-fold:

1) Quantify the effect of the geometry and orientation on the build quality of thin-wall features. To explain further, the geometry related factor is the ratio of the …

Microstructure And Mechanical Behavior Of Metastable Beta Type Titanium Alloys, Chirag Dhirajlal Rabadia

Theses: Doctorates and Masters

Current biomaterials such as stainless steel, Co-Cr alloys, commercially pure titanium and Ti-6Al- 4V either possess poor mechanical compatibility and/or produce toxic effects in the human body after several years of usage. Consequently, there is an enormous demand for long-lasting biomaterials which provide a better combination of mechanical, corrosion and biological properties. In addition to this, alloys used in high-strength applications possess either high-strength or large plasticity. However, a high-strength alloy should possess a better blend of both strength and plasticity when used in high-strength applications. Metastable β-titanium alloys are the best suited alloys for biomedical and high-strength applications because …

Very High Cycle Fatigue Behavior Of Laser Beam-Powder Bed Fused Inconel 718 Considering The Layer Orientation And Surface Finish Effects, Palmer Frye

UNF Graduate Theses and Dissertations

Additive Manufacturing (AM) techniques have recently gained popularity for fabrication of parts used in aerospace applications. Some of these parts may be subjected to cyclic loading at very high frequencies, leading to service life requirements exceeding ten-million cycles (>10⁷ cycles). Therefore, understanding the very high-cycle fatigue (VHCF) behavior of these AM parts is an important step in their design and qualification processes. In this thesis, both high-cycle fatigue (HCF) and VHCF behaviors of Inconel 718, a Ni-base superalloy, manufactured via a Laser Beam-Powder Bed Fusion (LB-PBF) process, are investigated. Uniaxial, fully reversed force-controlled fatigue tests were conducted utilizing …

Buckling Load Study On Pop Nut (Rivet) Using Finite Element Analysis, Saurabh Shankar Shegokar

Dissertations, Master's Theses and Master's Reports

This study highlights the material behavior in riveting operation that includes buckling load analysis using ABAQUS. Finite Element Analysis is used to find the buckling load vs. Displacement results and validated with the results obtained in physical testing of rivet (POP Nut). A mesh sensitivity study is performed using ABAQUS to understand the optimum mesh size for this analysis. An axisymmetric model with contact properties is created and simulated to reduce the simulation time using ABAQUS. The results obtained through Finite Element Analysis show a good resemblance with the testing results. Design changes were suggested to achieve better results that …

Design Of Efficient Carbon-Based Adsorbents For The Removal Of Organic And Inorganic Water Contaminants, Sayedeh Soroosh Mortazavian Dehkordi

UNLV Theses, Dissertations, Professional Papers, and Capstones

Granular activated carbon (AC) and biochar (BC) are two carbon-based adsorbents commonly used for water and wastewater treatment. However, these adsorbents have drawbacks that suppress their aqueous contaminants removal efficiency. Their major disadvantages are that AC has low selectivity and reusability potential, and BC has a hydrophobic nature.

The scope of this dissertation is to enhance the performance of commonly-used carbon-based adsorbents for the removal of organic and inorganic water contaminants and to understand the interactive mechanism of contaminants’ ions/molecules with adsorbents. Hexavalent chromium (Cr(VI)) and trichloroethylene (TCE) are two types of inorganic and organic water contaminants, respectively, which are …

A New Synthesized Microalloys Steel Ods Of High Amplitude Ultrasonically Irradiation, Marzuki Silalahi, Hanif Abdurrahman Wicaksana, Ferhat Aziz, Syahfandi Ahda, Mohamad Riza Iskandar

Makara Journal of Technology

Micropowders of oxide-dispersion-strengthened (ODS) steel have been synthesized using the ultrasonic irradiation method with variations in amplitude. The ultrasonic irradiation process is performed for 50 h at a frequency of 20 kHz with 40%, 50%, and 60% amplitudes in toluene solution. The formation of Fe-Cr microalloys in the preparation of Fe- 15Cr-0.5Y2O3 powder was analyzed using SEM-EDS, X-ray diffraction (XRD), and TEM-EDS. The percentage of Fe- Cr phase mass fraction of ODS steel micropowder formed during ultrasonic irradiation with 40%:50%:60% amplitude was 12.2%:34.1%:22.1%, with 25.67:77.02:38.51 nm crystallite size. The crystallite size at 50% amplitude was the largest, and the diffusion …

Comprehensive Inspection On The Experimental Ferritic Stainless Steel By Means Of Transmission Electron Microscopy And Neutron Diffraction Techniques, Parikin Parikin, Mohammad Dani, Riza Iskandar, Aziz Khan Jahja, Andon Insani, Joachim Mayer

Makara Journal of Technology

The field of physical metallurgy is one of the primary beacons that guide alloy developments for multipurpose materials such as the in-core structure materials for pressure vessel components and heat exchangers. The surface microstructure of new ferritic steel with significant local constituent materials was characterized by high resolution powder neutron diffractometer (HRPD) and transmission electron microscope (TEM), combined with the energy dispersive X-ray spectroscopy (EDX). The alloy contains73% Fe, 24% Cr, 2% Si, 0.8% Mn, and 0.1% Ni, in %wt. The charge materials were melted by the casting techniques. The neutron diffractograms obtained shows five dominant diffraction peaks at (110), …

Study On Antibacterial Of Chitosan/Hydroxyapatite Doped Magnesium Composite As A Material For Bone Graft Applications, Andromeda Dwi Laksono, Teodoro A. Amatosa, Jr., Hilda Pebrianti Octaviana Sitorus, Wentika Putri Kusuma Asih, Sulistijono Sulistijono

Makara Journal of Technology

Hydroxyapatite (HAp) is one of the constituent minerals of bone and teeth, that has been widely used for synthesizing bone graft. Due to the limitation on properties of the hydroxyapatite, it is doping with Magnesium (HAp-Mg). The addition of Chitosan (Chi) was expected to improve the antibacterial properties of HAp-Mg. The present research aims to study the influence of Chitosan with 0, 5, 15, and 25 wt% addition on biocompatibility properties of Chi/HAp-Mg composite. HAp-Mg was synthesized using the sol-gel method; meanwhile, Chi/HAp-Mg composite was manufactured by mixing Chitosan in acetic acid, and HAp-Mg was added into the mixture. The …

Evaluation Of Primal-Dual Splitting Algorithm For Mri Reconstruction Using Spatio-Temporal Structure Tensor And L1-2 Norm, Mia Rizkinia, Masahiro Okuda

Makara Journal of Technology

Magnetic resonance imaging (MRI) is an essential medical imaging technique which is widely used for medical research and diagnosis. Dynamic MRI provides the observed object visualization through time and results in a spatiotemporal signal. The image sequences often contain redundant information in both spatial and temporal domains. To utilize this characteristic, we propose a spatio-temporal reconstruction approach based on compressive sensing theory. We apply spatio-temporal structure tensor using nuclear norm, in addition to the wavelet sparsity regularization. The spatio-temporal structure tensor is a matrix that consists of gradient components of the MRI data w.r.t the spatial and temporal domains. For …

Influence Of Nh4f In Dextran Based Biopolymer Electrolytes: Conductivity And Electrical Analysis, Muhamad Hafiz Hamsan, Mohd Fakhrul Zamani Kadir, Shujahadeen Bakar Aziz, Muhammad Amirul Solihin Azha, Saifful Kamaluddin Muzakir

Makara Journal of Technology

Dextran polymer host was doped with different concentrations of ammonium fluoride (NH4F) via casting technique. In this present work, dextran-NH4F film has been employed to investigate the ionic conductivity using electrochemical impedance spectroscopy from 50 to 5 MHz. The highest room temperature conductivity is achieved at (2.33 ± 0.76) × 10-3 S cm-1 with 40 wt.% NH4F. The electrolyte is found to obey Arrhenius rule at high temperature with activation energy of 0.21 eV. Dielectric analysis has been performed to obtain better understanding on the conductivity pattern. The dielectric parameters e.g. ɛreal, ɛimag, Mreal, and Mimag have been tested as …

Acute Toxicitystudy Of Choline Based Ionic Liquids Towards Danio Rerio Fish And The Aggregation Behavior Of Their Binary Mixtures, Mansoor Ul Hassan Shah, Nasruddin Nasruddin, Suzana Bt Yusup, Muhammad Moniruzzaman

Makara Journal of Technology

Marine oil spills are effectively controlled by chemical dispersants. However, the toxicity associated with it reduce its employment in marine environment. To overcome this limitation, the acute toxicity of choline based ionic liquids was evaluated as a potential low toxic variant for oil spill remediation. Further, the aggregation behavior of the individual as well as their binary mixtures was also evaluated by employing tensiometry technique. The half-lethal concentration, LC50on zebrafish (Danio rerio) of three choline based ionic liquids showed that the studied ionic liquids (ILs) fall in the range of “practically nontoxic” ( 100-1000 mg L-1).Various micellar properties showed that …

Neutron Diffraction Study Of Multiferroic 0.6nife2o4/0.4batio3 Composite, Engkir Sukirman, Yosef Sarwanto, Syahfandi Ahda, Andon Insani

Makara Journal of Technology

Neutron diffraction study on the 0.6NiFe2O4/0.4BaTiO3 multiferroic composite has been carried out. The 0.6NiFe2O4/0.4BaTiO3 multiferroic composites have been synthesized by solid reaction method. In this study, 20 g of BaTiO3 (BTO) and 20 g of NiFe2O4 (NFO) compounds were prepared from the powder raw materials of BaO3 and TiO2 for BTO, and NiO and Fe2O3 for NFO. Furthermore, both BTO and NFO were each crushed for 5 hours using High Energy Milling (HEM). Then the BTO and NFO were calcined in the furnace at 950 °C/5 hours and 900 °C/5 hours, respectively. Both NFO and BTO precursors were manually mixed …

Multiscale Modeling Of Fracture In Quasi-Brittle Materials Using Bifurcation Analysis And Element Elimination Method, Keyvan Zare Rami

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Analyzing the fracture of heterogeneous materials is a complex problem, due to the fact that the mechanical behavior of a heterogeneous material is strongly dependent on a variety of factors, such as its microstructure, the properties of each constituent, and interactions between them. Therefore, these factors must be effectively taken into account for accurate analysis, for which the multiscale method has been widely used. In this scheme, the computational homogenization method is used to obtain the effective macroscopic properties of a heterogeneous material based on the response of a Representative Volume Element (RVE). The growth of damage in an RVE …

Bioresorbable Composite Stents For Enhanced Response Of Vascular Smooth Muscle Cells, Hozhabr Mozafari

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Formation of arterial plaque and stenosis is one of the main cardiovascular disease risk factors. Stenting is a popular approach to increase the inner diameter of the artery and provide an acceptable lumen gain. This is achieved by applying internal pressure to the arterial wall. Despite the desirable outcomes of this procedure, there are complexities and challenges that are being discussed among scholars in this area. Restenosis is one of these complications, in which smooth muscles cell start proliferation and remodeling in response of induced mechanical stresses. Another important issue is the placement of the stent and possible migration due …

Accelerated Relaxation In Disordered Solids Under Cyclic Loading With Alternating Shear Orientation, Nikolai V. Priezjev

Mechanical and Materials Engineering Faculty Publications

The effect of alternating shear orientation during cyclic loading on the relaxation dynamics in disordered solids is examined using molecular dynamics simulations. The model glass was initially prepared by rapid cooling from the liquid state and then subjected to cyclic shear along a single plane or periodically alternated in two or three dimensions. We showed that with increasing strain amplitude in the elastic range, the system is relocated to deeper energy minima. Remarkably, it was found that each additional alternation of the shear orientation in the deformation protocol brings the glass to lower energy states. The results of mechanical tests …

Publisher Correction: Pore Elimination Mechanisms During 3d Printing Of Metals (Nature Communications, (2019), 10, 1, (3088), 10.1038/S41467-019-10973-9), S. Mohammad H. Hojjatzadeh, Niranjan D. Parab, Wentao Yan, Qilin Guo, Lianghua Xiong, Cang Zhao, Mimglei Qu, Luis I. Escano, Xianghui Xiao, Kamel Fezzaa, Wes Everhart, Tao Sun, Lianyi Chen

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The original version of this Article contained an error in Fig. 4. The x-axis labels in Fig. 4a, b were incorrectly labelled 'Diameter (mm)', rather than the correct 'Diameter (µm)'. This has been corrected in both the PDF and HTML versions of the Article.

Ultrasonic Wave Propagation In Copper/Graphene Metal Matrix Composites, Casey Lindbloom

Mechanical Engineering Undergraduate Honors Theses

Emerging metallic composite materials implanted with graphene sheets are showing immense promise, with benefits being observed with regards to mechanical, thermal, and electrical material properties. This research aims to investigate the effects on ultrasonic wave propagation in Copper/Graphene Metal Matrix Composites (Cu/Gr MMCs) with varying graphene arrangements inspired from nacre and bone nanoscale material distributions. To accomplish this, the molecular dynamics (MD) method is utilized to simulate nanoscale wave propagation on a set of Cu/Gr MMCs with differing graphene arrangements and volume percentages ranging up to 4.56%. The computational model results are then analyzed to determine the variation in energy …

Nanothermomechanical Logic Gates For Thermal Computing, Ahmed Hamed

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Limited performance and reliability of electronic devices at extreme temperatures, intensive electromagnetic fields, and radiation found in space exploration missions (i.e., Venus & Jupiter planetary exploration, and heliophysics missions) and earth-based applications require the development of alternative computing technologies. Thermal computing, data processing based on heat instead of electricity, is proposed as a practical alternative and opens a new scientific area at the interface between thermal and computational sciences.

We successfully developed thermal AND, OR and NOT logic gates, achieved through the coupling between near-field thermal radiation and MEMS thermal actuation. In the process, we developed two novel non-linear thermal …

Magnetic Properties Of Nd–Fe–B Permanent Magnets Under Thermal Experimentation, Géraldine Houis

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Neodymium-Iron-Boron (Nd-Fe-B) magnets were developed in the 1980s, and since then, they have appeared as a common component in many fields. From the industry to consumers or defense applications, from turbines, computers, cellphones to most audio systems, Nd-Fe-B magnets are present everywhere. But when Nd-Fe-B magnets are applied to the motors of electric vehicles and wind-turbine generators, their temperature rises, therefore Nd-Fe-B-Dy magnets are used. However, while the use of these magnets is common at low temperatures, their properties decrease dramatically with the increase of temperature. In this paper, the Nd-Fe-B-based samples used were prepared by using arc melting, melt …

Extending Mission Duration Of Uas Multicopters: Multi-Disciplinary Approach, Marc Lussier

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Multicopters are important tools in industry, the military, and research but suffer from short flight times and mission durations. In this thesis, we discuss three different ways to increase flight times and therefore increase the viability of using multicopters in a variety of missions. Alternate fuel sources such as hydrogen fuel and solar cells are starting to be used on multicopters, in our research we simulate modern fuel cells and show how well they currently work as the power source for multicopters and how close they are to becoming useful in Unmanned Aircraft System (UAS) technology. Increasing the efficiency in …

The Flame Characteristics Of Diesel Fuel Blend With Kepuh (Sterculia Foetida) Biodiesel, Dani Hari Tunggal Prasetiyo, Nasrul Ilminnafik, Salahuddin Junus

Journal of Mechanical Engineering Science and Technology (JMEST)

Kepuh biodiesel fuel (sterculia foetida) is an alternative fuel that can be used to replace fossil fuel. Diesel fuel is performed to determine the laminar burning velocity and high flame by adding biodiesel kepuh volume of 10%, 20%, 30%. The purpose of this study was to study the effect of biodiesel and the effect of bunsen burners on the laminar burning velocity and flame height. Bunsen burner is made of copper and stainless steel. Testing of flame characteristics was carried out by heating the mixture of fuel and air at a temperature of 200°C. The purpose of heating the air …

Critical Solid Fraction Point Analysis: Case Study On Cement Mill Machine Diaphragm, Mochamad Achyarsyah, Poppy Puspitasari

Journal of Mechanical Engineering Science and Technology (JMEST)

During the solidification process, metal liquids turn into solid geometry units including the riser and gating system. The disruption in the liquid flow often causes shrinkage in the object. Critical Solid Fraction Point is a critical point where the continuous liquid supply turned solid and unable to pour to some sections. Simulation software can predict the critical solid fraction time of an object and the liquid supply behavior. The simulation helps the designer in the casting design. The application of low steel alloys in the cement industry, e.g., the Diaphragm, needs development to minimize the shrinkage. This research aimed to …

Characteristic Analysis Of Horizontal Axis Wind Turbine Using Airfoil Naca 4712, Bili Darnanto Susilo, Gaguk Jatisukamto, Nurkoyim Kustanto

Journal of Mechanical Engineering Science and Technology (JMEST)

Wind energy has been developed and used as a source of electrical energy by converting wind energy into electrical energy using a generator. There are some wind turbine parameters that important for wind turbines design and model, includes the size of the rotor radius, airfoil selection, chord length, and pitch angle. The study aims to characterize the performance of a horizontal axis wind turbine using computational methods. The methods used a design and simulation of NACA 4412 and NACA 4712 airfoil using QBlade software using wind conditions in the region of Pancer, Jember. Results show that the maximum Cl value …

Synthesis And Applications Of Hematite Α-Fe2o3 : A Review, Muhamad Muhajir, Poppy Puspitasari, Jeefferie Abdul Razak

Journal of Mechanical Engineering Science and Technology (JMEST)

This article reviewed the hematite α-Fe2O3. It focuses on its material properties, nanostructures, synthesis techniques, and its numerous applications. Researchers prepared the hematite nanostructure using the synthesis methods such as hydrothermal, and, further, enhanced it by improving the techniques to accommodate the best performance for specific applications and to explore new applications of hematite in humidity sensing.

Failure Analysis On Titen Proto-Xx Car Chassis, Gaguk Jatisukamto, Rika Dwi Hidayatul Qoryah, Santoso Mulyadi

Journal of Mechanical Engineering Science and Technology (JMEST)

The car chassis as a skeleton supports all loads and is the most important component. Car chassis requirements must be rigid, twisting resistant, vibration resistant and resistant to fatigue. This study aims to find the cause of the failure of the Titen Proto-XX car chassis connection. The research methodology was conducted by testing the composition of materials and structural analysis using Ansys Workbench Release 15.0 software. The conclusion of the research is that the skeletal structure material uses Aluminum AA series 1XXX with Al content greater than 99.5%, the welding ability is low, causing a failure in the welded joint. …

The Effect Of Chlorophyll Concentration From Papaya Leaves On The Performance Of Dye-Sensitized Solar Cell, Dede Rizali, Heru Suryanto, Sukarni Sukarni

Journal of Mechanical Engineering Science and Technology (JMEST)

Dye-Sensitized Solar Cell (DSSC) is the third generation solar cell that has sandwich structure consisted of organic dye material and other components such as titanium dioxide (TiO2) semiconductor, electrolyte, and substrates (counter electrode and working electrode). The dye in the device was made from green plant chlorophyll such as papaya. This research aimed to find the influence of dye concentration from papaya leaves chlorophyll on the performance of DSCC. The discussion covered the output power (Pout), Fill Factor (FF), and efficiency (ɳ). The method in this research was explorative experimental with independent variables such as direct and indirect sunlight. The …

Additively Manufactured Continuous Carbon Fiber Thermoplastic Composites For High-Performance Applications, Nekoda Van De Werken

Mechanical Engineering ETDs

The goal of this dissertation is to provide a foundation for the advancement of additive manufacturing (AM) toward production of high-performance carbon fiber reinforced polymer matrix composites (CFRPs). AM can provide valuable advantages over conventional composite manufacturing techniques, including the control over fiber orientation, capability of manufacturing complex geometries, out-of-autoclave processing, elimination of the need for composite tooling, and the ability to perform lights-out manufacturing. Currently, however, a suite of challenges related to modelling, design, manufacturing defects, and general limitations in the current understanding of the processing-structure-property relationships exist in AM of composites. To this end, this dissertation investigates novel …

Combined Molecular Dynamics And Phase Field Simulation Of Crystal Melt Interfacial Properties And Microstructure Evolution During Rapid Solidification Of Ti-Ni Alloys, Sepideh Kavousi

LSU Doctoral Dissertations

Phase field method has become a popular tool to investigate the microstructure evolution during the solidification. Quantitative predictions using this method is still limited, and in this dissertation, we try to study this problem from different perspectives.

Most of the phase field models consider the solid-liquid interface to be in local equilibrium. Solidification during some manufacturing processes like selective laser melting, and electron beam additive manufacturing is rapid and far from equilibrium which can result in supersaturated solid solutions, segregation-free crystals, or metastable phases. Before obtaining any conclusions from the phase field simulations, we must know the answer for “which …

An Investigation Of High-Speed Consolidation And Repair Of Carbon Fiber - Epoxy Composites Through Ultrasonic Welding, David A. Hoskins

LSU Master's Theses

Adhesive repair of carbon fiber composite structures is commonly done on damaged structures to extend the service life. This method requires careful preparation of the damaged surface with intricate steps to ensure good bonding between the repair patch and the parent structure by means of an adhesive film. As with many forms of composite manufacturing, it is required to perform vacuum bagging, debulking, and a heated cure depending on the resin. All these steps make the repair process costly and time consuming.

In this present work, an alternative method of repair is investigated which explores the experimental feasibility of using …