Me-Em Enewsbrief, March 2021, 2021 Michigan Technological University
Me-Em Enewsbrief, March 2021, Department Of Mechanical Engineering-Engineering Mechanics, Michigan Technological University
Department of Mechanical Engineering-Engineering Mechanics eNewsBrief
No abstract provided.
A Single-Stage Passive Vibration Isolation System For Scanning Tunneling Microscopy, 2021 California Polytechnic State University, San Luis Obispo
A Single-Stage Passive Vibration Isolation System For Scanning Tunneling Microscopy, Toan T. Le
Scanning Tunneling Microscopy (STM) uses quantum tunneling effect to study the surfaces of materials on an atomic scale. Since the probe of the microscope is on the order of nanometers away from the surface, the device is prone to noises due to vibrations from the surroundings. To minimize the random noises and floor vibrations, passive vibration isolation is a commonly used technique due to its low cost and simpler design compared to active vibration isolation, especially when the entire vibration isolation system (VIS) stays inside an Ultra High Vacuum (UHV) environment. This research aims to analyze and build a single-stage ...
Entertainment 721, 2021 The University of Akron
Entertainment 721, Mark Hendricks, Noah John, Jadon Vanyo, Chelsea Payne
Williams Honors College, Honors Research Projects
The goal of this project was to design a luxury, aesthetically pleasing entertainment system with a TV lift mechanism that could be remote controlled. The design would also include a cooling cabinet for gaming systems, a remote locking system, and additional storage. Using a morphological chart and weighted decision matrix for each subsystem key features were determined to be included in the design. Several performance benchmarks were determined to accomplish the team’s design. Almost every benchmark was successful in the build of the first prototype. Several heat calculations and FEA analyses were performed on the system to ensure the ...
Experimental Study Of Viscoelastic Fluid-Structure Interactions, 2020 University of Massachusetts Amherst
Experimental Study Of Viscoelastic Fluid-Structure Interactions, Anita Anup Dey
It is well known that when a flexible or flexibly-mounted structure is placed perpendicular to a Newtonian fluid flow, it can oscillate due to the shedding of vortices at high Reynolds numbers. Unlike Newtonian fluids, viscoelastic fluid flow can become unstable even at infinitesimal Reynolds numbers due to a purely elastic flow instability occurring at large Weissenberg numbers. This thesis focuses on exploring the mechanisms of viscoelastic fluid-structure interactions (VFSI) through experimental investigations on several different combinations of flexible and flexibly-mounted circular cylinders, micro and macro-scale cantilevered beams and viscoelastic fluids such as wormlike micelle solutions and polymer solutions.
An Improved Foam Modeling Technique And Its Application To Petroleum Drilling And Production Practice, 2020 Louisiana State University and Agricultural and Mechanical College
An Improved Foam Modeling Technique And Its Application To Petroleum Drilling And Production Practice, Yanfang Wang
LSU Doctoral Dissertations
Foam is one of the most common used multiphase fluid in Underbalanced Drilling (UBD) and Managed Pressure Drilling (MPD). Because of its low density, high capacity of lifting and carrying cuttings, low cost and compatibility with formations, foam has become more superior than the conventional drilling mud when depleted reservoir pressure, severe lost circulation, or unstable borehole are encountered. In general, the success of foam applications rely on the understanding of the fundamentals of foam rheology in downhole conditions.
Foam rheology has been studied for decades. Conventional foam rheological models such as Power Law, Bingham Plastic, Herschel-Bulkley to explain foam ...
Leveraging Biomimicry And Additive Manufacturing To Improve Load Transfer In Brittle Materials, 2020 University of Arkansas, Fayetteville
Leveraging Biomimicry And Additive Manufacturing To Improve Load Transfer In Brittle Materials, Ana Paula Bernardo
Theses and Dissertations
With the emergence of Additive Manufacturing (i.e., 3D printing) in construction, new strategically designed shapes can be created to improve load transfer through structural members and foundations. Cross-sections can be optimized to carry load using less material, or even using weaker constituent materials, like soils, which are cheap and abundant. The goal of this research is to investigate the benefits of using cellular patterns which leverage biomimicry in civil engineering applications, since nature has perfectly engineered materials and patterns which carry loads with the least amount of material possible. Most of the periodic cellular work to date has focused ...
An Investigation Into The Effects Of Fly Ash On Freeze-Thaw Durability Prediction, 2020 University of Arkansas, Fayetteville
An Investigation Into The Effects Of Fly Ash On Freeze-Thaw Durability Prediction, Yancy Schrader
Theses and Dissertations
Air is purposefully entrained into concrete primarily to improve resistance to freeze-thaw deterioration while saturated with water. Air entraining admixtures (AEAs) are chemical admixtures designed to entrain air into the concrete to provide adequate resistance to the effects of freezing and thawing. One of the challenges associated with air entrainment in concrete is the interaction of an AEA with supplementary cementitious materials present in the concrete, particularly fly ash. Fly ash is a by-product of the coal fired electrical generation industry, and often contains residual unburned carbon and other components that can increase the AEA demand of a particular concrete ...
Me-Em Enewsbrief, October-December 2020, 2020 Michigan Technological University
Me-Em Enewsbrief, October-December 2020, Department Of Mechanical Engineering-Engineering Mechanics, Michigan Technological University
Department of Mechanical Engineering-Engineering Mechanics eNewsBrief
No abstract provided.
Transformation Between Polar And Rectangular Coordinates Of Stiffness And Dampness Parameters In Hydrodynamic Journal Bearings, 2020 School of Mechanical Engineering, Hubei University of Arts and Science, Xiangyang 441053, China
Transformation Between Polar And Rectangular Coordinates Of Stiffness And Dampness Parameters In Hydrodynamic Journal Bearings, Zhuxin Tian, Yu Huang
The stiffness and dampness parameters of journal bearings are required in rectangular coordinates for analyzing the stability boundary and threshold speed of oil film bearings. On solving the Reynolds equation, the oil film force is always obtained in polar coordinates; thus, the stiffness and dampness parameters can be easily obtained in polar coordinates. Therefore, the transformation between the polar and rectangular coordinates of journal bearing stiffness and dampness parameters is discussed in this study.
A Finite Element Analysis (Fea) Approach To Simulate The Coefficient Of Friction Of A Brake System Starting From Material Friction Characterization, 2020 Brembo S.p.A., Stezzano (BG), Stezzano (BG) 24040, Italy
A Finite Element Analysis (Fea) Approach To Simulate The Coefficient Of Friction Of A Brake System Starting From Material Friction Characterization, Gabriele Riva, Francesco Varriale, Jens Wahlström
The coefficient of friction (COF) is one of the most important parameters to evaluate the performance of a brake system. To design proper brake systems, it is important to know the COF when estimating the brake force and resulting torque. It is challenging to simulate the COF since friction in disc brakes is a complex phenomenon that depends on several parameters such as sliding velocity, contact pressure, materials, and temperatures, etc. There is a lack of studies found in the literature focusing on simulation of the COF for a full brake system based on tribometer material characterization. The aim of ...
Grease Film Evolution In Rolling Elastohydrodynamic Lubrication Contacts, 2020 School of Mechanical and Automotive Engineering, Qingdao University of Technology, Qingdao 266250, China
Grease Film Evolution In Rolling Elastohydrodynamic Lubrication Contacts, Xinming Li, Feng Guo, Gerhard Poll, Yang Fei, Ping Yang
Although most rolling element bearings are grease lubricated, the underlying mechanisms of grease lubrication has not been fully explored. This study investigates grease film evolution with glass disc revolutions in rolling elastohydrodynamic lubrication (EHL) contacts. The evolution patterns of the grease films were highly related to the speed ranges and grease structures. The transference of thickener lumps, film thickness decay induced by starvation, and residual layer were recognized. The formation of an equilibrium film determined by the balance of lubricant loss and replenishment was analyzed. The primary mechanisms that dominate grease film formation in different lubricated contacts were clarified.
Tribological Behavior Of Ammonium-Based Protic Ionic Liquid As Lubricant Additive, 2020 Mechanical Engineering Department, Rochester Institute of Technology, New York 14623-5603, USA
Tribological Behavior Of Ammonium-Based Protic Ionic Liquid As Lubricant Additive, Hong Guo, Patricia Iglesias
In this study, the tribological behavior of an ammonium-based protic ionic liquid (PIL) as an additive in a base mineral oil (MO) is investigated on a steel-steel contact at room temperature and 100 °C. Tri-[bis(2-hydroxyethylammonium)] citrate (DCi) was synthesized in a simple and low-cost way, and the ionic structure of DCi was confirmed by proton nuclear magnetic resonance (1H NMR). The stability measurement of 1 wt% DCi to a MO was investigated, and the lubricating ability and anti-wear properties of DCi as an additive in MO were also examined using a custom-designed reciprocating ball-on-flat tribometer. Optical microscope ...
Influence Of Lubrication, Tool Steel Composition, And Topography On The High Temperature Tribological Behaviour Of Aluminium, 2020 Machine Elements, Luleå University of Technology, Luleå SE-97187, Sweden
Influence Of Lubrication, Tool Steel Composition, And Topography On The High Temperature Tribological Behaviour Of Aluminium, Justine Decrozant-Triquenaux, Leonardo Pelcastre, Braham Prakash, Jens Hardell
The use of high strength aluminium alloys, such as 6XXX and 7XXX series, is continuously increasing for automotive applications in view of their good strength-to-weight ratio. Their formability at room temperature is limited and they are thus often formed at high temperatures to enable production of complex geometries. Critical challenges during hot forming of aluminium are the occurrence of severe adhesion and material transfer onto the forming tools. This negatively affects the tool life and the quality of the produced parts. In general, the main mechanisms involved in the occurrence of material transfer of aluminium alloys at high temperature are ...
Modified Graphene As Novel Lubricating Additive With High Dispersion Stability In Oil, 2020 State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, China
Modified Graphene As Novel Lubricating Additive With High Dispersion Stability In Oil, Pu Wu, Xinchun Chen, Chenhui Zhang, Jiping Zhang, Jianbin Luo, Jiyang Zhang
Graphene is a promising material as a lubricant additive for reducing friction and wear. Here, a dispersing method which combines chemical modification of graphene by octadecylamine and dicyclohexylcarbodiimide with a kind of effective dispersant has been successfully developed to achieve the remarkable dispersion stability of graphene in base oil. The stable dispersion time of modified graphene (0.5 wt%) with dispersant (1 wt%) in PAO-6 could be up to about 120 days, which was the longest time reported so far. At the same time, the lubricant exhibits a significant improvement of tribological performance for a steel ball to plate tribo-system ...
Electroadhesion Between A Flat Touchscreen And The Human Finger With Randomly Self-Affine Fractal Surface, 2020 Department of Physics, University of Tehran, Tehran 14395-547, Iran Department of Physics, Alzahra University, Tehran 1993891167, Iran
Electroadhesion Between A Flat Touchscreen And The Human Finger With Randomly Self-Affine Fractal Surface, M. Feshanjerdi
In this study, the effects of finger roughness on the electrostatic potential, electrostatic field, and average effective squeezing pressure between a human finger and a touchscreen are calculated by the perturbation method. This theory is an extension of an earlier work by Persson. It is found that an additional potential <ϕ(2)> will appear between the solids when the roughness effect is considered in calculating the perturbation potential. This additional potential is still proportional to the distance u¯ from the bottom surface. Therefore, the effect of the roughness increases the effective potential <ϕ> between the two solids. As a result, the average electrostatic ...ϕ>ϕ(2)>
Multiscale Analysis Of Friction Behavior At Fretting Interfaces, 2020 State Key Laboratory of Mechanical Systems and Vibrations, Shanghai Jiao Tong University, Shanghai 200240, China
Multiscale Analysis Of Friction Behavior At Fretting Interfaces, Zhinan Zhang, Shuaihang Pan, Nian Yin, Bin Shen, Jie Song
Friction behavior at fretting interfaces is of fundamental interest in tribology and is important in material applications. However, friction has contact intervals, which can accurately determine the friction characteristics of a material; however, this has not been thoroughly investigated. Moreover, the fretting process with regard to different interfacial configurations have also not been systematically evaluated. To bridge these research gaps, molecular dynamics (MD) simulations on Al-Al, diamond-diamond, and diamond-silicon fretting interfaces were performed while considering bidirectional forces. This paper also proposes new energy theories, bonding principles, nanoscale friction laws, and wear rate analyses. With these models, semi-quantitative analyses of coefficient ...
Tribological And Anti-Corrosion Performance Of Epoxy Resin Composite Coatings Reinforced With Differently Sized Cubic Boron Nitride (Cbn) Particles, 2020 Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China University of Chinese Academy of Sciences, Beijing 100049, China
Tribological And Anti-Corrosion Performance Of Epoxy Resin Composite Coatings Reinforced With Differently Sized Cubic Boron Nitride (Cbn) Particles, Zhiping Huang, Wenjie Zhao, Wenchao Zhao, Xiaojing Ci, Wentao Li
A series of high solid content (30 wt%) epoxy resin (EP) composite coatings reinforced with differently sized cubic boron nitride (CBN) particles were fabricated successfully on 304L stainless steel. Polydopamine (PDA) was used to improve the dispersibility of CBN particles in EP. The structural and morphological features of the CBN particles and the composite coatings were characterized by Raman spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Moreover, a UMT-3 tribometer and surface profiler were used to investigate the tribological behaviors of the as-prepared composite coatings. Electrochemical impedance spectroscopy (EIS) and Tafel analysis were used to investigate the ...
A New Kind Of Resin-Based Wet Friction Material: Non-Woven Fabrics With Isotropic Fiber Networks As Preforms, 2020 State Key Laboratory of Solidification Processing, Shaanxi Province Key Laboratory of Fiber Reinforced Light Composite Materials, Northwestern Polytechnical University, Xi’an 710072, China
A New Kind Of Resin-Based Wet Friction Material: Non-Woven Fabrics With Isotropic Fiber Networks As Preforms, Yewei Fu, Le Zhou, Tao Yin, Zhongyao Luo, Hejin Li, Lehua Qi
As an alternative to short fibers, non-woven fabrics (NWFs) were made using different types of long fibers to optimize the performance of paper-based friction materials and their technology. In this investigation, the fillers and resin were impregnated into these NWFs to prepare three kinds of wet friction material. The tribological, mechanical, and thermal properties of the new wet friction material were studied. The results indicate that the dynamic friction coefficient of the new friction material is approximately 0.12 and the static friction coefficient is approximately 0.15; the better wear rate is 0.81334 × 10−14 m3·(N ...
Comparative Study On Corrosion Resistance And Lubrication Function Of Lithium Complex Grease And Polyurea Grease, 2020 Tribology Research Institute, School of Mechanical Engineering, Southwest Jiaotong University, Chengdu 610031, China
Comparative Study On Corrosion Resistance And Lubrication Function Of Lithium Complex Grease And Polyurea Grease, Guanlin Ren, Pengfei Zhang, Xiangyuan Ye, Wen Li, Xiaoqiang Fan, Minhao Zhu
In this study, lithium complex grease (LCG) and polyurea grease (PUG) were synthesized using mineral oil (500SN) and polyalphaolefin (PAO40) as base oil, adsorbed onto lithium complex soap and polyurea as thickeners, respectively. The effects of grease formulation (thickener and base oil with different amounts (80, 85, and 90 wt%) on the corrosion resistance and lubrication function were investigated in detail. The results have verified that the as-prepared greases have good anti-corrosion ability, ascribed to good salt-spray resistance and sealing function. Furthermore, the increase in the amount of base oil reduces the friction of the contact interface to some extent ...
Effects Of Magnetic Ionic Liquid As A Lubricant On The Friction And Wear Behavior Of A Steel-Steel Sliding Contact Under Elevated Temperatures, 2020 Engineering Research Center for Nanomaterials, Henan University, Kaifeng 475004, China
Effects Of Magnetic Ionic Liquid As A Lubricant On The Friction And Wear Behavior Of A Steel-Steel Sliding Contact Under Elevated Temperatures, Jiajia Jia, Guangbin Yang, Chunli Zhang, Shengmao Zhang, Yujuan Zhang, Pingyu Zhang
A magnetic ionic liquid (abridged as MIL) [C6mim]5[Dy(SCN)8] was prepared and used as the magnetic lubricant of a steel-steel sliding pair. The tribological properties of the as-prepared MIL were evaluated with a commercially obtained magnetic fluid lubricant (abridged as MF; the mixture of dioctyl sebacate and Fe3O4, denoted as DIOS-Fe3O4) as a control. The lubrication mechanisms of the two types of magnetic lubricants were discussed in relation to worn surface analyses by SEM-EDS, XPS, and profilometry, as well as measurement of the electric contact resistance of the rubbed ...