bluuebunny/crossref_metadata_2025 huggingface dataset:
Design Optimization of Driveshaft and Universal Joint Using Finite Element Technique
Authors: Rahman Mosfequr , Molina Gustavo , Salekeen Sirajus , Dungan Ana , Hyers Isaac , Griffin Daniel , Berman Alexander
Published: February 2017

Finite Element Analysis (FEA) has been performed on variety of a driveshaft and universal joints based on different shaft materials and shaft different operating angles. A driveshaft is particularly useful in applications such as taking of transferring torque from one piece of equipment to the other such as in vehicle of all kinds. A driveshaft transfers torque from the transmission to the rear end differential since these two pieces of equipment cannot be connected directly. The driveshaft has universal joints located on both ends of the shaft to allow for fluctuations in the angle of the transmission and rear differential. The driveshaft alone is composed of two parts, a female and male end, connected by a spline to allow changes in the length during operation. The driveshaft must be able to withstand the constant torque that is being applied throughout operation in order to increase safety for the operator and machine. Having a lower polar moment of inertia allows the driveshaft to turn with a lower torque value compared to a driveshaft with a higher moment of inertia. It is noted that driveshaft can be manufactured into a variety of lengths and diameters depending on the use and equipment it will be supporting. This paper describes a method of finite element implemented on variations of driveshaft and universal joints. Effect of material properties, geometry and operating angle of the driveshaft were considered for this numerical investigation. Five different materials such as structural steel, aluminum alloy, polyethylene, titanium, and carbon fiber with an outer diameter of 1.5 in of the driveshaft was used for this analysis. The effect of both metals and composite materials was observed.

Based on the analysis it was found that a 15° operating angle allowed for the longest life cycle of the driveshaft, while the carbon fiber composite presented the highest stress resistance and safety factor, approximately 6 GPa of yield tensile strength and a safety factor of 15. It was also found that titanium had an equivalent safety factor of 15. However, the tensile yield strength of titanium was much lower than that of its composite counterpart. All of the numerical experimentation was done using the Finite Element Analysis software ANSYS. Material properties for all materials were preset in the software except the composite carbon fiber whose properties were easily found from other research papers and experiments. Based on the data collected and the general assumptions that the most effective drive shaft is the one that lasts the longest. It can be concluded that a driveshaft made of carbon fiber operating at an angle of 15° presents the optimum driveshaft design.
Study on Forging Intelligent Production System for an Automotive Component
Authors: Sun Yu , Wu Kai , Cao Chunping
Published: February 2017

Crankshafts, connecting rods, gears and forks are basic components made by the forging machine. According to statistics data, more than 60% of the automotive components in weight are produced by forging, more than 80% of which are manufactured by hot forging. With the development of the automobile industry and the increase of market competition, the forging production of automotive components is becoming more complex, sophisticated and efficient. Moreover, in order to reduce the labor costs and improve the efficiency, flexibility, automation and intelligence of the forging equipment and process, research and development of the hot forging intelligent production system will be inevitable. Based on this background, an intelligent production system of a typical hot forging for automotive components is introduced in this paper. It includes the intelligent high precision hot die forging press, intelligent transport devices, the intelligent control system, the operation management system and intelligent interfaces. Moreover, it also can be linked into the smart factory of industrial 4.0. This intelligent system has been developed and been used for the production of the third generation hub bearing, which has shown that the production efficiency is improved and the labor costs are reduced.
Energy Consumption Modeling of a Heat Pump System for Combined Space Conditioning and Residential Water Heating in a Typical Household in Quito, Ecuador
Authors: Agila Gabriel , Soriano Guillermo
Published: February 2017

This research develops a detailed model for a Water to Water Heat Pump Water Heater (HPWH), operating for heating and cooling simultaneously, using two water storage tanks as thermal deposits. The primary function of the system is to produce useful heat for domestic hot water services according to the thermal requirements for an average household (two adults and one child) in the city of Quito, Ecuador. The purpose of the project is to analyze the technical and economic feasibility of implementing thermal storage and heat pump technology to provide efficient thermal services and reduce energy consumption; as well as environmental impacts associated with conventional systems for residential water heating. An energy simulation using TRNSYS 17 is carried to evaluate model operation for one year. The purpose of the simulation is to assess and quantifies the performance, energy consumption and potential savings of integrating heat pump systems with thermal energy storage technology, as well as determines the main parameter affecting the efficiency of the system.

Finally, a comparative analysis based on annual energy consumption for different ways to produce hot water is conducted. Five alternatives were examined: (1) electric storage water heater; (2) gas fired water heater; (3) solar water heater; (4) air source heat pump water heater; and (5) a heat pump water heater integrated with thermal storage.
Hierarchical Engineering Model of the Human Body
Authors: Karamchetty Somayajulu D.
Published: February 2017

Engineers and scientists are able to understand and analyze the behavior of complex engineering systems in a wide range of critical technologies through hierarchical modeling followed by simulation of the model operation. This process results in a high fidelity integrated model as each level in the hierarchy is modeled in sufficient detail.

The overall objective of this effort is to develop a sophisticated hierarchical model of the human body, followed by simulation of the model operation. In this initial research phase, the feasibility of the concept is explored and a framework for the model is described. A six-level model consisting of the whole body as a system, system of systems, organs, tissues, cells, and molecules is proposed and described. This paper explains that the human body is amenable to such hierarchical modeling and describes the benefits that can be achieved.

The systems in the body deal with numerous processes: electrical, chemical, biochemical, energy conversion, transportation, pumping, sensing, communications, and so on. Control volume models for the organs in the body capture the mass and energy balance and chemical reactions. Tissue can be represented similar to structural components made of various biomaterials. Cells can be represented as a manufacturing and maintenance workforce assisted by molecular reactions.

Following the representation of a healthy body, simulation runs by inserting faults and/or deficiencies in the operational parameters into the model could reveal the causes for specific diseases and illnesses. Such modeling and simulation will benefit medical, pharmaceutical, nutritional specialists, and engineers in designing, developing, and delivering products and services to enable humans to lead healthy lives.
Overview of the Oak Ridge National Laboratory Advanced Manufacturing Integrated Energy Demonstration Project: Case Study of Additive Manufacturing as a Tool to Enable Rapid Innovation in Integrated Energy Systems
Authors: Jackson Roderick , Curran Scott , Chambon Paul , Post Brian , Love Lonnie , Wagner Robert , Ozpineci Burak , Chinthavali Madhu , Starke Michael , Green Johney , Tryggestad Lucas , Lee Brian
Published: February 2017

Oak Ridge National Laboratory’s Additive Manufacturing Integrated Energy (AMIE) demonstration project leverages rapid innovation through additive manufacturing to connect a natural-gas-powered hybrid electric vehicle to a high-performance building designed to produce, consume, and store renewable energy. The AMIE demonstration project consists of a building and vehicle that were additively manufactured (3D-printed) using the laboratory’s big area additive manufacturing (BAAM) capabilities and an integrated energy system with smart controls that connects the two via wireless power transfer. The printed utility vehicle features a hybrid electric powertrain with onboard power generation from a natural gas fueled auxiliary power unit (APU). The APU extends vehicle range through a series hybrid powertrain configuration that recharges the vehicle’s lithium-ion energy storage system and acts as a mobile power generation system for the printed building. The development of the powertrain used for the printed range-extended electric vehicle was completed using a powertrain-in-the-loop development process and the vehicle prototype implementation was accelerated using BAAM. A flexible 3.2 kW solar photovoltaic system paired with electric vehicle batteries will provide renewable power generation and storage. Energy flows back and forth between the car and house using fast, efficient bidirectional wireless power transfer. The AMIE project marked the first demonstration of bidirectional level 2 charging through wireless power transfer. The accelerated creation and printing of the car and house will further demonstrate the program’s function as an applied science tool to get products to market more quickly than what currently is possible with traditional manufacturing. This paper presents a case study that summarizes the efforts and technical details for using the printed research platforms. This paper explores the focuses on printing of the vehicle, powertrain integration, and possibilities for vehicles providing power to buildings in different scenarios. The ability for BAAM to accelerate the prototype development for the integrated energy system process is explored. Details of how this was successfully accomplished in 9 months with more than 20 industry partners are discussed.
Design and Dynamic Characteristics of a Torsion Isolator With Negative Stiffness Structures
Authors: Liu Hui , Wang Xiaojie , Wang Weida , Xiang Changle
Published: February 2017

This paper proposes a torsion isolator with negative stiffness structures, which has low stiffness. The torsion isolator has been designed into disk structure, which is the installation position of the positive springs and negative stiffness structures. In this paper, the model of the torsion isolator is introduced firstly, and the nonlinear stiffness and torque are studied under different compression deformation of springs in negative stiffness structures. Then a two-degree-freedom equation of the torsional isolator is established and vibration transmissibility is obtained by using Harmonic Balance Method. Theoretical analysis results show that the isolator with negative stiffness structures has larger isolation frequency range than linear isolator. Finally, an initial experiment is completed. The experimental results show that the isolator has a good vibration isolation performance.
Identification of Key Parameters Affecting Energy Consumption of an Air Handling Unit
Authors: Goodman David , Chen Jie , Razban Ali , Li Jing
Published: February 2017

Air handling unit system (AHU) is one of the series of mechanical systems that regulate and circulate the air through the ducts inside the buildings. In a commercial setting, air handling units accounted for more than 50% of the total energy cost of the building in 2013. The energy efficiency of the system depends on multiple factors. The set points of discharge air temperature and supply air static pressure are important ones. ASHRAE Standard 90.1-2010 requires multi-zone HVAC systems to implement supply air temperature reset. Energy is wasted if the set points are set constant. However, the waste has never been quantified. The objectives of this study were to (1) develop and validate a mathematical model, which can be used to predict the system performance in response to various controls, specifically the set-point control strategies, and associated energy consumption, and (2) to recommend measures for optimizing the AHU performance by optimizing the setting schedules.

In this research, a gray box model was established to evaluate the performance of an AHU. Individual components were modeled using energy and mass balance governing equations that represent the inherent physical processes and interactions with other components. Engineering Equation Solver (EES) was selected for system simulation due to its capabilities of finding the solutions of a large set of complicated equations. The model was validated using two sets of sub hourly real time data. The model performance was evaluated employing Mean Absolute Percentage Error (MAPE) and Root Mean Square Deviation (RMSD). The model was used to create the baseline of energy consumption with constant set points and predict the energy savings using two different reset schedules.

The AHU, which serves the entire basement of a campus building on IUPUI campus, was used for this study. It normally has constant set points of discharge air temperature and supply air static pressure. The AHU was monitored using sensors. The data were filtered and transferred to a Building Automation system. Operation information and design specifications of the AHU were collected. Two reset schedules were investigated to determine the better control strategy to minimize energy consumption of the AHU. Discharge air temperature was reset based on return air temperature (RA-T) with a linear reset schedule from March 4 to March 7. Static pressure of the supply air was reset based on the widest open Variable Air Volume (VAV) box damper position from March 20 to March 23. Additionally, uncertainty propagation method was used to identify the dominant parameters affecting the energy consumption.

Results indicated that 17% energy savings was achieved using discharge air temperature reset while the energy consumption reduced by 7% using static pressure reset. The results also indicated that outside air temperature, supply airflow rate and return air temperature were the key parameters that impact the overall energy consumption.
Research on Influencing Factors for Proper Orthogonal Decomposition Basis Functions in a Hydrodynamic Retarder
Authors: Wei Wei , Han Xueyong , Yan Qingdong
Published: February 2017

This paper mainly investigates the factors influencing the Proper Orthogonal Decomposition (POD) basis functions created by the method of snapshots. The factors consist of the spitting of the snapshots, the sampling frequency of snapshots and the speed of the rotor. For this purpose, both the velocity and pressure fields on the surface between dual-rotor and stator of hydrodynamic retarder working in the full-filled conditions are treated as object to study. The factors are divided into the internal and external factors and discussed separately in the paper. The energy captured by the POD basis functions are used to weight the impact caused by the factors while the error of reconstruction by energetic POD basis functions is shown to analyze the effect of different factors quantitatively. Furthermore, the features of the POD basis functions created when the factors are different are shown separately for comparison. From the analysis of the results, it can be concluded that both the spiting of snapshots database and the frequency of sampling snapshots have a significant effect on POD basis functions while the features of POD basis functions are immune to the speed of the rotor.
Experiments on Quasi-Static and Dynamic Control of a PVDF Laminated Membrane-Like Mirror
Authors: Lu Yifan , Yue Honghao , Deng Zongquan , Tzou Hornsen
Published: February 2017

Due to their merits of low areal density, in-orbit deploying and low manufacturing cost properties, membrane-like deformable mirrors meet the ultra-lightweight and large aperture demand of space optical mirror systems well. Membrane-like mirrors has therefore become a hot spot in the field of space science research now. Surface of these in-orbit membrane-like structures are susceptible to external environment variation on account of their low stiffness and high flexibility properties. Once excited by external excitations, the membrane vibration endures and this would not only degrade its performance, but also lead to system or structural failures. So dynamic vibration control of the membrane-like mirror is indispensable. When the orbiting mirror passes from Earth’s shadow into sunlight, the surface temperature of the mirror changes and this will render membrane thermal distortion. Hence, quasi-static surface error adjustment of the mirror is also requisite. In this paper, a 0.2m diameter scaled-down Kapton membrane-like mirror is taken as the experiment subject. Polyvinylidene Fluoride (PVDF) patches are laminated on the non-reflective side of the mirror as in-plane actuators. High precision laser displacement sensors are used to measure the surface deviation of the mirror. A modal vibration control system based on the positive position feedback (PPF) algorithm and a quasi-static surface control system based on the proportional error feedback algorithm are established respectively. Several mirror control experiments are performed and the results indicate that the methods proposed could suppress the membrane vibration and alleviate the membrane thermal deformation effectively.
Principal Stress Model for Multi-Axial Fatigue of Preloaded Threaded Fasteners
Authors: Kazemi Amir , Nassar Sayed A. , Wu Zhijun
Published: February 2017

A principal stress-based high cycle fatigue (HCF) model is proposed for cyclic multiaxial stresses in threaded fasteners under tensile-shear loading. The proposed model uses the fastener principle stress amplitude in order to construct mean-stress adjusted S-N curves for multi-axial stresses. Experimental validation is provided using an MTS fatigue testing system, with a special fixture that would allow combined cyclic tensile-shear loading of the fastener at various angles relative to the axis of the MTS grip axis. Experimentally validated multiaxial fatigue model is compared to classical uniaxial S-N curves. Detailed discussion of the model results is provided.
Computational Analysis of Airfoil Merging and its Effect on Performance of Lift Based Vertical Axis Wind Turbine
Authors: Basavaraj Akshay
Published: February 2017

In regions of low wind speed, overcoming the starting torque of a Vertical Axis Wind Turbine (VAWT) becomes a challenge aspect. In order to overcome this adversity, careful selection of airfoils for the turbine blades becomes a priority. This paper tries to address the issue utilizing an approach wherein by observing the effect of merging two airfoils. Two airfoils which are of varying camber and thickness are merged and their aerodynamic characteristics are evaluated using the software XFOIL 6.96. For a variation in angle of attack from 0 to 90°, aerodynamic analysis is done in order to observe the behavior of one quarter of the entire VAWT cycle. An objective function is developed so as to observe the maximum possible torque generated by these airfoils at Reynolds number varying from 15,000–120,000. Due to change in the value of CL observed at Low Reynolds Number using commercial CFD softwares, multiple objective functions are utilized to observe the behavior over a range of Reynolds number. An experimental co-relation between the cut-in velocity and the lift-coefficient of the airfoils is developed in order to predict the cut-in velocity of the interpolated airfoils. The airfoils used for this paper are NACA 0012, NACA 0018, FX 66 S196, Clark Y (smooth), PT 40, SD 7032, A 18, SD 7080, SG 6043 and SG 6040.
Effect of Geometric and Material Properties on Thermoelastic Damping (TED) of 3D Hemispherical Inertial Resonator
Authors: Liu Jiewen , Jaekel Joshua , Ramdani Dharamdeo , Khan Nabeel , Ting David S.-K. , Ahamed Mohammed Jalal
Published: February 2017

High quality factor (Q-factor) is a crucial parameter for the development of precision inertial resonators. Q-factor indicates efficiency of a resonator in retaining its energy during oscillations. This paper explores the effects of different design parameters on Q-factor of a 3D hemispherical (wine-glass) inertial resonator. Thermo-elastic damping (TED) loss mechanisms in a 3D non-inverted wine-glass (hemispherical) shell resonator is systematically investigated and presented in this paper. We investigated TED loss resulting from the effects of hemisphere geometric parameters (such as thickness, height, and radius), mass imbalance, thickness non-uniformity, and edge defects. We used glassblowing to fabricate hemispherical 3D shell resonators. The results presented in this paper can facilitate selecting efficient geometric and material properties for achieving desired Q-factor in 3D inertial resonators. Enhancing the Q-factor in MEMS based 3D resonators can further enable the development of high precision resonators and gyroscopes.
Mechanical Properties of GF/CF Hybrid ABS Composite by DFFIM
Authors: Yuuki Hisakura , Kenichi Kitahara , Makoto Sugihara , Akihiko Imajo , Hiroyuki Hamada
Published: February 2017

GF reinforced polymer composites to improve the mechanical properties by increasing fiber content, but there is a limit. On the contrary, CF reinforced polymer composites are superior to the GF composites at a lower CF content in tensile and bending properties. However, CF is more expensive than GF. In this study, acrylonitrile butadiene styrene (ABS) was reinforced with single and hybrid reinforcing of glass fibers (GF) and carbon fibers (CF). The composites consisting of GF/ABS, CF/ABS and GF/CF/ABS were fabricated by direct fiber feeding injection molding (DFFIM). The reinforcing fiber was directly fed at the vent hole of the barrel in the DFFIM process. The effects of fiber Tex, fiber numbers and processing parameters on properties of the composites were investigated. Tensile, bending and Izod impact testing was conducted to compare mechanical properties of GF/ABS composites, CF/ABS composites and hybrid GF/CF/ABS composites. Morphology of the composites was observed by scanning electron microscopy. In addition, the cost advantage of each composite was compared with their mechanical properties. From the results, the addition of carbon fiber improved tensile, bending and impact properties of the hybrid composites. SEM photographs indicated that carbon fiber tended to agglomerate during the DFFIM process. The hybrid GF/CF/ABS composites presented an equivalent improvement in tensile and bending properties as compared to the CF/ABS composites. It can be noted that the low CF content was suitable for enhanced mechanical performances of the hybrid GF/CF/ABS composites. Therefore, the hybrid composites can be manufactured at a low cost as compared to the similar mechanical properties of the CF/ABS composites.
Effect of Tumor Variables and Sensor Design on the Measured Stiffness Distribution of Tumor-Embedded Tissues: A Numerical Study
Authors: Yang Yichao , Hao Zhili
Published: February 2017

This paper reports on a numerical study on how the measured stiffness distribution of a tumor-embedded tissue via a two-dimensional (2D) tactile sensor varies with the tumor variables (i.e., elasticity, size and depth) and the sensor design parameters. The sensor entails a polydimethylsiloxane (PDMS) microstructure embedded with a 3×3 sensing-plate/transducer array sitting on a Pyrex substrate. Pressing the sensor against a tissue region with a pre-defined indentation depth pattern, the tissue stiffness distribution is extracted from the measured slopes of the deflections of the 3×3 sensing-plate array versus the indentation depth. A finite element model (FEM) of the tissue-sensor interaction, which includes the Pyrex substrate, the microstructure, and a tumor-embedded tissue, is created using COMSOL Multiphysics. The tumor variables and the sensor design parameters are varied in the model to examine how the measured tissue stiffness distribution is affected by them. Based on the numerical results, the relation of the measured tissue stiffness distribution to the tumor variables and sensor design parameters is obtained, shedding insight on establishing a threshold on the stiffness contrast for tumor identification.
Experimental Study on Evacuation Process Considering Social Relation in a Tall Building
Authors: Ma Yaping , Li Lihua , Ding Ning , Zhang Hui , Chen Tao
Published: February 2017

Elevator evacuation has been considered in high-rise building evacuation in the world, especially in China. Elevator safety has been widely studied for this purpose and technical standards are also available in different countries. However, it is critical to understand human behaviors in elevator evacuation before elevators can be used in building evacuation. It is expected that social relation (family, friend, classmate, etc.) will play an important role on evacuation behaviors. However, researches are largely missing on social relation and its impacts on movement and behaviors of the evacuees. This paper aims to investigate the crowd evacuation considering social relation. An evacuation experiment is conducted in a 11-storey office building. Participants who take part in the experiment include individuals, families and lovers. Evacuation behaviors especially decision-making as well as important factors affecting evacuees’ choices are discussed. Movement characteristics of evacuees in the stair are also analyzed. It is concluded that family members will take actions, such as take elevators or stairs, together. Females and evacuees in poor condition prefer to take the elevator during evacuation. Many pairs or small groups may be formed owing to social relations. The groups take more time to make decision. The members in small groups may block the traffic and slow down the speed of the crowd. Evacuation efficiency changes greatly considering small group behaviors and social relations. Experimental results are helpful for determining the effective rules and regulations in elevator evacuation in high-rise buildings.
Investigation on Mechanical Behavior of Clinched Joint Using Extensible and Flat Die Techniques
Authors: Han Xiaolan , Zhao Shengdun
Published: February 2017

Lightweight materials, manufacturing technology and the car body structure optimization are the three main approaches to achieve the lightweight constructions. The lightweight materials, such as aluminum or magnesium alloys, are widely utilized in the automotive industry for the weight reduction. Mechanical clinching is used to connect the lightweight materials. In this study, the sheets were joined by the extensible die clinching and flat-clinching. The tensile strength and shear strength of the aluminum alloy 5052 were investigated by the two different tools. Compared with the extensible die clinching, both the tensile strength and shear strength of the clinched joint produced with flat-clinching is higher. And the tensile strength of the clinched joint is up to 54% higher than that of the extensible die clinching.
Design of an Innovative Solar Updraft Aeration System for Fish Ponds in the Developing World Using Thermofluidic Computational Modelling
Authors: Ebrahimi Khabbazi Ali , Sur Shakya , Mahmoud Ahmed , Pavlov Elan , Bilton Amy M.
Published: February 2017

This paper introduces an innovative design concept for a low-cost solar-thermal aeration system for fish ponds which is amenable to implementation in resource-constrained settings. In its most basic form, the system consists of a metallic solar thermal collector and a heat transfer column (referred to as conduction element in this paper), which induces convective circulation by dissipating heat to the cooler, deeper layers of the pond. As a result of the circulation, oxygen generated by phytoplankton at the top of the pond is distributed throughout the water column, preventing oxygen losses to the atmosphere due to surface supersaturation and increasing the overall dissolved oxygen (DO) content in the pond. This paper presents a design study to evaluate different system configurations. Thermofluidic numerical models were implemented to systematically analyze and compare the mass flow rate through the draft tube induced by convection. Furthermore, parametric studies were performed to evaluate the effect of the insulation patch length and the aluminum plate thickness on the overall performance of the device (i.e. the induced mass flow rate through the draft tube). It was found that the two-fin configuration with split conduction elements was superior to the central rod design in terms of performance. In addition, it was found that depending on the insulation patch length, the induced mass flow rates can be increased up to 5 times. The results from the computational models indicate that the device can induce the convective circulation in order to improve the DO content at deep levels of the ponds and has potential to improve aquaculture productivity in resource-constrained settings. The results from this study will be used to configure systems for future field evaluations that will be performed in fish ponds in Bangladesh.
Influence of Cutting Condition on Surface Roughness in Single Point Diamond Turning of Zr-Based Bulk Metallic Glass
Authors: Sakata Shu , Hayashi Akio , Terajima Takeshi , Nakao Yohichi
Published: February 2017

Bulk metallic glass (BMG) is an amorphous alloy. Thus, it does not have anisotropy and material defect due to its irregular atomic configuration. In addition, it has excellent mechanical properties. For these reasons, the BMG is expected to be substitute materials in various fields. Until now, a number of studies focusing on precise forming have been carried out. However, if the part geometries are complex, controls of the temperature and wettability are difficult. Therefore, single point diamond cutting of the BMG is needed to produce fine surfaces. However, only a few studies on the single point diamond cutting for the BMG have been reported. Thus, appropriate single point diamond cutting technique of the BMG is not established yet.

Therefore, single point diamond turning of Zr-based bulk metallic glass was conducted. In the paper, the influences of the depth of cut, feed rate and cutting atmosphere on the chip generation and finished surfaces are investigated. Visualization of the cutting chip generation with different cutting conditions was made with a high-speed camera. The influences of the cutting conditions on the finished surface are considered based on the observation and the measurement of chip and machined surfaces.
Infinitely Variable Process Control for Distributed Generation
Authors: Miller A. Keith
Published: February 2017

The global trend to power industrial operations using local fuel sources continues, rather than relying so heavily on electrical power from large, centralized generating plants. Using a local fuel source has come to be termed “distributed generation”, implying that electrical power is generated locally and then used to power the relevant on-site industrial processes. This paper presents an alternative to distributed generation, where prime movers, powered by a local fuel source, are coupled directly to the equipment of the industrial processes using Infinitely Variable Transmissions (IVTs). The argument is advanced that direct drive, where the load is managed by an IVT, has the potential to be more efficient than many current distributed generation systems. The characteristics of an IVT designed by VeriTran Inc. are given, and the effort to demonstrate the advantages of IVT controlled direct drive in the petroleum production industry is discussed.
Arctic Exposure Studies of Vinyl Foams for Sandwich Composites
Authors: Garcia Carlos D. , Avila Raudel O. , Prabhakar Pavana
Published: February 2017

Sea water and cold temperatures appear to have an adverse effect on naval materials resulting in the degradation of their mechanical properties. In this paper, the effects of sea water absorption and arctic conditioning have on the mechanical properties of divinycell foams are discussed. For this study, moisture absorption was periodically measured until weight gain equilibrium or saturation was reached for samples submerged in sea water and deionized water. Diffusivities and saturation values were obtained from moisture uptake curves. It was observed that the moisture content was higher for the vinyl foam samples submerged in deionized water compared to the samples submerged in synthetic sea water. Diffusivities were 9.227E-06 mm2sec and 1.390E-05 mm2sec for deionized water and sea water conditioning, respectively. Flexural and compression tests were then conducted on conditioned samples to compare their response against non-exposed samples. Experimental findings showed degradation in the flexural modulus and the compressive modulus for saturated wet samples and arctic-dry samples. This occurrence can be observed in both tests with more prominent reduction in its flexural modulus for arctic-dry samples and in compression for submerged in deionized water samples. Such a reduction is attributed to the degradation caused by the water, both deionized water and sea water, in the form of surface damage to specimens.
Stress Corrosion Cracking in Generic Aluminum Foil Under 3.5% NaCl Solution
Authors: Garcia Eduardo , Stewart Calvin M.
Published: February 2017

Recently, there has been an interest in aluminum alloys by many industrial areas as an environmentally-friendly material reducing environment pollution. Now, especially for maritime industries aluminum alloys are in the spotlight for ship construction instead of fiber reinforced plastics (FRP) or even stainless steel. Aluminum alloy ships are fast, lightweight, and exhibit a great load capacity when compared to traditional steel hulls. The Navy’s number one problem is maintenance due to corrosion impact. Annual combined costs of corrosion for army ground vehicles and navy ships range around $6.14B/year.

Corrosion impacts the readiness of most Navy systems and is a major factor contributor to life cycle cost. Hence the vision for corrosion technologies is to develop and implement corrosion control and prevention technologies to minimize the impact of material deterioration and maintenance costs. Stress corrosion cracking (SCC) and environment-induced cracking (EIC) has been extensively investigated using various methods to improve performance, designs, and service life for these structures. Present interested research areas are advanced smart coatings technologies for corrosion control and prevention of its effects under sea water and marine environments. With the rapid development of modern technology, foil metals have found applications in a variety of areas. The mechanical behavior of these materials may be different from that of bulk materials due to size effects. Therefore, models and conclusions for bulk characterization might not be applicable when analyzing foil materials. The purpose of this experiment is to describe and examine the susceptibility of aluminum alloy foil to stress corrosion cracking under 3.5% w.t NaCl solution. Mechanical properties of aluminum specimens were investigated using slow strain rate tests of 0.001 mm/min under load control while inside an environmental chamber at a flow rate of 150 ml/min. Smooth specimen samples with thickness of 0.0508 mm were subjected to monotonic tensile tests until fracture in ambient air and under corrosive solution environment. Scanning electron microscopy (SEM) was used to analyze stress corrosion cracking and crack propagation observing the different microstructural and intergranular fracture deformations. A digital microscope camera was used to observe and perform an analysis on the corroded specimen surface. A comparison of stress, strain, and time results of fracture between air and 3.5% NaCl solution at room temperature were calculated to demonstrate the susceptibility of the aluminum material to SCC. Test standards regarding stress corrosion cracking in metal foils are still limited.
Identification of Non-Linear Damping of Nuclear Reactor Components in Case of One-to-One Internal Resonance
Authors: Delannoy Joachim , Amabili Marco , Matthews Brett , Painter Brian , Karazis Kostas
Published: February 2017

In Pressurized Water Reactors (PWR) assemblies are exposed to challenging thermal, mechanical, and irradiation loads during operation. Global core and local fuel assembly flow fields coupled with seismic excitation result in fuel assembly and fuel rod vibrations. The fact that vibrations may become excessive in certain conditions has consequences on operational safety margins in fuel assemblies designs.

In order to understand how the fuel assembly responds dynamically to an external excitation, it is important to identify the main characteristics of the structures. Among them, the fuel assembly system damping is a fundamental parameter that is usually identified by a number of experiments involving fluid-structure interaction. Recent studies have shown that the damping ratio increases with the excitation force when the structure is entering large-amplitude vibrations, in which case the geometric non-linearities have to be taken into account.

The present paper presents an advanced identification procedure developed to identify the system characteristics from experimental non-linear response curves obtained from forced vibration tests, accounting for fluid-structure interaction, at different excitation levels. Furthermore, the numerical tool developed in this analysis is capable of working with systems presenting one-to-one internal resonance, i.e. systems with symmetry such as circular tubes and circular cylindrical shells. The method relies on a harmonic decomposition of the displacement to cope with the data usually available by vibration measurements.
Parameter Matching and Optimization of a Series Hybrid Electric Vehicle Powertrain System
Authors: Borthakur Swagata , Subramanian Shankar C.
Published: February 2017

The gradual decline of oil reserves and the increasing demand for energy have resulted in automotive manufacturers developing new environmentally friendly vehicles such as electric and hybrid vehicles. Selection of the correct hybrid configuration for a given driving condition is very important since it affects the performance of the vehicle and its fuel economy. This paper focuses on a detailed parametric analysis of a Series Hybrid Electric vehicle (SHEV). The objective of this paper was to develop a SHEV powertrain by initial parameter matching and component sizing, followed by its optimization for given design constraints. This involved study and calculation of components power specifications based on vehicle dynamics. Initial parameterization was followed by optimization to meet the design objective. The simulation of the optimized SHEV was done in the software ADVISOR for an Indian driving cycle (IDC). Based on the simulation results, an optimum range of the powertrain components was established.
Experiments and Simulations in Travelling Wave and Non-Stationary Nonlinear Vibrations of Circular Cylindrical Shells
Authors: Amabili Marco , Balasubramanian Prabakaran , Ferrari Giovanni
Published: February 2017

The nonlinear vibrations of a water-filled circular cylindrical shell subjected to radial harmonic excitation in the spectral neighborhood of the lowest resonances are investigated numerically and experimentally by using a seamless aluminum sample. The experimental boundary conditions are close to a simply supported circular cylindrical shell. Modal analysis reveals the presence of predominantly radial driven and companion modes in the low frequency range, implying the existence of a traveling wave phenomenon in the nonlinear field. Experimental studies previously carried out on cylindrical shells did not permit the complete identification of the characteristic traveling wave response and of its non-stationary nature. The added mass of the internal quiescent, incompressible and inviscid fluid results in an increase of the weakly softening behavior of the shell, as expected. The minimization of the added mass due to the excitation system and the negligible entity of the geometric imperfections of the shell allow the appearance of an exact one-to-one internal resonance between driven and companion modes. This internal resonance gives rise to a travelling wave response around the shell circumference and non-stationary, quasi-periodic vibrations, which are experimentally verified by means of stepped-sine testing with feedback control of the excitation amplitude. The same phenomenon is observed in the nonlinear response obtained numerically. The traveling wave is measured by means of state-of-the-art laser Doppler vibrometry applied to multiple points on the structure simultaneously. Previous studies present in literature did not show if this vibration can be chaotic for relatively small vibration amplitudes. Chaos is here observed in the frequency region where the travelling wave response is present for vibrations amplitudes smaller than the thickness of the shell. The relevant nonlinear reduced order model of the shell is based on the Novozhilov nonlinear shell theory retaining in-plane inertia and on an expansion of the displacements in terms of a properly chosen base of linear modes. An energy approach is used to obtain the nonlinear equations of motion, which are numerically studied (i) by using a code based on arc-length continuation and collocation method that allows bifurcation analysis in case of stationary vibrations, (ii) by a continuation code based on direct integration and Poincaré maps, which also evaluates the maximum Lyapunov exponent in case of non-stationary vibrations. The comparison of experimental and numerical results is particularly satisfactory throughout the various excitation amplitude levels considered. The two methods concur in describing the progressive development of the companion mode into a fully developed traveling wave and the subsequent appearance of quasi-periodic and eventually chaotic vibrations.
Development of a New Dynamic Modulus Predictive Model Based on Binder Viscosity for the Superpave Mixtures of New Mexico
Authors: Rahman A. S. M. Asifur , Tarefder Rafiqul A.
Published: February 2017

The newly developed mechanistic-empirical pavement design method uses the dynamic modulus as one of the crucial input parameters for the asphalt pavement to be designed or analyzed. This study proposes a new regression-based predictive model to estimate dynamic modulus of asphalt concrete from the viscosity of the asphalt binder used in the asphalt-aggregate mixture. Other parameters related to the aggregate gradation, such as, fineness modulus, and uniformity coefficient and the parameters related to the mixture volumetric are also incorporated in this model. A total of 21 asphalt concrete mixtures with asphalt binders having different performance grades and Superpave gradations were collected from different mixing plants and paving sites at various regions of New Mexico. The collected mixtures were then compacted, cored and sawed to cylindrical specimens. The asphalt concrete specimens were then tested for dynamic modulus at different temperatures and loading frequencies. The time-temperature superposition principle was then applied to develop dynamic modulus mastercurves at 70 °F (21.1 °C) reference temperature. The mastercurves were then fitted by the sigmoid function. The parameters of the sigmoid function were then correlated to the physical attributes of the asphalt concrete samples. Finally, a predictive model is developed to estimate the dynamic modulus of the AC mixtures typically used in New Mexico. Statistical evaluation showed that a fairly accurate estimation of dynamic modulus can be found by using this new dynamic modulus predictive model.
Design and Performance of Novel Low-Profile Heat Sinks Created Through Additive Manufacturing
Authors: KC Pratik , Shrestha Sangeet , Radadia Adarsh , Weiss Leland , Moore Arden
Published: February 2017

Traditional thermal management techniques such as air-cooled plate- and pin-fin heat sinks are today being pushed to their limits by the increasing power densities of computing hardware (power supplies, controllers, processors, and integrated circuits). In comparison, direct immersion cooling within an alternative cooling medium such as commercial dielectric fluids offers the ability to handle high power densities while also accommodating tighter printed circuit board spacing. Together, these attributes are critical to facilitating higher computing densities. However, this type of high density setup also requires that any heat sink present be low profile so as to not obstruct adjacent printed circuit boards. Such a stringent limit on heat sink height can make achieving cooling targets challenging with existing designs.

In this work, the performance of several low profile (height less than 6 mm) heat sinks of varying design are evaluated within a carefully controlled direct immersion cooling environment. Commercial copper heat sinks fabricated through conventional manufacturing (CM) approaches serve as baselines for these performance tests. These same heat sink designs are also replicated via additive manufacturing (AM) utilizing a conductive, carbon-filled printable polylactic acid (PLA) composite material. The performance of these AM heat sinks are then compared to the CM heat sinks, with special emphasis on differences in thermal conductivity between the constituent materials. Finally, novel bio-inspired heat sink designs are developed which would be difficult or impossible to achieve using CM approaches. The most promising of these designs were then created using AM and their performance evaluated for comparison. The overall goal of this is to ascertain whether the design and fabrication flexibility offered by AM can facilitate low profile heat sink designs that can meet or exceed the performance of conventional heat sinks even with perceived deficiencies in material properties for AM parts.

Experiments were carried out within Novec 7100 dielectric fluid for single-phase natural convection scenarios as well as two-phase subcooled boiling conditions at atmospheric pressure. A custom test rig was constructed consisting of mirror-polished stainless steel plates and polycarbonate viewing ports to allow visual access. A rotating sample stage allows for data to be obtained at varying heat sink orientation angles from 0° to 90°. For two-phase experiments, multi-angle video capture allows for analysis of the two-phase dynamics occurring at the heat sink samples to be visualized and temporally linked to the associated temperature and heat flux data.