bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical Investigation of Two-Phase Flow in 45 Degrees “Y” Junctions
Authors: Chacon Carlos , Moreno Carlos , Arbej Miguel , Asuaje Miguel
Published: March 2016

Frequently, Two-phase flow occurs in petroleum industry. It takes place on production and transportation of oil and natural gas. Initially, the most common patterns for vertical flow are Bubble, Slug, Churn and Annular Flow. Then, for horizontal flow, the most common patterns are Stratified Smooth, Stratified Wavy, Elongated Bubble, Slug, Annular, Wavy Annular and Dispersed Bubble Flow. It is also known that after separation, each fluid is carried through pipes, so oil is moved long distances. However, as it is known, the oil energy diminishes on the way. For that reason, it is needed a pumping station for keeping the oil flow energy high for proper movement. Additionally, that fluid is transported through a network, so fittings are present, like elbows, “T” and “Y” junctions, and others. As known, on a piping network, the losses can be classified in two groups: large and localized. The former consists on losses due to wall roughness-fluid interaction. The latter is related with fittings. This study is focused on 45° “Y” junctions. The main purpose of this study is to simulate the fluid flow on a 45° “Y” junction, using a 0.1143 m diameter 2 m length pipe, in which a 0.0603 m diameter 1 m length pipe confluences, using oil-gas as the working fluid, considering Dispersed Bubble Pattern. It can be attributed a “K” flow loss coefficient for each path, from each entry to the exit of the junction. For the Two-Phase Flow, it was supposed a horizontal Dispersed Bubble Pattern, which takes place at very high liquid flow rates. So the liquid phase is the continuous phase, in which the gas phase is dispersed as discrete bubbles. Particularly three API Grades were considered for the oil, corresponding to three main types of continuous phase. For the numerical model, it was generated several non-structured grids for validation, using water as a fluid. Then the simulations were carried out, using non-homogenous model, with oil and gas, changing the gas void fraction, and the superficial velocities for gas and liquid. A commercial package was used for numerical calculations. It was encountered that changing the value of the referred variables, in some cases the exit pressure of the “Y” junction diminishes. For validation of the results, a literature model was used for comparing both “K” loss coefficients: numerically and from the bibliography. It is important to highlight that these results, permit to analyze a way of diminishing the fluid energy losses in a Two-Phase oil-gas piping network, particularly in 45° “Y” junctions which represents economically saving.
Isogeometric Analysis of 3D Dynamic Thermo-Mechanical Phase-Field Model for Cubic-to-Tetragonal Phase Transformations in Shape Memory Alloys
Authors: Dhote Rakesh , Behdinan Kamran
Published: March 2016

In this paper, we study the dynamic thermo-mechanical behaviors of 3D shape memory alloy (SMA) nanostructures using the phase-field (PF) model. The PF model is based on the Ginzburg-Landau theory and requires a non-convex free energy function for an adequate description of the cubic-to-tetragonal martensitic phase transformations. We have developed a model that includes domain walls, treated as a diffuse interface, which leads to a fourth-order differential equation in a strain-based order parameter PF model. Arising numerical challenges have been overcome based on an isogeometric analysis (IGA) framework. Microstructure morphology evolution and consequent thermo-mechanical properties have been studied on SMA nanostructures of different geometries. The numerical results are in agreement with experimental observations. The developed coupled dynamic model has provided a better understanding of underlying microstructures and behaviors, which can be used for development of better SMA-based devices.
Liquid Water Interactions With PEFC Gas-Diffusion Layers: The Effect of Vibration
Authors: Santamaria Anthony D. , Haydu Jonathan , Senft Dylan , Riofrio Jose
Published: March 2016

Efficient removal of liquid-water from gas-diffusion layer (GDL) media in polymer-electrolyte fuel cells (PEFC) is critical to achieving reliable, high power operation. Studies have shown that PEFC systems exposed to vibration suffer from performance loss; however, fundamental understanding as to why is lacking. This work investigates vibrations ranging from 1–100 Hz and their effect on wetting behavior as well as liquid adhesion to the GDL surfaces. Vibrations are found to redistribute water in a way that raises its barrier to removal. An increased frequency reduced droplet contact area and height while expanding the wetting diameter. Moreover, while vibrations did not change the adhesion force, the increased wetting diameter resulted in a larger net force required to achieve droplet detachment.
Predicting Phonon Thermal Transport in Two-Dimensional Graphene-Boron Nitride Superlattices at the Short-Period Limit
Authors: da Silva Carlos , Saiz Fernan , Romero David A. , Amon Cristina H.
Published: March 2016

Two-dimensional superlattices are promising alternatives to traditional semiconductors for manufacturing power-dissipating devices with enhanced thermal and electronic properties. The goal of this work is to investigate the influence of the superlattice secondary periodicity and atomic interface orientation on the phonon properties and thermal conductivity of two-dimensional superlattices of graphene and boron nitride. We have employed harmonic lattice dynamics to predict the phonon group velocities and specific heats, and molecular dynamics to extract the relaxation times from normal mode analysis in the frequency domain. Density functional perturbation theory is applied to validate the phonon dispersion curves. The Boltzmann transport equation under single relaxation time approximation is then used to predict the thermal conductivities of the superlattices in the zigzag and armchair orientations with periodicities between one and five. Our results showed that the thermal conductivities increased by 15.68% when reducing the superlattice period from two to one. In addition, thermal conductivities parallel to the interface increase by 20.15% when switching the orientation from armchair to zigzag.
Gear Based Quasi-Continuous Variable Transmission for Wind Turbines
Authors: Hernandez Krista , Wilson Dania , Ressel Kyle , Nwoke Justus , Soto Martin , Azzouz M. Salim
Published: March 2016

Over the past decade wind turbines have been proven to be a competitive contender to produce cheap electricity. Their output electrical power went from few dozens of watts to several megawatts, and this trend is continuing to increase as they become larger in size. Most of these wind turbines are typically regulated through a set of controls acting on the electricity generator workload. These controls are achieved through the use of power electronics controlling the electrical load on the generator for variable speed wind turbine. This paper explores the possibility of implementing an alternative control system in variable wind speed turbines using a special gearbox with a high number of close consecutive discrete gear ratios. The proposed gear based Quasi-Continuous Variable Transmission, called QCVT, allows a variable speed at the input shaft and delivers a quasi-constant speed at the output shaft of the gearbox. The system consists of a special drivetrain assembly of spur gears run and controlled automatically through a set of clutch power shifters. The clutches are used to shift a set of compound gears, thus modifying the drivetrain total gear ratio. The designed system can produce up to 625 gear ratios and acts as a quasi-continuously variable transmission between the wind turbine hub and the electricity generator which requires a constant entry speed delivering a frequency of 60 Hz. The gearing transmission system has been designed using the SolidWorks CAD software for modeling and simulation and the gearing design theory has been used to dimension the special drivetrain assembly of spur gears. The kinematic gearing theory has been used to establish the multitude of close consecutive discrete gearing ratios of the transmission system. A wind driven rotor model for the wind turbine power coefficient has been used to determine the power absorbed by the wind turbine from the blowing wind and the power delivered to the electricity generator. The wind turbine torque generated by the wind and the torque produced at the electricity generator have also been determined using the multitude of gear ratios of the designed drivetrain. A new control law is established to keep the wind turbine generator running at a quasi-constant speed while producing maximum power. Considering the QCVT with its numerous close and consecutive gear ratios as the main torque regulator, the wind turbine system is expected to deliver the right needed torque for a specified electrical load. A set of results featuring how the electricity generator power and torque can be controlled by shifting the ratios of drivetrain transmissions are delivered. A particular emphasis is put on maximizing the generator delivered power using controlled gear ratios while the speed of the wind is changing. A small scale prototype of the QCVT powertrain transmission has been designed and built for concept demonstration and testing purposes.
Thermoacoustic Oscillations of Jet-A Fuel in Parallel Heated Flowpaths
Authors: Hunt Steven A.
Published: March 2016

Pressure oscillations in supercritical Jet-A fuel flowing through four parallel, heated tubes connected to common manifolds have been observed in this study. Tests were performed with fuel inlet temperatures ranging from 200°F to 700°F, and fuel pressures ranging from 360–700 psi. Total fuel flow rate ranged from 7–37 lb/hr. Tubes were heated by blowing 850–870°F nitrogen over them. Acoustic-mode oscillations, typically ranging from 300–350 Hz, occurred only when a single tube was heated at a time. Pressure oscillation amplitudes ranged from 0.1–1.0 psi. Tube inlet and outlet pressure waveforms were separated by a phase lag that was a function of the manifold cross-passage diameter.
Influence of Wheels on Frontal Crash Response of Small Lightweight Electric Vehicle
Authors: Zhang SongAn , Zhou Qing , Xia Yong
Published: March 2016

For vehicle frontal crash, the front wheels may affect impact load transfer and load path, and to some extent, the tire deformation may contribute to crash energy absorption. The effects would be especially prominent when it comes to the cases of micro car, offset crash and electric car. For a micro or small car, the front compartment space is small and the wheels are relatively large, and so the wheel’s role on transferring impact load to the A-pillar and the rocker is more significant and the energy absorbed by the tire deformation contributes to a relatively large portion. Moreover, in the case of an offset or small overlap collision, the wheel impacted is apparently engaged at a deeper level than that in full frontal crash. For an electric car when its electric motor is positioned in the rear of the car, the front compartment does not have space-taking engine and so the structural deformation and space use are more affected by the wheels. In this paper, by finite element simulations using a small lightweight electric vehicle (SLEV) model, the above-mentioned aspects are studied. The model has no complex components, and therefore is suitable for parametric study. The influence of the front wheels on the impact load transfer and the energy absorbed by the tire deformation are analyzed. Also front crash results of SLEV are compared with Yaris to show how front wheels affect load path in crash. The results show that the influence of wheels on frontal crash response of small lightweight electric vehicles should not be ignored and should be an integral part of crash safety design.
Advantage of Elliptical Confidence Limit Method for Bolted Joint Tightening Reliability
Authors: Hareyama Soichi , Manabe Ken-ichi
Published: March 2016

The calibrated wrench method is often used for tightening. When tightening bolted joints, it is important to apply high initial axial tension. However, since the axial tension is indirectly applied in this method, it varies and is widely distributed in the case of tightening carried out in the production line of a factory, for example. However, the calibrated wrench method is still widely used because of the simple tool used and easy standardization. Conventionally, this type of distribution has been considered to lie within a rhombus. In our previous paper, we analyzed and discussed the case when the distribution of the tightening torque and the equivalent stress of the bolted joint are considered to be independent random variables; in this case, the distribution becomes elliptical. Using this feature, a higher target tightening torque can be set than before. Finally, we established a procedure for the analysis and calculation of the optimum tightening torque for bolted joints. To ensure sufficient long-term tightening reliability to prevent breakage and loosening, a high initial axial tension and high equivalent stress can be realized using this proposed method. In this study, we analyze and discuss the case of differences in the tightening work condition (process control capability) and the tightening design condition. The tightening work coefficient a depends on the management state, the tightening working posture, and the process control capability of a tool or shop floor at a production site. According to the results of our trial calculation in Appendix A, the improvement ratio of the proposed target tightening torque is approximately 8.3% compared with the conventional method for dry friction and approximately 7.5% in the case of oily friction. Furthermore, in bolted joint tightening design, the tightening conditions under which the design conditions are satisfied are derived analytically. For the tightening design conditions of (1) a minimum axial stress of at least 50% at the yield point, and (2) an equivalent stress of 70% to 90% at the yield point, both the conventional and proposed areas of the confidence limit are obtained by precise analysis. Although the permitted limit of the tightening design condition cannot be realized by the conventional method, it can be realized by the proposed elliptical confidence limit method. Finally, we establish a method for maintaining the tightening reliability that involves applying high axial tension by increasing the target design tightening torque using the elliptical confidence limit.
Energy Expended in Robotic Deburring of Circular Components Using a SCARA Robot
Authors: Subhashini P. V. S. , Raju N. V. S. , Venkata Rao Ganapathiraju
Published: March 2016

It is well known that in mechanical engineering production systems, an estimated 15–30% of the manufacturing cost is towards deburring operations. While small components may be deburred using one of the many technologies available, larger components like castings have to be deburred manually or in recent times with assistance from robots. In fact, most of the present mass production systems aim towards automation and robotics for carrying out these operations. At present, substantial research effort is being spent towards robotic deburring. The major issue with robotic deburring is that the tool path gets affected in view of the interaction of cutting forces between the work piece and robot.

The objective of present research is to carry out multidirectional investigations on robotic deburring using a SCARA robot, the application being confined mostly to the deburring of circular components. It is well known that SCARA (selective Compliant articulated Robot Arm) is a robotic manipulator with four degrees of freedom (3 rotary and 1 prismatic) and is preferred where speed, high precision and accuracy is required.

In this work investigations on SCARA robot are carried out for different sized component which is positioned at different distances with respect to the base which leads to present a solution to component placement with in the workspace (solvability analysis) and also presents the placement position of a deburring component with minimum joint torques. A brief discussion on simulation of SCARA robot with force feedback control is presented, since this plays a major role in the maintenance of the path in the presence of varying cutting forces, and also presented kinematic and dynamic analysis of a SCARA robot for deburring of rectangular paths.

The overall kinematic and dynamic analyses of the SCARA robot with different positional configurations of the workpieces in the workspace enables the energy to be computed for assessing the most desirable state for deburring which consumes the least energy. This data thus obtained enables a comparison and pseudo-optimize the best configuration for the entire deburring operation. Although the methodology is at present confined mostly to circular paths, similar analyses can be carried out for rectangular path deburring (similar to those on engine cylinder heads) and oblong and elliptical profiles which are commonly found in many engineering components.
A Case Study: Design of an Automotive Seat Backrest by Carbon Fiber Reinforced Plastics
Authors: Zhang Haizhu , Sun Lingyu , Leng Dingxin , Huang Bincheng , Wang Ligang
Published: March 2016

The current automotive seats are mainly manufactured by steel that increases the vehicle weights, fuel consumption and CO2 emissions, and hence, lightweight carbon fiber-reinforced polymer (CFRP) will be a prospective substitute material. The integrated design method of a CFRP seat backrest will be studied and verified numerically. On the condition that the unchangeable seat dimensions and previous mounting positions on the floor, a three-dimensional CAD conceptual model in which the design and non-design domains were separated was established firstly, and then, the optimal material distribution in the design domain was determined by topology optimization technology according to the ECE (European Union standards) test standard. Next, the positions of ribs are determined and the manufacturing feasibility was verified numerically. Finally, the finite element model of the CFRP seat backrest was established, and static bending stiffness and crashworthiness were analyzed and the simulation results were compared with the previous all-steel structure. It is demonstrated that a 20.4% weight reduction is achieved, and previous 26 steel components could be replaced by only one CFRP component and no additional assembly is required. Both the static and impact test standards are satisfied.
Dynamic Stall Simulation of Flow Over NACA0012 Airfoil at 1 Million Reynolds Number
Authors: Kasibhotla Venkata Ravishankar , Tafti Danesh
Published: March 2016

The paper is concerned with the prediction and analysis of dynamic stall of flow past a pitching NACA0012 airfoil at 1 million Reynolds number based on the chord length of the airfoil and at reduced frequency of 0.25 in a three dimensional flow field. The turbulence in the flow field is resolved using large eddy simulations with the dynamic Smagorinsky model at the sub grid scale. The development of dynamic stall vortex, shedding and reattachment as predicted by the present study are discussed in detail. This study has shown that the downstroke phase of the pitching motion is strongly three dimensional and is highly complex, whereas the flow is practically two dimensional during the upstroke. The lift coefficient agrees well with the measurements during the upstroke. However, there are differences during the downstroke. The computed lift coefficient undergoes a sharp drop during the start of the downstroke as the convected leading edge vortex moves away from the airfoil surface. This is followed by a recovery of the lift coefficient with the formation of a secondary trailing edge vortex. While these dynamics are clearly reflected in the predicted lift coefficient, the experimental evolution of lift during the downstroke maintains a fairly smooth and monotonic decrease in the lift coefficient with no lift recovery. The simulations also show that the reattachment process of the stalled airfoil is completed before the start of the upstroke in the subsequent cycle due to the high reduced frequency of the pitching cycle.
Cylindrical Tensegrity Deployable Structure
Authors: Luo Ani , Li Quanhe , Xiao Te , Kong Lingying , Wang Longkun , Zhang Qinghua , Wang Yuanyuan , Liu Heping
Published: March 2016

The string-bar deployable structure should be a main direction for creating the new truss deployable structure applied in the spaceflight. A cylindrical tensegrtiy deployable structure is researched in the text. At first, referring to a cylinder folded with papers, a cylindrical tensegrity is presented in the text. Relationship between nodes and members of the structure is researched to set up the connectivity matrix. The coordinates of the nodes and connectivity matrix are applied further to obtain the lengths of all the members. Using nodes matrix, member matrices, connectivity matrix and external force matrix, the internal force density matrix of the tensegrity structure in equilibrium is solved. Considering the failure constraints, the force density of the members is optimized to get minimal mass of the structure. A model is built to verify the feasibility of the method for designing the tensegrity structure. Considering that lengths of all the bars are constant, length changes of all the strings are researched when the tensegrity structure is compressed and elongated along its axis. The methods for connecting the strings are analyzed further. All the analytical results are applied to set up an experimental model. The experimental model is tested to prove that the designed mechanism can be deployed and folded. So the design is successful. Through research in the text, a cylindrical tensegrity deployable structure is obtained. Methods for building the tensegrity structure and transforming it into a deployable structure can be proper to design of other deployable structures.
A Study on Residual Photovoltage and Photo-Induced Strain in PLZT Ceramic With Coupled Multi-Physics Fields
Authors: Huang J. H. , Wang X. J. , Wang J.
Published: March 2016

Lead lanthanum zirconate titanate (PLZT) ceramic has draw significant attention for its promising application as a wireless photo-driven micro actuator. However, the residual photovoltage and photo-induced strain have a great influence on the response speed of photostrictive effect and prevent PLZT ceramic from using as a micro actuator, especially in high frequency dynamic field. In this paper, the coupled opto-piezo-thermo-elastic fields in PLZT ceramics were analyzed, based on which the mathematical equations of temperature, voltage and deformation during the light switched off phase were established. After that, the photostrictive static experiments were performed to validate the mathematical equations proposed.
Humidification and Dehumidification Processes: Advantages and Disadvantages
Authors: Mentz Stephanus , Mehrabi Mehdi , Sharifpur Mohsen , Meyer Josua P.
Published: March 2016

Desalination systems based on the Humidification Dehumidification (HDH) process come in a large variety of forms. They all operate in very similar manners, all requiring the evaporation of salt water and the condensation of pure, distilled water, in the same way clouds are formed every day. As engineers we must pursue the processes that have the best possible efficiency for the specific situation we find ourselves in. The purpose of this paper is to explore the various Humidification Dehumidification desalination processes and thermodynamically compare them with one another in order to determine which one of these processes has the most potential in specific environmental situations. This paper explores the advantages and disadvantages of all HDH processes as well as compare them with more common desalination methods like reverse osmosis. An in depth study of available literature is conducted, listed and explained regarding these HDH processes and their specific characteristics, focusing on the key points of efficiency, limiting factors and environmental effects. In some cases these processes, especially those utilizing the open air cycle or solar collectors, can be severely affected by environmental situations. The environmental situations can include high humidity environments, high temperature environments, high rainfall environments and of course the polar opposites of these situations and any combination of them. The paper takes into account these environmental effects and makes recommendations based on different environmental situations that can be found around the world. The HDH processes can obtain the energy they need to operate from various sources. Recommendations are also made with this in mind. Recommendations are also made regarding possible processes and specific design areas, which, in the in the writers opinion, should be the focus of improvements made by future designers are noted. Considering the efficiency limiting areas that cause bottlenecks in the processes, the writer prescribes possible ways to limit the effects of these bottleneck areas. The writer’s own recommendations regarding possible processes and possible improvements are also stated, paying attention to the recommendations already found in literature.
Orthopedic Anterior Cruciate Ligament Evaluator (OR.A.C.L.E): A Preliminary Design
Authors: Piovesan Davide , Church David , Herron Sean , Oldham Calvin , Sebald Mollie , Michael Robert , Bitticker Steven
Published: March 2016

An anterior cruciate ligament (ACL) tear is one of the most prominent, and debilitating injuries currently to athletes. Physical therapist students need to be able to practice common physical examination techniques regularly and repeatedly in order to gain the skills necessary to accurately diagnose an ACL tear. A cost effective, adjustable knee apparatus that could mimic the behavior of both a healthy and an injured knee joint may mitigate this problem. We built an apparatus mimicking the geometry and function of a knee joint, including the effect of forces and stiffness proper of knee ligaments. SimWise 4D was used to dynamically simulate an anatomically approximated model of the knee joint during physical examination conditions. The numerical simulation tested the displacement between the femur and the tibia with and without an ACL ligament. The SimWise 4D simulation gave an increase in displacement of 1.58 mm or 30% after removing the ACL, which is comparable with known displacements in human test subjects. Finally, a design for a 3D rapid prototype is proposed and fabricated with fusion deposition modeling (FDM).
Research on the Relationship Between Feature Commonality of Generic Component and Manufacturing Cost
Authors: Hou Liang , Lai Rongshen
Published: March 2016

How to leverage the contradiction between commonality and diversity within a product family has been regarded as one of the crucial problems in Mass Customization. In order to support the process of product family design and optimization, a quantitative methodology for analyzing the relationship between feature commonality of generic components and manufacturing cost is proposed. Firstly, the information representation model for generic components is constructed based on generic bill-of-material (GBOM) and tabular layouts of article characteristics (SML). Then, by interviewing domain-specific experts and according to the relative importance of features and the influence of value difference of feature parameters on manufacturing process, the similarity matrix of generic component instances and overall feature commonality index (FCI) are proposed. After that, the manufacturing cost is estimated by customized activity-based costing (ABC) and the relationship between feature commonality and manufacturing cost is discussed to identify conditions of rational commonality decisions. Finally, a simple case study of rectangular steel plate product family is presented to verify the rationality of the proposed process and indexes.
On the Micromechanical Characterization of Metallic MEMS by a Hybrid Microtester
Authors: Wardlow Jennifer , Allameh Seyed
Published: March 2016

Mechanical testing of microelectromechanical systems (MEMS) components helps investigate the reliability of MEMS devices used especially in vital applications such as life-supporting, medical, aerospace or automotive technologies. This paper discusses the development and use of a hybrid micromechanical system that combines the advantages of a macroscale slow-action screw-driven stage producing large displacements with a small-scale fast-action piezo-driven actuator. The main advantage is to study mechanical properties of small structures such as thick and thin films developing cracks that travel on millimeter scale during fatigue. The combination of piezo position monitoring with image-recognition-based local deformation determination allows specification of the beginning of phenomena such as micro-void-induced softening with relative accuracy. Such studies are most useful for investigation of the onset of nucleation of microcracks from fatigue-induced surface flaws. The significance of finding the onset of crack propagation lies in the fact that crack initiation constitutes the major portion of fatigue life for small structures (occasionally up to 99.3%).
A Microporous Chitosan/Collagen Composite Encapsulated Small Tube of Nanoporous Anodic Aluminum Oxide for Long-Acting Drug Release
Authors: Lee Bao-Ying , Li Ching-Wen , Wang Gou-Jen
Published: March 2016

This study aims to develop a long-acting and implantable drug release device that can well control the release rate and concentration of the loaded drug. The proposed long-acting and implantable drug release device consists of a tubular nanoporous anodic aluminum oxide (AAO) and the microporous chitosan/collagen composite encapsulated inside it. The nanopore size of the AAO tube can be arranged by the anodization parameters to adjust the release rate and concentration, while the microporous chitosan/collagen composite can provide the device with a long-acting release property. Fabrication results indicated that the AAO tube has a uniform pore arrangement with pore size around 50 nm. And the synthesized microporous chitosan/collagen composites composites containing 90% of chitosan had the highest moisture content; therefore were used as the drug carriers. Release experiments demonstrate that the proposed long-acting drug release device had released only less than 60% of the loading drug at the 16th release day.
Mechanical Properties and Manufacturing Process of a Closed-Cell Cellular Metal Based on Cubic Structure
Authors: Dang Xiaobing , He Kai , Zuo Qiyang , Li Jiuhua , Du Ruxu
Published: March 2016

It is well known that cellular metal is an ideal structure used in transportation passive safety field for its low density and high energy absorption capacity. In this paper, a kind of regular cellular metal based on cubic structure is proposed. The cubic cells are manufactured through sheet metal stamping process. Then the cells could be bonded together by adhesive to form the cellular structure. The compressive properties of the cellular metal are studied by experiments. The dynamic behaviors are studied by numerical simulations. To distinguish the individual and interactive effects on the energy absorption capacity, a full factorial Design of Experiment with sixteen configurations is carried out based on the four parameters that are essential to the design of cellular metal. The effects of impact velocity on crushing deformation are analyzed. It has been shown that the regular cellular metal based on cubic structure will have a wide application in industry.
Hydrogen Sulfide Sensing Using Lab-on-a-Chip Device for Biomedical and Environmental Use
Authors: Baniya A. , Thapa S. , Borquist E. , Bailey D. , Wood D. , Glawe J. , Kevil C. , Weiss L.
Published: March 2016

Hydrogen sulfide (H2S) detection is an important capability for applications that range from environmental to biomedical use. In medical application, hydrogen sulfide may be an effective marker for various cardiovascular diseases. This work reports progress on H2S detection using a unique lab-on-a-chip device designed specifically for both environmental and biomedical applications. The chip consisted of three distinct layers of PEO/PDMS structures which have been bonded using various techniques including Reactive Ion Etching (RIE). First layer consisted of capillary channels to organize the flow of the sample. Also, liberation of the sulfide took place at this layer. The second layer was a H2S selective membrane. The third layer consisted of trapping chamber where trapped H2S samples were withdrawn for the quantification of H2S concentration. Fabrication of the first layer was accomplished using photolithography technique. Specifically, the chip incorporated unique design features and operation with advanced liberating chemistry that effectively released H2S from aqueous solutions introduced to the device. Mixture of poly-dimethylsiloxane-ethylene oxide polymeric (PDMS-b-PEO) and polydimethylsiloxane (PDMS) was cast on Su8 mold which produced super hydrophilic channels that allowed liquid flow via capillary action. The chip has been both fabricated and characterized as reported in this work. For each sample, 150 μL of the reaction volume was loaded in an HPLC vial and analyzed by a Shimadzu Prominence HPLC equipped with fluorescence detection and an eclipse XDB-C18 column. Sulfide transfer increased steadily at a rate of approximately 2% per minute until peaking at approximately 60% at 30 minutes. Percent transfer data show that sulfide diffused into the trapping chamber in a reproducible manner and that it was stable once it reached its peak at 30 minutes. Characterization and testing of the fully assembled device indicates significant promise and utility. Additional improvements may be made by optimizing parameters such as the decreasing ratio of the chamber volumes to the membrane area and the membrane thickness. The performance of this microfludic device was attributed to hydrophilic surface of PEO/PDMS, strong bonding of the chip using 3M transfer tape and well suited PDMS membrane that allow selective diffusion of hydrogen sulfide.
A Methodology to Design a Knowledge-Based Tool for Residential Buildings Simulation
Authors: Capitanelli Andrea , Germani Michele , Landi Daniele , Papetti Alessandra
Published: March 2016

The actual growing world energy demand is generating strong attention to the energy efficiency and to the environmental sustainability. The residential sector is one of the most energy-intensive reaching about 25% of global energy consumption. Furthermore, it is difficult to understand the real energy use in residential buildings suggesting the development of methodologies and tools to monitor and assess their energy performances. Such an analysis requires defining all the actors, their interaction rules and the intelligent management of a large amount of data. In addition to this, the energy performances of the home environment are closely related to the specific case under investigation, in fact it imposes the analysis of the particular application scenario and the target users to extract parameters able to describe the building behavior. They are related to the technological characteristics of the systems, to the external environment (e.g. external temperature, solar irradiation, etc.) and to the user needs and habits. It introduces some complexities, because many of these data are difficult to find and to predict. Another cause of complexity was introduced by the information and communication technologies (ICT) that creates new relationship between home devices fostering the spread of smart systems. In this scenario, simulation tools have been developed to grasp the real energy performance of a building, but they require a high level of detail for the input data which are often difficult to find. Otherwise, other tools are built for much simplified simulations and typically addressed to inexperienced users neglecting the real complexities of the system.

For this reason, the paper presents a new design approach that aims to develop knowledge-based tools with architecture able to simulate the real behavior of the building considering all the actors and their interaction rules, but at the same time containing the features that allow them to be used in fast simulations or by inexperienced users. One of the focuses is the development of an intelligent user interface that, when requested, is able to automate and simplify data entry process. It is particularly useful when the user does not know the necessary input data for the simulation, e.g. energy consumption profiles, detailed features of the building, etc. All the steps of the proposed approach are described in the paper. In the first section is highlighted how the key parameters have been found and how they are organized as creating a knowledge base, while in the second section is shown the operation of the smart user interface and of the simulation tool. The results demonstrate that the proposed knowledge-based approach generates real benefits by simplifying and speeding up the data entry. Furthermore, the study shows how the smart user interface allows performing complex simulations also to novice users.
Development of Bolted Flange Design Tool Based on Finite Element Analysis and Artificial Neural Network
Authors: Yildirim Alper , Akay Ahmet Arda , Gulasik Hasan , Coker Demirkan , Gurses Ercan , Kayran Altan
Published: March 2016

In bolted flange connections, commonly utilized in aircraft engine designs, structural integrity and minimization of the weight are achieved by the optimum combination of the design parameters utilizing the outcome of many structural analyses. Bolt size, the number of bolts, bolt locations, casing thickness, flange thickness, bolt preload, and axial external force are some of the critical design parameters in bolted flange connections. Theoretical analysis and finite element analysis (FEA) are two main approaches to perform structural analysis of bolted flange connections. Theoretical approaches require the simplification of the geometry and are generally oversafe. In contrast, finite element analysis is more reliable but at the cost of high computational power. In this paper, a methodology is developed for iterative analyses of bolted flange that utilizes artificial neural network approximation of a database formed with more than ten thousand non-linear analyses with contact algorithm. In the design tool, a structural analysis database is created by taking permutations of the parametric variables. The number of intervals for each variable in the upper and lower range of the variables is determined with the parameters correlation study in which the significance of parameters are evaluated. The prediction of the ANN based design tool is then compared with FEA results and the theoretical approach of ESDU. The results show excellent agreement of the ANN based design tool with the actual non-linear finite element analysis results within the training limits of the ANN.
A Methodology for Optimal Lightweight Design of Moulds and Dies: A Case Study
Authors: Nie Yi , Lin Yueh-Jaw , Sun Wei , Huang Tao
Published: March 2016

Attaining lightweight design of mechanical parts and components is an ever-lasting goal of designers during design process. In this paper, a systematic lightweight design methodology is proposed for mould and die design enabling us to avoid conventional ways of empirical approaches, leading to substantial cost reduction in part’s material utilization and minimizing environmental impacts in product realization.

At the initial stage, the characteristics of a lightweight mould or die are identified using the so-called lightweight coefficient defined as the ratio of the part’s functional performance to its mass. The proposed design methodology was implemented to attain an optimum lightweight coefficient resulting in desirable mass reduction as well as overall functional performance improvements of the final products.

In the case study, the design was started with numerical simulation to model the process-part interaction for a typical extrusion operation, which allowed the identification of the numerical design parameters that affect the required performances as well as the threshold values that must be met. Structural optimization scheme was then employed to achieve the targeted performances with structural components of minimum mass by applying the design criterion of reducing the thickness of components’ walls. The study was done on the redesign of an actual polymer pipe extrusion die. The results showed that 21.67% (3325.26 kg) mass reduction of the underlying extrusion die, together with the evaluated increase of lightweight coefficient by 25.23%, could be obtained with the specified performances of productivity, static stiffness, compressive strength and assembly property satisfied.

All in all, this work provides a foundation for dealing with lightweight mechanical parts design aimed at conventional heavy duty machine components with complex functionalities such as moulds and dies. The proposed lightweight coefficient design methodology proves to be effective in reducing parts’ weight without sacrificing the part’s specifications and desired functionalities. In future work other design criteria such as shortening the length of the flow channel or reducing the number of assembly parts are to be investigated to further improve the design outcomes. Moreover, life cycle assessment (LCA) will be performed to evaluate the positive impact of lightweight design on the environment due to material saving and machining wastes reduction in realizing the parts.
Piezoelectric Energy Harvester Array With Magnetic Tip Mass
Authors: Guo D. , Zhang X. F. , Li H. Y. , Li H.
Published: March 2016

Energy harvesting using piezoelectric materials is an alternative method for low power electronics, such as MEMS, wireless sensor network, portable devices, and nano structures, from extracting the ambient energy. Most piezoelectric energy harvesters are based on cantilever beams with laminated piezoelectric patches. To generate higher dynamic response of piezoelectric energy harvesters, tip mass is attached at the free end of the cantilever beams. Piezoelectric energy harvester array is another way to improve the power, i.e., installing a set of cantilever piezoelectric energy harvesters in close distance. In this research, a new design of piezoelectric energy harvester is proposed. The present design consists of an array of cantilever beams with permanent magnets at the free ends. The permanent magnets are introduced to transfer the excitation force to every cantilever beams. An experimental model is manufactured and experimental energy harvesting is carried out. Piezoelectric patches are laminated on clamped end of cantilever beams, and the permanent magnets are fixed at the free ends. All the magnets have opposite poles with each other to generate repelling force. Then these piezoelectric electric energy harvesters were connected to an AC/DC circuit and the power was measured. Also, the power of proposed piezoelectric energy harvester was compared with the piezoelectric harvesters without permanent magnets. The results show that, present design can generate higher power at the same excitation. Under the base excitation at the first natural frequency, the array of the cantilever beam show similar motion pattern, i.e., there is no phase difference between each other. At higher frequencies, the beams have a phase difference of π. Thus the crash between the cantilever beams can be effectively avoided. At lower excitation frequencies, the presented piezoelectric energy harvester vibration likes the first mode of a simple multi-degree-of-freedom system; and at higher excitation frequencies, the vibration of the presented piezoelectric vibrates like a second mode of a MDOF system.
Second Law Heat Release Modeling of a Compression Ignition Engine Fueled With Blends of Palm Biodiesel
Authors: Mattson Jonathan , Reznicek Evan , Depcik Christopher
Published: March 2016

Modeling of engine-out heat release is of great importance for engine combustion research. Variations in fuel properties bring about changing combustion behavior within the cylinder, which may be captured by modeling of the rate of heat release. This is particularly true for biodiesel fuels, where changes in fuel behavior are linked to viscosity, density, and energy content. Heat release may also be expanded into an analysis using the 2nd Law of Thermodynamics, which may ascertain the pathways through which availability is either captured as useful work, unused as thermal availability of the exhaust gas, or wasted as heat transfer. In specific, the 2nd Law model identifies the period of peak availability, and thus the ideal period to extract work, and is of use for power optimization.

A multi-zone (fuel, burned, and unburned) diagnostic model using a 1st Law of Thermodynamics analysis is utilized as a foundation for a 2nd Law analysis, allowing for a simultaneous energy and exergy analysis of engine combustion from a captured pressure trace. The model calibrates the rate and magnitude of combustion through an Arrhenius equation in place of a traditional Wiebe function, calibrated using exhaust emission measurements.

The created model is then utilized to categorize combustion of diesel and palm biodiesel fuels, as well as their blends. The 2nd Law analysis is used to highlight the effects of increasing biodiesel usage on engine efficiency, particularly with respect to fuel viscosity and combustion temperature. The 2nd Law model used is found to provide a more clear understanding of combustion than the original 1st Law model, particularly with respect to the relationships between biodiesel content, viscosity, temperature, and diffusion-dominated combustion.
Investigation of Hydro-Elastic Performance of Marine Propellers Using Fluid-Structure Interaction Analysis
Authors: Han Sangho , Lee Hyoungsuk , Song Min Churl , Chang Bong Jun
Published: March 2016

To investigate the hydrodynamic benefits of composite materials marine propeller, CFD-FEM fluid structure interaction (FSI) methodology using STAR-CCM+ and Abaqus with co-simulation is adapted for the hydro-elastic interaction simulation of composite propeller. FSI simulation reliabilities are validated with experimental data of P5479 marine propeller. KP458 propeller geometry are used for CFD simulation of rigid blade and FSI simulation of flexible one under the propeller open water (POW) test condition and compared with conventional BEM-FEM results to understand the blade deformation characteristics and induced performance changes. KVLCC2-KP458 self-propulsion FSI simulations were conducted and confirmed the effect of unsteady behavior of flexible marine propeller for the propulsion performance in the wake field. From the results, the decided difference between rigid and flexible one is observed and the merits of flexible marine propeller is confirmed quantitatively.