bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerically Constructed Energy Consumption Mapping for the Orthogonal Machining of Ti6Al4V
Authors: Nouzil Ibrahim , Pervaiz Salman , Kannan Sathish
Published: January 2020

Energy efficiency is an important aspect of all industrial processes. Sustainability in manufacturing sector can be improved by reducing and optimizing the energy requirements of the machine tool during the machining process. Growing energy demand and shortages in conventional energy sources have prompted research into energy conservation and sustainable development. Machining of difficult-to-cut materials such as titanium-based alloys involve high consumption of energy and hence it is compulsory to study the optimal combinations of process parameters that yield the best result with highest efficiency in terms of energy. This paper aims to develop a finite element (FE) assisted virtual energy consumption map for the machining of Ti6Al4V in orthogonal turning operation. The cutting power for the machining process is simulated in AdvantEdge specially designed machining software for specific cutting parameters. The map developed is universally applicable and independent of the machine tool as only cutting power is used. The visual energy map can be utilized at the shop floor level, as it is easily understandable to the operator. The information enabled through the map can help the operator select the optimal combination of process parameters for the machining process and maximize the energy based efficiency of the cutting process.
Parametric Study of Split Flow Cylindrical Packed Bed Reactor for High-Temperature Thermochemical Energy Storage Using Cobalt Oxide Redox Reaction
Authors: Vahedi Nasser , Oztekin Alparslan
Published: January 2020

Thermal energy storage has become an integral part of Concentrated Solar Power (CSP) plants to guarantee continuous supply of power demand. For cost-effective solar power generation, the size and operating temperatures of CSP plants should be increased. Thermochemical energy storage (TCES) is the only available solution to meet energy density and high-temperature requirements. Air is mostly used as Heat Transfer Fluid (HTF) for high-temperature CSP plants. For the air-based system, metal redox reactions are good candidates as storage reactant. Application of metal oxide gas-solid redox reaction in storage systems requires an efficient reactor design. Cost-effectiveness and simplicity have made packed bed reactors a viable candidate for high-temperature applications. The high-pressure drop along the bed is the main drawback of such reactors preventing them from widespread applications. Split flow design modification could aid in reducing pressure drop while providing more flexibility in reactor performance control. A cylindrical split-flow packed bed reactor with an annulus for HTF flow is considered as a modified reactor design. The transient two-dimensional axisymmetric numerical model is developed for solving mass, momentum, and energy equations for both gas and solid phases using suitable reaction kinetics for the cobalt oxide redox reaction. A parametric study is performed on cylindrical-shaped split-flow reactor design as a basis for future optimization for complete storage cycle. The effect of split flow ratio and side-channel width on reactor performance are considered. It is shown that both parameters could be used effectively to design and optimize the reactor.
On an Independent Period-1 Motion in a Flexible Rotor System
Authors: Xu Yeyin , Luo Albert C. J.
Published: January 2020

This paper investigates stable and unstable period-1 motions in a rotor system through the discrete mapping method. The discrete mapping of a nonlinear rotor system is for stable and unstable period-1 motions. The stability and bifurcation of periodic motions are determined. Numerical simulations of periodic motions are completed and phase trajectories, displacement orbits and velocity plane are illustrated. The period-1 motion near the internal resonance is determined with large vibration in the nonlinear rotor system.
Temperature Regulated Sleeve for Leg Prosthesis
Authors: Grubbs Rachel , Yough Matthew , Rose Olivia , Lee Anthony , Sicree Teresa , Tiari Saeed , Piovesan Davide
Published: January 2020

This paper presents the findings of the research and design of a heat generating thermal prosthetic sleeve. The goal of the project was to get the sleeve to be designed in a way that keeps a comfortable temperature of the amputation site. Heat transfer analysis as well as comfort tests were used to select the optimal materials for the body of the sleeve. A series of electrical tests using multimeters were used to determine which heating element should be used, as well as in which orientation they should be connected. A microcontroller system had also to be selected to give the sleeve some adjustability.
Design and Fabrication of a Universal Gripper for Children With Special Needs
Authors: Vijaya Kumar Ajay Kumar , Schweitzer Emily , Baer Julie , Piovesan Davide
Published: January 2020

One in every sixty-eight children in the United States is affected by autism or another form of developmental disability. For children with autism it is difficult to learn the basic hand movements, which are required for gripping and holding objects of complex shapes. Our goal was to help these children by designing an ergonomic, simple, and easy to use interface that can be used to grasp desired objects of various shapes. This grasper translates a full hand power grip to a more fine-tuned precision grip. The sphere-shaped interface design outperformed all other shapes when used as the ergonomic side to be grasped by the children. Using 3D software modeling, we were further able to fine tune the interface for ease of use, manufacturing, and robustness.
Experimental Study on Effects of Operational Parameters on a Single-Cell Test-Bed Vanadium Redox Flow Battery
Authors: Islam Rabiul , Jeong Kwangkook
Published: January 2020

This paper describes the experimental characterization of a laboratory scale single-cell vanadium redox flow battery (VRFB) with variations of operational parameters. The single cell was experimentally investigated with respect to energy storage capacity, charge-discharge time, voltage, coulombic and energy efficiencies under various operating parameters such as current densities, electrolyte flow rates, and the ratio of electrolyte volume in electrolyte storage tank and cell. It was found that the voltage efficiency was increased by 11% entailing energy efficiency improvement from 60 to 66% as the electrolyte flowrate was increased from 40 to 220 ml/min. The highest columbic efficiency was achieved at 96% for the current density of 40 mA/cm2 which was 14% higher than that of the current density of 15 mA/cm2. Energy storage capacity was linearly increased with higher ratio of tank to cell volume due to the larger number of vanadium ions present. The improvement in energy storage capacities was observed to be 60, and 41% as the ratio was raised by 67, and 40%, respectively.
Experimental Characterization of a Novel Piezoelectric Fan
Authors: Benner Jingru , Shilyuk Eric , Coletta Jarrod , Mortazavi Mehdi , Santamaria Anthony D. , Su Shun , Nguyen Tony
Published: January 2020

Piezoelectric fans have attracted attentions in the past decades because of their low energy consumption, low noise level, light weight and reliability. A novel form of piezoelectric flapping fan is characterized experimentally and numerically. An experimental setup was built to measure the pressure and flow rate of piezoelectric fans with low static pressure at various frequencies. The fan performance curve was established. A high speed camera system was used to analyze the oscillation motion of the fan wings. The displacement of the leading edge and trailing edge of the piezoelectric fan wings are used as inputs to describe the deflection of the fan in the numerical model. The flow field obtained from the model is analyzed. The vortex shedding is observed and discussed. The pressure and flow rate obtained from the 2D numerical model are compared with the experimental results. The results provide a fundamental understanding of a piezoelectric fan with opposing oscillating wings.
A Decision Support Tool for Distributed Solar and Storage Investments: A Case Study in Austin, TX
Authors: Bandyopadhyay Arkasama , Conger Julia P. , Webber Michael E. , Leibowicz Benjamin D.
Published: January 2020

This study builds a decision support tool to evaluate when it is a good economic decision (least cost with minimum discomfort) for the residential customer to invest in distributed energy resources (DERs) based on different electricity rate structures, DER ownership frameworks, and DER rebates offered by electric utilities. The tool is demonstrated using empirical electricity consumption data from Pecan Street Inc. (a non-profit entity based on Austin, Texas), residential rates from Austin Energy (the municipal electric utility in Austin, Texas), DER ownership costs from various nationwide pilot programs, and incentives offered by electric utilities in the United States. Results show that for constant electricity rates, the overall expenditure is least when the customer owns solar panels without storage, while for time-varying pricing structures, the least expensive scenario is one where the customer does not own any DERs. As the capital costs for DERs decline, utilities incentivize customer ownership of DERs, and more residential customers face the decision of whether to invest in DERs, this study aims to be a key tool in aiding that decision-making process.
Thermal Behavior and Melt-Pool Dynamics of Cu-Cr-Zr Alloy in Powder-Bed Selective Laser Melting Process
Authors: Rahman M. Shafiqur , Schilling Paul J. , Herrington Paul D. , Chakravarty Uttam K.
Published: January 2020

Selective laser melting (SLM) is a growing additive manufacturing (AM) technology which is capable of rapidly fabricating functional components in the medical and aviation industries. The thermophysical properties and melt-pool dynamics involved in the powder-bed SLM process play a crucial role to determine the part quality and process optimization. In this study, a 3-D computational fluid dynamics (CFD) model with Cu-Cr-Zr (C-18150) powder-bed is developed incorporating a moving conical volumetric heat source and temperature-dependent thermal properties to conduct the Multiphysics simulations of the SLM process. The melt-pool dynamics and its thermal behavior are investigated numerically and results for temperature profile, cooling rate, variation in density, thermal conductivity, specific heat capacity, and velocity in the melt pool are obtained for different laser beam specifications. The validation of the CFD model is conducted by comparing the simulation results for temperature and the melt-front motion with the analytical results found from the classical Stefan problem of the phase-change material. Studying the process parameters, melt-pool geometry, and thermal behavior of Cu-Cr-Zr alloy can generate valuable information to establish Cu-Cr-Zr as a low-cost engineering material in the AM industry.
Analysis of Bio-Inspired Structures for 3D Force Sensing Using Virtual Prototyping
Authors: Alotaibi Ahmed M. , Anwar Sohel
Published: January 2020

3D force sensors have been proven its effectiveness and appropriateness for robotics applications. It has been used in medical and physical therapy applications such as surgical robot and Instrument Assisted Soft Tissue Manipulation (IASTM) in the recent times. The 3D force sensors have been utilized in robot assisted surgeries and modern physical therapy devices to monitor the 3D forces for improved performances. The 3D force sensor performance and specifications depend on different design parameters, such as structural configuration, sensing elements placements, and load criterion. In this paper, different bioinspired structure configurations have been investigated and analyzed to obtain the optimal 3D force sensor configuration in terms of structural integrity, compactness, safety factor, and strain sensitivity. Finite Element Analysis (FEA) simulation was used for the analysis to minimize the time of the development cycle.
Investigation on Mechanical Properties and Corrosion Resistance of Cobalt-Based Alloy Cladding Layer
Authors: Jin Zhiyi , Yao Zhenqiang , Shen Hong
Published: January 2020

Austenitic stainless steel was cladded with Cobalt-based alloy by means of Tungsten inert gas (TIG) welding to improve the performance of the working parts such as the thrust bearing plates under dynamic loads and corrosive liquid. Specimens were prepared with different welding parameters, namely the cladding current, preheating temperature, inter-layer temperature and post heat treatment temperature, so as to investigate their influence on micro-hardness, as well as tensile and bending strength. It is revealed that the lower welding current coincides with higher micro-hardness as well as tensile and bending strength. The higher inter-layer temperature will result inhigher overlay micro-hardness. The post weld heat treatment temperature influences the bending strength of the overlay weld specimens. In addition, the accumulation of Cr and Ni compounds on weldment surface is found to coincide with higher corrosion resistance in over-layers by means of XRD.
A New Trefftz Based Finite Element for Static Analysis of Laminated Composite Structures
Authors: Dwibedi Subhasankar
Published: January 2020

Composite materials have been widely used in industries for several years owing to their capability to perform better than homogeneous isotropic materials. Numerical tools like finite element method are efficiently used for analysis of structures made of composite materials. However, for complex shapes or geometries of structures, it becomes uneconomical (computational resource wise) to use Rayleigh-Ritz based finite element analysis. An unique Trefftz based finite element has been developed in this article to efficiently fill the gap in the above mentioned scenario. Hybrid-Tefftz finite element method’s flexibility to use arbitrary shaped elements comes handy in modelling complex geometries. The developed hybrid-Trefftz finite element approach has been used on symmetric angle-ply laminated composite plate and the obtained results have been compared with bench mark solutions. The present method proposes an approach for development of hybrid-Trefftz type finite elements, by which analysis of antisymmetric structures is also possible, an area of research which has been less explored by such approach as revealed from survey of available open literature.
A Study of Mechanosensing of an Osteoblast at Focal Adhesions Under Cyclic Strain Using Magnetic Micropillars
Authors: Shiraishi Toshihiko , Nagai Kota
Published: January 2020

It has been reported that cells sense and respond to mechanical stimuli. Mechanical vibration promotes the cell proliferation and the cell differentiation of osteoblast cells at 12.5 Hz and 50 Hz, respectively. It indicates that osteoblast cells have a mechansensing system for mechanical vibration. There may be some mechanosensors and we focus on cellular focal adhesions through which mechanical and biochemical signals may be transmitted from extracellular matrices into a cell. However, it is very difficult to directly apply mechanical stimuli to focal adhesions. We developed a magnetic micropillar substrate on which micron-sized pillars are deflected according to applied magnetic field strength and focal adhesions adhering to the top surface of the pillars are given mechanical stimuli. In this paper, we focus on intracellular calcium ion as a second messenger of cellular mechanosensing and investigate the mechanosensing mechanism of an osteoblast cell at focal adhesions under cyclic strain using a magnetic micropillar substrate. The experimental results indicate that the magnetic micropillars have enough performance to response to an electric current applied to a coil in an electromagnet and to apply the cyclic strain of less than 3% to a cell. In the cyclic strain of less than 3%, the calcium response of a cell was not observed.
Comparative Structural Optimization Study of Composite and Aluminum Horizontal Tail Plane of a Helicopter
Authors: Arpacioglu Bertan , Kayran Altan
Published: January 2020

This work presents structural optimization studies of aluminum and composite material horizontal tail plane of a helicopter by using MSC. NASTRAN SOL200 optimization capabilities. Structural design process starts from conceptual design phase, and structural layout design is performed by using CATIA. In the preliminary design phase, study focuses on the minimum weight optimization with multiple design variables and similar constraints for both materials. Aerodynamic load calculation is performed using ANSYS and the finite element model of the horizontal tail plane is created by using MSC.PATRAN. According to the characteristics of materials, design variables are chosen. For the aluminum horizontal tail, thickness and flange areas are used as the design variables; and for composite horizontal tail, attention is mainly focused on the ply numbers and ply orientation angles of the laminated composite panels. By considering the manufacturability issues, discrete design variables are used. For three different mesh densities, different initial values of the design variables, and similar design constraints, optimizations are repeated and the results of optimizations are examined and compared with each other. In the optimizations performed, constraints are taken as strength and local buckling constraints. It is shown that the optimization methodology used in this study gives confident results for optimizing structures in the preliminary design phase.
Position Correcting Control System for the Vacuum Cleaning Robot Considering Hose Repulsion
Authors: Tsuno Takaya , Morimoto Tatsuhiro , Matsui Hirokazu , Yano Ken’ichi , Mizuochi Toyohisa , Arima Toshihiko , Fukui Shigeru
Published: January 2020

In our daily life, we live by using many resources such as electricity and gas energy, metal products such as automobiles. When imported iron ore or coal from overseas is transported by a conveyor, it drops from the conveyor due to vibration and strong wind during transportation. At present, people are doing cleaning directly using a vacuum car in the place where the track loader cannot enter. When a person performs cleaning work using a vacuum car, accidents such as getting caught in the mouth of a hose or a conveyor might. To cope with this problem, a vacuum robot that performs cleaning work on behalf of people are developed in previous work. However, since the hose for sucking iron ore and coal is hard, these robots cannot move freely. In this research, we developed a vacuum cleaning robot that can transport a hard and heavy hose with a small and light weighted robot. The developed vacuum cleaning robot independently controls the driving part and the suction part, whereby the robot can control the position of the suction port while suppressing the repulsive force of the hose.
Investigation on the Effect of Drilling Parameters on Quality of Hole in Epoxy Resin With and Without Carbon Fiber Reinforced With 6% and 10% Si3N4 Using FEA
Authors: Venkatadasu Ravindra Holalu , Murali Krishna Nodekoppalu Lingaiah , Doddagarudanahalli Shivaramaiah Rakshith Gowda
Published: January 2020

Now days drilling of fiber reinforced plastics become a challenging task in terms of obtaining defect free holes. Quality of drilling mainly depends on cutting parameters such as spindle speed, feed rate, diameter of the drill etc. Recently Finite element analysis (FEA) is found to be the most reliable method to investigate the effect of such parameters on quality of hole in drilling of composites. Present study focuses on the drilling of Epoxy resin with and without carbon fiber reinforced with 6% and 10% volume of Si3N4 composites as per the Taguchi’s L27 standard orthogonal array using HSS tool. FEA is carried out for each combination of cutting parameters given by taguchi’s table. Simulation results such as stress distribution, strain and deformation in the material are correlated with the with the drilled hole performance characteristics like Cylindricity, circularity, delamination and surface roughness. Simulation results depict the influence of thrust force and torque on the degree of deformation, strength, elasticity and stress distribution in the work material during drilling. From the simulation, it is found that deformation, and equivalent stress in the material decreases with increase in the % of Si3N4 reinforcement resulting in minimum surface roughness. The effect of feed rate is more on the value of thrust force resulting in maximum principal stress, equivalent stress and directional deformation in the material, which leads to delamination at the entry and exit of the hole. Further, influence of spindle speed is more on the value of torque resulting in maximum principal stress, equivalent stress and directional deformation in the material, which leads to maximum value of Cylindricity.
Comparative Study of Material Damage and Tool Wear Mechanisms During Drilling of CFRP/Ti Stack
Authors: Mathiyazhagan Vijayathithan , Meena Anil
Published: January 2020

The usage of CFRP and Ti stacks in the aerospace industry has widely increased due to its mechanical properties and improved structural functions but at the same time, different mechanical and thermal properties of the CFRP and Ti makes the process difficult. Major apprehensions in the drilling of CFRP/Ti stacks include rapid tool wear and poor hole quality. Typically, the surface quality of the holes in the drilling of CFRP/Ti stack is poor due to delamination, the progression of hole diameter in CFRP and burr formation in Ti. Moreover, the flank wear on the tool also influences the surface quality of the hole produced. Therefore, the present study is mainly focused on the influence of cutting parameters on cutting forces, hole quality and tool wear characteristics. Drilling was performed on CFRP/Ti stack using coated and uncoated carbide tools. The obtained results revealed a significant correlation between tool wear and delamination characteristics.
Simulation of a 7R Manipulator Inverse Calibration by Using an Optimized Neural Network Based on Beetle Antennae Search Algorithm
Authors: Wang Yuxiang , Chen Zhangwei , Zu Hongfei , Zhang Xiang
Published: January 2020

This paper proposes an intelligent technique by combining multilayer feed-forward neural networks (MLFNN) and beetle antennae search (BAS) algorithm for the inverse calibration of a 7R manipulator. First of all, the MLFNN is optimized by BAS. Then, the optimized BAS-MLFNN method is employed for the nonlinear mapping from the true angles of the joint to the errors of the joint. The true angle values of the joints are selected as the inputs and the joint errors as the outputs. The simulation of calibration is implemented on a Kuka’s LWR manipulator. Numerical simulation results show that compared with the commonly used BPNN, the proposed BAS-MLFNN method possesses better performance in terms of higher precision.
Integrated Optimization of Structure and Control in Ultra-Precision Motion Systems
Authors: Wang Jing , Zhang Ming , Zhu Yu , Li Xin , Wang Leijie
Published: January 2020

Ever-increasing demands for precision and efficiency in ultra-precision motion systems will result in a lightweight and flexible motion system with complex dynamics. In this paper, a systematic approach is proposed where control gains, 3D structural topology and actuator configuration are integrated into optimization to derive a system-level optimal design which possesses a high vibration control performance, and still satisfies multiple design constraints. A material interpolation model with high accuracy is proposed for the integrated optimization, a simple integral equation utilizing R-functions and level-set functions is established to represent complex non-overlapping constraints of actuators. Over-actuation degrees are utilized to actively control the dominant flexible modes. Responses of residual flexible modes are restricted by increasing the coincidence of their nodal areas at actuators (sensors) locations. The objective function is the constructed worst-case vibration energy of the flexible modes. A dual-loop solving strategy combining the genetic algorithm and the modified optimal criteria method is adopted to solve the optimization problem. A fine stage in the wafer stage is designed to prove the effectiveness of the proposed method.
Influence of Fuel on a Valveless Pulsejet Engine Performance and Pollutant Emissions
Authors: Melo Andreia , Brójo Francisco
Published: January 2020

In this work the performance of a valveless pulsejet with two different fuels and several fuel mass flows was numerically estimated. Results for pressures, velocities, traction and pollutant formation are presented. Even though this type of engine has many advantages over the conventional types, it still has many problems for application in civil aviation due to noise levels. Although having a very simple construction, operation is not completely understood, so studies continue to be made in order to have a better knowledge of the physics behind operation. For engine sizing, was performed a calculation procedure based on data of existing engines and equations reported in the literature. The pulsejet operation was then simulated using ANSYS Fluent 16.2. Simulations were 2D transient, three different fuel flows were analysed: 0.04 kg/s, 0.06 kg/s and 0.1 kg/s and two fuels used: propane and methane. For propane an additional case was defined, being the fuel mass flow of 0.12 kg/s. The results obtained are similar for the two fuels, the variables have the same behaviour with the variation of the fuel flow except for the operating frequency.
Investigation on Deep Hole Trepanning of TC10 Titanium Alloy
Authors: Han Xiaolan , Liu Zhanfeng
Published: January 2020

Titanium alloy is a typical hard-to-machine material, and has a relatively expensive material price. For deep-hole tubes made of titanium alloys, the material utilization rate of direct deep-hole drilling is relatively low, especially for large diameter holes. Deep-hole trepanning provides an effective method that reduces manufacturing cost and improves the material utilization which is used on larger diameter bars. In this paper, deep-hole trepanning tests are carried out on the TC10 titanium alloys to resolve the key technical problems. The thrust force and torque, tool wear, and chip morphology are analyzed based on the different process parameters. The results show that appropriate process parameters can remove the chips easily and reduce the thrust force and tool wear. The titanium alloy deep-hole trepanning has a good drilling effect and solves the problem of drilling deep, large diameter holes in titanium alloy tubes, which has practical significance for reducing production cost and improving material utilization.
Barriers for Virtual Assessment of Structural Robustness
Authors: Brix Nerenst Tim , Ebro Martin , Nielsen Morten , Eifler Tobias , Nielsen Kim Lau
Published: January 2020

Simulation techniques such as Finite Element Analysis (FEA) have substantially contributed to reducing the time and cost of developing new mechanical products over the last decades. However, FEA is primarily carried out on the nominal geometry, i.e. not considering the variation in geometrical and material parameters that originates from either the production or use-cases. This can lead to either overly conservative or overly optimistic designs, which in turn leads to unnecessary cost and/or unforeseen product failures. Despite the introduction of commercial FEA tool packages (such as 3DX/Abaqus/ANSYS etc.) that enables designers and engineers to combine FEA and Robust Design (RD) methods, performing sensitivity studies to identify robustness issues is rarely conducted in a systematic manner. The objective of this study is to identify the barriers for why the combined use of FEA and robust design techniques are not a standard part of the design process. The study concludes on identified barriers and that combining FEA and RD will require a substantial effort, however create significant value and enhance the design process.
Thermal Patterns and Internal Flow Mechanisms in Evaporating Inverted Sessile Drops of Pure Water
Authors: Josyula Tejaswi , Manghnani Chandan , Mahapatra Pallab Sinha , Pattamatta Arvind
Published: January 2020

We report an experimental investigation on contact line dynamics, thermal patterns, and internal fluid flow during the evaporation of inverted sessile drops of pure water. This configuration of sessile drop when placed on a heated substrate should lead to thermal stratification and any internal convective flow will be governed by surface tension driven Marangoni flow. First, we report contact line dynamics and thermal patterns recorded using an optical camera and infrared camera, respectively. An interesting outcome from the present study is the resemblance observed between the evolution of contact angle and interfacial temperature difference during evaporation. By performing Particle Image Velocimetry to delineate the internal flow characteristics, we report an axisymmetric counter-rotating flow inside the drop. This flow is directed towards the substrate from the apex at the centerline of the drop. In literature, a similar directional flow is reported to be due to Marangoni flow albeit for a normal sessile drop. Further, by extracting the magnitude of velocity, we report a maximum velocity in the flow occurring at the center of drop which in turn increases with substrate temperature. The results reported in the present study shed light on the presence of Marangoni flow in pure water drops whose understanding is of paramount importance in many academic and industrial applications.
Distributed Training for Data Driven Models in Power Machinery Online Monitoring
Authors: Wu Hang , Wang Wei , Zhou Dengji , Ma Shixi , Zhang Huisheng
Published: January 2020

Prognostics and Health Management (PHM) Systems have been widely applied in online monitoring of modern mechanical devices, and models in PHM systems are of vital importance. Traditional mechanism models are able to simulate parameters and evaluate the overall machine state accurately, but their defect is the high requirements in understanding the objects. Therefore, data driven models could be a suitable substitute. Data driven models take the advantage of machine learning technique and are able to be established only on the basis of past data. Models applied in this paper are based on Artificial Neural Network (ANN), but the complexity of network structures will occupy huge amount of computing resources and time in training. For online monitoring, spending too much time on training will postpone real time prediction and decrease the reaction speed of PHM systems in abnormal conditions. In this paper distributed training based on computer cluster is proposed to decrease training time. By dispatching computing task into several workers, the severs in the cluster will only undertake a small fraction of the total computing load and therefore accelerate the overall training process. On the other hand, there are some risks of losing prediction accuracy and stability because of the nonlinear gradient deviation in data parallelism. Aggregation period (AP) is an important factor in balancing the requirements of both ends. This paper analyzes the influence of AP on training speed, accuracy and stability, then proposes a novel distributed training algorism according to the regulations achieved. Then a distributed training and online monitoring process for a typical two-shaft gas turbine is taken as an example in the result and discussion section. It turns out that the experimental results fit the theoretical regulations well, and the revised distributed learning algorism is able to meet all the requirements of training speed, prediction accuracy and stability.
Physics-Based Simulation of Agile Robotic Systems
Authors: Piliptchak Pavel , Aksu Murat , Proctor Frederick M. , Michaloski John L.
Published: January 2020

Development and testing of industrial robot environments is hampered by the limited availability of hardware resources. Simulations provide a more accessible and readily modifiable alternative to physical testing, but also require careful design to maximize their fidelity to the real system. In this paper, we describe new progress in building an entirely physics-driven simulation of the Agility Performance of Robotic Systems (APRS) Laboratory at the National Institute of Standards and Technology (NIST). To maximize the accuracy of physics-based interactions in this environment, we develop several general-purpose improvements to the simulation of parallel grippers and multi-object collisions. We use pick-and-place tasks from the APRS Laboratory as well as generic benchmarks to verify the performance of our simulation. We demonstrate that our proposed improvements result in more physically-consistent simulations compared to standard implementations, regardless of the choice of physics engine or simulation parameters.
A Digital Twin for Intra-Logistics Process Planning for the Automotive Sector Supported by Big Data Analytics
Authors: Guerreiro Guilherme , Figueiras Paulo , Costa Ruben , Marques Maria , Graça Diogo , Garcia Gisela , Jardim-Gonçalves Ricardo
Published: January 2020

One of the areas that can heavily benefit with Industry 4.0 is the logistics, namely with the association of sensing technologies and the application of techniques such as Big Data Analytic, Data Visualization, prediction algorithms, and especially 3D simulation. The association of real data, prediction techniques, and 3D models, allow the creation of realistic Digital Twins that emulate factory processes, making possible the experimentation and testing of new ideas and different scenarios by tweaking key variables, without stopping production.

However, there are many challenges in order to handle and compute all fast-growing, multi dimension data generated, so that all this production related data can be quickly used for defect control, preventive maintenance, advanced analytics for production and resources management, or even later simulation. The work presented in this paper focus in this “in between” processing work, presenting an easily deployable and self-reconfigurable Big Data architecture, where different technologies can work together to extract, transform, load, apply analytics, and then feed a 3D Digital Simulation model. The work presented in this paper is funded by the EU project BOOST4.0 and focus in a specific logistic process of car manufacturing.
Mapping the Potential for Infectious Disease Transmission in a Wide-Body Aircraft Cabin
Authors: Mahmoud Seif , Bennett James S. , Hosni Mohammad H. , Jones Byron
Published: January 2020

With more than two billion passengers annually, in-flight transmission of infectious diseases is a major global health concern. It is widely believed that principal transmission risk associated with air travel for most respiratory infectious diseases is limited to within two rows of an infectious passenger. However, several passengers became infected despite sitting several rows away from the contagious passenger.

This work thoroughly investigated the potential for disease spread inside airplane cabins using tracer gas to quantify airborne dispersion. Measurements were conducted in a full-scale, 11-row mock-up of a wide-body aircraft cabin. Heated mannequins to simulate passengers’ thermal load were placed on the cabin seats. Tracer gas was injected at the breathing level at four different hypothetical contagious passenger locations. The tracer gas concentration was measured radially up to 3.35 m away from the injection location representing four rows of a standard aircraft. A four-port sampling tree was used to collect samples at the breathing level at four different radial locations simultaneously. Each port was sampled for 30 minutes.

A total of 42 tests were conducted in matching pairs to alleviate potential statistical or measurements bias. The results showed that the airflow pattern inside the mock-up airplane cabin plays a major role in determining tracer gas concentration meaning that the concentration at the same radial distance in different directions are not necessarily the same. Also, due to the air distribution pattern and cabin walls, concentrations at some seats may be higher than the source seat.
Modeling and Control of a Spherical Inverted Pendulum With Actuator Saturation
Authors: Bondo Geovani , Yuan Chengzhi , Duan Chang
Published: January 2020

This paper studies the modeling and control of a spherical inverted pendulum (SIP). The SIP is deemed to be a reasonable model for rocket-propelled body and is often used to test advanced control strategies. The mathematic model is derived based on a Quanser two degrees-of-freedom inverted pendulum commercial product. The pendulum is mounted on a five-bar mechanism that is actuated by two rotary servo base units. Unlike conventional assumption that the two motors are allowed to rotate simultaneously, we assume a more challenging scenario that at one time only one motor is working. The system is hence modeled as a switched system as two motors have to be switched in order to balance the pendulum at its unstable equilibrium. Switched controllers, together with a switching strategy are developed to ensure the stability of the system and satisfy a disturbance attenuation performance index. Simulation results are presented to show the effectiveness of the proposed method.
Wear Behavior of In-Situ Mg2Si/Al-Si Composite
Authors: Shanmugavel Balasivanandha Prabu , Mohan Vijayakumar
Published: January 2020

An in-situ Mg2Si/Al-Si composite was produced by the in-situ reaction approach. The in-situ Mg2Si particles were produced in an aluminum alloy (LM-6) melt due to the reaction between Potassium hexafluorotitanate (K2TiF6) and magnesium in the aluminium melt. The melt was maintained at 750°C for 30 minutes’ duration to complete the in-situ reaction. The microstructure examination revealed the homogeneous distribution of Mg2Si particles in the Al-Si matrix. The formation of the Mg2Si phase was confirmed by the X-Ray Diffraction technique. The Hardness measured on the composite is higher than that of the Aluminium alloy (LM-6). The wear behavior of both the materials was investigated using Pin-on-disk wear testing by considering parameters, such as loads (20N, 40N), sliding distance (1000m,1800m) and velocity (1.5m/s, 2m/s). The Signal to Noise (S/N) ratio was calculated to identify the parameters at which higher wear resistance was offered by both the materials. The experimental results show that the sliding distance and velocity are the major parameters influencing the wear rate in both the Al alloy and its composites. The presence of Mg2Si particles in the Al-Si matrix improved the wear resistance of the composites.
Numerical Verification of the Thermodynamic Determination of the Hydraulic Efficiency of Radial Fans
Authors: Epple Philipp , Fritsche Manuel , Reinker Felix , aus der Wiesche Stefan
Published: January 2020

For fans without cooling it is possible to determine the hydraulic efficiency measuring the pressure and the temperature rise through the fan. The shaft work can be determined according applying the first law of thermodynamics for an open system. Without any losses the change of state would be isotropic and the work done equal to the specific heat at constant pressure of the fluid times the isentropic temperature rise in the impeller. Due to the losses, however, the real temperature at the exit of the impeller will be higher than the isentropic temperature since the real process is polytropic. The isentropic temperature at the exit of the impeller can be computed by the isentropic relations with the inlet temperature and the pressure rise. The hydraulic efficiency can be computed as the ratio of the isentropic temperature rise divided by the real temperature rise.

In order to verify this thermodynamic approach for the determination of the hydraulic efficiency CFD simulations of a radial fan were performed. In the CFD simulation the hydraulic power, the shaft power, the pressure rise and the temperature rise can be read out and computed directly. In such a way the hydraulic efficiency computed by the ratio of the hydraulic power by the shaft power can be compared by the thermodynamically computed efficiency. In this work this comparison has been performed and the results and the precision of the thermodynamically predicted efficiency are presented and discussed in detail.
Modeling and Simulation of the Cooling and Heating Processes of Onions
Authors: T. G. Giorges Aklilu , Britton Doug
Published: January 2020

The shelf life of onions, or for that matter any food item, is defined as the time period where the produce has an acceptable quality and is safe to consume. For onion farmers and packers, the mode of determining the shelf life depends on the harvesting, drying, grading, packing, cooling, storing, and shipping processes and time. Quality loss can lead to economic loss as well as a decline in consumer confidence. Quality expectation should be maintained at an acceptable level for consumer purchase and consumption. In addition to post-harvest handling, the thermal history of the produce during storage and transportation plays a major part of shelf life and quality management. Due to the differences among onion varieties, some are more susceptible than others to damage resulting from temperature, high humidity, and other factors during processing. In general, the recommended storage temperatures range from 0 to 5 °C during cold storage and 20 to 30 °C during non-refrigerated storage. Both storage methods should have adequate air circulation of about 0.5 to 1.0 m3 of air per minute per 1.0 cubic meter of onions to maintain the temperature and prevent CO2 accumulation. In this study, the cooling and heating processes of different sizes of onions were conducted experimentally and numerically, and temperature readings were recorded. The cooling process was designed to simulate actual industry practice where cooling starts after the onions are placed in a cold storage room where the temperature is not constant. For the heating process, the experiment simulated industry practice where cold onions are transferred into a warm storage room where the temperature is uniform. These thermal environments are a common encounter during the storage and shipping of produce. Initially, the cooling and heating data were experimentally examined and used to estimate the cooling time as well as the cooling rate to gain an understanding of the heat transfer process. Furthermore, the data were used in evaluating the numerical simulation. In the case of small onions, the temperature changed from 21.1 to 4.4 °C after three and a half hours. However, in the case of large onions, a similar temperature change took nearly eight hours. The numerical simulation was conducted using 3D models and the thermal properties of the onions. This paper will discuss the experimental data and the CFD modeling and simulation. Based on this study, the thermal environment and critical time period that could cause changes in produce core temperature can be outlined and used to qualify thermal mishandling.
A Study of the Aerodynamics of a Helicopter Rotor Blade
Authors: Pulok Mohammad Khairul Habib , Chakravarty Uttam K.
Published: January 2020

In any congested area, where a fixed-wing aircraft cannot perform, rotary-wing counterparts are the best-suited option for its vertical take-off and landing capacity. The vibration induced by the rotor blade is a significant problem in helicopter performances. Rotor aerodynamic loading, rotor dynamics, and fuselage dynamics are the elements that contribute to the vibration of a helicopter. Among these elements, the key reason for the helicopter vibration is the aerodynamic loading. Determining aerodynamic loading is one of the most important criteria to design a rotor blade and to minimize vibration. Rotor harmonic airloads are generated from the rapid variation of flow around the rotor blade due to the vortex wake. A rapid drop in the circulation near the blade tip causes tip vortices which are the reason for the maximum lift at the tip of the blade. Consequently, tip vortices become the primary source of harmonic airloads. In this study, a specimen of Bo 105 helicopter rotor blade is considered to observe the aerodynamic characteristics under the external flow of air. The coefficients of lift and drag of the specimen for different angles of attack and azimuth angles are estimated. The resonance frequencies and the mode shapes are obtained. Computational results are validated by the experimental analyses of a small-scaled model of the rotor blade. From the study, the coefficient of lift is found to increase with the angle of attack up to a critical value. Similarly, the coefficient of drag increases with the angle of attack. The resonance frequencies significantly change with scaling the rotor blade.
Aeroelastic Modeling and Analysis of High Aspect Ratio Wings With Different Fidelity Structural Models
Authors: Çiçek Gökçen , Kayran Altan
Published: January 2020

This paper is concerned with the aeroelastic modeling and analysis of high aspect ratio wings with large torsional deflections with different fidelity structural models.

The approach for structural modeling presented here is based on linear and nonlinear theories. The linear theories are based on the slender-straight wing and bending-torsion beam finite element formulations. The nonlinear theory is based on the nonlinear finite element model with only a torsional rotation degree of freedom to study the static aeroelastic behavior. The aerodynamic theory used for aeroelastic coupling is ESDU 95010 [1], which uses steady lifting-surface theory based on Multhopp-Richardson’s solution to provide the spanwise loading of lifting surfaces with camber and twist.

Analyses are performed with three different structural models coupled with ESDU for simple plate-like wing models.

The results of linear structural models are verified with MSC NASTRAN® and the nonlinear structural model results are verified with the work of Trahair [2]. Linear aeroelastic models are compared with the MSC NASTRAN® solution performed by SOL144. Significant differences in torsional deflection of tip location are observed between the linear and the nonlinear solution methodologies. The linear theory is found to be conservative for the aeroelastic analysis of high aspect ratio wings.
Heat Transfer Characterization of 3D Printable Architected Heat Sinks
Authors: Hassan Ali Mohamed I. , Al-Ketan Oraib , Alhammadi Alya , Khalil Mohamad , Khan Kamran , Abu Al-Rub Rashid K.
Published: January 2020

The current developments in additive manufacturing (3D printing) overcome the limitations of traditional fabrication techniques such as milling, drilling and casting and allow to fabricate geometrically-complex heat sinks for which the topological features are capitalized upon to enhance the thermal performance. In this work, we propose new and novel 3D printable architected heat sinks with geometrically complex structures based on triply periodic minimal surfaces (TPMS). Their printability with laser-based metal additive manufacturing is assessed using electron microscopy techniques. Moreover, Computational fluid dynamics (CFD) modeling is used to assess the effect of geometry on the performance of the proposed TPMS-based heat sinks in active cooling using forced convection heat transfer environment. The convection heat transfer coefficient, surface temperature, pressure drop are predicted using CFD method. The results showed that the heat transfer performance does not depend on the architects porosity alone, but also depends on the heat sink solid-networks structure.