bluuebunny/crossref_metadata_2025 huggingface dataset:
A Thermo-Electro-Elasto-Viscoplastic Damage Internal State Variable (ISV) Model for Ductile Metals
Authors: Dimitrov Nikolay , Liu Yucheng , Horstemeyer M. F.
Published: January 2019

A multiphysics Internal State Variable (ISV) theory that couples the thermoelastoviscoplastic damage model of Bammann-Horstemeyer with electricity-related electromagnetic phenomena is presented in which the kinematics, thermodynamics, and kinetics are internally consistent. An extended multiplicative decomposition of the deformation gradient that accounts for elasticity, plasticity, damage, thermal expansion, electricity, and magnetism is introduced. The different geometrically-affected rate equations are given for each phenomenon after the ISV formalism and have a thermodynamic force pair that acts as an internal stress-like quantity. Guidelines for practical implementation, recommendations for simplifying assumptions, and suggestions for future work supplement the theoretical model. The abstraction of the model can capture the full multi-physics described above; however, the robustness of the model is realized when any of the listed phenomena are not included in the boundary value problem, the model reduces to the previous form — the model will revert to the Bammann-Horstemeyer plasticity-damage ISV model.
Effect of Underbody Geometry on the Fuel Efficiency of Gasoline and Electric Vehicles
Authors: Mahadevan Krishnaswamy , Barez Fred , Thurlow Ernie , Abdollahian Davood
Published: January 2019

Automotive industry in continuously expected to produce more fuel-efficient vehicles. Increasing fuel prices and environmental concerns such as emission of CO2 are two areas in vehicle design improvement. There are multiple factors that affect the fuel economy such as rolling resistance, aerodynamic drag, and weight of the vehicle. As the speed of the vehicle increases, aerodynamic drag force becomes the dominating factor affecting the fuel consumption. This aerodynamic drag is a result of the low-pressure region created at the rear end of the vehicle. This low-pressure region is due to the relative square shape of the vehicle at the rear end which generates vortices.

This project aims to investigate the effects of an underbody in reducing the aerodynamic drag forces and its effects on fuel usage. The underbody in vehicles is one such area in improving the aerodynamics of a vehicle which can have an impact on overall drag force.

Various underbody geometry modifications were carried out on a 3D model of Fiat 500 Electric and Gasoline versions to simulate the effect of underbody geometry on fuel consumption using the CFD simulation tool ANSYS Fluent. It was concluded that the underbody of vehicle influences the overall aerodynamic drag by 20%. Underbody geometry modification helps in reducing the fuel consumption by decreasing the overall aerodynamic drag of the vehicle.
CFD Simulation of Multiphase Flow in Concentric Annuli
Authors: Shynybayeva Amina , Rojas-Solórzano Luis R. , Sveen Kristian
Published: January 2019

Multiphase flow is commonly found in almost every process related to oil and gas industry. The precise prediction of the flow behavior is essential to provide safe and efficient hydrocarbon recovery. An accurate characterization of multiphase flow plays a major role in well design optimization and development of successful production and transportation facilitiess. Even though the hydrodynamic behavior of multiphase flow in various pipe geometries typically found in the industry has been widely studied, there is still very little known about the flow pattern and hydrodynamic conditions presented in horizontal annular geometry. Current work presents Computational Fluid Dynamics (CFD) simulation of two-phase oil-water flow in horizontal concentric annuli using different turbulence models and Eulerian-Eulerian continuous-disperse interphase drag model. Water was modelled as disperse phase, while oil was considered as continuous phase. Effect of water droplet diameter in the interphase model is extensively discussed in this paper. Results of the simulations are compared to the experimental data for a variety of liquid velocities and water cuts.
Tolerance Allocation With Simulation-Based Digital Twin for CFRP-Metal Countersunk Bolt Joint
Authors: Wang Hua , Zhou Mengqian , Liu Bo
Published: January 2019

Deviations in the countersunk hole’s angle and depth affect the strength of the bolted composites under tensile loading. Tolerance of the countersunk hole’s angle and depth could be allocated by the Digital Twin of the bolted CFRP-Metal bolt joint. The paper presents a simulation-based Digital Twin for tolerance allocation of CFRP-Metal countersunk bolt joint, mainly considering the strength of the single bolt countersunk joint. Using the design-of-experiment method, nine numerical models with different hole’s angle and depth are constructed to simulate the countersunk holes with different deviations. Simulation results are input into the Digital Twin of the CFRP-Metal countersunk bolt joint. Analysis of variation (ANOVA) method is employed to deeply investigate the interaction between the angle deviation and the depth deviation under tensile loading. Tolerance of the countersunk hole is allocated based on the proposed Digital Twin involving simulation information. The depth should be more strictly controlled than the angle during the course of countersinking. The reported work enhances the understanding of the tolerance allocation for the bolted joint of the composites, and of the simulation-based Digital Twin for CFRP-Metal countersunk bolt joint.
Influences of Plasticity-Induced Crack Closure on Fatigue Crack Healing of Carbon Steel With Heat Treatment
Authors: Hamada Eiichi , Furuya Yuto , Hosoi Atsushi , Morita Yuji , Kawada Hiroyuki
Published: January 2019

Healing technology for metallic materials is an important subject in terms of long-term reliability and durability of structural members, a healing technology to heal fatigue crack by applying heat treatment at annealing temperature level has been discovered. In this study, the influences of plasticity-induced crack closure on healing were evaluated by obtaining the crack opening load during the pre-crack introduction and evaluating the fatigue crack propagation characteristics before and after the healing heat treatment, using compact tension specimens made of carbon steel with different test conditions. As a result, the specimen with high crack opening load showed high healing effect and were able to heal up to 95% of the pre-crack length. This suggested that the residual compressive stress due to the plasticity-induced crack closure accelerates the solid-state diffusion bonding during the crack healing process and this leads to the improvement of the healing effect.
Technology Development and Tool Concepts for High-Temperature Forming of Titanium
Authors: Landgrebe Dirk , Demmler Matthias , Albert Andre , Schieck Frank , Weber Martin
Published: January 2019

Due to its excellent material properties, titanium is an important structural material for several application fields in the aerospace industry, the chemical industry, medical engineering or marine technologies. Especially its excellent weight-strength ratio, high-temperature strength corrosion resistance and not least its biocompatibility enables a wide field of special applications. These properties can be improved by alloying of other chemical elements.

Despite good availability of resources and moderate world market prices, there is only a limited application range for titanium. Main reasons comprise technological problems in manufacturing processes, particularly related to establish forming technologies such as deep drawing or hydroforming. The forming tool is of significant importance in forming technologies. Beside the function of shape storage the tool must provide the essential forming parameters such as mechanical functions (e.g. blank holder, sealing etc.), but also temperature and tribology. Especially the tribology, also related to forming temperatures, is very critical during titanium forming due to a distinctive tendency of adhesion.

For this reason, a high number of titanium components are manufactured by milling. Parts made by forming of basically thin blank, show only low complexity. More complex components are made by welding of simple shaped parts. Thus, large-series manufacturing of titanium components is limited due to the extensive production cost.

By describing three examples, this paper shows possibilities and challenges in manufacturing of titanium components based on sheet metals. Beside the process parameters, a special focus of the investigations lies on the coating of forming tools. Example one is cold forming of thin titanium blanks to speaker cones. The second example demonstrates superplastic forming of a medical application, and finally the third example consists of hot gas forming of a titanium exhaust manifold.

The investigations have shown that based on optimized technological parameters in combination with new tool coatings, the manufacturing of complex sheet metal based titanium applications is applicable for large-series production.
A Study on the Corrosion and Mechanical Properties of an Al6063 Reinforced With Egg Shell Ash and Rice Husk Ash
Authors: Idusuyi Nosa , Oviroh Peter Ozaveshe , Adekoya Adetoye Henry
Published: January 2019

Aluminium based metal matrix composites (MMCs) have received considerable attention in the last decade for its potential industrial applications. One of the challenges encountered using Aluminium based MMCs is understanding the influence of the reinforcement particles on the corrosion resistance and mechanical properties. In this study the corrosion behaviour and mechanical properties of Al6063 reinforced with egg shell ash and rice husk ash were investigated. Waste Egg Shell Ash (ESA) and Rice Husk Ash (RHA) 212 μm in size were used to produce the composites with 10 wt% of reinforcements via stir casting technique. The RHA and ESA were added in the ratios of 10:0, 7.5:2.5, 5:5, 2.5:7.5, 0:10. Unreinforced Al6063 was used as baseline material. Immersion tests, potentiodynamic polarization techniques, tensile tests, optical microscopy (OM) and scanning electron microscopy (SEM) were used to characterize the composites. The results showed that reinforcing with 7.5 wt% RHA + 2.5 wt% ESA provided the highest resistance to corrosion. Generally, a reduction in the corrosion rates were observed for the reinforced composites as the wt% of RHA increased. Porosity levels of the composites reduced with an increase in the percentage of ESA in the matrix. Microstructural characterization using SEM and OM revealed a distribution of pits on the composite surfaces which was more severe with increasing RHA percentage. The UTS (ultimate tensile stress) results revealed that the composite containing 10 wt% RHA had the maximum value of 161 MPa. The results demonstrate that rice husk ash and eggshell ash can be useful in producing low cost Aluminium composites with improved corrosion resistance and tensile properties.
Biomimetic Membrane Simulation for Water Desalination
Authors: Oviroh Peter Ozaveshe , Akbarzadeh Rokhsareh , Jen Tien-Chien
Published: January 2019

Reverse Osmosis (RO) for the desalination of saline water is associated with tremendous energy costs and low efficiency. Improvements in nanotechnology have led to the development of a variety of nanoporous membranes for water purification. Biomimetic membrane is an emerging new technology for water purification. Consequently, there is still much to study about the function and structure of these kinds of membranes. The purpose of this work was to determine which factors influence membrane performance. The focus was on those factors affecting membranes in pure water. Biomimetic membrane using MoS2 which has a higher rate of ion rejection and higher water permeability was studied through molecular dynamics simulations using reactive force fields (ReaxFF). The behaviour of the membrane before subjecting it to desalination was studied. The effect of water temperature, atmospheric pressure and membrane thickness on performance of membrane was studied. The permeability flux was calculated and compared in different conditions and the relation between these factors was revealed.
Experimental and CFD Investigation of Aerodynamic Forces and Moments in a Linear Turbine Blade Cascade
Authors: Slama Vaclav , Rudas Bartolomej , Ira Jiri , Macalka Ales , Eret Petr , Tsymbalyuk Volodymyr
Published: January 2019

In order to eliminate occurrences of flutter of low pressure turbine blades it is necessary to understand the associated unsteady aerodynamics. For this reason, an experimental and numerical study of controlled flutter (travelling wave mode) in a linear turbine blade cascade oscillating in a torsional as well as translation motion is conducted. Unsteady aerodynamic forces and moments were measured on a subsonic eight-blade turbine cascade rig where central four blades are flexibly mounted each with two degrees of freedom. Thin blades in the cascade represent the tip section of the last stage rotor blades, which defines the turbine overall performance. A commercially available 3D CFD software ANSYS CFX is used to simulate the unsteady aerodynamic loading in the blade cascade. Experimental data and simulations are compared and influence of aerodynamic forces and moments on flutter is analysed.
Numerical Investigations of a Rotating Wire-Wrapped Cylinder
Authors: Begum Assma , Gada Komal , Rahai Hamid
Published: January 2019

Previous investigations [1–3] on the effects of rotating cylinder with either a smooth surface or cylinders with different surface geometries, placed at either the leading or the trailing edge of a symmetric airfoil on its aerodynamic parameters have shown that rotation at the leading edge does not provide significant lift, while placing the rotating cylinder at the training edge results in more than 20% increase in lift at all angles of attack (AOA) investigated. Increasing the rotation rate (α), the ratio of tangential velocity at the surface of the cylinders (Uτ) to the free stream mean velocity (U∞), increases the lift and grooved cylinders produced more lift than the smooth cylinder. There is an increase in drag when the rotating cylinder is placed at the trailing edge of the airfoil. Here we performed unsteady numerical investigations of a rotating wire-wrapped cylinder, placed in steady flow with α varied between 0 and 2. The free stream mean velocity was constant at 10 m/sec. and the smooth cylinder diameter was 5 cm, which corresponds to an approximate Reynolds number of 3.2 × 104. The wire wrapped had a wire diameter of 5 mm and the ratio of pitch spacing to the cylinder diameter was 1. The wire was wrapped tightly around the entire cylinder. The cylinder has a length to diameter ratio of 20. The rotation rate (α) ranged from 0.5 to 2.0. Results indicate wire-wrapped rotating cylinder produce higher lift than the rotating smooth cylinder and at α equal to 2, the lift for the wire-wrapped cylinder is nearly 150% of the lift of the smooth cylinder. However, wire-wrapped cylinder has higher drag force at higher rotation rate. At α = 2, the lift to drag ratio for the smooth rotating cylinder is 3.89, while the corresponding value for the rotating wire-wrapped cylinder is 3.54. Details of the flow indicates wire-wrapping reduces coherency and increases phase angle of vortices, resulting in increased lift.
Combined Magnetohydrodynamic/Pressure Driven Flow of Multi-Layer Pseudoplastic Fluids Through a Parallel Flat Plates Microchannel
Authors: Gómez Juan R. , Escandón Juan P.
Published: January 2019

With the advance of microfluidic platforms and due to the need to solve different implications that still exist on the transport of electrically conducting fluids, the analysis on strategies in micropumps that involve a simplicity in its structure, absence of mechanical moving parts, flow reversibility and low power requirement is current. Therefore, the present investigation contributes with the analysis of the combined magnetohydrodynamic/pressure driven flow of multilayer immiscible fluids in a microchannel formed by two parallel flat plates. The mathematical model is based in a steady fully developed flow and the pumped fluids follow the power law model to describe the pseudoplastic fluids rheology, while magnetic effects on the flow are given from the Lorentz forces. The velocity profiles and flow rate are obtained in the limit of small Hartmann numbers by solving analytically a closed system of ordinary differential equations, together to the corresponding boundary conditions at the solid-liquid interfaces in the channel walls and at the liquid-liquid interfaces between the fluid layers. The results show that the flow field is controlled by the dimensionless parameters that arise from the mathematical modeling being a parameter that indicates the competition between pressure to the magnetic forces, magnetic parameters related to Hartmann numbers, viscosities ratios between the fluids, flow behavior indexes and the dimensionless position of the liquid-liquid interfaces.
Numerical Modeling for a Supercritical CO2-Liquid Sodium Hybrid Compact Heat Exchanger
Authors: Kissick Sean M. , Wang Hailei
Published: January 2019

As research continues into the generation IV advanced nuclear reactors, exploration of liquid sodium as a coolant, or Sodium Fast Reactors (SFRs), coupled to supercritical CO2 (sCO2) Brayton cycles are currently underway. Liquid sodium offers unique and beneficial fluid properties that can achieve higher efficiencies and longer equipment lifespans compared to conventional water cooled reactors. Coupling sodium with sCO2 matches well with sodium’s temperature profile and is less reactive with sodium when compared to water used in standard Rankine cycles. To achieve commercial viability, methods for developing diffusion-bonded Hybrid Compact Heat Exchangers (H-CHX) to couple SFRs with sCO2 Brayton cycles are being developed. This paper includes thermal-hydraulic analysis of these fluids to quantify thermal and pressure stresses within the H-CHX for use in determining a structurally sound design. Two models for predicting the temperature profiles within a practical H-CHX channel design are presented. The first is a 1-D heat transfer model employing heat transfer correlations to provide both bulk fluid and wall temperatures. The second is a 3-D computational fluid dynamics model (CFD) providing a three-dimensional temperature profile, but at a significantly increased simulation time. By comparing the results of the two models for specific design conditions, significant temperature deviation is shown between the models at a short channel length of 10 cm. However, for longer channel lengths, although the 1-D model neglected the strong axial conduction on the sodium side, it generally shows good agreement with the CFD model. Thus, for any practical H-CHX designs, the findings reveal both simulation methods can be used to extrapolate the temperature gradient along the channel length for use in designing a H-CHX, as well as predicting the overall size and mass of the heat exchanger for component costing.
Development of Structural Countermeasures for NHTSA’s Oblique Impact
Authors: Reichert Rudolf , Kan Cing-Dao (Steve)
Published: January 2019

Crash test results have shown that vehicles which receive good ratings in existing co-linear consumer information tests still may require structural modifications for good performance in NHTSA’s frontal oblique test procedure. The purpose of this study was to determine incremental vehicle structural change requirements and their associated mass and cost to significantly reduce occupant compartment intrusion. An available finite element model of a mid-size sedan was updated and validated using data from a 2015 Toyota Camry. The generated baseline model correlated well with the New Car Assessment Program (NCAP) full overlap test, NHTSA’s left and right oblique impact tests, and with the IIHS small and moderate overlap crash configurations. An iterative optimization process was used to develop necessary countermeasures to reduce occupant compartment intrusion according to defined design goals for the left and right oblique impact configuration. No unintended consequences, i.e. no considerable increase of vehicle pulse for oblique and co-linear load cases were observed. The associated added mass was 10.8kg and the associated cost was $30. Occupant risk analysis was not part of this study. Additional research in concert with restraint systems and occupants would ensure that the optimized structure does not adversely affect the measured occupant injury predictions.
Experimental Study of a Robust Foil Regenerator in the Oscillating Flow
Authors: Yanaga Koji , Qiu Songgang , Yadav Pawan Kumar
Published: January 2019

The Stirling engine is a high efficiency and high reliability energy converter which is expected to be a solution for future space power generation and commercial applications. One of the key components in a Stirling engine, to keep high efficiency, is the regenerator. Currently, woven screens or random fibers are mostly used as the regenerator material. However, since both woven screen and random fiber regenerators are composed of wires, the flow across the wires is similar to cylinders in cross flows. As a result, flow separation occurs and the regenerator results in high friction losses and thermal dispersion. In the previous study, a robust foil type regenerator is designed and CFD analysis of the regenerator was conducted to predict the friction coefficient and the thermal efficiency under oscillating flow conditions. In this research, a regenerator test bench was designed and constructed to investigate the friction coefficient and thermal efficiency of the regenerator. The experiment conditions are decided based on the one-dimension thermodynamic modeling software SAGE. The experiment result shows that the friction coefficient of the experiment is close to CFD prediction at high Reynolds number.
A Reduced-Order Model for Predicting the Performance of a Liquid-Ring Vacuum Pump
Authors: Pardeshi Irsha , Pandey Ashutosh , Shih Tom I-P.
Published: January 2019

Vacuum and low pressures are needed in many applications, and the liquid-ring vacuum pump, which does not have any solid-solid contacts between moving and stationary parts, is widely used because of its low operational cost and long service life. Though progress has been made in advancing this pump, industry still has aggressive goals on improving its efficiency and performance.

In this study, a reduced-order model was developed to predict the ability of liquid-ring pumps to ingest air and thereby create lower pressure as a function of pump design and operating parameters. The model developed is semi-empirical — constructed by first analyzing available experimental data to extract features and trends and then encapsulating them into a model through appropriate dimensionless parameters. This model by being in closed form shows the functional relationship between the pump’s design and operating parameters and its ability to ingest air and create a vacuum. To make predictions, this model only requires the following inputs: suction pressure, impeller’s rotational speed, and a few dimensions of the pump.

The model developed was assessed by using it to predict the ability of the pump to ingest air for a wide range of suction pressures (cavitation pressure to 760 torr), rotor speeds (up to 1,750 rpm), and dimensions of the pump (radius and span of the impeller blade, hub radius) and then comparing predictions with experimental data not used in the creation of the model. The model developed was found to be accurate within 11% of the experimental data.
A Systems Engineering Approach to Incorporating the Internet of Things to Reliability-Risk Modeling for Ranking Conceptual Designs
Authors: D’Angelo Anthony , Chong Edwin K. P.
Published: January 2019

This paper establishes the baseline for incorporating the Internet of Things (IoT) into the Reliability-Risk model. The authors developed the original Reliability-Risk model as a “trade-off” tool for ranking conceptual designs as a function of reliability. We summarize the original Reliability-Risk model and algorithm and discuss the process of updating the standard Integration Definition Function Modeling (IDEF0) technique with the IoT. Inserting the updated IDEF0 into the Reliability-Risk modeling framework creates a dynamic closed-loop system. We identified a concept for using a probabilistic workflow to automate the new closed-loop system and discuss a Reliability-Risk sensitivity approach.

The Reliability-Risk model ranked five conceptual packaging designs against 17 criteria for incorporation into the supply chain. The authors use a Multi-Criteria-Decision System (MCDS) to establish the rankings. The paper re-visits the original example to include data (the IoT) such as shock, temperature, and humidity obtained from various nodes in the logistics cycle. After the sensor data are incorporated, updated systems specification and reliability models resulted in a new ranking. We will discuss the results of the rankings.

Current research in developing the Digital Twin and Digital Thread are lacking in the area of logistics modeling. The incorporation of Discrete Event Simulation models to simulate transportation, handling, and storage shows promise to address these shortcomings. Therefore, we will briefly discuss our approach on incorporating Discrete Event Simulation modeling into the Reliability-Risk-IoT model to create a “logistics twin.”
Application of Systems Engineering to Machine Design for Technology Students
Authors: D’Angelo Anthony , Chong Edwin K. P.
Published: January 2019

This paper discusses the results of a literature search on implementing novel approaches to teaching engineering design as well as the need for teaching Systems Engineering (SE) at an undergraduate level. In addition, the paper presents the results and lessons learned by assigning a capstone project requiring students to develop a conveyor system using the 8-phase SE process and a project based collaborative design methodology.

The instructor teaches the fundamentals of systems engineering, the concept of synthesis, and the basics of trade-off studies. Students learn how to use functional modeling and the proper use of a functional flow block diagram to transform design requirements into failure modes.

Students perform traditional failure mode calculations, using a strength-resistance approach, on machine components such as shafts, bearings, gears, belts, chains, keyways, splines, clutches, springs, brakes, and bolts for the conveyor system’s transmission.

The instructor assigns a conveyor system and its systems requirements and students must demonstrate their understanding of the SE process as well as being able to perform design calculations on various machine components.

The students demonstrate their understanding of SE and failure modes by taking part in design reviews throughout the semester and a final engineering report.
Adaptive Industrial Robots Using Machine Vision
Authors: Kuts Vladimir , Otto Tauno , Tähemaa Toivo , Bukhari Khuldoon , Pataraia Tengiz
Published: January 2019

The use of industrial robots in modern manufacturing scenarios is a rising trend in the engineering industry. Currently, industrial robots are able to perform pre-programmed tasks very efficiently irrespective of time and complexity. However, often robots encounter unknown scenarios and to solve those, they need to cooperate with humans, leading to unnecessary downtime of the machine and the need for human intervention. The main aim of this study is to propose a method to develop adaptive industrial robots using Machine Learning (ML)/Machine Vision (MV) tools. The proposed method aims to reduce the effort of re-programming and enable self-learning in industrial robots. The elaborated online programming method can lead to fully automated industrial robotic cells in accordance with the human-robot collaboration standard and provide multiple usage options of this approach in the manufacturing industry. Machine Vision (MV) tools used for online programming allow industrial robots to make autonomous decisions during sorting or assembling operations based on the color and/or shape of the test object. The test setup consisted of an industrial robot cell, cameras and LIDAR connected to MATLAB through a Robot Operation System (ROS). The online programming tests and simulations were performed using Virtual/Augmented Reality (VR/AR) toolkits together with a Digital Twin (DT) concept, to test the industrial robot program on a digital object before executing it on the real object, thus creating a safe and secure test environment.
Torch End-Effector and TIG Electrode Changeout Design for a TIG Welding Robot Used in Metal Big Area Additive Manufacturing
Authors: Masuo Christopher , Nycz Andrzej , Noakes Mark W. , Bell Jared , Killian Justin , Oakley Chandler , Hamel William R.
Published: January 2019

Metal Big Area Additive Manufacturing (mBAAM) is a promising approach to large-scale metal additive manufacturing (AM) or 3D printing. The mBAAM system uses an arc-based wire-fed welding robot to build metal parts. A multi-degree-of-freedom robotic arm is known for its extensive range of motion and reliable tool handling. Attaching a torch end-effector to a robotic arm gives it welding capabilities; however, this decreases the motion range and dynamics of the robot. As a result, build volume and printing accuracy are decreased. Additionally, only a portion of time is spent printing in an arc-based process. Maintenance leads to downtime on the system. In a tungsten inert gas (TIG)-based process, the torch electrode wears out over time and must be changed to avoid defective deposition. This paper proposes an approach for a compact torch end-effector to improve the robot’s build volume. This paper also proposes an approach to reducing non-printing process time by designing and implementing a semi-automated electrode changing system.
The Effect of Temperature, Thickness, and Working Time on Adhesive Properties
Authors: Aerne Nicholas , Parmigiani John P.
Published: January 2019

The need for lightweight components and non-destructive fastening techniques has led to the growth of adhesive use in many industries. Modeling the behavior of adhesives in fastening joints can help in the design process to make an optimized joint. To optimize joints in the design process, the loading conditions, environmental conditions of service, thickness of bond, and bonding procedures all need to be refined for the adhesive of interest. However, in available technical data sheets of adhesives provided by manufactures there is a gap in what is sufficient to accurately model and predict the behavior of real-world adhesive conditions. This body of research presents the results of the effects of temperature, thickness, and working time on adhesive properties. These effects can be observed with test specimens from the loading modes of interest. The loading modes of interest are mode I and mode II loading for the current study. The specimen for mode I loading is the Double Cantilever Beam, and for mode II loading is the Shear Loaded Dual Cantilever Beam. The effect of temperature will be tested by testing each specimen at −20°C, 20°C, and 40°C. Two bond thicknesses for adhesive thickness effects were tested. The working time had a control group bonded in the recommended working time and an expired working time group where the specimens were not joined until 10 minutes had passed from the recommended working time. Triplicates of each specimen at the respective conditions were tested. The adhesive selected for this research was Plexus MA832. The results of the experiment show that adhesive factors such as temperature, thickness, and working time can have degrading effects on adhesive performance in mode I and mode II.
Deep Convolutional Neural Networks for Breast Image Analysis on Holographic Microwave Imaging
Authors: Wang Lulu , Xu Jinzhang
Published: January 2019

This paper presents the development of a deep convolutional neural network (CNN) method namely super-solution CNN to produce a high-resolution microwave breast image from a low-resolution model, which helps to improve the accuracy and efficiency of breast lesion detection within microwave image. Various experiments are conducted to validate the proposed method. Experimental results show that the proposed approach has the potential to produce a high-resolution breast image with high-accuracy.
Numerical Study on Explosion Cutting Process of PMMA Plate and Key Factors Influence on Cutting Performance
Authors: Ge Lei , Wang Yantao , Hu Huipeng , Li Lijun , Zhang Yiben
Published: January 2019

Polymethylmethacrylate (PMMA) has been widely utilized to manufacture the covers of aircraft cockpits, naval vessels, car windows and so on, due to their high transmittance, low density, easy processing formability, high corrosion resistance and excellent mechanical properties. Under special conditions such as ejection lifesaving, the PMMA plate needs to be split precisely by explosion cutting technology. Hence, an accurate numerical simulation of PMMA structures is significantly important in engineering application. This paper aims to study the cutting behavior of PMMA plate numerically and investigate the influencing factors on cutting performance of PMMA plates. First of all, the simulation of explosion cutting process of PMMA plate is carried out by a non-linear explicit solver in LS-DYNA software using the fluid-solid coupling method. Jones-Wilkins-Lee (JWL) equation of state is used to simulate the relationship between the transient pressure and specific volume of explosives during explosion. The material model considering failure behaviors is used in the simulation. Additionally, the influence of explosive dosage as well as explosive type on the cutting performance of PMMA plate is investigated. Furthermore, the effect of PMMA geometry size on cutting performance is discussed. This study contributes to the knowledge for the design of PMMA structures which needs explosion cutting and the selection of explosive dosage and explosive type.
Exploring Training Methodologies Towards the Improvement of Elderly Balance
Authors: Thompson Lara A. , Brusamolin Joao Augusto Renno , Guise Jelani , Badache Mehdi , Estrada Sandy Collado , Behera Lonika , Savadkoohi Marzieh , Coombs Tyra , Guerrero Pablo Sanchez , Shetty Devdas
Published: January 2019

The purpose of this study was to investigate the effects of utilizing sensory (i.e., vision and touch), as well as static and dynamic base of support training on the balance of senior participants aged 60–80 years old. For each participant, there were several weeks of training, two sessions per week and assessments every two weeks. Training included walking and standing exercises on a hard surface, compliant and stiffer foam walking and standing balance training, and navigating obstacles. Within each session, to modify vision, all training included eyes-open and closed. Further, there were increases in training difficulty as the sessions progressed.

It was observed that training over several weeks resulted in increases in stability, as observed by the decreases in Balance Error Scoring System (BESS) assessment results. However, increases in balance confidence, as observed by the Activities-Specific Balance Confidence (ABC) scale were less certain in this healthy elderly (or senior) population. It is an interesting and positive finding that, in doing relatively simple, but targeted exercises and training, senior individuals can have moderate improvements in their balance and, perhaps ultimately, reduce their fall-risk.
Aerodynamic Shape Optimization of Diffuser Augmented Wind Turbine Shrouds Using Asynchronous Differential Evolution
Authors: Leloudas Stavros N. , Lygidakis Georgios N. , Strofylas Giorgos A. , Nikolos Ioannis K.
Published: January 2019

An adaptable numerical scheme for the aerodynamic shape optimization of axisymmetric diffuser-augmented wind turbine shrouds is demonstrated in this work, using an asynchronous and parallel version of a Differential Evolution (DE) algorithm. The simulation of the incompressible flow field about each candidate geometry is succeeded by means of an in-house Computational Fluid Dynamics (CFD) solver, that has been developed based on the specially modified, by the artificial compressibility approach, Navier-Stokes equations, expressed in non-dimensional form, for 2D-axisymmetric frames of reference. The discretization of the computational domain is made with 2D hybrid unstructured meshes, composed by both triangular and quadrilateral elements, combined with a node-centered finite-volume scheme, while the Free-Form Deformation (FFD) technique is applied, for both the parameterization of the design geometry and the morphing of the computational mesh. The required data transfer between the DE algorithm and the CFD solver is accomplished with appropriate text files, while the parallel implementation is achieved utilizing the Message Passing Interface (MPI) library functions. Further acceleration of the optimization procedure is succeeded by the combination of the DE with surrogate models, in order to replace the costly CFD-based evaluations of the candidate solutions with fast, but approximate estimations of their cost function.
Thermodynamic Analysis and Multi-Objective Optimizations of a Combined Recompression sCO2 Brayton Cycle: tCO2 Rankine Cycles for Waste Heat Recovery
Authors: Alsagri Ali S. , Chiasson Andrew , Aljabr Ahmad
Published: January 2019

A thermodynamic analysis and optimization of a newly-conceived combined power cycle were conducted in this paper for the purpose of improving overall thermal efficiency of power cycles by attempting to minimize thermodynamic irreversibilities and waste heat as a consequence of the Second Law. The power cycle concept comprises a topping advanced recompression supercritical carbon dioxide (sCO2) Brayton cycle and a bottoming transcritical carbon dioxide (tCO2) Rankine cycle. The bottoming cycle configurations included a simple tCO2 Rankine cycle and a split tCO2 Rankine cycle. The topping sCO2 recompression Brayton cycle used a combustion chamber as a heat source, and waste heat from a topping cycle was recovered by the tCO2 Rankine cycle due to an added high efficiency recuperator for generating electricity. The combined cycle configurations were thermodynamically modeled and optimized using an Engineering Equation Solver (EES) software. Simple bottoming tCO2 Rankine cycle cannot fully recover the waste heat due to the high exhaust temperature from the top cycle, and therefore an advance split tCO2 Rankine cycle was employed in order to recover most of the waste heat. Results show that the highest thermal efficiency was obtained with recompression sCO2 Brayton cycle – split flow tCO2 Rankine cycle. Also, the results show that the combined CO2 cycles is a promising technology compared to conventional cycles.
Novel Twin-Screw Stirling Cycle Machine for Cryogenic and Refrigeration Applications
Authors: Mahkamov Khamid , Makhkamova Irina , Kahwash Fadi
Published: January 2019

This paper describes design and principles of operation of a novel rotary type Stirling cycle machines based on rotary positive displacement mechanisms such as twin-screw, gate rotor screw, scroll, and conical screw compressors and expanders. When these mechanisms are used as separate expanding or compressing machines, the flow of the gas is one-directional with volumes of chambers varying in accordance with a saw-tooth type function. The proposed design solution combines at least two units of gas-coupled compressor and expander arrangements with a required shift in the shaft angle. Every unit has a series of gas channels for timing the connection of its compressor and expander parts. Units are connected to each other via a set of heat exchangers, which are conventional for Stirling cycle machines: recuperative cooling and warm heat exchangers with a regenerator, built between them. The operational capability is demonstrated using three-dimensional CFD simulations. Computational results demonstrate reciprocating flow of the gas between units, as in conventional Stirling machines, and functioning of the proposed design as a multi-cylinder, double acting Stirling machine. The suggested design makes it possible to achieve full dynamic balancing, especially in the case of twin-screw and gate rotor mechanisms, due to the rotation of screws around their axes. It also eliminates a number of problems, which are specific to Stirling machines with reciprocating pistons and their kinematic drive mechanisms.
An Acoustic Analogy to Evaluate the Total Acoustic Power of a Cooling Fan Using Mesh Morpher Optimizer
Authors: Kheirallah Mike A. , Hamieh Abdallah , Jawad Badih , Liu Liping
Published: January 2019

The pressure fluctuation over the fan blades can generate unpleasant noises that affect the fan performance. Therefore, the noise control is considered as a significant factor in the design process. The purpose of this study is to estimate the total acoustic power of the surface on a cooling fan as a key function to improve design parameters.

The design process of a cooling fan to achieve low acoustic power can be lengthy and expensive through prototyping and experiments. The Mesh Morpher Optimizer (MMO) in ANSYS Fluent in coupling with the Powell’s model was applied to estimate the acoustic power over a cooling fan surface at a low speed. The Powell’s model in ANSYS was proved successfully in reducing the total acoustic power on the surface of the cooling fan which is shown by the numerical results. Comparison of the base model and Powell’s model, the Acoustic Power Level was reduced from 23.68 to 21.69 dB. The Surface Acoustic Power Level dropped from 62.24 to 61.26 dB. Likewise, the Surface Acoustic Power decreased from 9.67e−5 to 5.24e−5 W/m2. Also, the contour visualization results verified the success of the Powell’s model in combination of the Mesh Morpher Optimizer (MMO) to evaluate the total acoustic power and propose a new model that will assist in the design process in minimizing the manufacturing process of a new design model.
MCFC-Based System for Active CO2 Capture From Flue Gases
Authors: Carapellucci Roberto , Cipollone Roberto , Di Battista Davide
Published: January 2019

Carbon dioxide emissions reduction in the atmosphere is the major driver of technological innovations, in particular in energy and industrial sectors. Those sectors are dominated by the use of fossil fuels whose main concern on the combustion gases is the presence of CO2. Their emission in atmosphere accumulates Carbon, the main cause of global warming. The only way to continue to make reference to fossil fuel in the medium-long term and to avoid the carbon accumulation in the atmosphere is to use technologies capable to capture and sequester the carbon in the flue gases (CCS). In the sector of electricity production, several technologies have been proposed for the capture CO2, including absorption, adsorption, cryogenic distillation or membrane separation. All of them offer flexibility and easiness of application, but they need external energy to operate. On the other hand, particular interest is reversed to those technological options that are able to remove CO2 without energy consumption; even more attention is reserved to those technologies which, suitably integrated with other conversion systems, can produce electrical energy at the same time, so increasing the electricity production with respect to the original plant. They are defined active systems and one of these is represented by Molten Carbonate Fuel Cells (MCFCs). In fact, MCFCs are fuel cell capable to concentrate CO2 at anode exhaust, making easier its capture, separation and storage and in parallel to contribute to the electricity production.

In this paper, a comprehensive model of the MCFC is used to assess the opportunity related to its use as a CO2 remover from a flue gas as a CCS active device, without energy penalties related to traditional carbon capture methods (MEA, pre and post-combustion, oxy-combustion, etc.). Hence, it has been integrated in a wider system with auxiliary components: compressors to overcome pressure drops, steam generator (also using heat recovered from MCFC exhausts) for fuel dilution, fresh air integration in cathode inlet section, heat exchangers for thermal management and recovery. A CO2 compression and drying section has been considered and represented as a multi-step intercooled compression.

The so-defined system can be used as a plug-in device able to be coupled to flue gases with different compositions and thermodynamic operating parameters (temperature, pressure, flow rates). Finally, it has been applied to a case study (a Natural Gas Combined Cycle power plant - NGCC) and the performance of the MCFC in terms of CO2 removal capacity, electrical power generation and size have been evaluated as well the energetic and environmental impact on the reference NGCC power plant.
Pulsatory Mixing of Laminar Flow Using Bubble-Driven Micro-Pumps
Authors: Hayes Brandon , Hayes Austin , Rolleston Matthew , Ferreira Alexander , Krisher James
Published: January 2019

Y-shaped microfluidic channels have been built with Computer Numerical Control (CNC) and laser cutting manufacturing techniques. Fluid is delivered to each port via external syringe pumps. Each Y-shaped channel contains thermal inkjet (TIJ) resistors built using conventional microfabrication techniques. The resistors vaporize water and generate drive bubbles. This work focuses on utilizing TIJ technology as an active mixing technique in microfluidics. By varying the electrical firing frequency of the resistors, fluid was successfully mixed with an effective mixing length equal to the length of the TIJ resistor. As such, we demonstrate the use of TIJ resistors as a scalable, active mixing approach in microfluidics. A metric to characterize the extent of mixing using TIJ resistors was proposed and utilized. In addition, the fundamental framework of TIJ bubble dynamics with respects to mixing was assessed.
Study on Grinding Force and Surface Roughness of Ni3Al Based Superalloy
Authors: Zhu Xiaoxiang , Wang Wenhu , Jiang Ruisong , Liu Xiaofen
Published: January 2019

Ni3Al based superalloy is a kind of intermetallics, it is a relatively new superalloy, its superior high temperature characteristic makes it the fifth generation aero-engine turbine blade material. The machinability of Ni3Al based superalloy is poor, and its process parameters have significant influence on grinding force and surface integrity. The creep feed grinding experiments of Ni3Al based superalloy IC10 were carried out with different process parameters. The experimental results show that the workpiece speed has the greatest effect on grinding force, surface roughness and 3D surface topography, followed by grinding depth, the wheel speed has the smallest influence. Grinding force is positively correlated with grinding depth and workpiece speed, and negatively correlated with grinding wheel speed. Similarly, surface roughness is positively correlated with grinding depth and workpiece speed, and negatively correlated with grinding wheel speed. The higher the workpiece speed, the deeper the grooves and the higher the peaks of the surface topography. In order to maintain high surface quality, small workpiece speed and grinding depth should be chosen during grinding process.