bluuebunny/crossref_metadata_2025 huggingface dataset:
Axiomatic Design: Review, Impact, and Future Direction
Authors: Tate Derrick
Published: March 2016

Design broadly defined deals with mapping from societal wants or needs to means for satisfying these needs. Axiomatic design is a well-known approach to design that was initially proposed by Nam P. Suh in the late 1970s. Since that time, it has underpinned much academic research in engineering design; it has been taught internationally as part of engineering curricula; and it has been used across many industries. This paper attempts to assess the impact of axiomatic design in guiding design research; its practical, industrial applications; as well as its role in stimulating and renewing engineering education. This paper also provides a brief review of the concepts underlying axiomatic design theory including its motivation and history of development, recent activity within the axiomatic design community, and suggestions for future research directions.
Reliability Analysis of Repairable System With Multiple-Input and Multi-Function Component Based on GO Methodology
Authors: Yi Xiaojian , Shi Jian , Mu Huina , Dong Haiping , Zhang Zhong
Published: March 2016

GO methodology is a success-oriented method for system reliability analysis. There are Multiple-Input, which contain control signal, oil provided and electrical signal et.al and MultiFunction Components (MIMFC) in some repairable systems, such as double-action variable displacement pump, multiple directional control valve, and hydraulic coupler etc. Because existing 17 basic GO operators in GO methodology can’t describe these MIMFCs accurately, it is a problem to adopt existing GO methodology to conduct the reliability analysis for these systems with MIMFC. In this paper, firstly a new GO operator combination, which is composed of a new function GO operator and a new auxiliary GO operator, is created to represent MIMFC. The new function GO operator named as Type 22 operator is created to represent MIMFC itself, and the auxiliary GO operator named as Type 15B operator is created to represent multi-conditions control signals of MIMFC. Then, quantitative calculation formulas of new GO operator combination are derived based on logical relationships among inputs, outputs, and component itself. Thirdly, this new GO operator combination is applied for the first time in steady availability analysis and qualitative analysis of the fan drive system of a Power-shift Steering Transmission. Finally, the results obtained by the method in this paper are compared with the result of Fault Tree Analysis (FTA) and result of Monte Carlo simulation, and the comparison results show that this new GO operator combination is usable and correct for reliability analysis of repairable system with MIMFC, and it has more advantageous in the aspects of building system model and quantitative analysis. Meantime, this paper provides guidance for reliability analysis of other repairable systems with MIMFC.
On Primary Resonance of Electrostatically Actuated Double Walled Carbon Nanotube Cantilever Biosensors
Authors: Caruntu Dumitru I. , Juarez Ezequiel
Published: March 2016

This paper investigates electrostatically actuated Double Walled Carbon Nanotubes (DWCNT) cantilever biosensors using the Method of Multiple Scales (MMS) and the Harmonic Balance Method (HBM). Forces acting on the outer tube of the DWCNT are electrostatic, damping, and van der Waals, while only van der Waals acts on the inner tube. The electrostatic actuation is provided by a soft AC voltage. Van der Waals forces are present between the carbon nanotubes, coupling the deflections of the tubes; herein, for modal coordinate transformation, only the linear term of the van der Waals force will be considered. The nonlinearity of the motion is produced by the electrostatic and van der Waals forces. The DWCNT undergoes nonlinear parametric dynamics. MMS is employed to investigate the system under soft excitations and/or weak nonlinearities. The frequency-amplitude response is found in the case of primary resonance. DWCNTs are modelled after the Euler-Bernoulli cantilever beam. The expected nonlinear dynamic behavior is important to improve DWCNT resonator sensitivity in the application of mass sensing.
Recent Developments in Steel Friction Stir Welding: Project HILDA
Authors: Toumpis Athanasios I. , Galloway Alexander M. , Camilleri Duncan , Arbaoui Larbi
Published: March 2016

Friction stir welding of steel presents an array of advantages across many industrial sectors compared to conventional fusion welding techniques. Preliminary studies have identified many positive effects on the properties of welded steel components. However, the fundamental knowledge of the process in relation to structural steel remains relatively limited, hence industrial uptake has been essentially non-existent to this date. The European-funded project HILDA, the first of its kind in terms of breadth and depth, is concerned with enhancing the understanding of the process on low alloy steel, establishing its limits in terms of the two more significant parameters which can be directly controlled, tool traverse and rotational speed, thus improving its techno-economic competitiveness to fusion welding.

A detailed study investigated the effect of process parameters on the evolved microstructure. In parallel, a full programme of mechanical testing was undertaken to generate data on hardness, impact toughness and fatigue. From this, it has been established that friction stir welding of steel produces high integrity joints that exhibit excellent fatigue properties.

From a simulation perspective, a local microstructural numerical model has been developed to predict the microstructural evolution within the weld zone during friction stir welding of low alloy steel. This model concentrates on predicting grain size evolution due to dynamic recrystallization with respect to tool traverse and rotational speed. Furthermore, a computational efficient local-global numerical model capable of predicting the thermal transients, stir and heat affected zone, residual stresses and distortion produced by friction stir welding of DH36 plates is presented.
Optimized Planar 3PRR Mechanism for 5 Degrees-of-Freedom Hybrid Kinematics Manipulator
Authors: Rosyid Abdur , El-Khasawneh Bashar , Alazzam Anas
Published: March 2016

Hybrid kinematics mechanisms combines the advantages of purely serial and purely parallel kinematics mechanisms. Several hybrid kinematics mechanisms have been proposed. This paper proposes a novel hybrid kinematics mechanism using planar 3PRR planar kinematics mechanism, which can be utilized for machine tool. As the common main drawback of parallel mechanism is the workspace, the proposed mechanism has been optimized by using constrained nonlinear optimization. It is shown that the optimization gives significant improvement of the workspace area and shape.
Passive Multi-Degree-of-Freedom Structural Control Using LPC Impact Dampers
Authors: Gharib Mohamed , Karkoub Mansour
Published: March 2016

Excessive vibration is one of the main reasons leading to partial damage and in some cases collapse of tall buildings and structures. Impact dampers provide an effective, economical, and easy to install solution to the vibration problem in several applications. The latest developed type in the impact dampers family is the Linear Particle Chain (LPC) impact damper. It consists of a linear arrangement of two sizes of freely moving masses, constrained by two stops. This paper presents the results of an experimental investigation on the effectiveness of the LPC impact damper in damping the vibrations of a multi-degree-of-freedom system under different types of excitations. A prototype of the LPC impact dampers is fabricated and tested in our lab using a three-story frame structure. The experimental outcomes clearly show that the LPC impact damper can effectively attenuate the free and forced vibrations of flexible structures.
The Relationship Between Tensile and Fatigue Strength of Friction Welded Steel Joints
Authors: Selvamani S. T. , Palanikumar K. , Shanmugam K. , Divagar S. , Vigneshwar M.
Published: March 2016

The friction welding of AISI 52100 grade low chromium and high carbon steel joints are investigated in this work to evaluate the fatigue life of the joints by conducting the experiments using servo hydraulic fatigue testing machine at different stress levels. All the experiments are conducted under uniaxial tensile loading condition (stress ratio=0). Fatigue strength, fatigue notch factor (Kf) and notch sensitivity factor (q) are evaluated for the optimized joints and the relationship between tensile and fatigue properties of Fully Deformed None (FDZ) is established. Finally, the Characteristics of friction welded joint is investigated with the help of Scanning Electron Microscope and Optical Microscopy under optimized condition.
Performance Evaluation of a Modified Cross Section Grooved Channel as Turbulence Promoter in Internal Cooling Channel of a Gas Turbine Blade
Authors: Saha Krishnendu , Prabhudharwadkar Deoras
Published: March 2016

Internal cooling channel in gas turbine blades use ribs as turbulence promoter to increase local turbulence and improve heat transfer from hot wall to coolant air flowing through the internal cooling channels. The ribs protrude into the flow and result in a significant pressure drop of the coolant air. Indentations like grooves in the cooling channel wall can also be used as turbulence promoters to enhance local heat transfer and as they do not protrude into the mainstream flow, the pressure drop penalty could be much lesser than a conventional ribbed channel. A numerical study is conducted under stationary condition on a square cross section channel representing an internal cooling channel of a turbine airfoil. Some standard and modified cross sections of grooved channel are used as turbulence promoters with a goal to enhance heat transfer from the internal cooling channel wall with minimal pressure drop. The steady state solution is based on using the Reynolds Averaged Navier-Stokes (RANS) equation and k-omega-SST turbulence model. Numerical calculations are done at four Reynolds numbers (Re=15000, 30000, 68000 and 88000) based on fluid properties at the inlet of the internal cooling channel. The grooves are placed on two opposite sides of the square cross section channel and other two walls are smooth walls without any turbulence promoters. A hemispherical cross section continuous groove which is placed perpendicular to the mainstream flow direction is taken as baseline case and a teardrop shaped groove is used to compare the performance difference between the two groove cross section. A broken shaped angled groove configuration with the teardrop cross section groove is also investigated to find the relative performance improvement with the baseline case. Performance comparison with standard 90° rib geometry is done to understand the overall effectiveness of the grooved geometries with respect to common standard in gas turbine blade internal cooling. The straight teardrop cross section groove improves the heat transfer values compared to the hemispherical cross section groove by 8–12% and the broken angled teardrop groove case improves heat transfer by 11–14% compared to the hemispherical cross section groove case. The pressure drop produced by all the groove geometries is about the same. It is seen that the broken angled groove can produce the same heat transfer enhancement compared to a 90° ribbed channel but the pressure drop is more than 3 times lesser compared to the ribbed case. Considering the heat transfer and pressure drop, an increase in thermal performance factor of 37–41% is seen for the angled grooved case compared to the 90° ribbed geometry.
Determination of Heat Transfer Characteristics of Solar Thermal Collectors as Heat Source for a Residential Heat Pump
Authors: Sourbron Maarten G. , Ozalp Nesrin
Published: March 2016

One of the best ways of making efficient use of energy in residential units is to use heat pump. Heat pump performance can be further enhanced by integrating a solar thermal unit to provide hot water and subsidize space heating. This paper presents numerically examined energy feasibility study of a solar driven heat pump system for a low energy residence, where a flat plate solar collector served as the sole low temperature heat source. A parametric study on the ambient-to-solar fluid heat transfer coefficient has been conducted to determine the required solar collector heat transfer characteristics in this system. Solar collector area and storage tank volume were varied to investigate their impact on the system performance. A new performance indicator availability was defined to assess the contribution of the solar collector as low temperature energy source of the heat pump. Results showed that the use of a solar collector as low temperature heat source was feasible if its heat transfer rate (UA-value) was 200 W/K or higher. Achievement of this value with a realistic solar collector area (A-value) required an increase of the overall ambient-to-solar fluid heat transfer coefficient (U-value) with a factor of 6 to 8 compared to the base case with only natural convection heat exchange between solar collector cover and ambient.
Harmonic Elimination in a Solar Powered Cascaded Multilevel Inverter Using Genetic Algorithm and Differential Evolution Optimization Techniques
Authors: Sudha Letha Shimi , Thakur Tilak , Kumar Jagdish
Published: March 2016

In the present work the authors propose a solar powered cascaded multilevel inverter which can be integrated with the grid. To connect the solar photovoltaic system to the grid a dc to ac conversion of power is required which is made possible using a multilevel inverter, but the power electronic switches introduces harmonics during the switching process. Thus the investigators propose a selective harmonic elimination technique using Genetic Algorithm and Differential Evolution Optimization Techniques. The performance comparisons of the proposed techniques will be carried out by comparing the Total Harmonic Distortion (THD) and the selective harmonics such as 5th, 7th,11th and 13th using FFT analysis in MATLAB/SIMULINK. The authors anticipate that the comparative analysis presented in this work will be very useful for further research.
Sustainable Reform of an Introductory Mechanics Course Sequence Driven by a Community of Practice
Authors: West Matthew , Silva Sohn Mariana , Herman Geoffrey L.
Published: March 2016

As part of a broader effort to promote the sustainable adoption of evidence-based pedagogies at our institution, the three-course sequence consisting of Introductory Statics, Introductory Dynamics, and Introductory Solid Mechanics has been redesigned to (1) improve students’ low engagement and enthusiasm, (2) improve instructors’ experience and reduce their high workload, and (3) maintain and elevate the current standards for content. These three courses are the core second-year mechanics classes in our engineering curriculum, serving approximately 2500 students per year from seven engineering departments. To promote sustainability of the reforms, the courses were redesigned through a Community of Practice (CoP), consisting of faculty who collaborated closely to design and implement changes and who developed communal knowledge of the reforms. Evaluation of reforms focused on student satisfaction as expressed through surveys and focus groups.
Integrated Roller Coaster Design Environment: Dynamic and Structural Vehicle Analysis
Authors: Braccesi Claudio , Cianetti Filippo , Landi Luca
Published: March 2016

In this paper a tool for the multibody simulation and structural analysis of roller coaster (RC) is illustrated. It was developed in order to support the designer and manufacturer of rides during the design stage. The goodness of the modelling and simulation procedure was validated in terms of dynamic behaviour by experimental/numerical comparisons by conducting an experimental tests campaign on the existing Roller Coaster. Another aim was to verify and illustrate the possibility to recover the stress state of RC axles not from a rigid multibody model and by an indirect approach but, directly, by a rigid/flexible model by their modal modelling.
Numerical Study of the Effect of Plane Blind Side Gap Size on the Heat Transfer Rate From a Recessed Window to a Room
Authors: Oosthuizen Patrick H.
Published: March 2016

Heat transfer from a window recessed into a wall when there is a plane blind mounted over the window, the blind being in the same plane as the wall, has been considered. In such situations the blind is sometimes narrower than the window, i.e., there are gaps between the vertical edges of the blind and the vertical edges of the wall window opening. In the present study the effect of the size of the blind edge gaps on the window heat transfer has been numerically investigated. Conditions under which the flow over the window-blind system is laminar and under which it is turbulent have been considered. The present study, as in many previous window heat transfer studies, has only considered the convective heat transfer from the window to the surrounding room. The flow has been assumed to be steady and symmetrical about the window-blind vertical center-plane. The Boussinesq approach has been used and it has been assumed that the “window”, which is modeled as a plane surface, is at a uniform temperature. Attention has been restricted to the case where the window is at a higher temperature than the temperature of the room air, this room air being assumed to be at a uniform temperature far from the window. The solution has been obtained by numerically solving the governing equations using the commercial CFD solver FLUENT©. The k-epsilon turbulence model has been used in obtaining the solution. Results have only been obtained for a Prandtl number of 0.74, i.e., effectively the value for air. The effect of the dimensionless size of the blind side gaps on the window Nusselt number has been studied for various Rayleigh numbers; the results being used to determine under what conditions the blind side openings have a significant effect on the window heat transfer rate.
Two-Phase Flow Regimes in Exchangers and Piping: Part 1
Authors: Talapatra Siddharth , Farrell Kevin
Published: March 2016

The ability to predict the liquid-gas two-phase flow regime and void fraction in exchangers and piping is a critical engineering requirement in the process industry. The distribution of the liquid and gas phases depend on many factors including flow conditions, physical properties of the two fluids, and geometry of the flow conduit. The problem of correctly predicting the two-phase distribution is of enormous complexity, and generalized correlations that adequately describe the flow regime and/or the void fraction have not been yet been developed even for the simplest of geometries. While Computational Fluid Dynamics codes that model two-phase flows exist, they are limited in their applicability and usually require a priori knowledge of the flow regime. In this part of a two paper series, we discuss the state-of-the-art in two-phase flow regime studies inside shell-and-tube heat exchangers, while in the second part, we will discuss two-phase flows inside piping. We have performed air-water tests inside a glass shell-and-tube exchanger at HTRI, and by systematically varying various geometrical parameters, compiled the largest flow visualization database inside such exchangers. We have evaluated the best available flow regime maps available in the open literature, and shown how our results help enhance understanding of liquid-gas distribution inside heat exchangers. We have shown how, for a given flow rate, increasing the baffle spacing and reducing baffle-cut enhances two-phase separation. While these results are expected, they have never been quantified before. However, the use of flow visualization limits the liquid and gas phases to water and air mixtures, which limits the range of applicability. Shellside studies using various industrially relevant fluids such as hydrocarbon mixtures, steam water are planned, where non-visual flow regime detection techniques need to be applied.
Upgradation of HVAC Systems in Exisiting Commercial Green House Using Evaporative Coolers in Middle East Climatic Conditions
Authors: MattaraChalill Subin , Kalamegam Miller Jothi , Parveen Mallika
Published: March 2016

Commercial green houses are the back bone of farming industry in world where the climatic conditions are not stable especially in Middle East, Europe and United states. The commercial greenhouses are often high tech production facilities for vegetables or flowers. The glass greenhouses are filled with equipment like screening installations, heating, cooling, and lighting and also may be automatically controlled by a computer to maximize potential growth. Greenhouse concept will provide the stable indoor plant growth environment throughout the year irrespective of the outside climate variance. The indoor climate conditions can be maintained using the properly designed HAVC systems. The conventional commercial green houses are equipped with axial fans and the cooling pads to control the indoor climate conditions without central control of the equipment’s. Financial conditions of the commercial green houses are very important since the cost per plant will be determined by the overall contribution of the capital and operational expenses. In the present scenario the almost 30% of the net profit is eating by the HVAC systems operational cost. The major operation cost is due to the cooling pads work force and the electricity operational cost for the axial fans equipped with metal blade. The up gradation involves mainly the involvement of individual evaporative air-conditioned system instead of conventional systems. The green houses are equipped with individual evaporative cooling units, circulating fans, top mounted air louvers and the control systems to control the entire set up. The initial heat load calculations will give us an idea about the total heat load required to maintain the ambient conditions for indoor plant cultivation. CFD analysis will provide the exact equipment orientation and the load requirement. In conventional greenhouses the conventional equipment’s are equipped to get the results but the same will consume more electrical power and which is not effective in all weather conditions. Heat load calculations will provide us the system demand in a conditioned space based on the available material properties. Based on the heat load results we can do the proper equipment selection and set the airflow based on the demand. CFD analysis will help the modeling of the system in the actual condition. The aim of the study was to analysis the performance study of the individual evaporative cooling units in the greenhouse conditioned space. The results obtained from the heat loads and CFD analysis can be compared. The objective of the present work is to examine the designed Air conditioning system effectiveness in peak summer heat load conditions to check the design parameters (25 °C temperature and 50%RH) inside the greenhouse using Computational Fluid Dynamics (CFD) Analysis.
A Novel Mass Spring Model Topology for Modeling of Linear Isotropic Homogeneous Materials
Authors: Suryawanshi Pradeepkumar , Gupta Abhishek
Published: March 2016

Mass Spring Systems (MSS) have been extensively used for real-time computer simulations of deformable objects. However, identification of parameters for MSS is a challenging task, and increase in mesh resolution for MSS does not guarantee convergence to a better solution. We propose a modification to the square unit cell of a MSS, for modelling linear homogenous isotropic materials by utilizing additional shear springs. For this element, we derive the spring stiffness expressions analytically using the material properties. This proposed element can accurately model the deformation behaviour of a continuum element under tensile and pure shear loading, for all values of modulus of elasticity and Poisson’s ratio less than 1/3. The bulk behavior of the MSS model was verified for a beam and a plate subjected to tensile and transverse loading. It was found that as mesh resolution increases, the MSS solutions converge to values that are very close to the solutions obtained through FEM. This model was then used for predicting crack growth direction in a brittle linear elastic isotropic material.
Thermoforming of Polymer Laminate Films: Thermo-Viscoelastic Characterization
Authors: Truszkiewicz E. , Tscharnuter D. , Pilz G. , Pinter G.
Published: March 2016

The thermo-viscoelastic behavior of a polymer laminate film was characterized by mechanical measurements to obtain data for material modeling. The strain was measured using digital image correlation. The film is anisotropic and sustains uniaxial strains up to 60%. Additionally, the thermal expansion was measured for both materials that form the laminate.
Hyperbolicity Analysis of a One-Dimensional Two-Fluid Two-Phase Flow Model for Stratified-Flow Pattern
Authors: Sondermann Carina N. , Patrício Rodrigo A. C. , Figueiredo Aline B. , Baptista Renan M. , Rachid Felipe B. F. , Bodstein Gustavo C. R.
Published: March 2016

Two-phase flows in pipelines occur in a variety of processes in the nuclear, petroleum and gas industries. Because of the practical importance of accurately predicting steady and unsteady flows along the line, one-dimensional two-fluid flow models have been extensively employed in numerical simulations. These models are usually written as a system of non-linear hyperbolic partial-differential equations, but some of the available formulations are physically inconsistent due to a loss of the hyperbolicity property. In these cases, the associated eigenvalues become complex numbers and the model loses physical meaning locally. This paper presents a numerical study of a one-dimensional single-pressure four-equation two-fluid model for an isothermal stratified flow that occurs in a horizontal pipeline. The diameter, pressure and volume fraction are kept constant, whereas the liquid and gas velocities are varied to cover the entire range of superficial velocities in the stratified region. For each point, the eigenvalues are numerically computed to verify whether they are real numbers and to assess their signs. The results show that hyperbolicity is lost near the boundaries of the stratified pattern and in a vast area of the region itself. Moreover, the eigenvalue signs alternate, which has implications on the prescription of numerical boundary conditions.
Development of Novel 3D Scaffolds With Embedded Core-Shell Nanoparticles for Nerve Regeneration
Authors: Lee Se-Jun , Zhu Wei , Zhang Lijie Grace
Published: March 2016

Neural tissue engineering has emerged as a promising alternative to address various nerve injuries. Particularly, advancement in both 3D biomimetic scaffold fabrication strategies and nanotechnology has inspired this field into a new era. In this study, we fabricated a novel 3D biomimetic scaffold, which has tunable porous structure and embedded core-shell nanoparticles with neurogenic factor delivery system, using stereolithography (SL) based 3D printing and core-shell electrospraying techniques. Our results indicated that scaffolds with higher porosity significantly improve PC-12 neural cell adhesion compared to ones with smaller porosity. Furthermore, scaffolds embedded bovine serum albumin (BSA) containing nanoparticles showed an enhancement in cell proliferation relative to bared control scaffolds. In addition, confocal microscopy images illustrated that the scaffold with nerve growth factor (NGF) nanoparticles increased the length of neuritis and directed neurite extension of PC-12 cells along the fiber. The results in this study demonstrate the potential of this 3D scaffold in improving neural cell function and nerve growth.
An Alternative Concept for Maintaining Occupant Compartment Integrity During Narrow Overlap Vehicle Crashes
Authors: Brar Bavneet S.
Published: March 2016

Front Small Overlap (FSO), a new test mode introduced by IIHS is used for differentiating North American market vehicles on their safety ratings with the Top Safety Pick (TSP) status. Current paper describes a production ready version of a non-traditional (door insert) concept. Small overlap test mode demands occupant cage integrity which can be achieved from structural countermeasures in the Side Sill, A-pillar or Front body hinge pillar. These structural measures add mass and need lead time for development (not feasible for existing vehicles). Current study describes door insert design that can be incorporated into the doors for providing improved strength for small overlap loading conditions. Paper investigates composites / structural plastic design onto existing impact door beams (Within the available packaging space). The door insert, along with improved CAB deployment capability, would provide improvement on existing vehicle safety ratings.
Accurate Prediction of Strains and Stresses in 2-D Elasticity Using Adini’s Finite Element
Authors: Aguirre-Rivas Donovan A. , Muci-Küchler Karim H.
Published: March 2016

In the interest of obtaining accurate stress predictions in linear elastic problems while keeping the computational cost low, a finite element solution approach using cubic elements that include not only the displacement but also the spatial derivatives of the displacement as nodal degrees of freedom (DOFs) is explored in this paper.

The proposed approach has the advantage that the nodal values of the strains, and hence the stresses, can be directly computed from the finite element solution and, as shown in this paper, it is capable of converging faster to the analytical solution than the commonly used reduced integration Serendipity quadratic element.

Because the proposed approach is capable of achieving high accuracy using less DOFs, it is possible to use coarser meshes than with conventional elements. This is of particular importance in dynamic problems in which explicit techniques are used and the size of the time step is tied to the element size. Moreover, the proposed approach can be beneficial in non-linear problems in which stepping techniques are used to solve a linearized problem and the strains or stresses of the current step are used as input for the following step.
Fatigue Modeling for Polyether Ether Ketone (PEEK) With Mean Strain Effects
Authors: Shrestha Rakish , Simsiriwong Jutima , Shamsaei Nima
Published: March 2016

In this study, the fatigue behavior of a polyether ether ketone (PEEK) polymer was investigated under uniaxial strain-controlled conditions with and without mean strain. Experimental study included a series of fully-reversed fatigue tests at five strain amplitudes (2%, 2.5%, 3%, 3.5%, and 4%) and fatigue tests at three mean strain values (2%, 2.5%, and 3%) at various frequencies. Stress responses of PEEK obtained from the tests under fully-reversed cyclic loading condition indicated a significant cyclic softening, while a stress relaxation was observed for the PEEK specimens under mean strain cyclic loading. Two different types of fatigue models, including a strain-based (Coffin-Manson) and energy-based, were employed to correlate fatigue life obtained from all experimental data. Among the two fatigue models, the fatigue life prediction using the energy-based approach was found to provide a better correlation to PEEK experimental data for both fully-reversed and mean strain conditions when compared to the Coffin-Manson model.
Planning, Evaluation and Comparison of Electric Drive Systems Using Various Configurations to Increase Energy Efficiency and Optimize Alternating Current Drive Systems
Authors: Javied Tallal , Menk Jochen , Franke Joerg
Published: March 2016

The industrial sector is the largest consumer of produced electric energy worldwide. Electric motor systems account for about 70 percent of the total industrial electricity demand and possess a great cost and energy saving potential. The paper provides an overview of global and regional efforts to create awareness for potential cost drivers in the industry. Various software and excel-based tools for a preliminary estimation of the energy consumption of electric motor systems are available in the market, but a holistic approach is missing. Therefore a framework and a systematic process for the estimation of potential energy savings in motor systems running on alternating current are illustrated in this paper. Moreover a new software tool is discussed, that allows a holistic view on all motor systems within a company without cost-intensive measurements or the use of external consultants.
A Validated TRNSYS Model of Thermally Activated Layer With Phase Change Material
Authors: Charvat Pavel , Klimes Lubomir , Ostry Milan , Stetina Josef
Published: March 2016

Simulations of building performance or HVAC systems performance usually cover a time period of several weeks, months or even a year. Therefore, the computational demand of simulation models of buildings or HVAC systems can be quite constraining for their practical application. A substantial simplification of the simulated problem is usually necessary to reduce the computational demand. The paper reports the development of a quasi 1D model of a thermally activated layer with phase change material. The model was developed in MATLAB and subsequently implemented as a TRNSYS type. The model was validated with data obtained from experiments with thermally activated panels. The experimental panels contained a 15 mm thick layer of gypsum plaster comprising 30 wt.% of microencapsulated phase change material. Plastic tubes for liquid heat carrier (water in the presented study) were embedded at the bottom of the plaster layer. Thermal imaging was used to acquire the average surface temperatures of the panels in the experimental investigations. The experimental and numerical results were in a good agreement.
Pneumothorax Training System
Authors: Martinuzzi Valeria , Trabing Emily C. , Dow Douglas E.
Published: March 2016

Pneumothorax is a moderately common condition in the respiratory system, which can result in significant impairment or even death. Prompt treatment is urgent for sustaining quality of life. One contributing factor when there is a delay in the administration of treatment is a lack of training for the medical staff, especially active hands-on training. This insufficient training may delay recognition and diagnosis of pneumothorax, and also delay the start of the treatment. An improved training method would potentially enable a wider range of medical staff to be ready to identify pneumothorax and administer treatment in an efficient manner.

The purpose of this project was to develop a hands on automated system for training. The system was based on a commercially available manual simulator with a hand pump. Automation was incorporated for filling of the air bag which simulated the trapped air of pneumothorax. Visual indications were presented to the user to show what state of training the simulator was in. This automated system reduced the fatigue factor, and improved the efficiency of the simulator for training trials by 60%. The automated system allowed for more trials to be performed in a given amount of time, with feedback given to the user so the trainee could be assured they were performing the treatment procedure correctly.
Experimental Investigation on Particle Deposition Patterns From Turbulent Pipe Flow
Authors: Dai Y. , Khan T. S. , Alshehhi M. S. , Khezzar L.
Published: March 2016

This paper reports an experimental study on sand particles deposition pattern in a horizontal circular pipe for several air flow rates and particle - air volumetric loading ratios. The experiments are conducted in a horizontal circular pipe with air - sand particles flow to simulate the solid particles movement in turbulent flow. A 50 mm diameter pipe was used in the current study while the averaged sand particles size used is around 100 μm. The particles are injected into the fully developed turbulent air flow. Digital cameras are used to capture the images of scaled test sections. The time dependent deposition layer properties including the geometry of deposition layers and the agglomeration pitch are studied. Hence, the average velocity of dune movement could also be calculated.

The experimental results show that, in general, the deposition layer is continuous near the injection point, while small agglomerates are observed at the remote end. For the low air flow rate, striped-like dunes were found near injection point. For relatively higher air flow rates, the dunes became longer in size. Similarly, the length of agglomerates increased and the area fraction occupied by the agglomerates increased. Small aggregates are re-entrained from the frontal dunes of the deposition layer, and new agglomerates were gradually formed behind the next dune. The free flight length of solid particles for a range of air flow rates with different solid loading ratios was studied. It is found that for a given solid loading ratio, decreasing air velocity decreased the free-flight length of particles.
A Novel Approach for Predicting Thermal Runaway in Electric Vehicle Batteries When Involved in a Collision
Authors: Sheikh Muhammad , Baglee David , Knowles Michael , Elmarakbi Ahmed , Al-Hariri Mohammad
Published: March 2016

Electric Vehicle (EV) battery manufactures are under pressure to ensure their products are safe and not prone to undetectable heat after an impact, which could lead to thermal runaway. Constant monitoring of the battery’s behaviour and, in particular, heat generation is therefore important for the safety of the vehicle and the occupant. An aim of this research is to use a series of battery models to study the charge/discharge and thermal behaviour of EV lithium ion batteries under normal and damaged conditions through modelling and physical/electrical testing. An equivalent circuit model is identified and tested to determine the electrical behaviour of the batteries and a 2 degree of freedom (DOF) model is discussed for the plastic deformational behaviour of the battery compartment as the result of an impact. The ultimate goal of this work is to develop a new model integrating physical, chemical, thermal and electrical behaviour to improve safety.
Second Law Analysis of Different Channel Geometries for Micro-Mixing
Authors: Meng Zhaotong , Lemley Evan C. , Hossan Mohammad R.
Published: March 2016

Micro-mixing in different channel geometries may increase entropy generation and lead to improved efficiency of fluid mixing. The entropy generation rate corresponds to irreversibility due to the heat transfer and viscous effects in fluid flow through a channel. The objectives of this study are to validate the entropy generation rate of three expansion/contraction geometries [1] by using an analysis based on the Second Law of Thermodynamics (SLT) numerically and to study how entropy generation rate changes by placing flow obstacles in the channel. The geometries presented are not unique. In this paper the focus is on using CFD combined with the SLT as a tool to explore the effectiveness of micro-mixers. The entropy generation field in the expansion/contraction region between a 100 micrometer wide and a 200 micrometer wide rectangular micro-channel was analyzed using computational fluid dynamics (CFD) ANSYS-Fluent, and compared with the experimental results from Saffaripour et al. [1]. The numerical velocity profiles in the fully developed region of the channel in the flow direction and normal to flow direction were compared with experimental profile [1], and determined to be in agreement with the experimental profile. Using CFD, the entropy generation rates were determined for combinations of channel expansion/contraction geometry and the presence/lack of flow obstacles. The results presented here show that flow obstacles, which generally lead to better mixing, also lead to higher entropy generation rates.
Computational Studies on the Effects of Non-Linear Temperature Functions in Thermal Creep Membranes of Radiantly Driven Knudsen Compressors
Authors: Han Yen-Lin
Published: March 2016

Employing rarefied gas phenomenon of thermal creep (also known as thermal transpiration), Knudsen Compressor is a micro/meso-scale gas compressor/pump without moving parts. Driven by a temperature difference, gas molecules moved from the cold side of the thermal creep channel, which has a size less than the molecular mean free path, to the hot side of the channel. To utilize its low thermal conductivity and nanometer range size pores, carbon opacified aerogel membranes, treated as a bundle of thermal creep channels, were used in prior experimental studies of radiantly driven Knudsen Compressors. By absorbing the radiation energy, a temperature gradient will develop inside of a carbon opacified aerogel membrane to drive thermal creep flows. Analytical studies of the radiation energy absorbed by a carbon opacified aerogel membrane were performed and the resulting non-linear temperature distribution function within the carbon opacified aerogel thermal creep membrane was identified previously. This paper presents DSMC (Direct Simulation Monte Carlo) simulation studies that incorporate the previously reported non-linear temperature distribution function to investigate the performance of the radiantly driven Knudsen Compressor with a carbon opacified aerogel membrane. Cases with different connector temperatures for a closed system Knudsen Compressor were studied to observe the maximum pressure differences. Comparison of results indicates that radiantly driven Knudsen Compressor with a carbon opacified aerogel membrane could achieve a larger pressure gradient than what is predicted by the theoretical model reported by Muntz et al.
A Brief Model to Evaluate the Behaviour of R134a/R1234yf Mixtures on a Reciprocating Compressor
Authors: Barroso-Maldonado J. M. , Belman-Flores J. M. , Rubio-Maya C.
Published: March 2016

Transitioning from R134a refrigerant to a low global warming potential (GWP) refrigerant is a current issue of global importance. Although any refrigerant still has set; there are a few options to replace it such as the R1234yf. In this paper is presented a semi-empirical model to assess the energy performance of mixtures with R134a and its possible substitute R1234yf. The inputs variables to the computational model are: suction conditions (pressure and temperature), discharge pressure and rotation speed. With these variables the model must compute the following parameters: mass flow rate, discharge temperature and energy consumption. The model is validated with data obtained from an experimental facility; calculations are obtained within a relative error band of ±10% for mass flow rate and energy consumption, and an error of ±1 K for discharge temperature. Finally, the model is carried out to an energy simulation in order to predict the behavior of different mass fractions of R1234yf. Energy savings are found when R1234yf mass fraction is reduced from 1 to 0.9. Knowing that the mixture with y=0.9 may be used as its GWP is 150.
Applying Transient Analysis to Estimate Fail Safe Operating Time of Heating Coils in LNG Plant
Authors: Ahamad Sultan , Vallavanatt Rimon , Izadi Mahmood
Published: March 2016

A semi-analytical method is proposed in this study to estimate tube wall temperature versus time for Waste Heat Recovery Units (WHRU) and fired heaters in a typical LNG plant. The results are used to estimate Safety Time to avoid failure of tubes. Safety time estimation is crucial for control loop design of equipment in the operating plant. Two case studies are presented based on real control loop design data for an LNG plant. The results show that for both case studies, process safety time for control loop is less than the tubes safety time. Therefore the control system is capable of safely stopping the equipment from operation without tube failure or degrading of the process fluid.

The proposed semi-analytical method is capable of calculating the Safety Time for WHRUs and fired heaters in an economical way while the method offers a reasonable accuracy due to its analytical nature. The proposed method can be used in Fundamental Engineering and Evaluation Designs (FEEDs), Hazard and Operability studies (HAZOPs) and Hazard Identification (HAZID) studies for LNG plants and power plants.
Second Sandia Fracture Challenge: CanmetMATERIALS’ Prediction
Authors: Williams Bruce W. , Simha Hari
Published: March 2016

This paper is a description of the models and methods used by CanmetMATERIALS to model failure and fracture of Ti-6Al-4V alloy sample as part of the Second Sandia Fracture Challenge. Finite element models, meshed with 8-noded brick elements, were used to simulate loading of the tensile, shear, and fracture specimens. The approximate element size near localization and failure in each of the specimens ranged from about 0.2 to 0.4 mm transitioning to larger elements away from the failure zone. Simulations were performed using the explicit dynamic solvers in ABAQUS and DYNA3D. For both solvers, a user-defined subroutine was implemented to describe the material behavior. The Xue-Weirzbicki damage model was used to describe the failure of the material. The foregoing is a general three-dimensional damage-mechanics-based approach to model failure and fracture under low to high constraint and also ductile and shear failure. Plastic deformation was modeled using both isotropic von-Mises and the Cazacu-Plunkett-Barlat 2006 (CPB06) asymmetric/anisotropic yield function. Both subroutines used the Bazant-Pijaudier-Cabot non-local approach to mitigate the mesh dependence of finite element simulations. Crack growth was modeled using the element deletion technique. Though the two subroutines were very similar, there were small differences in the implementations of the two models, such as the tolerances utilized for convergence, which led to two slightly different predictions. The yield and failure models were approximately calibrated using a combination of the tensile, shear data, and supplemented with data from the open literature. Blind predictions of the loading of the challenge-sample geometry were made and subsequently found to be in reasonable agreement with the experiments carried out at Sandia National Labs. Sources of discrepancies are identified and discussed in this report.
An Exergy-Based Analysis of Temperature Profiles for an Over-Pressure Reflow Oven Technology
Authors: Esfandyari Alireza , Syed-Khaja Aarief , Landskrone Torben , Franke Joerg
Published: March 2016

In electronics assembly, the convection based soldering technologies in the production lines consumes massive resources and energy. The recent advancements in soldering technologies consume comparatively higher resources and needs to be optimized for resource efficient production which is also the motivation for the present work. This study is devoted to quantify the resource consumption and qualify this consumption through exergy flows in an over-pressure reflow technology as an energy intensive process in electronics manufacturing.

The analysis implies on a big saving potential for energy consumption specifically during the over-pressure process which also defines the void reduction quality of solder joints. Exergy efficiency is the fraction of the work potential of the heat that is converted to work, and it illustrates the quality of consumed resources during the soldering oven process. Shortening the production lead-time, and increasing the production rate increase the efficiency of exergy and prevents wastage of usable energy. Furthermore, the set-up improvements for the temperature profiles are necessary, and the changes toward developing new technologies in pre-heating and over-pressure chamber zones are mandatory if a high efficiency of resources used is expected.