bluuebunny/crossref_metadata_2025 huggingface dataset:
Micro-Macro Modeling of Continuous Cast Steel to Simulate the Effect of Casting Velocity and Pouring Temperature on Copper Segregation
Authors: Shahhosseini A. Mehran , Srinivasan Malur N.
Published: October 2013

One of the most serious problems in using recycled scrap for steel production is the occurrence of surface hot shortness during hot deformation due to the presence of copper in scrap. Copper causes surface hot shortness by liquid embrittlement. Therefore, the amount of the liquid copper-enriched phase penetrating into the grain boundaries should be identified in order to keep its effects within acceptable limits. In this regard, understanding the mechanism of segregation during solidification of steel is essential. This paper attempts to demonstrate micro-macro modeling of continuous cast steel to simulate the effect of casting velocity and pouring temperature on copper segregation. First, the temperature profiles at different times were determined using a finite element (macro) model and a segregation (micro) model based on Giovanola-Kurz approach is coupled with the macro model. It is necessary to couple the heat flow calculations from the macro model and the segregation calculations from the micro model because the rate of latent heat liberation is affected by the solute redistribution process, while the solute redistribution process depends on the cooling rates. As the casting velocity and pouring temperature strongly affect the solidification of continuous cast steel, they were chosen as the variables in this study. It is hoped that this study will enable the optimization of these variable to minimize the segregation of copper. This paper also demonstrates that by decreasing casting velocity and pouring temperature of a steel billet during continuous casting, solid-liquid interface moves faster to the center of the billet and there is less chance for diffusion of the residual elements in steel. Therefore, the chance of hot shortness of copper in the steel increases.
KrioBlastTM: A Hyper-Fast Cooling and Thawing Scalable Device for Vitrification of Stem and Other Cells in Large Volumes
Authors: Bolyukh Vladimir F. , Katkov Igor I. , Katkov Vsevolod , Yakhnenko Ilya
Published: October 2013

Kinetic (very rapid) vitrification (KVF) is a very promising approach in cryopreservation (CP) of biological materials as it is simple, avoids lethal intracellular ice formation (IIF) and minimizes damaging dehydration effects of extracellular crystallization. Moreover, achieving the ultra-high rates, which would prevent IIF during cooling and devitrification during resuscitation, and achieve KVF for practically any type of cells with one protocol of cooling and re-warming would be the “Holy Grail” of cell cryobiology [3]. However such hyperrapid rates currently require very small sample size which, however, is insufficient for many applications such as stem cells, blood or sperm. As the result, even smallest droplets of 0.25 microliters cannot be vitrified sufficiently fast to avoid the use of potentially toxic external vitrification agents such as DMSO or EG due to the Leidenfrost effect (LFE). In this presentation, we describe an entirely new system for hyperfast cooling of one-two order of magnitude larger samples that we call “KrioBlastTM”, which completely eliminates LFE. We have successfully vitrified up to 4,000 microliters of 15% glycerol solutions, which theoretically corresponds to the critical cooling rate of hundreds of thousands °C/min. We believe that such a system can revolutionize the future cryobiological paradigm.
Improved Tool Life in Heat-Pipe Assisted Drilling Operations
Authors: Zhu Lin , Jen Tien-Chien , Liu Yong-Bin , Liu Wei-Lai , Zhao Ji-Wen , Yen Yi-Hsin
Published: October 2013

This paper focuses on the feasibility and effectiveness of heat-pipe cooling in drilling operations. The basic idea is to embed a heat-pipe at the center of the tool with the evaporator close to the tool-tip, and the condenser at the end of the tool. Consequently, the heat generated at the tool-chip interface can be removed by convection heat transfer. To achieve this, a combination of numerical analyses and experimental measurements was used under three different cooling conditions, e.g., dry drilling, fluid cooling and heat-pipe cooling. The thermal characteristics of the drills were predicted using a numerical calculation with Fast Finite Element (FFE) plus solvers, whilst flank wear is considered as the criterion for tool failure and the wear was measured using a Hisomet II Toolmaker’s microscope. Tool life was also evaluated based on the foregoing tool wear morphology under each condition. The evidences obtained from the experimental study and finite element analyses were compared. The results demonstrate that heat-pipe assisted cooling in drilling processes can effectively perform thermal management comparable to the fluid cooling used pervasively in the manufacturing industry, extending the tool life of the drill.
Low – Cost, Accelerated High-Cycle Fatigue Testing by Resonant Dwell
Authors: Whaley P. W. , Killingsworth L. A. , Bow T. D.
Published: October 2013

Characterization of the fatigue properties of new materials using conventional empirical procedures will be very expensive and time-consuming because of the need for sufficient fatigue life data, especially in the high cycle fatigue (HCF) region. Fatigue specimens tested at 30 Hz require over nine hours to accumulate 106 cycles for each fatigue data point. Resonant-dwell double-cantilever beam specimens resonating at approximately 260 Hz accumulate 106 cycles in about an hour. This paper describes low–cost, accelerated HCF fatigue testing using resonant – dwell specimens and a small, inexpensive electrodynamic shaker. Using this method, HCF data needed for characterizing the fatigue properties of new materials can be collected about nine times faster than a servo–hydraulic test machine operating at 30 Hz.
Study on Welding Seam Strength and Die Life Assessment for Square Tube Extrusion of Aluminum Alloy 7075
Authors: Hsu Quang-Cherng , Kuo Kun-Hong , Sheng Bo-Feng
Published: October 2013

AA7075 has many good mechanical properties; however, its bonding strength is poor and is difficult to produce extruded hollow products. Although some researchers proposed different method to study welding strength of Aluminum alloy, related study for high strength Aluminum alloy in hollow extrusion process is not enough. This study use DEFORM 3D finite element analysis software to simulate two different types of hollow extruding die configurations for square tube extrusion process, namely: type I welding position at the corners of the square tube and type II on the side faces. The welding strengths of these two kinds of extruded tube are studied by expanding test and tensile test. The service lives of these two extrusion die components are studied based on the die stress and die wear information. Some information about the study are as follows: ingot material is AA7075, ingot diameter is 127mm, the extruded tube outside dimension is 54mm × 54mm, thickness is 5mm, extrusion temperature is 480°C, and ramp speed is 0.5mm/s, die material is SKD61 with HRC48. Research results show that the maximum extrusion force for type II is greater than type I. The maximum equivalent die stress occurs in upper die rather than in lower die both for type I and II. However, the predicted die life for type II is greater than type I due to extrusion die design. The welding strength for type II square tube is about 300 MPa on each welding seam.
Geometrical Coupling Analysis to Reduce Complete Assembly Line Complexity
Authors: Edholm Peter , Lindkvist Lars , Söderberg Rikard
Published: October 2013

Modern assembly lines for mass production need to fulfill several important criteria. One of them is to produce products with high geometrical quality (small geometric variation). For sheet metal assemblies, focused on in this paper, it is a very complex process to achieve good geometrical quality due to the large number of assembly steps and the geometrical variation (tolerances) of the incoming parts. One “golden rule” for sheet metal assembly lines is to always reuse fixturing points (locators) throughout the whole assembly line to minimize the geometrical variation and also the complexity of root cause analysis.

A new method to measure the complexity in an assembly line has been developed and also implemented in a commercial software for Computer Aided Tolerancing. This new tool not only demonstrates the “golden rule” but could also be used to ensure minimum geometrical complexity in assembly lines to ensure controlled production and high quality products.
Retracted: “Evaluation of Cam Shaft Profile Form Error by an Electronic Height Gauge” [ASME 2012 International Mechanical Engineering Congress and Exposition, Volume 3: Design, Materials and Manufacturing, Parts A, B, and C, Houston, Texas, USA, November 9-15, 2012, Conference Sponsors: ASME, ISBN: 978-0-7918-4519-6, Copyright © 2012 by ASME. Paper No. IMECE2012-85789, pp. 1481-1486; 6 pages; doi: 10.1115/IMECE2012-85789]
Authors: ASME
Published: October 2013

The above referenced paper has been removed from publication. April 22, 2015.

Copyright© 2015 by ASME
Supporting the Ideation Process and Representation of the Design of a Product as Part of a Real Life Use Process
Authors: Opiyo Eliab Z.
Published: October 2013

Numerous virtual and physical prototyping techniques have been developed in the past decades. These techniques are typically used for prototyping of products in the embodiment and detail design phases of the product development process, without taking into consideration the processes associated with products. These processes include sub-processes related to the operation of the products, interactivity of the product developer or the user with the product, and thinking and manipulative control of humans. The main challenge addressed in this paper is how to conceptualize and communicate ideas about products together with all accompanying processes. We have developed a new concept of abstract prototyping (AP), with the intent to enable the ideation and representation of products or systems as real life processes. In this paper, we present application case studies to demonstrate the applicability of this new concept of abstract prototyping. The preliminary results show that this is indeed the case and prove that process-focused abstract prototyping can be a useful new enabler for design communication. One of the major benefits of the proposed method over the competing approaches such as the application of VR solutions is that it provides a low-cost, but yet effective solution for the challenge of taking into consideration how the product will be used in user’s context or scenario at the very early design stage.
Performance of Reground Tools in Drilling
Authors: Gomes de Sousa Jose Aecio , do Nascimento Sousa Marcelo , Machado Alisson Rocha
Published: October 2013

The present work evaluates the performance of step drills, new and after regrinding. The tools were made of P20 cemented carbide coated with TiAlN. The routine of re-coating them after regrinding were varied (no recoating, recoating over the previous coating and recoating after removing the previous coating). The output parameters considered for determining the machining performance were: tool life, thrust force, torque, form errors (roundness and cylindricity) and surface roughness (Ra and Rz parameters). The results generated with the resharpened tools were compared to those obtained with a new tool (first time used). The results showed that in general the reground tools showed worse performance than the new tools, regardless the parameter considered. Only the tools that have undergone the process of cleanness of the previous coating and then reground and recoated (with the same type of coating) showed results similar to the new tools. The tools with no recoating and those that received the recoating over the previous showed, practically in all tests, higher thrust force and torque, larger form errors and worse surface roughness than the new tools.
Sensitivity Analysis of Dynamics System in the Upper Limb Movement Control
Authors: Chen Kai , Foulds Richard A.
Published: October 2013

The dependence of muscle force on muscle length gives rise to a “spring–like” behavior which has been shown to play an important role during human movement.

Neville Hogan (Hogan, 1985) proposed a mathematical model in terms of impedance control of arm movement. Discussing this work, Dr. Hogan admits that it can not effectively model all aspects of the performance of the system. He said “Controlling the complete dynamic behavior of the limb may be beyond the capacity of the central nervous system. If the disturbance is sufficiently abrupt, then, because of the inevitable transmission delays, continuous intervention based on neural feedback information will not be a feasible method of modulating these quantities.”. However, the model proposed in this study, accomplished most the work which Hogan believed was not feasible. In order to validate the result of proposed model, this study perform sensitivity analysis between the results produced by the dynamics system and the results measured, the comparison showed the difference between these two results were less than 10%, which strongly support the idea that proposed dynamic model can accurately reflect dynamics system in the upper limb movement control.
Effect of Area Ratio on the Aerodynamic Performance of Parallel Wall Volute Casing of an Industrial Centrifugal Fan
Authors: Hariharan C. , Govardhan M.
Published: October 2013

To design a compact centrifugal fan with parallel wall volute, the ratio between the impeller exit width (B2) and volute width (B5) is kept high. In the present study, a detailed numerical simulation of parallel wall volutes for backward curved centrifugal blower with different (B5/B2) ratios (4 and 5) is carried out. These simulations are done for varying mass flow rates. By increasing the ratio from 4 to 5, the material required by the volute can be reduced by 15%. The analysis of the flow field shows that an increase in the B5/B2 ratio causes a slight decrease in the pressure ratio and efficiency at higher mass flow rates. At the outlet of the impeller, higher ratio volute generates a more uniform flow distribution which reduces the structural load on the impeller.
Theoretical Prediction of the Anisotropic Effective Thermal Conductivity of Composite Materials
Authors: Gori Fabio , Corasaniti Sandra , Ciparisse Jean-François
Published: October 2013

The composite is made of a matrix and a fiber-reinforced material to form a non-homogeneous anisotropic material. Thermal behaviour of composite materials is very important in many applications as heat shields and heat guides. The present paper investigates theoretically a composite material made of a silica matrix and a fiber reinforcement made of steel. The steady state effective thermal conductivity in the main directions are calculated theoretically for two extreme thermal assumptions, i.e. parallel isothermal lines and parallel heat flux lines. The effective thermal conductivity of the composite is evaluated for a variable thickness of the reinforcement, i.e. for a variable volume fraction. The anisotropy degree, defined as the ratio between the thermal conductivities along the two main directions, increases with the ratio between the thermal conductivities of the reinforcement material and the matrix. The composite material, made of two homogeneous and isotropic materials, is thermally anisotropic and can be used to drive heat towards colder regions. This phenomenon is very useful when a device, such as a spacecraft, must be thermally protected.
Shape Memory Polymer With Aluminum Tube Reinforced Impact Resistant Sandwich Core
Authors: Ji Gefu , Li Guoqiang , Pang Su-Seng
Published: October 2013

Sandwich construction has been extensively used in various fields. However, sandwich panels have not been fully exploited in critical structural applications due to damage tolerance and safety concern. A major problem of sandwich panels is the debonding at or near the core/face sheet interface, especially under impact loading, which can lead to a sudden loss of structural integrity and cause catastrophic consequences. In order to improve the debonding resistance and energy absorption of sandwich panel under impact loadings, a new sandwich core is proposed which is a hybrid core consisting of hollow metallic millitubes reinforced Shape Memory Polymer matrix. The objective of this study was to characterize its dynamic performances. The core consisted of programmed shape memory polymer resin. Low velocity (4m/s) impact tests demonstrated that new core panel may be considered a promising option for critical structural applications featured by debonding and multiple impact tolerance.
Low Velocity Impact Damage on CFRPs: A Parametric Study
Authors: Hundekari R. , Gururaja S.
Published: October 2013

Carbon Fiber Reinforced Plastics (CFRPs) are extensively used in modern aircraft structures due to their high specific strength and stiffness properties. Upon impact by the foreign objects, the strength and stiffness of CFRP structures reduces drastically which is of major concern for aircraft designers since aircraft structures often witness sudden impact events during their life cycle. Typical impact events include tool drop during manufacturing and maintenance, runway debris during take-offs/landings or bird strike events. In particular, low velocity impact (LVI) events have been found to be specially detrimental to the load-carrying capability of aero-structures. It is therefore very important to characterize the loss of strength and stiffness accompanying such impacts on composite structures.

The present work presents an idealized problem of LVI on a square CFRP plate using a spherical impactor. A parametric study has been carried out to investigate the behaviour of CFRP plate under varying impactor velocity, size, laminate thickness and stacking sequence. Impact damage initiation data has been developed for the parameters considered using the numerical framework developed for LVI. It is believed that the numerical simulations discussed in this paper will help aircraft designers to predict the response of different laminate systems under various impact scenarios and will guide them to choose appropriate material system.
A Fixture Failure Control Chart for Variation Caused by Assembly Fixtures
Authors: Wärmefjord Kristina , Carlson Johan S.
Published: October 2013

In the auto body assembly process, fixtures are used to position parts during assembly and inspection. If there is variation in the positioning process, this will propagate to the final assembly. There are also other sources of variation in the final assembly, such as variation in parts due to previous manufacturing steps. To facilitate the separation of the different sources of variation, and thereby also improve fault diagnosis, a fixture failure subspace control chart is proposed. This control chart is based on a multivariate T2-chart, but only variations in the fixture failure subspace are considered. The method is applied to two industrial case studies with satisfying results.
Effects of Parallel Misalignment on Performance of Hydrodynamic-Rolling Hybrid Bearing
Authors: Lu Dun , Lu Bingheng , Zhang Jun , Liu Kejia
Published: October 2013

A hydrodynamic-rolling hybrid bearing (HRHB) arranged in parallel is introduced, in which the radial clearance of rolling bearing is used to prevent the rotor and hydrodynamic bearing from contacting during starts and stops. The aim of this study is to investigate the effects of rolling bearing misalignment on performance of HRHB for providing a design guide of machining and assembling tolerance. An analytic model is developed to predict the static performance of HRHBs with a misalignment. The misalignment is represented as an offset and an include angle. Taking the misalignment into account, a force balance equation about oil film force, rolling bearing reaction and external load is derived. The effects of the misalignment on the locus of equilibrium position, the maximum eccentricity, and the transition speed are investigated. The results show that misalignment has significant influences on performance of HRHBs, but there are regions of included angle which are insensitive to the performance of HRHBs; according to the insensitive regions, requirement of alignment errors, machining and concentricity tolerance can be determined; distinct from conventional hydrodynamic bearings, the locus of equilibrium positions of misaligned HRHBs have three variation modes of monotone decreasing, monotone increasing, and increasing first and decreasing afterwards; the monotone decreasing mode of conventional hydrodynamic is not suitable for HRHBs below transition speed; and before the maximum eccentricity ratio, the variation mode of equilibrium positions locus should be determined.
Biomechanics Investigation of Skillful Technician in Hand Lay Up Fabrication Method
Authors: Kikuchi Tetsuo , Koyanagi Takuji , Hamada Hiroyuki , Nakai Asami , Takai Yuka , Goto Akihiko , Fujii Yoshimichi , Narita Chieko , Endo Atsushi , Koshino Tetsushi
Published: October 2013

Hand lay-up is one of methods for FRP molding and it is the most traditional and common molding method that can deal with various shapes according to workmen skill. However, the quality of the composites depends on the techniques of workmen and the judgment with hand lay-up technique is too difficult, because it has not clarified that the difference of that techniques has how influence with manufactured products. In this study, motion analysis was used to compare the difference between hand lay-up techniques by expert and non-expert. Expert’s carrier of hand lay-up was 25 years and non-expert’s carrier was a year. Motion analysis, which is applied to various fields like sports or traditional crafts and so on, can visualize human motion. The Mac 3D System was used as equipment, since it is the most powerful tool for the motion capture and analysis particularly. The sampling rate was 60 Hz. The object of this study was to contribute that technique back to fabrication fields by analyzing and considering what was important factor. Furthermore, this trial is thought that leads to the development of new technology. As the result, the motion of expert’s lower half of body indicated different motion compared with non-expert one. Expert’s centroid moved smoothly and his motion showed constant tendency. On the other hand, non-expert’s motion was awkward in several points and his motion didn’t show the tendency like expert. Furthermore their total processes were almost same; however, non-expert spent more time on finishing touches than expert. Expert spent a third of his total time on finishing touches but non-expert one was a half of his total process. In addition, the quality of manufactured products that they made was different. Hand lay-up technique is discussed based on the motion analysis method, and moreover, it is possible to evolve hand lay-up technique further (We are calling “advanced-Hand lay-up”).
Kinetics Parameters Evaluation of Paraffin-Based Fuel
Authors: Santos Genivaldo P. , Lacava Pedro T. , Gomes Susane R. , Rocco José Atíllio F. F.
Published: October 2013

In recent years, Hybrid Propulsion is turning into a significant alternative to Liquid and Solid Propulsion Systems, it presents attractive features and good balance between performance and environmental impact. Thus, paraffin based propellant grains are indicated as a substitute for hydroxyl-terminated polybutadiene (HTPB), the actual solid propellant fuel grain. Despite being a well-known material, scarce data on the relation of activation energy (Ea) and molecular weight (WCxHy) of paraffin is available. In this work, the kinetic parameters (activation energy and pre-exponential factor) of microcrystalline 140/145°F paraffin have been raised through Thermo Gravimetric Analysis in conjunction with the Arrhenius kinetic mechanism, according to ASTM-E1461 and the dependence of molecular weight with melting point from Etessam and Sawyer approach. The 140/145°F paraffin activation energy calculated in this study was compared with different activation energy from alkanes and substances used as fuel in the propulsion systems field. The analysis indicated that the microcrystalline 140/145°F paraffin, manufactured by Petrobras, presents activation energy of 224 KJ.mol−1 and pre-exponential factor of 5.48×1022 min−1. Ignition was achieved with a 50 W pyrotechnic igniter. The firing test with 140/145°F paraffin fuel and gaseous oxygen (GOX) mass flux of 130 Kg.s−1 m−2 at pressure above 0.80 MPa, was easily sustained.
Modeling Tape Cast Ceramics With Multiple Layers of Fugitive Phase Materials
Authors: Wimmer Stephanie A. , Pan Ming-Jen , DeGiorgi Virginia G. , Gorzkowski Edward P. , Leung Alan C.
Published: October 2013

The fabrication of complex ceramic components requires new processing methods that are able to produce components with intricate geometries and accurate dimensions. The accuracy of the finished ceramic component depends upon precise control of the green ceramic body dimensions and uniformity prior to sintering. The authors are investigating the application of the fugitive phase approach, where a sacrificial material is used to form cavities or channels in the finished ceramic component. This paper, a continuation of a previous work, examines the lamination step of the fugitive phase approach for ceramic fabrication. The lamination step is where the fugitive phase pieces are combined with the tape cast green ceramic pieces. The multilayer green body is pressed to laminate the ceramic tape and fugitive phase layers together. Topological complexity is greatly increased when the tape cast ceramic pieces are interspersed with fugitive phase pieces to build up a consolidated multilayer green body. This paper examines the movement of the fugitive phase pieces, viscoelastic deformation of the ceramic phase, the filling of voids, pressure gradients, and the rebounding that occurs when the green ceramic body is removed from the press. This information will be used to complement parallel experimental investigations of the fugitive phase approach to ceramic fabrication.
Computer Simulation and Modelling of Standing Wave Piezoelectric Ultrasonic Motor Using a Single Flexural Transducer
Authors: Shafik M.
Published: October 2013

This paper presents a standing wave piezoelectric ultrasonic using a flexural vibration transducer. The motor consists of three main parts, stator, rotor and sliding element. The stator is a single piezoceramic flexural vibration bar. The rotor is made up of the motor driving wheel and the shaft. A computer simulation and modelling using finite element analysis for the proposed motor is discussed and used in the motor design development process. Finite element analysis has been used to evaluate the motor structure by performing an algebraic solution of a set of equations, describing an ideal model structure, with a finite number of variables. The established simulation and modelling for ultrasonic motor using finite element analysis enabled to select, the material of the flexural transducer, defining the operating parameters for the motor, determining the principles of motion and proposing an innovative technique to control the direction of motion, by controlling the phase between the two modes of vibrations. This enabled to create two directions of motion from a single vibration bar. A prototype of the proposed motor was fabricated and measured. This showed that operating parameters of the fabricated prototype are: frequency equal to 40.7 KHz, voltage: 50: 100 volt and current: 50: 100 m-amperes. This is showed a close agreement with FEA. Typical output of the prototype is no-load travelling speed of 28 mm/s, a resolution on the order of micrometers and a dynamic response <100 μsec. The motor is able to carry a load equal to 0.78 Newton. The developed motor has been used successfully in EDM industrial applications.
Stress Singularity Analysis of a Viscoelastic/Viscoelastic Bonded Joint
Authors: Chowdhuri M. A. K. , Xia Z.
Published: October 2013

Measurement of bi-material interface bonding strengths has drawn considerable attentions because damages or failures are most likely to occur at the interfaces in many advanced materials and structures. However, the measurement of the interface bonding strength is hindered by the presence of the stress singularity at the interface corner. In order to determine the actual bonding strength of bi-material interface, the determination/elimination of the stress singularity is thus very crucial. This paper presents an analytical model for the determination of the stress singularity and its elimination for a viscoelastic/viscoelastic bonded joint. Two viscoelastic materials with different material properties are considered for this study. Each material is modelled as a standard linear solid and the properties of both materials are considered as time-dependent. The elastic-viscoelastic corresponding principle is used to find the analytical solution for the subjected viscoelastic/viscoelastic bonded joint from the available analytical solution for an elastic/elastic bonded joint. The developed solution is applied for a bonded joint between Polyvinyl-chloride (PVC) and Epoxy materials. It is found that the stress singularity at the interface corner may increase with time due to the viscoelasticity of the materials. Finite element analyses have also been carried out to verify the results obtained from the analytical solution and the two results are in good agreement.
A Subject Specific Kinematic and Kinetic Relationship During a Single-Leg Drop Landing
Authors: Tse Chi-Yin , Nayeb-Hashemi Hamid , Vaziri Ashkan , Canavan Paul K.
Published: October 2013

A single-leg landing is a common type of high-risk maneuver performed by athletes. The majority of anterior cruciate ligament injury is accounted for by non-contact mechanisms, such as single-leg landings. The purpose of this study was to develop a subject specific single-leg drop landing to analyze the kinematics and kinetics of two different types of landings. Kinematic data was analyzed at five points during the landing phase: initial contact (IC), peak vertical ground reaction force (pVGRF), peak joint reaction force (pJRF), maximum knee flexion (MKF), and maximum valgus angle (MFP). A linear relationship was noted in comparing the average maximum peak vertical ground reaction force, average maximum knee flexion, and average maximum valgus angle to the platform heights in both landing styles. An increase in platform height was directly related to increased knee valgus angle in both landing styles. Significant difference (p < 0.05) was noted in the peak vertical ground reaction force between the 60% and 80% platform heights, as well as between 60% and 100% with arms above. Landing with arms across the body yielded more significant difference (p < 0.05) between platform heights in both frontal and sagittal planes. However, comparing both landing styles to each other only yielded significant difference (p < 0.05) at the 100% platform height. A valgus-varus-valgus movement was observed in all landings, and is a probable contributor to single-leg landing ACL ruptures.
Design of a Massively Reconfigurable Origami Space Structure Incorporating Shape Memory Alloys
Authors: Hartl Darren , Lane Kathryn , Malak Richard
Published: October 2013

The subject of origami design has recently garnered increasing attention from the science, mathematics, and engineering communities. Mathematically rigorous frameworks have been developed that allow the identification of folding patterns needed to obtain a final three-dimensional goal shape. However, relatively little research exists on the problem of understanding the behavioral aspects of the material system undergoing the folding operations. This work considers the design and analysis of a novel concept for a self-folding material system. The system consists of an active, self-morphing laminate structure that includes thermally actuated shape memory alloy (SMA) layers and a compliant passive layer. Multiple layers allow folds in both directions (e.g., cross-folds). The layers are configured to allow continuously variable folding operations based only on which regions are heated. For the purposes of demonstration, an example problem is considered whereby an autonomous planetary landing craft is designed that can be stored in a flat sheet configuration, morph using a set of folds into a stable shape for safe descent through a gaseous atmosphere, and then, once landed, morph again toward a cylindrical shape for the purpose of rolling locomotion. We examine the effects of fold width, layer thicknesses, and activation parameters on the geometric configurations that can be obtained. The design efforts are supported by realistic morphing structural analysis tools. These include a comprehensive and accurate three-dimensional constitutive model for SMAs implemented into a finite element analysis (FEA) framework (the Abaqus Unified FEA suite) using a robust and efficient numerical integration scheme. Shell elements and laminate theory are used to increase the computational efficiency of the analysis. Model pre-processing, submission, and post-processing scripting methods are used to automate the design assessment tasks.
Application of Fusion Algorithm to Human Lung Dynamics
Authors: Seyfi Behnaz , Santhanam Anand P. , Ilegbusi Olusegun J.
Published: October 2013

This paper integrates computational fluid dynamics (CFD) and radiotherapy data for accurate simulation of spatio-temporal flow and deformation in real human lung. Specifically, it utilizes a mathematical formulation that fuses the CFD predictions of lung displacement with the corresponding radiotherapy data using the theory of Tikhonov regularization. The lung is assumed to behave as a poro-elastic medium with heterogeneous Young’s modulus. The CFD scheme utilizes a flow-structure interaction model to simultaneously solve the airflow equations and structural dynamics of the lung tissue, with allowance for interaction at the interface. The simulation is performed on a 3D lung geometry reconstructed from 4D CT scan dataset of real human patients. The predicted deformation is fused with inverse estimation data by means of the fusion algorithm to obtain the optimal results.
Investigation on the Rotordynamics of a Rotor System With Air Film Damper (AFD)
Authors: Zhang Zhenbo , Wang Hong , Tong Xiaolong , Ma Yanhong , Hong Jie
Published: October 2013

The flexible rotor systems are widely applied in the modern aero-engines which causes large radial displacement when passing through the bending mode. The vibration will develop after a long time working which may cause the rubbing between the stator and the rotor. Therefore, more effective damping should be introduced into the rotor system in order to control the vibration of the rotor system. In this paper, a novel air film damper (AFD) with metal rubber (MR) as an elastic outer ring is put forward as a supporting and damping component for rotor systems, which can not only provide effective additional stiffness and damping for rotor systems generated by the air film and metal rubber, but also adjust the clearance between the stator and rotor automatically due to the motion of MR in order to avoid the rubbing effectively.

The mechanical model that explains the mechanism of AFD is established by describing the fluid structure interactions based on the motion of the components in AFD in a steady-state. The motion equation of the rotor system with AFD is constructed and the rotordynamic coefficients of the rotor system were obtained. The effects of AFD on the rotordynamic were analyzed. A test rig was constructed to verify the mechanism of AFD and the effects on the rotordynamics of the rotor system. The theoretical and experimental results identify that AFD can provide effective damping and additional stiffness for the rotor system and improve the rotordynamics of a rotor system significantly.
Finite Element Modeling of the Elastic-Plastic Contact Between Two Rough Surfaces
Authors: Yang Guoqing , Hong Jun , Zhu Linbo , Wang Shaofeng , Xiong Meihua , Yang Guoqing
Published: October 2013

In order to investigate the complex contact behaviors of micro-rough interfaces, this paper proposed a novel finite element method (FEM) for simulating the contact between two rough surfaces. The numerical methods for generating Gaussian and non-Gaussian rough surfaces were introduced, and the contact surfaces were produced with given autocorrelation function (ACF) and the first four moments of surface height. Finite element (FE) models were constructed based on the generated rough surfaces, in which 3D structural modeling and meshing strategies were utilized to improve the mesh quality and solution efficiency. A 3D finite element analysis (FEA) was conducted to investigate the contact characteristics including the contact stiffness, real contact area and the contact pressure distribution of rough interfaces. The results of the contacts between two rough surfaces were compared with those of the conventional equivalent contact models in which an equivalent rough surface contacted with a rigid smooth plane. The proposed FEM makes it effective to predicate or evaluate the contact characteristics of the contact of two rough surfaces, and may provide a new way to optimize the design of surface topographies and improve the performances of contact interfaces.
Characteristic Aircraft Landing Gear Thermo-Tribo-Mechanical Model
Authors: Heirendt Laurent , Liu Hugh H. T. , Wang Phillip
Published: October 2013

A methodology for studying the characteristic thermal response of a landing gear (LG) shock absorber is presented. Rough runways induce high loads on the shock absorber bearings and because of high relative sliding speeds of the shock absorber piston, heat is dissipated which is known to have led to structural damage. In this work, an overall model has been developed that is used to outline the characteristics of the thermal behavior and identify the heat sources and sinks in the landing gear shock absorber. The developed thermo-tribo-mechanical model (TTM model) is subdivided into four parts, all using simplified but representative equations. Emphasis is placed on developing a methodological framework and studying the evolution of the average temperature in the TZI (thermal zone of interest) while taxiing and taking-off.
Application of DSmT in Facial Expression Recognition
Authors: Zhao C. M. , Wei J. , Xing Z. G. , Wei Z.
Published: October 2013

As the sample in facial expression database is small, the influence of the environment and the actual expression image processing can cause face feature information uncertainty and conflict of different information. This paper presents how to solve the small sample problem and the fusion of global feature recognition results and local feature recognition results based on DSmT (Dezert-Smarandache Theory) by matlab, the results show that DSmT can better handle the face expression of uncertainty information and contradictory information than DST (Dempster-Shafer Theory), recognition effect has better performance.
Study on the Early Diagnosis of Cancer Inversion Problem Based on the Infrared Thermography
Authors: Zhou H. , Guo F. , Zhang M. , Wei J. , Wei Z.
Published: October 2013

For the early diagnosis of cancer, capturing the unusual temperature distribution of organism surface by using the infrared thermography has become one of the hot spots in the research methods. However, at present this method can only qualitatively judge the early cancer lesion, while it cannot ascertain the lesion area and range accurately. In this paper, we have conducted some exploratory research in the light of this problem, and tried to apply the nonlinear inverse mathematical method in the quantitative analysis for the infrared medical diagnosis. Through this inversion algorithm, the lesion region and range will be judged quantitatively, which makes the value of infrared thermography improve in the field of cancer early diagnosis.
Multi Objective Optimization of Laser Welding Process Parameters by Desirability Approach of Design of Experiments
Authors: Suthakar T. , Balasubramanian K. R. , Sankaranarayanasamy K.
Published: October 2013

Laser welding process is the high energy beam welding process which is very much used for thin and thick section industrial applications. The weld bead profile relies on the selection of process parameter. Due to its high power density optimal selection of process parameters is vital. In this research the optimization of the input process parameters namely power density (PD), welding speed (WS), beam angle (BA) and gas flow rate (GFR) on the response bead width (BW), depth of penetration (DOP) and depth to width aspect ratio (D/W) is analyzed. As the process parameters are highly non-linear, quadratic equations are generated for determining the desired response. The experimental trials are performed on an AISI 304 austenitic stainless steel using the four-factor-five-level central composite experimental design (CCED). Optimization of process parameters is performed using the desirability approach and the results obtained from the mathematical model is compared with the experimental results and found to be in agreement. The target fixed for the weld is to determine the optimal process parameters for the minimization of bead width and the maximization of depth of penetration and depth to width aspect ratio.
Fabrication and Characterization of Hydroxyapatite-Magnesium Composite Thin Films on Magnesium Plates for Implant Applications
Authors: Mensah-Darkwa Kwadwo , Gupta Ram K. , Kumar Dhananjay
Published: October 2013

Hydroxyapatite (HA)-magnesium (Mg) composite thin films were grown on magnesium substrates using a multitarget pulsed laser deposition technique. The microstructural and corrosion properties of HA-Mg composite thin films were investigated using methods such as x-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive x-ray (EDX) analysis, and potentiodynamic polarization. While the XRD studies have indicated the amorphous nature of the HA-Mg composite coating, SEM and EDX studies have shown that the composite films are stoichiometric. The potentiodynamic polarization study indicates that the corrosion of magnesium decreases with increase in the hydroxyapatite content in the composite film. The corrosion potential (Ecorr) and corrosion current density (Icorr) for the uncoated magnesium, 30HA-70Mg, and 50HA-50Mg coated magnesium are −1.59, −1.57, −1.54 V and 1.21×10−5, 1.38×10−6, 2.52×10−7 A/cm2, respectively. Preliminary cytotoxicity test conducted on the samples shows no adverse effect on human bone marrow stromal cells. The advantage of the composite coatings is the realization of adjustable corrosion and biological properties by a simple maneuvering of composition which in turn is realized by changing the number of laser pulses on a respective target.
System Dynamic Modeling of Vapor Compression Cycles
Authors: Miller Eric S. , Patnaik Soumya S. , Jog Milind A.
Published: October 2013

Vapor Compression cycle Systems (VCSs) are being considered for thermal management aboard modern aircraft where dynamic changes in heat loads are very common. Predicting dynamic behavior of VCSs is critical to design, sizing, and control of aircraft thermal management systems. A novel Lagrangian method to model the dynamic behavior of VCSs has been developed. This approach divides each fluid flow into a large number of elements having fixed mass, but variable volume and position. At discrete time steps, heat transferred to or from each mass element is determined by component models. This paper gives simulation results showing system startup under PID feedback control. Then, from steady state, the system response to an increase in heat load, an increase in sink availability, a decrease in valve throttle and an increase in compressor speed are simulated and the results reported. Results indicate that the Lagrangian method can provide results for a wide range of cases and that VCC systems require extensive control to meet performance objectives.
Microfabrication of Single-Cell Scale Sample Holder for Scanning Thermal Analysis
Authors: Compton Logan M. , Armes James L. , Solbrekken Gary L.
Published: October 2013

Successful cryopreservation protocols have been developed for a limited number of cell types through an extensive amount of experimentation. To optimize current protocols and to develop more effective protocols for a larger range of cells and tissues it is imperative that accurate transport models be developed for the cooling process. Such models are dependent on the thermodynamic properties of intracellular and extracellular solutions, including heat capacity, latent heat, and the physical phase change temperatures. Scanning techniques, such as differential-scanning calorimetry (DSC) and differential thermal analysis (DTA), are effective tools for measuring those thermodynamic properties.

Conventional thermal scanning tools require sample sizes that are multi-celled in nature. An issue with tools that require multiple cells is that the measurements effectively average the behavior of the cell sample, masking individual cell behavior. Further, extracellular solution further dismisses the desired measurement signal. It is hypothesized that evaluating thermodynamic properties of individual cells will allow more fundamental understanding of cell-level transport, and lead to more effective cryopreservation protocols.

To detect a phase change within a prototypical mouse oocyte cell (∼100 μm diameter) sample holders for the scanning tools must be on the same order of size as the cell to reduce the relative thermal mass of the sample holder and to ultimately improve the measurement sensitivity. A proof-of-concept DTA sample holder with a ‘bowl’ to cradle the cell has been designed and fabricated using micro-electrical mechanical systems (MEMS) manufacturing techniques. Control software has been developed which is capable of providing any desired heating or cooling profile within a humidity controlled environment. Repeatable scans using water samples have been demonstrated.
Chest Response to Vibratory Excitation: Advances Beyond Percussion
Authors: Peng Ying , Dai Zoujun , Royston Thomas J. , Mansy Hansen A. , Sandler Richard H.
Published: October 2013

Extension of the percussion technique is implemented by applying vibro-acoustic excitation to the torso surface and using an array of measurement locations on the torso of three healthy human subjects via noncontacting scanning laser Doppler vibrometry. A 3-dimensional finite element model for simulating the vibro-acoustic response of the human upper torso is also developed. The soft tissue, ribcage, sternum and major internal organs were detailed to create an accurate geometric model. Experimental measurements partially validate the FE simulation model.