bluuebunny/crossref_metadata_2025_split huggingface dataset:
Impact Damage and Residual Strength of Composite Joints in Car Bodies
Authors: Sun Juanjuan , Sun Lingyu , Du Junmin , Wang Taikun 
Published: April 2014

With the weight reduction requirements for vehicles and the cost reduction tendency for carbon fibers, carbon fiber reinforced plastics (CFRPs) will be applied more and more in automobile bodies in place of some steel materials. However, the structural design method using CFRPs is much different from that using steel. For example, the anisotropic material properties and the brittle plastics matrix need to be considered, and the connection between components is through adhesive joints, which is possibly weaker than the traditional spot welding. These features make CFRPs sensitive to impact loads, especially the repeated low-energy impact.
This paper presents a damage-based residual modulus and strength prediction method, which may be utilized in the design of composites components subject to repeated impact loads.
First, the CFRPs samples were impacted repeatedly by the pendulum hammer at a constant kinetic energy, 2J, and then, the residual bending modulus and strength were measured by static three-point bending machine. According to the test data, the relationship between impact number and residual stiffness and residual strength were established, and the damage factors after each impact were calculated. In subsequent numerical simulation, the damage accumulation effect was included in the one-step prediction model through replacing the initial modulus by the degradation modulus, and this method was verified numerically by comparison with N-step prediction results after N-times impact calculations. Finally, two kinds of composite joints were analyzed numerically, which provides theoretical guide for the design of composite joints in automobile body.
Study of Turbulent Incompressible Flow Separation on High Lift Devices Using Cutcell Meshing
Authors: Ghmati Ramadan , Arslan Selin , Jawad Badih A. , Liu Liping 
Published: April 2014

Generating the mesh is a crucial part in all Computational Fluid Dynamics (CFD) analysis. Considerable time and effort have to be devoted into deciding the appropriate mesh densities that compromise between computing time and the desired accuracy. It is important that engineers generate high quality meshes around complex geometries which can capture the fine details of the inner layer.
Flow separation develops when the velocity near a solid surface just becoming negative. An inflection point exists in the velocity profile due to a positive or adverse pressure gradient occurring in the direction of flow. The computational analysis carried out near wall sub-layer is one of the challenging issues due to the need for complex mesh generation.
Separation has a major effect on the drag predictions, in this paper the authors look to extend their previous work [1, 2] to assess the capability of CutCell Cartesian meshing method for predicting the turbulent incompressible flow separation when applied to high lift devices. Although there is no experimental data available to verify the computational work, results can be the subject of future work to identify the factors which lead to flow separation experimentally. Complex aerodynamics shapes will be used and numerical simulation will be conducted using ANSYS Meshing and Fluent.
Numerical Modeling of the Acoustic Damping of Perforated Liners With Bias Flow
Authors: Mazdeh Alireza , Kashani Ahmad Reza 
Published: April 2014

Acoustic damping properties of perforated liners are highly dependent on a number of variables which can be categorized as “flow variables” such as the extent and Mach number of grazing flow as well as bias flow and “geometric variable” such as the shape of the hole which can be rectangular, cylindrical, conical with diverging or converging nozzle, thickness to radius ratio, radius to hole spacing ratio and hole orientation which can be normal to or inclined with respect to the perforated plate.
Theoretical and empirical approaches have provided the foundation for understanding the damping properties of liners but they are based on certain simplifying assumptions making them inadequate in addressing the realistic conditions encountered in industrial applications. These limitations have highlighted the importance of numerical methods for studying damping behavior of liners. Acoustic attributes of perforated plates (mainly in terms of impedance as a function of non-dimensional variables like Reynolds, Strouhal, Mach, and Helmholtz numbers have been studied by various researchers, including the authors, using a variety of numerical tools starting from the simple 1D network scheme based on linear acoustics all the way to the computationally intensive Large-Eddy Simulations (LES) and Scaled Adaptive Simulation (SAS) reconstructing the full unsteady turbulent structures. Although the impacts of some geometry variations such as hole inclination angle and diameter, in conjunction with various fluid dynamic parameters, have been investigated using 1D network tools, the focus of LES has been mainly on analysis of a single circular hole with periodic boundary conditions as the representation of multi-perforation (assuming the perforations are spaced far enough from each other so that there is no interaction between neighboring holes). There is certainly a need for thorough investigation of the acoustic impact of these geometric parameters as well as the shape of the holes using LES.
In an on-going research we are extending the numerical modeling work on characterizing the acoustic damping attributes of a perforation, beyond the current state of the art, by including the geometric variables including hole size, shape, orientation, and radius to thickness ratio, amongst others, in the study. In this paper, following a short review of the research conducted in the recent past, we present our findings on the impact of the thickness/radius ratio on the acoustic damping attribute of a perforation.
Detection of DNA in a Nanopore Fabricated From Glass Tube
Authors: Sha Jingjie , Chen Yunfei 
Published: April 2014

Nanopores are increasingly utilized as tools for single molecule detection in biotechnology. Here, we report an improved fabrication process to make solid-state nanopores from glass tubes with the help of paraffin. Based on the physical footprint of the phase change of the paraffin, nanocavity is formed in the broken terminal after thermally compressing and pulling the glass capillary. Nanopores with the minimum diameter of 20 nm are fabricated. The key step is to control the thickness of paraffin layer attached in the inner wall, which could affect the diameter of the nanopore.
We investigate 48Kb λ-DNA molecules translocate through the fabricated glass nanopore. Because DNA molecules with the negative charges could be driven by the electrical force to pass through the nanopore and could physically block the pore to produce measurable changes in ionic currents. A transient electrical current changing is used to detect the DNA molecules in the solution. In the experiments, many events of DNA translocation were observed under the positive potential. We demonstrate that DNA molecules could be detected by the nanopore fabricated from glass tube.
However, we also find the events of DNA translocation under the negative potential, which is because of the electro-osmotic flow (EOF) effects. It is found that the electro-osmotic flow inside the nanopore plays an important role in the DNA translocation process, and thus depends on the size of the pore. We shows that the effective driving force on DNA in a nanopore is the co-effects of the force of the electric field and the drag force of the electro-osmotic flow.
Developing a 3D Multi-Body Model of a Scoliotic Spine During Lateral Bending for Comparison of Ribcage Flexibility and Lumbar Joint Loading to the Normal Model
Authors: Hajizadeh Khatereh , Huang Mengjie , Gibson Ian , Liu Gabriel 
Published: April 2014

Knowledge of the movements of the whole spine and lumbosacral joint is important for evaluating clinical pathologic conditions that may potentially produce unstable situations in human body movements. At present there are few studies that report systematic three-dimensional (3D) movement and force analysis of the whole spine. In this paper, a fully discretized bio-fidelity 3D musculoskeletal simulation model for biomechanical (kinematic) analysis of scoliosis for a patient with right thoracolumbar scoliosis is presented. It is important to note that this method can be used for modeling various types of scoliosis. It should be noted that this is the first time that such a detailed model of this kind has been constructed according to known literature.
The combined loading conditions acting on the intervertebral joints and corresponding angles between vertebrae were analyzed during lateral bending through the motion capturing and musculoskeletal modeling of two female subjects, one with normal spine and the other with scoliosis. The scoliosis subject who participated in this study has thoracolumbar scoliosis with convexity to the right. Since lateral bending is one of the typical tasks used by clinicians to determine the severity of scoliosis condition, the motion data of the subjects in lateral bending while standing was captured. These motion data were assigned to train the musculoskeletal multi-body models for the inverse and forward dynamics simulations.
The mobility of the ribcage, joint angle, as well as joint force were analyzed using the developed simulation model. According to the results obtained the combined loadings at the lumbar joints in the scoliosis model are considerably higher than the loads of the normal model in this exercise. This research has investigated the effect of thoracolumbar scoliosis on spinal angles and joint forces in lateral bending by the application of motion data capturing and virtual musculoskeletal modeling. The results of this study contribute to a better understanding of human spine biomechanics and help future investigations on scoliosis to understand its development as well as improved treatment processes.
Multiple Fault Detection and Diagnosis in a Gas Turbine Using Nonlinear Principal Component Analysis and Structured Residuals
Authors: Rincon-Charris Amilcar , Quevedo-Casin Joseba 
Published: April 2014

Multiple fault detection and diagnosis is a challenging problem because the number of candidates grows exponentially in the number of faults. In addition, multiple faults in dynamic systems may be hard to detect, because they can mask or compensate each other’s effects.
This paper presents the study of the detection and diagnosis of multiple faults in a SR-30 Gas Turbine using nonlinear principal component analysis as the detection method and structured residuals as the diagnosis method.
The study includes developing a mathematical model, software simulation with Matlab Simulink and implementation of algorithms for detection and diagnosis of multiple faults in the system using nonlinear principal component analysis and structured residuals.
A real SR-30 gas turbine was used for our studies. The equipment is at the moment installed in the Inter American University of Puerto Rico, Bayamon Campus, and Department of Mechanical Engineering.
Dynamic Analysis of Offshore Oil Pipe Installation Using the Absolute Nodal Coordinate Formulation
Authors: Nielsen Jimmy D. , Madsen Søren B. , Hyldahl Per , Balling Ole 
Published: April 2014

The Absolute Nodal Coordinate Formulation (ANCF) has shown promising results in dynamic analysis of structures that undergo large deformation. The method relaxes the assumption of infinitesimal rotations. Being based in a fixed inertial reference frame leads to a constant mass matrix and zero centrifugal and Coriolis forces [12]. This makes the method attractive for multibody dynamics implementation. The focus in this paper is the application of ANCF beam elements and their performance on large deformation dynamic analysis.
Large dynamic deformation is characteristic for the installation process of offshore submerged oil pipes using oceangoing vessels. In this investigation such an oil pipe is modeled using ANCF beam elements to simulate the dynamic behavior of the pipe during the installation process. Multiple physical effects such as gravity, buoyancy, seabed contact, and fluid damping, are included to mimic the external forces acting on the pipe during installation. The scope of this investigation is to demonstrate the ability using the ANCF to analyze the dynamic behavior of an offshore oil pipe during installation.
Measurements and Models for the Thermal Conductance Through Surfaces Joined by Screws
Authors: Konkle Nicholas , Pautsch Adam , Amir Yosef 
Published: April 2014

In electronics cooling with limited local convective or irradiative cooling, conduction path optimization is critical. Decreased junction temperatures (resulting in increased performance and reliability) can be achieved by maximizing the conductance through screw joints.
Thermal contact conductance across an Aluminum-Aluminum screw joint was experimentally measured which compared well with published data for uniformly distributed pressure, with increasing conductance versus the published data as the screw preload was applied. The geometry was modeled using a meshed surface application of an available model for thermal conductance of contacts with uniformly-applied pressure, resulting in a poor correlation due to limitations in the applied technique. Modifications to the model were explored, including capping pressure, imposing a non-zero pressure in the area not influenced by screw pressure, simplifying the pressure distribution, and scaling the model to match experimental results. Each resulted in somewhat better correlation between calculated and experimental results. Recommendations are made regarding the calculation of conductance in general, leaning toward more simplified models. Further work is suggested in the area of experimentally-verified modeling of other materials and surface conditions, geometry, and with an interstitial material other than air.
Systems in Prosthetic Hands and the Relationship With Their Performance
Authors: Díaz-Montes Julio C. , Dorador-González Jesús Manuel 
Published: April 2014

A review of the state of the art in prosthetic hands is presented; this review covers the most common commercial prosthesis and prototypes under development.
In this analysis, prosthetic devices were divided in six systems: actuation, reduction, blocking, transmission, flexion and support. The information obtained is presented according to those systems.
The most important features of each system are presented together with their relationship with the performance of the entire prosthesis. An analysis that indicates the way in which prosthesis take advantage of the capabilities of current technologies is presented. Recommendations for improving the performance of upper limb prosthesis are proposed.
Comparing Engineering Education Systems Among USA, EU, Philippines and South Africa
Authors: Alves Anabela C. , Kahlen Franz-Josef , Flumerfelt Shannon , Siriban Manalang Anna Bella 
Published: April 2014

Globalization has permeated our personal and professional lives and careers over the past two decades, to a point where communication, product development, and service delivery now are globally distributed. This means that the globalization of engineering practice is in effect. Large corporations tap into the global market for recruitment of engineers. However, the education of engineers occurs within the context of individual Higher Education Institutions. Engineers are educated with varying pacing and scoping of higher education programming with varying methods and pedagogy of higher education teaching. The expectations for engineering practice normed from the corporate side within the engineering marketplace, therefore, often do not match the widely dispersed educational experiences and outcomes of engineering education delivery. This gap brings challenges for all stakeholders, employers, higher education and the engineering graduate. But particularly, university education systems which traditionally are slow to respond to shifting market trends and demands, are expected to realign and restructure to answer this shortfall.
A response to this shortfall has been prepared independently in different regions and countries. This paper discusses the response from Europe, USA, South Africa and Philippines. The European Commission started building a European Higher Education Area (EHEA) with the intention of promoting the mobility and the free movement of students and teachers in European tertiary education. US universities are introducing a design spine and strengthening students’ systems thinking and problem solving competencies. Philippines is trying to be aligned with ABET system from US. South Africa universities are evolving to a solid core undergraduate engineering curriculum with a limited set of electives available to students which include project-based learning. This is intended to address the education-workplace gap as well.
This theoretical paper will provide a comparison study of the differences between the Engineering Education in USA, EU, Philippines and South Africa. The authors will compare current trends and initiatives, aimed at improving the readiness and competitiveness of regional engineering graduates in the workplace. Given that several worthwhile initiatives are underway, it is possible that these initiatives will remain as disparate responses to the need for the globalization of engineering education. Lean performance management systems are widely used in engineering practice internationally and represent one possible rallying concept for the globalization of engineering education in order to address the education-workplace gap. Therefore, this paper examines whether the introduction of a Lean Engineering Education philosophy is a worthwhile global curricular innovation for engineering courses.
Integrated Design and Production Problem Solving in Industry-Sponsored Academic Education
Authors: Bzymek Zbigniew M. , Nunez Manuel A. 
Published: April 2014

In this paper the authors’ experience of teaching an industry sponsored course in Senior Design. The course has been jointly taught by two instructors, one from the Mechanical Engineering Department of the School of Engineering, and the other from the Operations and Information Management Department of the School of Business; and it is part of the Management and Engineering for Manufacturing program at UConn [1]. The student projects have been sponsored by local companies in industries ranging from aerospace to food production. The projects have one main goal: to find the best possible engineering design solution while achieving high production process efficiency. Such an approach relies on the talent of the designer, i.e., the student’s or engineer’s ability to develop a “perfect product” on one side, and the efficiency of the production solutions on the other. In practice, it is difficult to achieve such combined design process formalization successfully. For this reason, the problem solving relies on students’ skills, their knowledge and experience, and the instruction in the course. In particular, the Arena and DELMIA/Quest simulation packages were used for both design and production problem solving. In searching for an ideal solution cost effectiveness and economic constraints were also considered.
The experience gained from over ten years teaching of this course is described and analyzed in the paper. Some results of the course are presented and recommendations for further teaching and practice of industry-sponsored courses integrating engineering and production problem solving are discussed.
Quantifying the Effect of Plug-In Electric Vehicles on Future Grid Operations and Ancillary Service Procurement Requirements
Authors: Harris Chioke B. , Webber Michael E. 
Published: April 2014

As plug-in electric vehicles (PEVs) grow in popularity, there is increasing research interest in the interaction between PEVs and the electric grid. Much of the previous work in the literature relies on an assumption that PEV charging will be scheduled, and that the duration and magnitude of charging loads can be modulated to suit the needs of the utility and the system operator. While access to the data or owner input necessary for charge scheduling and management might be technically feasible today, it is unclear whether vehicle owners will be amenable to providing these data or accepting utility control of their charging choices.
Because of these uncertainties in the future relationship between electric utilities and PEV owners, this study seeks to examine the market effects of vehicles in the absence of the additional data utilities would need to realize these alternate, “optimal” PEV charging scenarios. In particular, this study focuses on quantifying the potential uncertainty in vehicle charging loads on an energy and power basis.
Monte Carlo methods were applied to vehicle trip data from the National Household Travel Survey (NHTS) to generate simulated driving profiles for individual vehicles. Using these profiles, six PEV fleet sizes were studied, ranging from 1,000 to 500,000 vehicles, to determine whether fleet size had a linear effect on the stochasticity of vehicle charging loads. Following the Monte Carlo simulations, these loads were examined independent of and compared to net load (load minus wind generation).
Results from the Monte Carlo simulations indicate that even for the largest PEV fleet sizes studied, variability in average charging loads is on the order of 10 MW, less than 0.2% of the magnitude of charging load for those fleet sizes. In comparison with electricity demand in the Electric Reliability Council of Texas’ (ERCOT) operating area, these charging loads represent a 1% increase above typical summer peak loads. Unfortunately, while the relative increase in demand is small, the timing of peak charging load is nearly coincident with summer peak demand.
The simulation approach was validated by comparing the results against empirical vehicle charging data collected by the Pecan Street Research Consortium from households in Austin, Texas. Simulated and empirical vehicle charging trends showed generally good agreement, with similar charging times but slightly different charging durations. The alignment between the two charging profiles indicates that the simulation methodology applied here with NHTS travel data can be used to predict electric load for vehicle charging when empirical historical charging data are not available.