bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Geometry Projection Method for the Optimal Design of Panel Reinforcements With Ribs Made of Plates
Authors: Zhang Shanglong , Norato Julián A. 
Published: December 2016

The stiffness of plate structures can be significantly improved by adding reinforcing ribs. In this paper, we are in particular concerned with stiffening of panels using ribs made of constant-thickness plates that may be, for example, welded to the panel. These ribs are common in, for example, the reinforcement of ship hulls, aircraft wings, pressure vessels and storage tanks. Existing methods either produce rib designs that cannot be fabricated with plates, or employ heuristics that produce non-optimal designs. This paper presents a method for optimally designing the topology, locations and dimensions of rectangular ribs to reinforce a panel. To this end, we smoothly project an analytic, explicit geometry representation of a set of ribs onto a continuous density field over a design envelope. This density field is discretized in an element-wise manner on a uniform grid for analysis. The initial design consists of a prescribed set of ribs, constrained to remain perpendicular to the panel to facilitate manufacturing and joining of the ribs.
The advantages of our method are two-fold. On one hand, as in classical density-based topology optimization, we circumvent re-meshing by using a fixed finite element grid for the analysis, and the differentiability of the projection allows us to employ efficient and robust gradient-based optimization methods. On the other hand, the explicit geometry representation provides a direct translation into CAD, it produces reinforcement designs that conform to available plate cutting and joining processes, and it allows us to impose a constraint on the minimum separation between any two ribs to guarantee clear gaps for weld gun access. Also, bounds on the ribs dimensions can be naturally and directly accommodated. We present numerical examples of our panel reinforcement design under different types of loadings to demonstrate the applicability of the proposed method.
A New Smart Strategy for Web Searching of Commercial Products
Authors: Cavalieri Lorenzo , Capitanelli Andrea , Ceccacci Silvia , Gullà Francesca , Papetti Alessandra , Germani Michele 
Published: December 2016

Search engine efficiency is an essential prerequisite to ensure a satisfactory on-line purchasing experience. Despite powerful tools available today, search engine is limited to a semantic elaboration of keywords and they do not allow users finding product categories that do not belong to their knowledge sphere. In this context, in order to make an effective search engine it is necessary to provide tools able to understand what the user is looking for and suggest the products that best satisfy their needs, regardless of users’ background.
To this aim, this paper proposes an innovative smart search strategy, based on artificial intelligence technologies. In order to highlight the system potential, the smart object market case study has been considered. The SOs market is grown so quickly to disorient the average user and it offer a wide variety of products apparently similar, but that are characterized by different features that the average user fails to perceive.
Countersteering to Recover Straight Ahead Running After a Disturbance
Authors: della Rossa Fabio , Gobbi Massimiliano , Mastinu Giampiero , Previati Giorgio 
Published: December 2016

The paper deals with the analysis of a manoeuvre occurring frequently before crashes. Due to an external disturbance the straight ahead running of a vehicle is degradated into an oscillating motion. The driver is required to countersteer to recover the straight ahead motion. The bifurcation analysis of a simple model describing a vehicle+driver running straight ahead is performed. The mechanical model of the car has two degrees of freedom and the related equations of motion contain the non linear tyre characteristics. The driver is described by a non linear model defined by three parameters, namely the gain (steering wheel angle per lateral deviation from desired path), the prevision distance, the reaction time delay.
Unreferenced bifurcations are discovered for the understeering vehicle. A supercritical Hopf bifurcation may occur as forward speed is increased. Also tangent (fold) bifurcations occur as the speed (or disturbance) are further increased.
The vehicle+driver model is validated by means of a number of tests performed in a track. The validation relies on the identification of driver’s parameters. The track is equipped with a plank sliding laterally when the vehicle rear axle passes on it. Such a lateral excitation applies a disturbance to the vehicle which initiates a spin to be counteracted by the driver. An analysis is performed on driver’s parameters identification. Such parameter identification seems a possible way to assess single driver’s ability to perform recovery manoeuvres.
Human Action Modeling and Application to a Control System Using the Mahalanobis-Taguchi System
Authors: Asaka Yusuke , Watanuki Keiichi , Fukuda Shuichi , Muramatsu Keiichi , Kaede Kazunori 
Published: December 2016

This paper discusses human action modeling and its application to a control system that uses the Mahalanobis – Taguchi System (MTS). In this study, we define embodied knowledge as being included in tacit knowledge. We also define a set of skills based on experiences and intuitive sense as seen in creating an art, sport, craft, or other skilled task. Embodied knowledge is difficult to express explicitly. As our goals, we analyze embodied knowledge acquisition for human action modeling and apply to a control system by using MTS.
An analysis of embodied knowledge using devices and pattern-recognition techniques to recognize un-explicit knowledge are being developed owing to recent improvements in technology. Embodied knowledge acquisition element of recognition can be represented as a pattern recognition technique. In this paper, we confirm that MTS is an adaptive method for recognizing pattern in human action modeling.
We set up a control model including a controller using the MTS, which is modeled after an internal model of the cerebellum. We apply the controller based on the Recognition Taguchi (RT) method to invert the control of the pendulum. The result indicate that the controller is capable of detecting disturbance.
Problem Discovery With Many-Objective Visual Analytics
Authors: Woodruff Matthew , Simpson Timothy W. 
Published: December 2016

Problem discovery is messy. It involves many mistakes, which may be regarded as a failure to address a design problem correctly. Mistakes, however, are inevitable, and misunderstanding the problems we are working on is the natural, default state of affairs. Only through engaging in a series of mistakes can we learn important things about our design problems.
This study provides a case study in Many-Objective Visual Analytics (MOVA), as applied to the problem of problem discovery. It demonstrates the process of continually correcting and improving a problem formulation while visualizing its optimization results. This process produces a new, clearer understanding of the problem and puts the designer in a position to proceed with more-detailed design decisions.
Designing Integrated STEM Education: Linking STEM Teachers and Learners in a K-20 Continuum
Authors: Shahbazi Zahra , Jacobs MaryAnn , Lehnes Alexandra , Mancuso Kathleen 
Published: December 2016

To address the grand challenge of the severe shortage of qualified engineering workforce and equally important educators, engineering and education departments at Manhattan College created a holistic program called Engineering Scholars Training and Retention (STAR) program. Engineering STAR program created a collaboration among undergraduate education and engineering majors, the professors who teach them and current STEM teachers and their students in local urban middle and high schools.
We developed three new academic programs (engineering education minor and certificate programs for both undergraduate and graduate engineering and education majors) to support engineering and education students who are passionate about promoting engineering for 6–12 grade students and become qualified and competent engineering educators.
In addition, through partnership with local middle/high schools we developed an engineering ambassadors’ program where students from engineering and education majors develop hands-on design projects and present them to middle/high school students to encourage and inspire more students to study engineering.
Next, we engaged in a professional development program to support current STEM teachers to develop skills in engineering and increase the number of teachers who possess the pedagogical content knowledge to prepare students to be successful in engineering fields.
All three aspects of the STAR program employees engineering design projects to introduce engineering to students and teachers. This integrative model could serve initially as a template to design such programs.
Numerical Investigations of Parametrically Excited Non-Linear Multi Degree of Freedom Micro-Electromechanical Systems
Authors: Kniffka Till J. , Ecker Horst , Mace Brian R. , Halkyard Roger 
Published: December 2016

More and more systems exploit parametric excitation (PE) to improve their performance compared to conventional system. Especially in the field of micro-electromechanical systems (MEMS) such technologies rapidly gain in importance. Different to conventional resonance cases PE may destabilise the system’s rest position when parametrically excited time-periodically with a certain PE frequency. At such parametric resonances vibrations are only limited due to non-linearities. The system is repelled by the unstable rest position and enters a bifurcated limit cycle.
Finding these limit cycles has become more easy in recent years. Advances have been made in numerical path following tools regarding both their power and their user friendliness. As a result, designing such systems has become more common. Indeed, the focus of studies has been on 1DOF systems mostly.
However, for multi degree of freedom systems choosing a meaningful phase space to discuss the results is a task on its own. Quasi-modally transforming the equations of motion, the vibrations are decomposed allowing one to focus on the predominant modes. By concentrating on these predominant modes, continuation results can be displayed in meaningfully reduced phase-parameter spaces. Basins of attraction can be found in Poincaré sections of these phase-parameter spaces.
Employing these approaches, it is demonstrated how to investigate a non-linear 2DOF PE MEMS, how to change the characteristics of the limit cycles and how this affects their basins of attraction.
The Impact of Abstraction and Fidelity Levels on the Usefulness of Early System Functional Models
Authors: Hunter Sean C. , Jensen David C. , Tumer Irem Y. , Hoyle Christopher 
Published: December 2016

For many complex engineered systems, a risk informed approach to design is critical to ensure both robust safety and system reliability. Early identification of failure paths in complex systems can greatly reduce the costs and risks absorbed by a project in future failure mitigation strategies. By exploring the functional effect of potential failures, designers can identify preferred architectures and technologies prior to acquiring specific knowledge of detailed physical system forms and behaviors. Early design-stage failure analysis is enabled by model-based design, with several research methodologies having been developed to support this design stage analysis through the use of computational models. The abstraction necessary for implementation at the design stage, however, leads to challenges in validating the analysis results presented by these models.
This paper describes initial work on the comparison of models at varying levels of abstraction with results obtained on an experimental testbed in an effort to validate a function-based failure analysis method. Specifically, the potential functional losses of a simple rover vehicle are compared with experimental findings of similar failure scenarios. Expected results of the validation procedure suggest that a model’s validity and quality are a function of the depth to which functional details are described.
Kinematics and Statics Including Cable Sag for Large Cable-Suspended Robots
Authors: Sridhar Dheerendra , Williams Robert L. 
Published: December 2016

Cable sag can have significant effects on the cable length computation in a cable-suspended robot and this is more pronounced in large-scale outdoor systems. This requires modeling the cable as a catenary instead of an approximated straight-line model. Furthermore, when there is actuation redundancy involved, the modeling and simulation of the system becomes much more complex, requiring optimizing routines to solve the problem.
A cable-sag-compensated (catenary) model was implemented in simulation for an example large outdoor cable-suspended robot system to solve the coupled kinematics and statics problems. This involved optimization of cable tensions and finding the errors involved in the cable length. A comparative analysis between the straight-line and cable sag model is presented, the main contribution of this paper. Based on the qualitative and quantitative results obtained, recommendations were made on the choice of model and solution methodologies.
Estimation of the Total Fatigue Life of Metallic Structures
Authors: Abdo Peter , Fardoun Farouk , Huynh Phuoc 
Published: December 2016

The fatigue life of a component is defined as the total number of cycles or time to induce fatigue damage and to initiate a dominant fatigue flaw which is propagated to final failure.(Shigley & Mischke 2002)
The aim of this project is to calculate the total fatigue life of metallic structures under cyclic loading by applying equations found by Basquin and Manson-Coffin. The local stresses and strains necessary for the calculation are determined by the finite element method. Former studies concerning this subject have used analytical methods to find the local conditions at the critical section. The analytical methods, based on Neuber and Molski-Glinka’s approaches, permit the calculation of the local stresses and strains at the critical section of the structure’s geometry as a function of the nominal stress (forces) applied.
For the finite elements method, ABAQUS is used to determine the local conditions at the critical section of a T-shaped model.
The Same Initial Condition of the Optimum Method for All Specifications
Authors: Tsugawa Takuji 
Published: December 2016

In the previous study (AJK2015-09034 A meridian profile obtained by no restriction in optimum process), an optimum meridian profile of impeller and guidevane by no restriction was obtained. In case of no restriction, all the design parameters and specifications are variable optimum parameters. As the result, the combination of the best design parameters and specifications were selected. In optimum process, blade number, outlet impeller mid span diameter, rotational speed of impeller and specific speed were also variable optimum parameters. As the variable design parameters need to change gradually, the blade number considering as solidity is used as real number in optimum process. There are two kinds of object functions in previous case study. One object function is composed of efficiency and initiated suction specific speed. The ideal goal of efficiency is 100%. The goal of initiated suction specific speed is 1000. The best specific speed of best efficiency was 680 and 852. The other object function is composed of only efficiency. The best specific speed of best efficiency was 520 and 539. The unit of specific speed is composed of m, min−1 and m3/min. In this case study, the initial conditions of design parameters for all design specifications are born from the best one combination of optimum design parameters obtained by no restriction in the previous case study. In this method, the optimum profile for various specifications are obtained by the optimum profile of the best specific speed in condition of changing the specific speed little by little. In previous study, the suitable initial value of all design parameters for each design specifications was not able to obtain. In this case study, the two optimum meridian profiles of low and high specific speed (200 and 3000) was born from one same meridian profile obtained by no restriction in previous optimum process, that is, it become clear that all design parameters calculated by no restriction produces initial value of all design parameters for all specifications in case study of the two kind of specific speed 200 and 3000.
If the ideal goal value of efficiency is 100% and the goal value of the initiated suction specific speed is 1000, the initiated suction specific speed looks like as restriction. If the ideal goal value of the initiated suction specific speed is very large value and the efficiency is not 100% but small value, the efficiency looks like as restriction. The object function contains the efficiency and suction specific speed. The coupling constant combined efficiency and suction specific speed is important constant for the object function. As the result of this case study, one of a meridian profile obtained by no restriction in optimum process was able to become the same initial condition of the optimum method for all specifications.
Investigation of Mean and Turbulent Flow Behaviour Over an Escarpment
Authors: Kilpatrick R. , Siddiqui K. , Hangan H. , Parvu D. 
Published: December 2016

Mean and turbulent flow behaviour over a 1:25 scale model of Bolund hill was investigated at Western University’s Wind Engineering, Energy, and Environment Research Institute (WindEEE) using Particle Image Velocimetry (PIV). A range of upstream flow and surface conditions were considered.
Results showed almost no Reynolds dependency on the mean flow and weak dependency of Reynolds number on the upstream surface roughness conditions. However, a strong Reynolds number and upstream surface rough dependency is observed on the turbulent flow particularly in the shear layer formed in the immediate downstream region of the escarpment. It is concluded that the consideration of Reynolds number independency must be cautiously used when extrapolating the flow parameters from scaled model testing to full scale in the field.
Design and Performance Assessments of a Partial Admission Axial Turbine Using Supercritical Carbon Dioxide
Authors: Kang Young-Seok , Huh Jae-Sung , Cho Junhyun , Shin Hyungki , Baik Young-Jin 
Published: December 2016

Power density of a super-critical carbon dioxide cycle is very high due to its fluid-like density. For this reason, generally size of turbines are very compact compared to that of the air Brayton cycle. However, such an advantage sometimes becomes a challenge for aerodynamic design, because low volume flow rate of the turbine requires design point at a very low specific speed. One of the solution for the challenge is to design a turbine stage as a partial admission stage in which flow enters the turbine nozzle over only a portion of its annulus. Then it secures a sufficient turbine inlet area, even though performance degradation should be taken in to account.
In this study, aerodynamic design of an axial turbine has been carried out and its performance has been assessed with numerical simulations. One of design requirements for the axial turbine was to minimize rotor inlet and outlet pressure difference to avoid potential axial thrust. In spite of a small amount of expansion ratio in the turbine stage, the absolute pressure difference could cause severe damage to rotor dynamic system and require complicated bearing system. For this reason, in this study, the turbine was designed as impulse type axial turbine with partial admission.
Required rotating speed and resultant low volume flow rate restricted mean diameter and blade height at the stage inlet. The final design has a very low aspect ratio, less than unity. The number of nozzle and rotor are 12 and 34, respectively. The rotating speed of the rotor is 45,000 rpm. The ratio of nozzle arc to blade pitch is approximately 3, which determines efficiency deterioration due to the partial admission.
During the numerical simulations, to implement real gas property, Redlich-Kwong-Aungier cubic equation was used. As the turbine operating point is far from its critical point, the Redlich-Kwong-Aungier cubic equation showed a good agreement with real supercritical gas property.
To assess full and partial admission turbine performance, steady state numerical simulations have been performed. The full annulus CFD domain was constructed for the partial admission stage. At the design condition, there was 15% isentropic efficiency drop in case of the partial admission stage relative to the full admission stage. Also similar amount of power output penalty was investigated from the partial admission case. As the nozzle was choked at the design condition, the mass flow rate was conserved regardless of the admission type. Then in the flowing region, design velocity triangle in front of the rotor well established, while additional loss was generated along the circumferential direction over non flowing region.