Search results for: Fundamental frequency of vibration

Authors: Devdutt, M. L. Aggarwal

Abstract:

Semi-active Fuzzy control of quarter car system having three degrees of freedom and assembled with magneto-rheological (MR) shock absorber is studied in present paper. First, experimental work was performed on an MR shock absorber under different excitation conditions to obtain force-displacement and force-velocity curves. Then, for the application of experimental data in semi-active quarter car system, a polynomial model was selected. Finally, Fuzzy logic controller was designed having the combination of Forward fuzzy controller and Inverse fuzzy controller for integration in secondary suspension system of concerned model. The proposed controlled quarter car model was compared with uncontrolled system using simulation work under bump type of road excitation. Results obtained by simulation work shows the effectiveness of fuzzy controlled suspension system in improving the ride comfort and safety of travelling passengers compared to uncontrolled suspension system.

Keywords: MR shock absorber, three degrees of freedom, quarter car model, fuzzy controller.

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Authors: M. Ziółkowska, J. T. Duda, J. Milewska-Duda

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This paper describes an approach to the adsorption phenomena modeling aimed at specifying the adsorption mechanisms on localized or nonlocalized adsorbent sites, when applied to the nanocarbons. The concept comes from the fundamental thermodynamic description of adsorption equilibrium and is based on numerical calculations of the hydrogen adsorbed particles volume on the surface of selected nanocarbons: single-walled nanotube and nanocone. This approach enables to obtain information on adsorption mechanism and then as a consequence to take appropriate mathematical adsorption model, thus allowing for a more reliable identification of the material porous structure. Theoretical basis of the approach is discussed and newly derived results of the numerical calculations are presented for the selected nanocarbons.

Keywords: Adsorption, mathematical modeling, nanocarbons, numerical analysis.

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Authors: M. Najafi

Abstract:

In the present paper, a large turbo-generator shaft train including a heavy-duty gas turbine engine, a coupling, and a generator is established. The method of analysis is based on finite element simplified model for lateral and torsional vibration calculation. The basic elements of rotor are the shafts and the disks which are represented as circular cross section flexible beams and rigid body elements, respectively. For more accurate results, the gyroscopic effect and bearing dynamics coefficients and function of rotation are taken into account, and for the influence of shear effect, rotor has been modeled in the form of Timoshenko beam. Lateral critical speeds, critical speed map, damped mode shapes, Campbell diagram, zones of instability, amplitudes, phase angles response due to synchronous forces of excitation and amplification factor are calculated. Also, in the present paper, the effect of imbalanced rotor and effects of changing in internal force and temperature are studied.

Keywords: Rotor dynamic analysis, Finite element method, shaft train, Campbell diagram.

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Authors: Hayder Natiq Jasem, Zuriati Ahmad Zukarnain, Mohamed Othman, Shamala Subramaniam

Abstract:

Congestion control is one of the fundamental issues in computer networks. Without proper congestion control mechanisms there is the possibility of inefficient utilization of resources, ultimately leading to network collapse. Hence congestion control is an effort to adapt the performance of a network to changes in the traffic load without adversely affecting users perceived utilities. AIMD (Additive Increase Multiplicative Decrease) is the best algorithm among the set of liner algorithms because it reflects good efficiency as well as good fairness. Our control model is based on the assumption of the original AIMD algorithm; we show that both efficiency and fairness of AIMD can be improved. We call our approach is New AIMD. We present experimental results with TCP that match the expectation of our theoretical analysis.

Keywords: Congestion control, Efficiency, Fairness, TCP, AIMD.

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Authors: Danesh Nourzadeh, Sepideh Khorshid, Shiro Takada, Khosrow Bargi

Abstract:

In this paper, transversal vibration of buried pipelines during loading induced by underground explosions is analyzed. The pipeline is modeled as an infinite beam on an elastic foundation, so that soil-structure interaction is considered by means of transverse linear springs along the pipeline. The pipeline behavior is assumed to be ideal elasto-plastic which an ultimate strain value limits the plastic behavior. The blast loading is considered as a point load, considering the affected length at some point of the pipeline, in which the magnitude decreases exponentially with time. A closed-form solution for the quasi-static problem is carried out for both elastic and elasticperfect plastic behaviors of pipe materials. At the end, a comparative study on steel and polyethylene pipes with different sizes buried in various soil conditions, affected by a predefined underground explosion is conducted, in which effect of each parameter is discussed.

Keywords: Beam on elastic foundation, Buried pipelines, External explosion, Non-linear quasi-static solution.

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Authors: Edwaldo R. B. Monteiro, Patricia D. M. Plentz, Edson R. De Pieri

Abstract:

Mobile robotics is gaining an increasingly important role in modern society. Several potentially dangerous or laborious tasks for human are assigned to mobile robots, which are increasingly capable. Many of these tasks need to be performed within a specified period, i.e, meet a deadline. Missing the deadline can result in financial and/or material losses. Mechanisms for predicting the missing of deadlines are fundamental because corrective actions can be taken to avoid or minimize the losses resulting from missing the deadline. In this work we propose a simple but reliable deadline missing prediction mechanism for mobile robots through the use of historical data and we use the Pioneer 3-DX robot for experiments and simulations, one of the most popular robots in academia.

Keywords: Deadline missing, historical data, mobile robots, prediction mechanism.

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Authors: Ali Fellah Jahromi, Wen Fang Xie, Rama B. Bhat

Abstract:

A semi-active control strategy for suspension systems of passenger cars is presented employing Magnetorheological (MR) dampers. The vehicle is modeled with seven DOFs including the, roll pitch and bounce of car body, and the vertical motion of the four tires. In order to design an optimal controller based on the actuator constraints, a Linear-Quadratic Regulator (LQR) is designed. The design procedure of the LQR consists of selecting two weighting matrices to minimize the energy of the control system. This paper presents a hybrid optimization procedure which is a combination of gradient-based and evolutionary algorithms to choose the weighting matrices with regards to the actuator constraint. The optimization algorithm is defined based on maximum comfort and actuator constraints. It is noted that utilizing the present control algorithm may significantly reduce the vibration response of the passenger car, thus, providing a comfortable ride.

Keywords: Full car model, Linear Quadratic Regulator, Sequential Quadratic Programming, Genetic Algorithm

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Authors: C. Iihoshi, G.A. MacRae, G.W. Rodgers, J.G. Chase

Abstract:

Slab sliding system (SSS) with Coulomb friction  interface between slab and supporting frame is a passive structural  vibration control technology. The system can significantly reduce the  slab acceleration and accompanied lateral force of the frame. At the  same time it is expected to cause the slab displacement magnification  by sliding movement. To obtain the general comprehensive seismic  response of a single story structure, inelastic response spectra were  computed for a large ensemble of ground motions and a practical range  of structural periods and friction coefficient values. It was shown that  long period structures have no trade-off relation between force  reduction and displacement magnification with respect to elastic  response, unlike short period structures. For structures with the  majority of mass in the slab, the displacement magnification value can  be predicted according to simple inelastic displacement relation for  inelastically responding SDOF structures because the system behaves  elastically to a SDOF structure.

 

Keywords: Earthquake, Isolation, Slab, Sliding.

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Authors: Manoj Parmar

Abstract:

The article uses reflexivity as a research method to investigate and propose an architectural theory plan for climate change. It hypothecates that to discuss or formulate discourse on "architectural paradigm and climate change," firstly, we need to understand the modes of integration that enable architectural thinking with climate change. The research intends to study the various integration modes that have evolved historically and situate them in time. Subsequently, it analyzes the integration pattern, challenges the existing model, and finds a way towards climate change as central to architectural thinking. The study is fundamental on-premises that ecology and climate change scholarship has consistently out lashed the asymmetrical and nonlinear knowledge and needs approaches for architecture that are less burden to climate change to people and minimize its impact on ecology.

Keywords: Climate change, architectural theory, reflexivity, modernity.

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Authors: H.Hosseini, A.A. Azemati

Abstract:

The fundamental defect inherent to the thermoforming technology is wall-thickness variation of the products due to inadequate thermal processing during production of polymer. A nonlinear viscoelastic rheological model is implemented for developing the process model. This model describes deformation process of a sheet in thermoforming process. Because of relaxation pause after plug-assist stage and also implementation of two stage thermoforming process have minor wall-thickness variation and consequently better mechanical properties of polymeric articles. For model validation, a comparative analysis of the theoretical and experimental data is presented.

Keywords: High-quality polymeric article, Thermal Processing, Rheological model, Minor wall-thickness variation.

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Authors: Asem M. Othman

Abstract:

The expansion of the hospitality industry is distinctive in the 21st century. Services, by nature, are intangible. Hence, service quality, in general, is a complicated process to be measured and evaluated. Hotels, as a service sector and part of the hospitality industry, are growing rapidly. This research paper was carried out to identify the quality determinants that may affect hotel guests’ service quality perception. In this research paper, each quality determinant will be discussed, illustrated, and justified thoroughly via a systematic literature review. This paper sets the stage to measure the significant influence of the service quality determinants on guest satisfaction. The knowledge contribution from this study proposes to practitioners and/or hotel service providers, fundamental elements to adopt the implications into their policies.

Keywords: Hotel service, service quality, quality determinants, quality management.

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Authors: Linda, Sau-ling LAI

Abstract:

This paper addresses the fundamental requirements for starting an online business. It covers the process of ideation, conceptualization, formulation, and implementation of new venture ideas on the Web. Using Facebook as an illustrative example, we learn how to turn an idea into a successful electronic business and to execute a business plan with IT skills, management expertise, a good entrepreneurial attitude, and an understanding of Internet culture. The personality traits and characteristics of a successful e-commerce entrepreneur are discussed with reference to Facebook-s founder, Mark Zuckerberg. Facebook is a social and e-commerce success. It provides a trusted environment of which participants can conduct business with social experience. People are able to discuss products before, during the after the sale within the Facebook environment. The paper also highlights the challenges and opportunities for e-commerce entrepreneurial startups to go public and of entering the China market.

Keywords: F-Commerce, Entrepreneur, Startup, E-Commerce

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Authors: Federico Valenzuela-Beltran, Sonia E. Ruiz, Alfredo Reyes-Salazar, Juan Bojorquez

Abstract:

A reliability-based methodology which uses structural demand hazard curves to consider the increment of the ductility demands of structures with tilting is proposed. The approach considers the effect of two orthogonal components of the ground motions as well as the influence of soil-structure interaction. The approach involves the calculation of ductility demand hazard curves for symmetric systems and, alternatively, for systems with different degrees of asymmetry. To get this objective, demand hazard curves corresponding to different global ductility demands of the systems are calculated. Next, Uniform Exceedance Rate Spectra (UERS) are developed for a specific mean annual rate of exceedance value. Ratios between UERS corresponding to asymmetric and to symmetric systems located in soft soil of the valley of Mexico are obtained. Results indicate that the ductility demands corresponding to tilted structures may be several times higher than those corresponding to symmetric structures, depending on several factors such as tilting angle and vibration period of structure and soil.

Keywords: Asymmetric yielding, tilted structures, seismic performance, structural reliability

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Authors: Saadia Drissi, Siham Benhadou, Hicham Medromi

Abstract:

The cloud computing is an innovative paradigm that introduces several changes in technology that have resulted a new ways for cloud providers to deliver their services to cloud consumers mainly in term of security risk assessment, thus, adapting a current risk assessment tools to cloud computing is a very difficult task due to its several characteristics that challenge the effectiveness of risk assessment approaches. As consequence, there is a need of risk assessment model adapted to cloud computing. This paper requires a new risk assessment model based on multi-agent system and AHP model as fundamental steps towards the development of flexible risk assessment approach regarding cloud consumers.

Keywords: Cloud computing, risk assessment model, multi-agent system, AHP model, cloud consumer.

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Authors: Solyman Sharifi, Naghdali Choupani

Abstract:

Adhesively bonded joints are preferred over the conventional methods of joining such as riveting, welding, bolting and soldering. Some of the main advantages of adhesive joints compared to conventional joints are the ability to join dissimilar materials and damage-sensitive materials, better stress distribution, weight reduction, fabrication of complicated shapes, excellent thermal and insulation properties, vibration response and enhanced damping control, smoother aerodynamic surfaces and an improvement in corrosion and fatigue resistance. This paper presents the behavior of adhesively bonded joints subjected to combined thermal loadings, using the numerical methods. The joint configuration considers aluminum as central adherend with six different outer adherends including aluminum, steel, titanium, boronepoxy, unidirectional graphite-epoxy and cross-ply graphite-epoxy and epoxy-based adhesives. Free expansion of the joint in x direction was permitted and stresses in adhesive layer and interfaces calculated for different adherends.

Keywords: Thermal stress, patch repair, Adhesive joint, Finiteelement analysis.

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Authors: К. R. Aida–Zade, C. Ardil, S. S. Rustamov

Abstract:

Statement of the automatic speech recognition problem, the assignment of speech recognition and the application fields are shown in the paper. At the same time as Azerbaijan speech, the establishment principles of speech recognition system and the problems arising in the system are investigated. The computing algorithms of speech features, being the main part of speech recognition system, are analyzed. From this point of view, the determination algorithms of Mel Frequency Cepstral Coefficients (MFCC) and Linear Predictive Coding (LPC) coefficients expressing the basic speech features are developed. Combined use of cepstrals of MFCC and LPC in speech recognition system is suggested to improve the reliability of speech recognition system. To this end, the recognition system is divided into MFCC and LPC-based recognition subsystems. The training and recognition processes are realized in both subsystems separately, and recognition system gets the decision being the same results of each subsystems. This results in decrease of error rate during recognition. The training and recognition processes are realized by artificial neural networks in the automatic speech recognition system. The neural networks are trained by the conjugate gradient method. In the paper the problems observed by the number of speech features at training the neural networks of MFCC and LPC-based speech recognition subsystems are investigated. The variety of results of neural networks trained from different initial points in training process is analyzed. Methodology of combined use of neural networks trained from different initial points in speech recognition system is suggested to improve the reliability of recognition system and increase the recognition quality, and obtained practical results are shown.

Keywords: Speech recognition, cepstral analysis, Voice activation detection algorithm, Mel Frequency Cepstral Coefficients, features of speech, Cepstral Mean Subtraction, neural networks, Linear Predictive Coding.

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Authors: Hidetoshi Nonaka, Masahito Kurihara

Abstract:

In this paper, an authentication system using keystroke dynamics is presented. We introduced pressure sensing for the improvement of the accuracy of measurement and durability against intrusion using key-logger, and so on, however additional instrument is needed. As the result, it has been found that the pressure sensing is also effective for estimation of real moment of keystroke.

Keywords: Biometric authentication, Keystroke dynamics, Pressure sensing, Time-frequency analysis.

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Authors: Zeinab Zeinalpour-Tabrizi, Faeze Asdaghi, Mahmooh Fathy, Mohammad Reza Jahed-Motlagh

Abstract:

Shot boundary detection is a fundamental step for the organization of large video data. In this paper, we propose a new method for video gradual shots detection and classification, using advantages of fractal analysis and AIS-based classifier. Proposed features are “vertical intercept" and “fractal dimension" of each frame of videos which are computed using Fourier transform coefficients. We also used a classifier based on Clonal Selection Algorithm. We have carried out our solution and assessed it according to the TRECVID2006 benchmark dataset.

Keywords: shot boundary detection, gradual shots, fractal analysis, artificial immune system, choose Clooney.

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Authors: L. Zehtaban, D. Roller

Abstract:

Apart from geometry, functionality is one of the most significant hallmarks of a product. The functionality of a product can be considered as the fundamental justification for a product existence. Therefore a functional analysis including a complete and reliable descriptor has a high potential to improve product development process in various fields especially in knowledge-based design. One of the important applications of the functional analysis and indexing is in retrieval and design reuse concept. More than 75% of design activity for a new product development contains reusing earlier and existing design know-how. Thus, analysis and categorization of product functions concluded by functional indexing, influences directly in design optimization. This paper elucidates and evaluates major classes for functional analysis by discussing their major methods. Moreover it is finalized by presenting a noble hybrid approach for functional analysis.

Keywords: Functional analysis, design reuse, functionalindexing and representation.

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Authors: Daniel Badulescu

Abstract:

Under the difficult access to finance of SMEs, they expect that its relationship with the banks shall constitute a real help to access appropriate financing, at reasonable costs and requirements, given the possibility of mutually beneficial and long lasting relation. The literature, but also the research we have carried on, is centered on such determinants as concentration and the length of the relationship, but at the same time, there is little certainty that banks are responding positively to them. Furthermore, although the trust is considered as being a fundamental element of bank relationship – see the case house bank – SMEs find that the banks finance them looking rather on collaterals and covenants than to trust. Moreover, a positive behavior, such as prompt or advance repayments of loans, doesn-t generate any positive feedback from the banks side. All these show a deep un-satisfaction of the SMEs concerning their relationship banking.

Keywords: Banks' behavior, relationship banking, SMEs.

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Authors: S. Dorbani, M. Badaoui, D. Benouar

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The goal of the paper is to highlight the effect of the building design and epicentral distance on the storey lateral displacements, for several reinforced concrete buildings (6, 9 and 12 stories). These structures are subjected to seismic accelerations from the Boumerdes earthquake (Algeria, May 21st, Mw = 6.8). Using the response spectrum method (modal spectral approach), the analysis is performed in both longitudinal and transverse directions. The building design is expressed through the fundamental period and epicentral distance is used to represent the earthquake effect variation on storey lateral displacements and interstory drift for the considered buildings.

Keywords: Epicentral distance, interstory drift, lateral displacement, natural period, reinforced concrete buildings.

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Authors: Sebastian Tschöpe, Konja Knüppel, Peter Nyhuis

Abstract:

In times when product life cycles are decreasing, while market demands are increasing, manufacturing enterprises are confronted with the challenge of more frequent and more complex ramp-ups. Thus it becomes obvious that ramp-up management is going to be a topic enterprises have to focus on in the future. Since each ramp-up is unique concerning the product, the process, the technology, the circumstances and the coaction of these four factors, the knowledge of the ramp-up situation and the current ramp-up capability of the enterprise are fundamental requirements for the subsequent improvement of the ramp-up capability of the production system.

In this article a methodology is going to be presented which can be used to define typical production ramp-up situations, to identify the current ramp-up capability of a production system and to improve it with respect to a specific situation. Additionally there will be a description of the functionality of a software-tool developed based on this methodology.

Keywords: Assessment methodology, ramp-up, ramp-up capability, software-tool.

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Authors: Sanjeeva Balasuriya

Abstract:

A phenomenological model for species spreading which incorporates the Allee effect, a species- maximum attainable growth rate, collective dispersal rate and dispersal adaptability is presented. This builds on a well-established reaction-diffusion model for spatial spreading of invading organisms. The model is phrased in terms of the “hostility" (which quantifies the Allee threshold in relation to environmental sustainability) and dispersal adaptability (which measures how a species is able to adapt its migratory response to environmental conditions). The species- invading/retreating speed and the sharpness of the invading boundary are explicitly characterised in terms of the fundamental parameters, and analysed in detail.

Keywords: Allee effect, dispersal, migration speed, diffusion, invasion.

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Authors: S. V. Yendiyarov

Abstract:

Pattern discovery from time series is of fundamental importance. Particularly, when information about the structure of a pattern is not complete, an algorithm to discover specific patterns or shapes automatically from the time series data is necessary. The dynamic time warping is a technique that allows local flexibility in aligning time series. Because of this, it is widely used in many fields such as science, medicine, industry, finance and others. However, a major problem of the dynamic time warping is that it is not able to work with structural changes of a pattern. This problem arises when the structure is influenced by noise, which is a common thing in practice for almost every application. This paper addresses this problem by means of developing a novel technique called adaptive dynamic time warping.

Keywords: Pattern recognition, optimal control, quadratic programming, dynamic programming, dynamic time warping, sintering control.

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Authors: Danilo López, Nelson Vera, Luis Pedraza

Abstract:

This paper analyzes fundamental ideas and concepts related to neural networks, which provide the reader a theoretical explanation of Long Short-Term Memory (LSTM) networks operation classified as Deep Learning Systems, and to explicitly present the mathematical development of Backward Pass equations of the LSTM network model. This mathematical modeling associated with software development will provide the necessary tools to develop an intelligent system capable of predicting the behavior of licensed users in wireless cognitive radio networks.

Keywords: Neural networks, multilayer perceptron, long short-term memory, recurrent neuronal network, mathematical analysis.

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Authors: M. Kashfi, K. Jahani

Abstract:

Sound attenuation in absorptive silencers has been analyzed in this paper. The structure of such devices is as follows. When the rigid duct of an expansion chamber has been lined by a packed absorptive material under a perforated membrane, incident sound waves will be dissipated by the absorptive liners. This kind of silencer, usually are applicable for medium to high frequency ranges. Several conditions for different absorptive materials, variety in their thicknesses, and different shapes of the expansion chambers have been studied in this paper. Also, graphs of sound attenuation have been compared between empty expansion chamber and duct of silencer with applying liner. Plane waves have been assumed in inlet and outlet regions of the silencer. Presented results that have been achieved by applying finite element method (FEM), have shown the dependence of the sound attenuation spectrum to flow resistivity and the thicknesses of the absorptive materials, and geometries of the cross section (configuration of the silencer). As flow resistivity and thickness of absorptive materials increase, sound attenuation improves. In this paper, diagrams of the transmission loss (TL) for absorptive silencers in five different cross sections (rectangle, circle, ellipse, square, and rounded rectangle as the main geometry) have been presented. Also, TL graphs for silencers using different absorptive material (glass wool, wood fiber, and kind of spongy materials) as liner with three different thicknesses of 5 mm, 15 mm, and 30 mm for glass wool liner have been exhibited. At first, the effect of substances of the absorptive materials with the specific flow resistivity and densities on the TL spectrum, then the effect of the thicknesses of the glass wool, and at last the efficacy of the shape of the cross section of the silencer have been investigated.

Keywords: Transmission loss, absorptive material, flow resistivity, thickness, frequency.

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Authors: Seema Chopra, R. Mitra, Vijay Kumar

Abstract:

In this paper, a neural network tuned fuzzy controller is proposed for controlling Multi-Input Multi-Output (MIMO) systems. For the convenience of analysis, the structure of MIMO fuzzy controller is divided into single input single-output (SISO) controllers for controlling each degree of freedom. Secondly, according to the characteristics of the system-s dynamics coupling, an appropriate coupling fuzzy controller is incorporated to improve the performance. The simulation analysis on a two-level mass–spring MIMO vibration system is carried out and results show the effectiveness of the proposed fuzzy controller. The performance though improved, the computational time and memory used is comparatively higher, because it has four fuzzy reasoning blocks and number may increase in case of other MIMO system. Then a fuzzy neural network is designed from a set of input-output training data to reduce the computing burden during implementation. This control strategy can not only simplify the implementation problem of fuzzy control, but also reduce computational time and consume less memory.

Keywords: Fuzzy Control, Neural Network, MIMO System, Optimization of Membership functions.

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Authors: Takuya Sumi, Syoko Nukaya, Takashi Kaburagi, Hiroshi Tanaka, Kajiro Watanabe, Yosuke Kurihara

Abstract:

We propose an unconstrained measurement system for scratching motion based on mathematical model of unconstrained bed sensing method which could measure the bed vibrations due to the motion of the person on the bed. In this paper, we construct mathematical model of the unconstrained bed monitoring system; and we apply the unconstrained bed sensing method to the system for detecting scratching motion. The proposed sensors are placed under the three bed feet. When the person is lying on the bed, the output signals from the sensors are proportional to the magnitude of the vibration due to the scratching motion. Hence, we could detect the subject’s scratching motion from the output signals from ceramic sensors. We evaluated two scratching motions using the proposed system in the validity experiment as follows: 1st experiment is the subject’s scratching the right side cheek with his right hand, and; 2nd experiment is the subject’s scratching the shin with another foot. As the results of the experiment, we recognized the scratching signals that enable the determination when the scratching occurred. Furthermore, the difference among the amplitudes of the output signals enabled us to estimate where the subject scratched.

Keywords: Unconstrained bed sensing method, scratching, body movement, itchy, piezoceramics.

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Authors: Iman Hadipour, Javad Marzbanrad

Abstract:

In this paper, the strength of a stabilizer is determined when the static and fatigue multiaxial loading are applied. Stabilizer is a part of suspension system in the heavy truck for stabilizing the cabin against the vibration of the road which composes of a thin-walled tube joined to a forge component by fillet weld. The component is loaded by non proportional random sequence of torsion and bending. Residual stress of welding process is considered here for static loading. This static loading with road irregularities are applied in this study as fatigue case that can affected in the fillet welded area of this part. The stresses in the welded structure are calculated using FEA. In addition, the fatigue with multi axial loading in the fillet weld is also investigated and the critical zone of the stabilizer is specified and presented by graphs. Residual stresses that have been resulted by the thermal forces are considered in FEA. Force increasing is the element of finding the critical point of the component.

Keywords: Fillet weld, fatigue, weld toe crack, weld root crack, S-N curve, multiaxial load, residual stress, combined force.

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Authors: Vikas Rastogi, Vipan Kumar, Loveleen Kumar Bhagi

Abstract:

The present work deals with the structural analysis of turbine blades and modeling of turbine blades. A common failure mode for turbine machines is high cycle of fatigue of compressor and turbine blades due to high dynamic stresses caused by blade vibration and resonance within the operation range of the machinery. In this work, proper damping system will be analyzed to reduce the vibrating blade. The main focus of the work is the modeling of under platform damper to evaluate the dynamic analysis of turbine-blade vibrations. The system is analyzed using Bond graph technique. Bond graph is one of the most convenient ways to represent a system from the physical aspect in foreground. It has advantage of putting together multi-energy domains of a system in a single representation in a unified manner. The bond graph model of dry friction damper is simulated on SYMBOLS-shakti® software. In this work, the blades are modeled as Timoshenko beam. Blade Vibrations under different working conditions are being analyzed numerically.

Keywords: Turbine blade vibrations, Friction dampers, Timoshenko Beam, Bond graph modeling.

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