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Seismic analysis of the condensate storage tank in a nuclear power plant
Get PDFFollowing the nuclear power plant accident in Fukushima Japan, seismic capacity evaluation has become a crucial issue in combination building safety. Condensate storage tanks are designed to supplies water to the condensate transfer pumps, the control rod drive hydraulic system pumps, and the condenser makeup. A separate connection to the condensate storage tank is used to supply water for the high pressure coolant injection system, reactor core isolation cooling system, and core spray system pumps. A condensate storage tank is defined as a seismic class I structure, playing the important role of providing flow to the operational system and the required static head for the suction of the condensate transfer pumps and the normal supply pump. According to the latest nuclear safety requirements, soil structure interaction must be considered in all seismic analyses. This study aims to rebuild the computer model of condensate storage tanks in Taiwan using the SAP 2000 program in conjunction with the lumped mass stick model and to evaluate the soil structure interaction by employing the SASSI 2000 program. The differences between the results with the soil structure interaction and spring model are compared via natural frequency and response spectrum curves. This computer model enables engineers to rapidly evaluate the safety margin of condensate storage tank following the occurrence of earthquakes or tsunamis
Dynamics of hybrid PM/EM electromagnetic valve in SI engines
Get PDFSome previous studies demonstrated the advantages of electromagnetic valve train (EMV) for controlling variable valve timing (VVT) in SI engines. EMV allows valve timings and duration events are optimized in wide operating ranges. However, conventional EMV with solenoid actuator consumes a larger amount of energy in catching the valve at engine start and in keeping valve at open or closed position. A new EMV with hybrid permanent magnet and electromagnetic coil (PM/EM) has been proposed in this paper. An engine model with new EMV has been built to simulate the valve dynamics. Additionally, the effects of the flow gas resistance and damp coefficient have also been examined and analyzed. The results show that the new EMV can satisfy the valve dynamics in transition time, valve velocity, acceleration, energy consumption, etc. in controlling valve timing for SI engines
Free vibration of transversely isotropic magneto-electro-elastic plates in contact with fluid
Get PDFIn this study, one investigates the free vibration behaviors of transversely isotropic Magneto-electro-elastic (MEE) rectangular plates in contact with fluid. In particular, one derives the mathematical formulation on the determination of added virtual mass for MEE rectangular plates with uniform thickness, which is in contact with fluid. A fluid-structure interaction model is constructed and analyzed on the basis of the recently derived differential equation governing the dynamical responses of the MEE rectangular plates. The added virtual mass incremental (AVMI) factor of the system is computed by adopting the proposed method and the added virtual mass can then be estimated. The natural frequencies based on the proposed approach play an important role in the vibration analysis and design of the fluidcontacting MEE plate
Biomedical signal identification and analysis
Get PDFIn the article there have been presented methods of measuring and analysis biological signals, which may be used as signals control mechanical system. Among others, ther have been decribed the usage of EEG (electroencephalographic signal). Like in the case of other signals, the analysis of bio-medical signals most often resolves itself to the frequency analysis of their content with the help of Fourier transformation, and their processing the most often has a form of frequency filtering; in other words, removing from a signal its components with defined frequencies, for example, interferences. The researches have two parts. In the first part date was generated in Lab View program, and next the analysis was done (it was an example of EEG signal). In the next part the EEG signal was measured using 32 channels apertures and next real signal was analyzed using Lab View
Combustion variability and uniqueness in cylinders of a large power radial engine
Get PDFThis paper analyzes variability and uniqueness of a combustion process in the spark ignition radial engine having nine cylinders. In the case of single cylinder disturbances, multifractal approach is proposed to identify faults in the measured cylinder pressure. For better clarity, the pressure cyclic response is illustrated by means of wavelet results. The examined engine was powered by an electronic fuel injection, giving the possibility of varying doses supplied to the individual cylinders
Characterization of mechanical properties by inverse technique for composite reinforced by knitted fabric. Part 1. Material modeling and direct experimental evaluation of mechanical properties
Get PDFPolymer composites reinforced with knitted fabrics are materials with high potential in aerospace and machine building industries [1-6]. Such materials are mechanically non-linear with a high dynamic energy absorption capacity. Accurate prediction of mechanical properties is of great importance for these materials when considering their applications in novel structures. Three different approaches were implemented to this aim in the reported research work and the results are presented in: Part 1- numerical structural modeling (FEM using Solid Works) based on application of experimentally measured mechanical and geometrical properties of reinforcement and matrix, accompanied by direct measurements of mechanical properties; Part 2 - application of inverse method for characterization of mechanical properties by means of vibration modal analysis. The goal was to obtain and predict mechanical behavior of a weft knitted fabric reinforced multilayered composite plate. Results of all three approaches were compared and discussed
Research of lateral vibrations of a passenger wagon running along the curved path
Get PDFThe objective of this work is to study transverse vibration of a passenger car body running at various speeds over the track irregularities, which are usually encountered in practice. The tasks that are addressed in this research work: perform tests at track irregularities of symmetrical sinusoidal shape running both along straight and curved paths, as well as driving over the junctions along the straight and curved paths, and compare the results
A new method for building risk level estimation under dynamic load
Get PDFA building, as mechanical system, is composed of elements with different properties and distinctions. Vibration or shock impact action is one of the most effective methods to produce substantial qualitative and quantitative changes in such system. Buildings may be conditionally divided into three main categories: residential, public or social and manufacturing or industrial buildings. Any building during interaction with the dynamic load could pose hazard to human safety in the crowded place, particularly in the case of accidental progressive collapse. This phenomenon is a relatively rare event but study of its behavior is very important both for newly erected and existing buildings in order to reduce the number of casualties in accidents. In general, civil engineering structures such as buildings are composed of elements with different properties. Interaction between these elements subjected to shock loading can be analyzed using „missing column” or „missing slab (beam)” scenarios. It is obvious that the most dangerous buildings are those with massive gathering of people, i.e. leisure, entertainment, shopping centers, high-volume administrative or industrial buildings, residential buildings, buildings of national significance, etc. Our goal is to propose a method to assess each building on a comprehensive hazard risk level under the influence of special effects, especially when the building experiences impact loading. The result would be a given expression of building index which is called a point of risk level D. The use of this point summon up additional assumptions for the assessment of building as integral building system, the consequences of accidents, as well as their prevention
An adaptive lifting scheme and its application in rolling bearing fault diagnosis
Get PDFVibration signals of rolling bearings usually are corrupted by heavy noise and it is very important to extract fault features from such signals. In this paper, an adaptive lifting scheme is proposed for fault diagnosis of rolling bearings. The kurtosis indexes of scale decomposition signals are used as the optimization indicator to select the prediction operator and update operator, which can adapt to the dominant signal characteristics, and reveal the fault feature. Fourier transform is adopted to remove the overlapping signal frequency components at every scale decomposition signal. Experimental results confirm the advantage of the adaptive lifting scheme over lifting scheme for feature extraction, and the typical features of rolling bearing in time domain are successfully extracted by adaptive lifting scheme
Experimental analysis of power harvesting on vehicle vibration using smart piezoelectric materials
Get PDFIn this paper the experimental analysis for power harvesting from mechanical vibration on a vehicle has been studied by using QuickPack smart materials with piezoelectric effect. The finite element ANSYS method (ANSYS FEM) was applied to explore the required mechanical structure, modal and harmonic analysis, and electrical feature, i.e., output voltage, admittance. The experimental platform consists of a shocker and a lever, which simulated a periodical oscillation on vehicle vibration, for evaluating conversion efficiency from mechanical energy to electrical energy. During loading experiments of power generation, the electromechanical coupling characteristics of smart materials were investigated via a proposed testing circuit. Also, various electrical output loadings were specified within resistance of 5~3000 kΩ. Through the experiment analysis, the power harvesting test with a buck converter at the output terminal was processed to obtain the spectrum analysis of output voltage within the vibrating frequencies below 200 Hz, controlled by the electromagnetic shaker. Based on the comparison between ANSYS FEM and spectrum analysis, the optimal results of mechanical oscillating quantities have been verified by the maximum output voltage for the QuickPack NQ45N material. Hence, the optimum power harvesting of the smart material has the maximum output power of 0.18 mW at 26-Hz-vibration on a vehicle