Papers by Keyword: Identification

Abstract: The self-inductance is the inherent phenomenon in a wire. Through the comparison of two kinds of method for solving the self-inductance, stated that note in the current contribution rate problem in the process by the first method to solve the self-inductance coefficient. Through solving the relationship between the coefficient of self-inductance and cable radial thickness for coaxial cables that cable, the coefficient of self-inductance decreases monotonously with the radial thickness of the reduction.

Abstract: Fatigue analysis of steel parts of structures, which are subjected to complex irregular loading programs caused by wind, thermal, wave loads, earthquakes and combined imposed actions, requires in some cases using special methods of stress-strain evaluation. The model of the low cycle fatigue nonlinear damage accumulation is developed with taking into account the history of the deformation process. The damage is defined on the base of considering the quasi-static accumulation of maximal strain (stress) and hysteresis loops. The identification of material constants of the model is discussed. Application of the damage model for fatigue analysis of the antennas, pipelines, basements and fasteners units is considered and a comparison with experiments is given.

Abstract: The knowledge of the dynamic state and structure of the system allows to describe its behavior, and allows creating prognosis models of the system behavior in the function of dynamic evolution time, based on the model of the technical state symptoms growth. Most often, however, there are no known equations describing behaviors of the system in the function of dynamic evolution time, which accounts for the need to apply new tools to examine the dynamic state. There is, therefore, the requirement to experimentally verify analytical technical models as the proper one is a model which is verified in practice. An experiment is, therefore, often only an inspiration for further researches leading to the optimization of the construction. In this work presented are chosen problems of machines’ technical state diagnosis with the use of identification and technical diagnostics methods. Relations between methods of dynamic state evaluation and methods of technical state evaluation were indicated. Example modal analysis results illustrate the complexity of projecting dynamic state researches into diagnostic researches of machine state evaluation.

Abstract: Mechanical fracture parameters obtained from three-point bending tests on concrete specimens with a central edge notch are introduced in this paper. A total of four sets of specimens were tested. The concrete used in each set differed in cement dosage, which ranged from 250 to 455 kg per m³ of fresh concrete. Three specimens in each set were tested at the age of 28 days. Increasing the dosage of cement influences the mechanical fracture properties of concretes in both positive and negative ways.

Abstract: Six oil degradation strains were obtained from the tropic ocean of Hainan province using diesel oil as the sole carbon source in the research, which aim is to prevent and restore the ocean oil pollution at present and in future. The degradation rate of diesel oil by these strains was tested and three stains were filtrated as the dominant bacteria from Soh7, Soh11, Soh23, Soh26, Soh38 and Soh53 which were Soh7, Soh11 and Soh53. The 15d DR were 40.6%,31.3%,37.1% and 25d DR were 51.2%, 40.3%, 47.8% (TDR were 63.1%, 54.9%, 60.6%) separately under 24°C. Based on the morphological, physiological and biochemical test results, the Soh7 was identified as Sporolactobacillus sp. and Soh11 and Soh53 were Acidothermus sp..

Abstract: This article deals with the influence of optimal actuator and sensor placement on the active control of thin-walled mechanical systems. The approach used for optimal actuator and sensor placement is based on the evaluation norms and. The optimal actuator and sensor placement satisfied the requirements on the controllability, observability and spillover prevention. The investigation of the optimal placement of actuators and sensors is demonstrated on the active vibration of the thin-walled two dimensional mechanical systems.

Abstract: The paper presents concept and application of mathematical and simulation model of variable-speed drives (hereafter VSD or VSDs). The models were/are used in rolling mills engineering, commissioning and maintenance. The VSDs are the main actuators there. In order to reach optimal performance in terms of material tolerances, wear and tear, and reliability it is necessary to have good VSD control which meets not only technology targets but also properties of the VSD mechanical train (set of motor rotors, shafts, gear boxes, couplings, clutches, spindles, working and backup rolls, etc.). Only the optimal VSD control and appropriate operation and maintenance can ensure trouble-free operation and long lifetime of the VSDs. We have been dealing with the VSDs models since 1990. Since then we have used the models in many practical applications. Currently, we concentrate mainly on an optimal and advanced interstand section control. Apart from various PID control strategies, also Fuzzy control has been tested and analyzed. The paper mentions some of our experiences we have achieved in this area.

Abstract: Analysis of inhomogeneous residual stress (RS) fields in bodies is one of the major problems of the mechanics of deformable solid bodies. In the present research the new techniques of identification of inhomogeneous RS in bodies are developed on the basis of surface displacement measurement in a set of points under vibrating sounding load. Corresponding nonlinear ill-posed inverse problems (IP) are formulated and solved numerically by means of iterative regularization. Based on computational experiments, the most advantageous sounding load types and frequency ranges providing the best reconstruction accuracy are revealed. The examples for a cantilever, a plate, a layer, and a cylindrical tube are presented.

Abstract: Abstract. Currently, traffic law enforcement agencies rely mainly on the license plate to identify illegal vehicles. But for those vehicles with no license plates or license plates are obscured or slipped, the existing techniques do not work. In this paper, a method to reconstruct the external dimensions of vehicles from 2D images is therefore proposed to identify those illegal vehicles above. The external characteristics of vehicles and methods to model vehicles are analyzed. Based on the analysis, we simplified vehicles as a combination of a rectangular parallelepiped and trapezoidal polyhedron which can be produced with corner points from 2D images. The process to establish the vehicle model with corner points is studied. Finally with Visual C++ and SolidWorks API, the 3D model of a vehicle is established based on a 2D image. The vehicle's primary outlines information including length, width and height are restored, and the information can be used to identify the vehicle.

Abstract: In this paper, microscopic method, transmission technique and attenuated total reflection method of infrared spectroscopy and differential scanning calorimetry were investigated for analyzing the component of inner and outer layer of sheath-core polymer fiber. Results showed that transmission technique and attenuated total reflection method of infrared spectroscopy was a quick and accurate method for identification of sheath-core fiber of fiber.