Papers by Keyword: Nonlinear

Abstract: Adhesive bonding as a promising join technique for composites is not widely used for the absence of absolutely understanding of loading behavior. In this paper both electric-strain gages and FBG sensors were employed to get the internal and surface strain of adhesive joint. In the experiment, nonlinear behavior is observed. Then the test data were compared with FEM results. It is showed that they meet each other well, FEM could get the stress distribution in adhesive bond composite joint, and both biggest peel stress and shear stress are appear at the end of adhesive.

Abstract: The nonlinear feature of the rotating machinery signal in fault situation was extracted and researched based on the collected the vibration signal. And the extraction algorithm was researched. On the basis of the phase space reconstitution the recurrence plot (RP) algorithm was researched with the nonlinear time series analysis method. The inner feature of the recurrence plots was analyzed quantitatively, the feature called recurrence rate was extracted finally. Simulation result shows that the extracted feature has the function and property diagnosis of the machinery faults based on the RP and recurrence quantification analysis (RQA) methods and also with nice engineering application value.

Abstract: The circuit in this paper is an effective solution to interference and noise of input signal during data acquisition and the circuit designed is based on an active low pass circuit with output frequency from 0~100Hz. The low pass circuit consisted mainly of an OPAMP TL084. Chaos theory is applied in this active nonlinear filter.The designed circuit is analysed by Matlab simulation software and the simulation results show the method can effectively improve effects of the filtering circuit.

Abstract: Based on the Orowan unit pressure differential equation, a vertical-horizontal dynamic rolling force model of workpiece was studied. Then, considering the influence of the rolling mill structure, the vertical-horizontal coupling vibration dynamic model of mill rollers was estabilished. The parse approximation solution of coupling system were carried out by using multiple-scale method, and the equations of amplitude frequency were obtained. Finally, the computer simulation analzed the characteristics of the system in different parameters, which can supply theoretical bases for suppressing vibration of rolling mill.

Abstract: The aim of the present paper is to establish some new nonlinear retarded integral inequalities which provide explicit bounds on unknown functions. The inequalities given here can be used as tools in the qualitative theory of certain integral equations

Abstract: In this paper, investigation on starter solenoid to develop a generalized model based simulation methodology to simulate contact bounce characteristics and tuning of the parameters to reduce or eliminate the contact bounce in existing solenoids complying with all functional and cost constraints. Using the measured data, a generalized model based simulation methodology is built using Matlab Simulink to establish contact bouncing characteristics, which is highly non-linear in nature, under various conditions/parametric variations like electromagnetic force, air gap, hard stops, spring rate and mass. The simulation model reveals that the contact bounce is reduced to zero when the stiffness of the spindle spring is in the range of 1050 N/m to 1250 N/m. Thus we can conclude that the methodology adopted helps in understanding the characteristics of existing solenoids and providing practical suggestions for potential feasible modifications that can be incorporated in the existing solenoids so as to tune their physical system parameters for an optimum response.

Abstract: To solve the strong coupling and nonlinear of switched reluctance motor (SRM) used in the Electric valve ,we use a fuzzy compound PID control method, and apply it to the switched reluctance motors speed control system.The simulation applys that this method combines the advantages of fuzzy control and PID control and is well applied to non-linears object.Based on the theory, we design the core to the outer loops speed feedback and inner current loops feedback system in TMS320F28335,and describe the specific hardware and software structure, morely verify the feasibilitys test. The theory can solve the problem that the traditional PID cannot meet the variation of the parameter from the electric valve.

Abstract: In this paper, we use chaos theory to explain the phenomenon in the field of fashion design. First we do a comparative analysis between nonlinear and garment industry trends of chaos theory, and then discuss the effect of Butterfly Effect to the product positioning of clothing brand, study the relationship of the fractal theory between the integrity and locality of the garment industry brand design. Finally, make examples of the wide range of applications of chaos theory in the field of artistic form design. This paper introduces chaos theory into the field of garment industry and design, which will bring far-reaching influence to the development of the garment industry and the future design.

Abstract: The switch reluctance motor (SRM) speed control system is often difficult to control due to its nonlinearities and parameter variations. In this paper, a fuzzy logic control (FLC) system has been presented to speed control of the SRM. The control system is composed of speed controller and current controller. The main task of the speed controller is to provide the appropriate control signal to the current controller based on the difference between the desired speed and the actual speed of the motor. In the speed control part, the fuzzy controller is used to reject the unknown and uncertain parameters in the SRM and in the load torque. The current controller evaluates the difference between the actual and the desired phase current and implements hysteresis current control. Simulation results demonstrate the effectiveness of the proposed control strategy under different operating conditions of the SRM.

Abstract: Traditional models of power plant boiler superheater are incapable of simulating the operating conditions under large disturbances with high precision. To resolve this challenging problem, this paper presents a nonlinear lumped-parameter dynamic model of power plant boiler superheater. The present model describes the dynamic processes of the pressure-flowrate and the enthalpy-temperature channels with sufficient consideration of their coupling effect. To better capture the distributed-parameter property of superheater temperature, the multi-segment lumped-parameter modeling method is employed for modeling the enthalpy-temperature channel. Dynamic responses of the last-stage superheater of a 600 MW controlled circulation boiler to disturbances of the spray water flowrate, the superheater inlet enthalpy, and the absorbed heat flux are simulated. Simulation results show that dynamic responses of the present model are reasonable, and the model has high precision, which can meet the requirements for full scale simulation and control system simulation.