Problems arising in the use of nondestructive dielectric relaxation spectrometry with unilateral capacitance transducers for quality control of composites are treated. A proposal is made to base dielectric spectrometr...
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Problems arising in the use of nondestructive dielectric relaxation spectrometry with unilateral capacitance transducers for quality control of composites are treated. A proposal is made to base dielectric spectrometry on identification of the ‘test-piece/unilateral capacitance transducer’ system in combination with multi-parameter control by variation of the electric field topography and relaxation analysis. The test-piece in multi-parameter dielectric spectrometry is treated as a system having one input and several outputs, the number of which corresponds to the number of input parameters, while the model of the unilateral capacitance transducer is conceived as a system with several inputs and one output. It is suggested that the processing should be accomplished by logarithmic sampling; this is in accordance with the behaviour of relaxation signals and allows one, by digital filtering, to perform integral transforms in order to change the information from the time to the frequency domain and calculate relaxation spectra. Results of quality control of composites by means of dielectric spectrometry in the processes of polymerization, damage accumulation and water absorption are presented.
The authors propose a new method of function diagnostics of electromagnetic devices (EMD) of automation systems. They have developed a flowchart of an implementation option with a simple design. A new method of EMD di...
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ISBN:
(纸本)9781538643075
The authors propose a new method of function diagnostics of electromagnetic devices (EMD) of automation systems. They have developed a flowchart of an implementation option with a simple design. A new method of EMD diagnostics is based on eddy currents. As the paper proves, an initial EMD design can be used as an attachable eddy-current converter with one winding that contemporary uses two EMD modes: operational one providing coil supply with low-frequency operating voltage and that of eddy-current control method involving coil supply with high frequency (about 500 divided by 10,000 Hz) and about 1 divided by 10 V low voltage. The required level of decoupling between operating and measuring AC voltage supplies is provided by the proposed design. A movable EMD armature is proposed to be used as a monitored unit (MU). It was shown that measuring data provide continuous control of not only the gap between movable EMD elements during operation, but also many other physical parameters, e.g. surface condition, MU defects, material structure, temperature, mechanical stresses etc. It enables on-line non-destructive EMD control with AC and DC operating voltage supplies.
Since the model parameters of the shaking table exist in a non-linear form, this leads to distortion of the reproduced waveforms and can even lead to bias in the ground vibration test results. Therefore, the selection...
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Since the model parameters of the shaking table exist in a non-linear form, this leads to distortion of the reproduced waveforms and can even lead to bias in the ground vibration test results. Therefore, the selection of the controller is particularly critical. multi-variable (MVC) controllers are often used in shaking table control, to improve the control effect of MVC controllers. In this paper, a multi-parametric (BP-MVC) controller based on BP neural network is proposed. The BP neural network is applied to the multi-parameter (MVC) controller to identify the shaking table model, adjust the parameters in real-time, accelerate the convergence speed, and reduce the system error. The simulation results show that the correlation coefficient (CC) of the BP-MVC controller is greater than 0.985, and the root-mean-square error (RMSE) and mean absolute error (MAE) are less than 0.04 and 0.25, respectively, in a nonlinear, time-varying hydraulic system. This suggests that the BP-MVC controller has a better control performance and parameter adaptivity, which can provide a reference for the subsequent ground vibration tests.
When testing earthquake simulation shaking tables, it is commonly assumed that the test load, table, and actuator are integrated, which differs significantly from the actual situation and negatively impacts the accura...
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When testing earthquake simulation shaking tables, it is commonly assumed that the test load, table, and actuator are integrated, which differs significantly from the actual situation and negatively impacts the accuracy of system waveform reproduction. This paper simplifies the connection between the three as a spring-damping model for simulation modeling. The effects of different load mass, different connection intrinsic frequency, different connection damping ratios, and other factors on the control performance of the system are analyzed, and based on the results of the analysis, a method to improve the effects of the connection characteristics on the performance of the system, called flexible connection reaction force compensation algorithm, is proposed. Resonance peaks caused by flexible connections reduce the effective bandwidth. To broaden the bandwidth and enhance system stability, the paper introduces a flexible connection force compensation algorithm based on a multi-parameter control algorithm to compensate for the interaction force caused by the connection characteristics. This compensation strategy expands the effective bandwidth, eliminates resonance peaks, improves the waveform correlation coefficient (CC), and reduces the root-mean-square error (RMSE).
This contribution presents a novel modification of a behavioral model for a generalized current conveyor of second generation based on commercially available active devices. This model is suitable for preliminary test...
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ISBN:
(纸本)9781538624852
This contribution presents a novel modification of a behavioral model for a generalized current conveyor of second generation based on commercially available active devices. This model is suitable for preliminary tests of applications before demanding stage of expensive IC design and fabrication starts. Its main features aim at simplifying and unifying topology where three independently electronically adjustable parameters are available. Operation of the model is verified in several introduced applications (an electronically reconfigurable filter and generation of sine waveform). Substantial extension of tunability has been obtained in applying the model in the proposed oscillator in comparison to the standard linear tuning method. All expectations were confirmed by PSpice simulations.
This contribution presents a novel modification of a behavioral model for a generalized current conveyor of second generation based on commercially available active devices. This model is suitable for preliminary test...
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This contribution presents a novel modification of a behavioral model for a generalized current conveyor of second generation based on commercially available active devices. This model is suitable for preliminary tests of applications before demanding stage of expensive IC design and fabrication starts. Its main features aim at simplifying and unifying topology where three independently electronically adjustable parameters are available. Operation of the model is verified in several introduced applications (an electronically reconfigurable filter and generation of sine waveform). Substantial extension of tunability has been obtained in applying the model in the proposed oscillator in comparison to the standard linear tuning method. All expectations were confirmed by PSpice simulations.
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