Piezoelectric Smart Module Parameter Measurement And Virtual Instrument System

The security of architecture ensures the safety of the society living. Piezoelectric smart concrete system can be constructed by embedding piezoelectric transducers into concrete structure, which are companied with the corresponding measurement devices. It can provide active, real-time and long-term monitory of the static and dynamic performances of the concrete structure. Accordingly the safety condition of the building can be mastered in time and the unnecessary disaster can be avoided. This paper establishes piezoelectric smart module parameter measurement system by using software based on virtual instrument platform. The system aims at measuring characteristic frequencies, resistances and piezoelectric parameters. The cost is reduced greatly and the use is more convenient, meanwhile, the measurement function and precision are guaranteed.The paper analyses the physical characteristics of the piezoelectric smart module, deduces the relationships between the physical parameters and equivalent circuit parameters, and constructs the lumped parameter circuit model. After the domestic and overseas traditional piezoelectric parameter measurement methods are referenced, based on the network analysis theory and the syntony characteristic of the piezoelectric resonator, a piezoelectric parameter virtual measurement system is established, combined with computer's abundant software and hardware resources.The actuating signal source in virtual measurement system uses direct digital frequency synthesizing and each performance index of the waveform generator implemented by computer and DAQ can meet measurement requirements. The influence of each harmonic component in output signal on spectrum purity is analyzed comprehensively and the corresponding noise suppression means are provided. The generation and real-time output of waveform data in segmentation make signals have better frequency resolution and spectrum purity than traditional frequency synthesizing. By measuring the correlation of two-channel input signals, the synchronism of acquisition signals is verified. Through a lowpass filter, the analog output signal is separated into two channels, one as reference signal, and the other as test signal passing by the piezoelectric resonator. Filtered by a harming window, the test signal is compared with the reference signal on the amplitude and phrase in time domain, and on spectrum analysis in frequency domain. The resonance and antiresonance frequency, namely zero-phase points, are checked by using digital sampling method with sine signal based...