Industries

Modal Test on Civil Foundation of Thermal Power Station

Dynamic characteristics of civil foundation acts as a main influential factor which affects the running condition of installed machinery. Therefore, studying the dynamics of civil foundation is necessary during the design and construction phase.
Implementing modal test on civil foundation can obtain the dynamics parameters. In order to do on-site test, engineers make use of AVANT Integer data acquisition and signal analyzer, which is produced by Hangzhou Econ Technologies Co., Ltd.

 
    

 
    
On-site pictures
 
This state-of-art product, integrated DAQ and signal analyzer with industrial computer, is the new innovation technology of R&D team from Hangzhou Econ Technologies Co., Ltd. It is equipped DAQ and signal analyzer with modal test software, plus with several acceleration transducers and a special impact hammer with a force transducer.
 

Figures of modal test
 During the process of modal test on civil foundation, engineers use single charge acceleration transducers, which need conditioning amplifier to convert the charge signals to voltage signals, so they connect it with AVANT MI-2004 Conditioning Amplifier to do the test.
In order to understand vibration modal completely, engineers adopt a triaxial transducer to collect three direction transfer functions of all test points when doing the modal test. Therefore, they collect response signals by the triaxial acceleration transducer which is result from three single transducers that stuck to a cube aluminum block.
Modal data acquisition:
Hardware parameters:
Channel 1 is connected with an impact hammer for generating excitation signals, Channel 2~7 are connected with an acceleration sensor for receiving response signals.
Analysis parameters:
640Hz sampling rate; 2048 sampling points; exponential average
Operation mode: Channel 1 is set to trigger with an impact hammer.
Test points settings: set the motion direction of each test points and current test points.
Window settings: excitation channel, force window, response channel, exponential channel.
Figures of modal data acquisition section (time domain signals, frequency response, auto power spectrum, coherent signals)

 


    
            
excitation signals                                                              time domain response signal

    
Frequency response
    

Coherent signals                                                                            auto power signals

Modal parameter identification:
The engineer imports all recorded data into modal parameter identification software, and then gets all order trial parameters including modal frequency, modal vibration modal, modal damping ratio etc. from curve fitting identification.
During the whole test, AVANT Integer data acquisition and signal analyzer integrates industrial computer and perfect solutions, which ensures real-time and high quality of multi-functional analysis, such as data acquisition, spectrum analysis, data recording, playback analysis and modal analysis. With features of light & stable, wireless operation and huge data storage function, the on-site test is convenient and efficient without worrying about the power supply. Engineers have enjoyed their working journey with improved reliability system.
The simple setup of data acquisition software and user-friendly operating system simplify the whole test process. Using the post-processing software can get the according analysis results and generate the relative reports in a short time.