| The quality of the highway guardrail pillars is directly related to the degree of damage caused by accidents when traffic accidents occur,thus directly affecting the safety of drivers and passengers.Due to lack of effective and convenient guardrail column safety testing instruments and means,the quality of the erection of the guardrail column can not achieve the expected results.As far as the research results at home and abroad are concerned,the detection method of the guardrail column is divided into two directions: lossy detection and non-destructive testing.There are many bad factors such as destructive,high-cost and so on using common column detection technology,which is pulling pile method.Therefore,based on the current burial depth standard of the Ministry of Communications road barrier and the existing column detection technology,non-destructive testing method based on Magnetostrictive guided wave is proposed,and a set of column detectors and Corresponding analysis software.Exciting and propagating performance propagation characteristics in a column by studying magnetostrictive guided waves and use the magnetostrictive material to design the excitation source to overcome the defect of the traditional hammer stroke excitation and the poor repeat ability.An exciter with an adjustable excitation intensity is used to generate a guided wave excitation signal.By setting the YD61 D sensor and CKZY-18 A stored programmed control source developed in this paper focal role column surface of different position,in order to optimize the best and the receive mode.Multiple sets of signal that collected through optimize excitation and receiving locations analyzed by auto correlation and power spectral density using excite the initial wave and the reflection wave at the bottom of the column.The time history and attenuation velocity of the magnetostrictive guided wave in the column are analyzed and calculated,thus measuring the length of the buried depth of the column and degree of compaction with the sub-grade.It also provides a test method for the impact resistance of the column.In view of the non-destructive testing requirements of the subject,this paper implements the analysis software system design.Firstly,using Qt and other development frameworks,the visual data analysis software with simple operation and friendly interface was developed.QDataStream、QPixmap and other libraries were called to optimize the display interface of the analysis software.Some controls also used their unique signals and The slot mechanism is built.The hardware module selects the STM32F205 processor of ARM Cortex-M3 architecture as the core,cooperates with FLASH memory,and forms the embedded instrument system with the highly integrated SSD1963 chip as the display driver and the digital-to-analog converter of ADS8556.The instrument data is exported using a USB interface.According to the functional requirements of the instrument system,the corresponding acquisition software was also developed,and the overall design of the software and hardware of the column detector was completed.Through the multiple field tests on the highway site and the test column model,12 sets of column test data were selected.Six sets of column data were tested based on the relative position of the sensor receiver and the exciter source excitation,and the optimal installation position of the sensor and excitation controller source was obtained.In the same way,according to the factors such as the presence or absence of the guardrail device connection and the difference of the buried depth of the column,six sets of columns with different depths were tested.It was found that when the detector was connected with the guardrail device,the guardrail device had a large error in the system test.According to the analysis of the guided wave signal by matlab data processing platform,it is calculated that the measurement error of the 2# and 3# columns of the highway connected to the guardrail device is less than 20 mm,the measurement error rate is less than 1%,and the measurement error of 4#、5# and 6# columns is less than 11 mm in the internal test,the measurement error rate is less than 0.8%.In addition,according to the use of precision measurement regulations,the standard highway column 7#~12# guardrail column is tested in multiple groups to obtain the optimal waveform data of each group,and the measurement error accuracy of the detector system is 16.95 mm,and the measurement error rate accuracy is 0.9%.Therefore,the measurement accuracy of the detection system is within 4% of the national burial depth.The non-destructive detector based on Magnetostrictive guided wave column developed in this paper has been used in highway inspection field after many outdoor tests. |
