Study On The Shock Characteristics And Experimental Of Mid-Low-Frequency Shock Spectrum Measuring Equipment

For the shock analysis of ship equipment,the measurement of shock environment is the first basic problem to be considered.Due to the high-intensity impact of the piezoelectric accelerometer,the measurement data of the middle and low frequency bands will have zero drift and noise fluctuations.In order to obtain accurate and complete shock spectrum data,it is necessary to use the mid-low-frequency shock spectrum measuring device when measuring the shock environment in the mid-low-frequency band.In the measurement of ship shock environment,the shock resistance ability of the mid-low-frequency shock spectrum measurement device is particularly important.Only if it has enough shock resistance ability,can it carry out the measurement of shock environment reliably and accurately.Therefore,it is of great practical significance to study the mechanical structure of the mid-low-frequency shock spectrum measurement device and the shock resistance of the electrical component protection system.This paper includes the following aspects:Firstly,with the mid-low-frequency shock spectrum measuring device as the research object,a finite element model was established according to it’s own structural characteristics and model simplification method.Through the modal analysis of the measuring device,the natural frequency and mode shape of the model were extracted,and the correctness of the finite element model was verified.The stiffness characteristics of the structure were obtained from the stiffness analysis.On this basis,combined with the relevant theories of ship equipment shock resistance analysis,the time domain simulation method was used to simulate the shock response of the mid-low-frequency shock spectrum measuring device structure in the transverse,longitudinal and vertical directions.Based on the study of the shock response characteristics of the measuring device,the structural shock risk area was determined,and the response law of the measuring device was analyzed.Secondly,in order to ensure the shock protection performance of the electrical system of the measuring device in the complex environment,combined with the vibration isolation and shock isolation principle,three kinds of vibration isolation buffer structure schemes of electrical components were proposed.The quasi-static stiffness test was carried out to explore the applicability of elastic elements used in different vibration isolation and buffer structures in each scheme.On this basis,through the shock test of different vibration isolation buffer structure schemes under different shock excitation peak value and pulse width,the shock isolation performance and shock response law of vibration isolation buffer system were obtained,and the applicability of different schemes was studied and analyzed.Finally,aimed at the unstable phenomenon of occasional measurement signal in the process of ship shock environment measurement,the failure modes of various types of electrical connectors in the weak link of data acquisition system of measurement device were analyzed.The electrical contact reliability of the electrical connector under different excitation frequencies was verified by the vibration frequency sweep test.Based on the shock test method and test conditions of electrical connector,the various working conditions of shock loading were determined.The electrical contact characteristics of electrical connector used in data acquisition system of measuring device were analyzed by DC voltage drop measurement method,and the variation law of electrical contact characteristics was analyzed.Combined with the above analysis results of shock response characteristics,the theoretical and experimental basis is provided for the study of the shock resistance ability of the mid-low-frequency shock spectrum measuring device,and the corresponding reference is provided for the further shock resistance optimization design of the overall structure of the measuring device and the electrical component system.