Development Of High Sampling Rate Real-time Data Acquisition System For Impact Wear Test Rig

The impact wear test rig is intended to study the crucial test equipment for impact instantaneous contact wear.Because the impact contact are instantaneous procedures,contact duration is short,the performance of the existing equipment on the market cannot satisfy the demands of test equipment in terms of sampling rate and accuracy at the same time,thus generating rather big obstacles to the research on impact wear.Thereupon,it's of utmost significance to develop the data acquisition equipment featuring high frequency,high accuracy and high synchronization rate for impact test rigs while conducting researches on impact wear.This paper is intended to analyze the demand and technical index of the data acquisition equipment for the impact test rigs,thereby designing the data acquisition equipment which can be utilized in various platforms,and the integrated overriding control and acquisition software accessible to various kinds of controlling equipment.By means of the coordinated operation among data acquisition,overriding control and acquisition software,it can be possible to collect the high frequency,high accuracy and high synchronization rate of two position encoder channels and four high precision ADC channels,and can calculate the contact force,velocity,energy,interfacial deformation,contact duration,energy dissipation process and a series of other parameters.Furthermore,the thesis regards CFRP laminate board as the research subject and explores its effect of mechanical properties and abrasion mechanism during cyclic low-velocity impact test by means of altering the velocity and kinetic energy due to impact.The thesis focuses on the development of data acquisition equipment for impact abrasion as follows:This paper analyzes the deficiencies concerning hardware functional design of data acquisition for impact test rigs,ensuring data sampling function characterized with the high frequency,high accuracy and high synchronization rate by means of High-performance STM32 microcontroller.It draws upon the demands for other test rigs and multiplies encoder and AD input signal channel,thus completing the related module selection,circuit design and STM32 microcontroller programming and debugging.The modular function planning and design is implemented in terms of human-machine interface software,thereby witnessing the advent of device control module,acquisitionsaving-control module,the automatic saving module,data display module.respectively.In the final analysis,efforts are made to connect impact test rigs for functional tests which are universal data acquisition devices.The effects of the mechanical properties and wear mechanism of the carbon fiber reinforced plastic(CFRP)laminates under the impact of different impact kinetic energy cycle were also studied.The following conclusions were drawn.(1)During the single impact wear process of the CFRP laminates,the absorption rate of the impact energy increases with the impact velocity,while the contact time of the impact head and the sample decreases slightly with the increase of the impact velocity.(2)The wear principle of the CFRP laminates with cyclic impact changes with the increase of impact velocity.When the impact velocity is low,the damage form of the impact interface is mainly worn,and when the impact velocity is high,the damage form of the impact interface is wear,fracture and stratification.(3)There is a higher correlation between the cumulative absorption energy and the wear volume and the projected area of the wear mark.(4)The damage will accumulate under the impact energy of the carbon fiber laminating composite material under a certain threshold,which leads to the stratified destruction of the material.According to the experimental data,the single impact energy threshold of the CFRP laminates can be under the 0.4104mJ~5.586mJ(impact velocity 120mm/s~140mm/s).The experiment shows that the data acquisition system has good accuracy and real-time for the sampling of the impact test data,and the energy dissipation process in the impact process is accurately calculated.