Study Of Multi-channel Strain Measurement System

The subject is applied in college mechanical experimental teaching. In order to improvethe level of experimental mechanics teaching, we designed a new generation of multi-channelstrain measurement system. The system greatly improved data transfer rates using hardwareconsisted of FPGA + USB, which solved the problem of increasing the sampling frequencyand expansion of the sampling channel impossibly due to the limitations of the data transferrate. Mean while, it optimized real-time data display design. All of this brings a newgeneration of multi-channel strain test system with a better performance. With theincreasingly widespread application of virtual instrument in the test field, the design of thehost computer, the system used LabVIEW to design man-machine interface with morefriendly and more powerful interface. Meanwhile, in order to conduct in-depth study of thetransient excitation signal, the system concludes hammering experiment. And the excitationpulse produced by the hammering experiment is widely used in scientific research on themechanics of materials elastic modulus testing, modal analysis and anchor non-destructivetesting the work. Hammering experiment is one of the important experimental projects in themechanics of materials.Based on introducing Strain Measurement principle and the hammer incentive testingtechnology, the paper focus on the system design, data acquisition and process control module:auto-tune the balance on the bridge in the data acquisition modules , signal conditioning, andthe A / D data conversion which is controlled by FPGA; we also designed and debugreal-time acquisition part and control part concluding of command recognition and separationfrom the host computer. This paper describes the host computer software designed byG-language and the LabVIEW developed environment, including the introduction of thedynamic link library, sub-module design of soft front panel. The system achieved the function of acquisition, processing, analysis, real-time display, process control for the load signal, thehammer signal, and the strain signal.Finally, through theoretical analysis to the mechanical test bench, the force pulseanalysis generated by hammering experiment, combined with the analysis of test data toobtain more satisfactory results. The end of this article lists the advantages , disadvantagesand potential applications of the entire system.