Research Of The Measurement And Analysis On Forming Limit Experimental System

According to the requirement of plastic working and the defects in the forming limit experiment. Associating with the recent progress in forming limit experiment research, the following tasks were accomplished:(1) Image technology was applied in forming limit experiment. The application of this technology was studied. Compared with traditional measurement technology, this method had a higher demand on illumination and vibration condition of the measurement environment, while rich data can be obtained through this method. Using this method, not only the strain distribution of the specimens'surface was acknowledged, but also the measurement of strain data in forming process was achieved. The curved surface of test pieces was rebuilt from the three dimensional coordinates of the measured points.(2) The comparison was done between BHB tensile test machine and the multifunction sheet metal formability test machine through experiments, the advantage and the function need to be improved of the latter one was discussed.(3) The triangle strain calculation based on Lagrangian strain was studied with traditional manual measurement. This method was considered more suitable for computer aided measurement, and the accuracy would be enhanced through this method.(4) The effects of fitting method in reducing the influence of necking area were studied. The comparison of experimental and theory limit strain values incorporate in the analysis on the different forming strain paths was done to investigate the accuracy of different forming limit prediction theory. How the thickness of the sheet, the age hardening and the heat treatment affected the formability was analyzed.