Design And Related Technology Research Of Tensile Strength Test Device For Carbon Fiber Monofilament

Carbon fiber which was developed from the 1960 s has excellent physical and chemical properties. It has been widely used in most areas of the engineering, and has become strategic materials. Due to the characteristic size of the carbon fiber’s diameter reaches microns degree, there are still some limitations in the micro-tensile test equipment about carbon fiber monofilament both at home and abroad. It is necessary to develop a new type of carbon fiber tensile testing apparatus for directly testing filaments. In this paper, a kind of micro-tensile test equipment for carbon fiber filaments has been designed, which has the characteristics of simple structure, convenient clamp, lower cost and high precision.Firstly, the whole design of carbon fiber micro tensile testing device has been determined according to the requirement of carbon fiber tensile test. Force sensor, displacement sensor, micro positioning stage, and CCD camera have been demonstrated and selected. The mechanical structure of the testing device such as the clamp mechanism has been studied and designed.Secondly, the form of flexure hinge, micro-displacement magnifying mechanism and guiding mechanism have been selected and analyzed. The three-dimensional modeling, finite element analysis and calculation, structure optimization of the amplifier have been completed. To obtain the maximum stress load, the static properties of displacement amplifier has been analyzed by finite element analysis software and structure strength check has been handled. Through the study of the modal analysis of the amplification mechanism, the inherence frequency and modal nephogram have been obtained, which can avoid the resonance of the mechanism and improve the working performance of the amplification mechanism.And then, according to the functional requirements of test equipment, the overall scheme of data acquisition system has been proposed. The hardware of the data acquisition system was contained in a computer, a data acquisition card, a force sensor, a display instrument and the grating measurement system. Based on LabVIEW software platform, a data acquisition program and analysis processing system have been designed and developed.Finally, the performances test system of micro-displacement magnifying mechanism has been designed and built, and the performance of the piezoelectric ceramic actuator and the micro-drive apparatus has been tested. The output displacement characteristic curve, the hysteresis error curve and the output displacement curve of the amplification mechanism have been obtained. And the actual magnification of the amplification mechanism was 6.17 times. By comparing the test results with theoretical calculations and the finite element simulation results, it then analyzes the main factors that affect the performance of the test.