Composite Pore Content Ultrasonic Parameter Evaluation Method And Equipment Research

RTM/textile composite material has the characteristics of low cost, high performance, but it is easy to produce pore micro defects in the forming process, which significantly reduce mechanical properties of materials. Therefore it is of great significance to evaluate RTM/textile composites pore content. The composite pore content ultrasonic evaluation methods mainly include method of sound velocity, sound attenuation method and nonlinear ultrasonic testing method, etc. Due to the above three methods have their own advantages, this paper put forward the composite material porosity content ultrasonic parameters evaluation method, and develop the composite material pore content ultrasonic parameters testing system by taking advantage of three kinds of method, specific work content is as follows:Firstly, based on the pulse reflection method and the finite amplitude method, the paper is developed the composite material pore content ultrasonic parameters test system. Test system included the RPR-4000 high power pulse deviser/receiver, filter, amplifier, transducer, transducer clamping device and supporting software, etc.Secondly, in order to validate the reliability of the test system, the performance of the system is analyzed, the influence of the driving voltage, the coupling way, transducer clamping device and filter amplifier for the test system is studied.Finally, using the test system, the velocity, acoustic attenuation coefficient, the second order nonlinear coefficient and the third order nonlinear coefficient of six different porosity content in sample is measured, the relationship between the pore micro defects and various parameters is set up, and through metallographic micrograph method the accuracy of parameter evaluation pore content is verified.The research results show that the test system can realize the speed of sound, sound attenuation coefficient, second order nonlinear coefficient and the third order nonlinear coefficient measurement, adding filter and amplifier can effectively improve the extraction of signal. Through the use of transducer clamping device, the realization of the system software and, etc., make the test system is more stable, reliable and convenient; Velocity of sound, sound attenuation coefficient and order nonlinear coefficient change with the pore content is a good linear relationship, which can be used to evaluate the RTM/textile composites pore content. Compared to the speed of sound and sound attenuation coefficient, nonlinear coefficient are more sensitive to pore micro defects; Pore evaluation results are consistent with the metallographic micrograph method, it indicates that using the system and evaluation method can effectively evaluate the RTM/textile composites pore micro defects. It is of great significance to research on RTM/textile composites ultrasonic testing.