Investigation of ultrasound velocity measurements of polymeric parts with different surface roughness

Abstract

Ultrasound velocity is a crucial parameter for polymeric parts because it characterizes the mechanical properties and micro structure. In our previous study, we proposed a frequency-domain method for measuring ultrasound velocity via full spectrum analysis (UFSA). In this study, we conducted a series of experiments to compare the accuracy and feasibility of three measurement methods: time of flight method (TOF), ultrasonic water immersion method (UWI) and UFSA. The methods were applied to measure polymeric parts with different surface roughnesses; in addition, experiments were conducted to evaluate the effect of an external disturbance and to characterize the micro structure. Error analyses were performed for the methods. The experimental results showed that the TOF method was only suitable for measuring polymeric parts with flat surfaces, whereas the UWI and UFSA methods performed well for the measurement and characterization of polymeric parts with rough surfaces. The UFSA method had higher anti-interference ability than the other two methods. X-ray diffraction experiments indicated a negative correlation between the ultrasound velocity measured by the UWI and UFSA methods and the degree of orientation of the polymeric parts. The results obtained in this study provide guidance for the application of these methods.