Switching Action of a Bistable Fluidic Amplifier for Ultrasonic Testing

Thorge Schweitzer,Bernhard Bobusch,Marla Hörmann,Benjamin Bühling

doi:10.3390/fluids6050171

Abstract

Air-coupled ultrasonic testing is widely used in the industry for the non-destructive testing of compound materials. It provides a fast and efficient way to inspect large concrete civil infrastructures for damage that might lead to catastrophic failure. Due to the large penetration depths required for concrete structures, the use of traditional piezoelectric transducer requires high power electric systems. In this study, a novel fluidic transducer based on a bistable fluidic amplifier is investigated. Previous experiments have shown that the switching action of the device produces a high-power broadband ultrasonic signal. This study will provide further insight into the switching behaviour of the fluidic switch. Therefore, parametric CFD simulations based on compressible supersonic RANS simulations were performed, varying the inlet pressure and velocity profiles for the control flow. Switching times are analyzed with different methods, and it was found that these are mostly independent of the slope of the velocity profile at the control port. Furthermore, it was found that an inversely proportional relationship exists between flow velocity in the throat and the switching time. The results agree with the theoretical background established by experimental studies that can be found in the literature.

Highlights

IntroductionMorandi-Bridge [3] have shown the need for comprehensive testing and health-monitoring systems for concrete civil infrastructures
The parameters that are used for this study are based on experimental challenges involved in the usage of the fluidic transducer
The findings of this study have shown the utility that computational fluid dynamics (CFD) can bring to the design of novel fluidic components

Summary

Introduction

Morandi-Bridge [3] have shown the need for comprehensive testing and health-monitoring systems for concrete civil infrastructures. Standard industrial practice is the use of the pulse-echo-method with contact-based systems [5,6]. These measurements are time-consuming and, only financially feasible for small areas where damage is expected. The currently available systems use piezoelectric transducers in through-transmission setups and have small penetration depths in concrete [7,8]. They require high-powered electrical supplies and other sensitive equipment to generate the ultrasound signal

Methods

Results

Discussion

Conclusion