Microwave Antenna Sensors for Fatigue Crack Monitoring Under Lap Joints

Abstract

This paper presents a microwave antenna sensor that has the ability to monitor fatigue cracks between lap joints where compressive force is present or in any other areas where a crack is hidden between two parts of a structure. The sensor is designed to be low profile, light weight, and conformal, making it ideal for aerospace applications where lap joints are a common design feature, and thus minimizing manual inspection times. The design of the fatigue sample for simulating a lap joint will be presented. The experiment results validated the microwave antenna sensor’s capability to effectively monitor fatigue cracks under lap joints.

Antenna Sensors in Passive Wireless Sensing Systems

“…Mohammad and Huang (2010) demonstrated an antenna sensor that can detect not only the crack growth but also the crack opening. Later on, the same group also demonstrated that it is possible to use a rectangular patch antenna to detect the crack orientation (Mohammad et al 2012) and the propagation of a hidden crack (Erdmann and Huang 2011). Similar to the antenna strain sensors, these antenna crack sensors operate on the principle that a crack changes the electric dimensions of the antenna and thus can be detected from the resulting frequency shift.…”

Wielomodalne monitorowanie postępu zmian zmęczeniowych w stalowych elementach konstrukcji

“…Podczas monitorowania procesu statycznego obciążania próbki, metoda termowizyjna wspierana była przez odczyty z mikrofalowych przetworników wykonanych w technice mikropaskowej. Antenowe czujniki mikropaskowe mogą służyć do monitorowania wzrostu naprężeń i pęknięć w materiale przewodzącym [8,9]. Czujnik stosowany jedynie do pomiaru naprężeń składa się z trzech warstw: promiennika (z materiału przewodzącego naniesionego na izolator), izolatora i masy (płaszczyzna masy wykonana z materiału przewodzącego naniesiona na drugą stronę izolatora).…”

Multimodal fatigue progress monitoring of construction steel elements

“…In case of MW technique, an applied stress changes the dimensions of the microstrip patch sensor fixed on materials surface, resulting in the change of its electrical length and frequency domain parameters like resonant frequency fr [8]- [12]. Structure and dimensions of proposed sensor are presented in Fig.…”

“…In this method the microwave patch sensors is used to monitoring the stress and crack growth in conductive material [8,9]. In case of stress monitoring microstrip sensor has its own ground plane (it is a part of the sensor).…”