Dual Mode Sensing with Low-Profile Piezoelectric Thin Wafer Sensors for Steel Bridge Crack Detection and Diagnosis

Abstract

Monitoring of fatigue cracking in steel bridges is of high interest to many bridge owners and agencies. Due to the variety of deterioration sources and locations of bridge defects, there is currently no single method that can detect and address the potential sources globally. In this paper, we presented a dual mode sensing methodology integrating acoustic emission and ultrasonic wave inspection based on the use of low-profile piezoelectric wafer active sensors (PWAS). After introducing the research background and piezoelectric sensing principles, PWAS crack detection in passive acoustic emission mode is first presented. Their acoustic emission detection capability has been validated through both static and compact tension fatigue tests. With the use of coaxial cable wiring, PWAS AE signal quality has been improved. The active ultrasonic inspection is conducted by the damage index and wave imaging approach. The results in the paper show that such an integration of passive acoustic emission detection with active ultrasonic sensing is a technological leap forward from the current practice of periodic and subjective visual inspection and bridge management based primarily on history of past performance.

Analysis of local influences in structural details of the bridges

“…On the other hand, parameters of the structure's elements, both structural and non-structural, determine its safety and reliability. An important issue is therefore the structural health monitoring (SHM), which is the widely undertaken subject in the national and international literature [4][5][6][7][8][9][10][11].…”

Köprü Yapilarinda Yeralti Radari (Yr) Ve Kablosuz Sensör Aği (Ksa) İle Oluşturulan Sağlik Değerlendi̇rme Si̇stemi̇

“…Sistem (Şekil 3), bir Kablosuz Sensör ünitesi içerir. Uygun biçimde kullanıldığında, herhangi bir statik veya dinamik yüklemeden kaynaklanan titreşimlerden ötürü meydana gelen kayma ve doğal frekanslar ile ilgili sağlanan veriler, oldukça hassas ve doğru olacaktır [22], [23] , [24] , [25] , [26] , [27].…”

Monitoring of acoustic emission activity using thin wafer piezoelectric sensors

“…Shielding with coaxial cable (suggested in [8]) is certainly an option, but additional shielding of the sensor is also suggested. Delicacy of sensor/structure interface precludes direct encapsulation of the sensor in a metallic enclosure.…”

“…Although such a design effectively translates out-of-plane structural vibrations, sensor thickness profile is enlarged and sensitivity to in-plane vibrations is limited. Recently, there has been interest in adapting thin piezoelectric wafer active sensors (PWAS) to monitoring acoustic emission activity [7][8][9]. Studies have demonstrated that although PWAS can be used as AE sensor, it collected smaller number of hits than a conventional AE sensor and suffered from less favorable signal to noise ratio.…”