Develop Sonic Infrared Imaging Nde For Local Damage Assessment In Civil Structures

摘要

Nondestructive Evaluation (NDE) is an interdisciplinary field of study, which is concerned with the development of analysis techniques and measurement technologies for the quantitative characterization of materials, tissues and structures. Ultrasonic IR Imaging is a novel NDE technique, which combines a short ultrasonic pulse excitation and infrared imaging to detect defects in materials and structures. In this technique, a sound pulse with a frequency in the range of 20-40kHz is infused on a target material for a short duration (usually less than one second). The sonic/ultrasonic sound waves travel into the material and cause rubbing and clapping between the surfaces of any defects (such as cracks, delamination) that may be present in that material. The rubbing causes friction that generates heat in the defect area and ultimately raises the temperature at that region. an infrared video camera is set up to record the series of IR radiation change from the target object. Ultrasonic Infrared Imaging technique has several advantages compared with other traditional NDE techniques. This technique is able to detect both surface and subsurface cracks and it is effective for metallic, ceramic and composite materials, it is also very efficient for detecting delaminations in coupled structures, disbonds between coatings and substrates. This technique is wide-area, fast, non-invasive and truly dark-field since only the defects respond to the excitation.The purpose of this research work is to explore the application potentials of Sonic IR Imaging NDE technique in civil engineering structures. Experiments had been done on various my samples and different structures. Finite Element Method analysis had been used to correlate with experimental data. Multiple very realistic Finite Element models had been built for both structural and thermal analysis based on really material prosperities and structure information.