Advanced methods in ultrasonic non destructive testing techniques for detection and sizing of fatigue cracks.

作者：Mahaut S^*; Chatillon S; Bredif P; Poidevin C

来源：Revue de Metallurgie-Cahiers d Informations Techniques, 2010, 107(2-3): 59-68.

DOI：10.1051/metal/2010013

Advanced methods in ultrasonic non destructive testing techniques for detection and sizing of fatigue cracks. The phenomena of thermal or mechanical fatigue of materials lead to the alteration of structures, up to the creation of cracks. The aim of nondestructive testing (NDT) is to detect these cracks and determine their size, required for determination of their harmfulness and damage to the structure. Among the various NDT methods, ultrasonic techniques also provide a volumic inspection of the entire structure with a relatively easy implementation and is not binding in terms of safety and regulation. The interaction between ultrasound waves and discontinuities or cracks present in the structure leads to echoes observed at reception, whose interpretation will enable to size or to characterize the defects responsible for these echoes. Depending on the nature of the damage ( crack isolation or network defects, such as in the case of a thermal cracking, crack open or partially closed) and the control technique used, more or less complex phenomena are involved: Interaction between a crack and a network of cracks, near partial contact between the faces of the crack under the effect of stress. These phenomena may limit the capacity of sizing, or even detection of cracks. In this paper, different applications conducted by the CEA LIST in the nuclear field, are discussed. These techniques rely on ultrasonic phased arrays probes, to master the direction and focus the ultrasound beam radiated in the component, so as optimize the detection and sizing of defects. Different defects were studied: mechanical fatigue crack inspected by ultrasonic stress or unstressed, thermal fatigue crack, with or without a network of small cracks. These techniques are optimized from the simulation tools available in the multiple techniques software platform(ultrasonic, eddy current, radiography) CIVA to predict the results of inspections and so develop and/or optimize control techniques. The performance of these different techniques are evaluated experimentally and compared with simulations.

• 出版日期2010-2
• 单位中国地震局