ESTIMATING THE RELIABILITY OF WELDED JOINTS OF THIN-WALLED STRUCTURES BASED ON THE RESULTS OF THEIR NONDESTRUCTIVE CONTROL

Abstract

The problem of estimating the reliability of welded thin-walled structures under static loading is solved. The stochastic nature of the stability of structures is determined by the presence of defects in welded joints. The earlier introduced by the present authors condition when the maximum value of the membrane component of the plastic crack opening reaches its critical value is used as the failure criterion for surface defects. The probability distribution density of the depth of defects is determined based on the corresponding density for detected defects and the probability of their detection. For the Poisson-type distribution of a random value of the number of crack-like defects, the problem is reduced to determining the probability of the absence in the welded joint of cracks with the opening in excess of the allowable value. A case of correcting unallowable defects is studied, where the reliability of the welded joints is determined by the defects overlooked during
the inspection. Numerical analyses of the reliability of welded joints based on the results of the ultrasonic detection are presented.

Key words: welded joint, defect, failure criterion, defect detection probability, reliability.