No abstract

A. O. Lukashevich, V. A. Leonets', UDC 621.791.052 and L. M. Chaus Detection of subcritical fatigue cracks in low-carbon steel welds with the strain-gauge nullindicator method based on the amplitude difference and phase difference procedures was investigated. It was established that a marked growth of the difference in strain amplitudes pointed to the origin of a main crack 1 mm long near the weld. An initial increase in strain amplitude differences reveals fatigue damage much earlier in comparison with the visual crack detection. The phase difference procedure cuts down the time of fatigue damage detection in low-carbon steel welds tens of times from the visual method.

Assessment of the value of thermal residual stresses in stiffness ribs produced in accordance with the second constructive and set on in bogie frames of ВЛ60 electric locomotives. Resonant frequency of their lateral oscillation is calculated. A conclusion is made concerning the possibility of their fracture due to the impact loading acting on a bogie frame.

The results of studies on the origination and growth of fatigue cracks in the stiffening ribs of VL60 electric locomotive truck frames were presented. It was caused by the deformation of truck frames in the horizontal plane and resonance vibrations of stiffening ribs. The new design of the stiffening rib was proposed, which provided its performance.