| Abstract Scope |
Vibratory stress relief (VSR) is an emerging technique for mitigating welding-induced
residual stresses through controlled mechanical vibration. Compared with conventional
post-weld heat treatment, VSR requires substantially less energy and treatment time
and can be more readily applied to large or in-situ structures. However, the mechanisms
governing vibration-induced stress redistribution remain less understood, and most past
studies have been limited to laboratory-scale specimens. This study experimentally and
numerically investigates the effectiveness and underlying mechanisms of VSR in largescale
welded steel structures. Preliminary trials were conducted on an industrial-scale
overlay-welded plate to establish the treatment and measurement procedures. VSR
was then applied to an industrial-scale butt-jointed steel plate at frequencies selected
from its measured vibration-response spectrum. Residual stresses before and after
successive VSR treatments were quantified using the hole-drilling method, while the
local vibration response was measured using accelerometers. The results show that VSR
effectively reduced peak residual stresses near the weld fusion line, with the majority
of the stress relief occurring during the first few vibration cycles. Additional vibration
primarily caused localized stress redistribution rather than a uniform reduction across
the entire plates. Importantly, regions exhibiting greater displacement amplitudes during
vibration generally showed more pronounced residual-stress reduction, indicating that
VSR effectiveness is strongly governed by the vibrational mode shape and local dynamic
response. A series of coupled thermal–mechanical and dynamic finite element models
was also developed to simulate welding-induced residual stresses and their subsequent
redistribution during VSR. The simulations reproduced the experimentally observed
stress-redistribution behaviour and provided a framework for evaluating the effects of
vibration frequency, amplitude, loading position, structural constraints, and treatment
duration. |