Analysis of the residual stress stability of high frequency mechanical impact (HFMI)-treated transverse stiffeners of mild steel (S355) and high strength steels (S700) under p (1/3) and straight-line shaped spectrum loading

Author:  Paul Diekhoff1, Th. Nitschke-Pagel1, K. Dilger1 D.Löschner2, R. Schiller2,I. Engelhardt2 1 Institut für Füge- und Schweißtechnik, Technische Universität Braunschweig 2 Laboratory for Steel and Lightweight Structures, Institute for Material and Building Re
Source:  ICSP14 Milan
Doc ID:  2022085
Year of Publication:  2022
Abstract:  
ABSTRACT The effectiveness of high-frequency mechanical impact treatments (HFMI) and the associated increase in fatigue resistance is still being discussed, because it is generally assumed that the generated residual compressive stresses probably may be reduced by variable amplitude loading (VAL) and may therefore lose their beneficial effect. This study analyses further results for the sequence effect of VAL of a p (1/3) and straight-line shaped spectrum loading on the fatigue strength as well as the residual stress behavior of HFMI-treated transverse stiffeners (TS) of mild steel (S355) and high strength steels (S700). Fatigue test results with Random and High- Low loading for the two states as-welded (AW) and HFMI-treated joints together with in-situ residual stress measurements will be presented. The effect of VA loading on the residual stress behavior of as-welded (AW) and HFMI-treated joints and on the resulting fatigue improvement will be discussed. Keywords: High strength steel, Welded joints, spectrum loading strength, residual stresses