TY - JOUR

T1 - Stability of high frequency mechanical impact (HFMI) post-treatment induced residual stress states under cyclic loading of welded steel joints

AU - Leitner, Martin

AU - Khurshid, Mansoor

AU - Barsoum, Zuheir

PY - 2017/7/15

Y1 - 2017/7/15

N2 - This paper investigates the effect of cyclic loading on the stability of compressive residual stress fields induced by high frequency mechanical impact (HFMI) post-weld treatment. First, the effectiveness of the post-treatment technique is shown by fatigue tests incorporating mild steel S355 and high-strength steel S960 longitudinal stiffener specimens. Extensive X-ray residual stress measurements support the beneficial impact on the compressive residual stress state for mild and high-strength steel structures. They also illustrate that cyclic loading leads to a significant local relaxation of this condition. Second, a numerical simulation chain incorporating a structural weld simulation, numerical analysis of the HFMI-treatment, and a final cyclic loading step for the investigated mild steel specimen is set-up. The results show that the residual stresses at the surface of the weld toe are in agreement to the X-ray measurements for both the as-welded and HFMI-treated condition, which basically proofs the applicability of the manufacturing simulation. The numerical computation including the first five load-cycles demonstrates that the simulated residual stress relaxation again exhibits consistent results with the measurements. An additional utilization of an analytical relaxation model from literature reveals that the estimation of the residual stress state in the high-cycle fatigue region is well employable. Therefore, the scientific results in this paper proof the applicability of the presented consecutive numerical-analytical procedure to assess the local compressive residual stress stability of HFMI-treated welded steel joints in both the low- and high-cycle fatigue region.

AB - This paper investigates the effect of cyclic loading on the stability of compressive residual stress fields induced by high frequency mechanical impact (HFMI) post-weld treatment. First, the effectiveness of the post-treatment technique is shown by fatigue tests incorporating mild steel S355 and high-strength steel S960 longitudinal stiffener specimens. Extensive X-ray residual stress measurements support the beneficial impact on the compressive residual stress state for mild and high-strength steel structures. They also illustrate that cyclic loading leads to a significant local relaxation of this condition. Second, a numerical simulation chain incorporating a structural weld simulation, numerical analysis of the HFMI-treatment, and a final cyclic loading step for the investigated mild steel specimen is set-up. The results show that the residual stresses at the surface of the weld toe are in agreement to the X-ray measurements for both the as-welded and HFMI-treated condition, which basically proofs the applicability of the manufacturing simulation. The numerical computation including the first five load-cycles demonstrates that the simulated residual stress relaxation again exhibits consistent results with the measurements. An additional utilization of an analytical relaxation model from literature reveals that the estimation of the residual stress state in the high-cycle fatigue region is well employable. Therefore, the scientific results in this paper proof the applicability of the presented consecutive numerical-analytical procedure to assess the local compressive residual stress stability of HFMI-treated welded steel joints in both the low- and high-cycle fatigue region.

KW - Analytical residual stress relaxation models

KW - Cyclic residual stress stability

KW - HFMI-treatment

KW - Numerical simulation

KW - Welded joints

KW - X-ray measurement

UR - http://www.scopus.com/inward/record.url?scp=85018959428&partnerID=8YFLogxK

U2 - 10.1016/j.engstruct.2017.04.046

DO - 10.1016/j.engstruct.2017.04.046

M3 - Article

AN - SCOPUS:85018959428

VL - 143.2017

SP - 589

EP - 602

JO - Engineering Structures

JF - Engineering Structures

SN - 0141-0296

IS - 15 July

ER -