Experimentelle Untersuchungen zur pharmakologischen Wirkung des Ergotamins

Kauffmann, Friedrich; Kalk, Heinz

doi:10.1007/bf02630599

Cited by 18 publications

(5 citation statements)

References 3 publications

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“…Moreover, higher fatigue strengths in both investigated conditions are reached than in the investigation [13]. Similar transverse stiffener of S355 structural steel at R = 0.1 were tested in the AW condition and show a FAT-value of 98 MPa [41,42] and 93 MPa [15]. However, in that case, the specimens were tested under tensile load.…”

Section: Discussionmentioning

confidence: 76%

Fatigue Performance of High- and Low-Strength Repaired Welded Steel Joints

Schubnell

Ladendorf

Sarmast

et al. 2021

Metals

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Large portions of infrastructure buildings, for example highway- and railway bridges, are steel constructions and reach the end of their service life, as a reason of an increase of traffic volume. As lifetime extension of a commonly used weld detail (transverse stiffener) of these structures, a validated approach for the weld repair was proposed in this study. For this, welded joints made of S355J2+N and S960QL steels were subjected to cyclic loading until a pre-determined crack depth was reached. The cracks were detected by non-destructive testing methods and repaired by removal of the material around the crack and re-welding with the gas metal arc welding (GMAW). Then, the specimens were subjected to cyclic loading again. The hardness, the weld geometry, and the residual stress state was investigated for both the original- and the repaired conditions. It was determined that nearly all repaired specimens reached at least the fatigue life of the original specimen.

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Section: Discussionmentioning

confidence: 76%

Fatigue Performance of High- and Low-Strength Repaired Welded Steel Joints

Schubnell

Ladendorf

Sarmast

et al. 2021

Metals

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“…A comparison of in-depth profiles These measurement results of the HFMI cases were discussed together with the existing studies in the literature for in-depth distribution at x = 0 mm on the HFMI groove bottom. The data were collected for the same joint type with HFMI treatments and two types of steel grades [14,22,[31][32][33][34][35][36][37]. These steels are S690 steel grade, which is the same as this study, and S355 steel grade to confirm the influence of material strength on the distribution.…”

Section: Results Of the Residual Stress Measurementmentioning

confidence: 99%

Damage-Based Assessment of the Fatigue Crack Initiation Site in High-Strength Steel Welded Joints Treated by HFMI

Ono

Yıldırım

Kinoshita

et al. 2022

Metals

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This study aimed to identify the fatigue crack initiation site of high-frequency mechanical impact (HFMI)-treated high-strength steel welded joints subjected to high peak stresses; the impact of HFMI treatment residual stress relaxation being of particular interest. First, the compressive residual stresses induced by HFMI treatment and their changes due to applied high peak stresses were quantified using advanced measurement techniques. Then, several features of crack initiation sites according to levels of applied peak stresses were identified through fracture surface observation of failed specimens. The relaxation behavior was simulated with finite element (FE) analyses incorporating the experimentally characterized residual stress field, load cycles including high peak load, improved weld geometry and non-linear material behavior. With local strain and local mean stress after relaxation, fatigue damage assessments along the surface of the HFMI groove were performed using the Smith–Watson–Topper (SWT) parameter to identify the critical location and compared with actual crack initiation sites. The obtained results demonstrate the shift of the crack initiation most prone position along the surface of the HFMI groove, resulting from a combination of stress concentration and residual stress relaxation effect.

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“…The plastic deformation of the weld toe region results in cold hardening of the near surface microstructure. Micro hardness measurements show that the hardened zone can reach depths up to 1.5 mm [7,9]. The application of HFHP yields a modified residual stress state by inducing compressive residual stresses influencing the fatigue behaviour of the treated weld toes significantly.…”

Section: High Frequency Hammer Peeningmentioning

confidence: 99%

“…The magnitude of compressive residual stresses depends on the yield strength fy of the treated material and increases with increasing yield strength. Residual stress measurements [5][6][7][8][10][11][12][13][14] show that compressive residual stresses at the treated surfaces transverse to the welding direction can reach values of approximately 75 % of fy and values that are higher than fy because the local strength can be increased due to cold hardening. Induced compressive residual stresses can appear up to a depth of 1 to 2 mm from the treated surfaces.…”

Section: High Frequency Hammer Peeningmentioning

confidence: 99%

“…3. The depth e of the treatment line is approximately 0.1 to 0.3 mm [5][6][7][8] and depends on the geometric shape of the indenter´s tip and predominantly on the strength of the treated material and its hardness, respectivel y. The plastic deformation of the weld toe region results in cold hardening of the near surface microstructure.…”

Section: High Frequency Hammer Peeningmentioning

confidence: 99%

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