Session: 02-04-01 Fatigue and Fracture Reliability 1

Paper Number: 78431

78431 - The Influence of Edge Treatment on Fatigue Behavior of Thermal Cut Edges 

Thermal cut edges can be found in most maritime structures, e.g. in window openings or hatch corners on ships. In general, it is very common to treat free edges by grinding or sandblasting due to coating requirements within the production process. The aim of this study is to review the fatigue behavior of typical treatment methods and to define guidelines to optimize the parameters related to strength issues of thermal cut edges. Within this study several fatigue tests are performed to outline the influence of treatment methods used for different steel grades, plate thicknesses and cutting processes.  Especially the influence of the detailed design of edge geometries caused by treatment works such as grinding or milling is not covered by the common rule and guideline sets like Eurocode or IIW. Also the influence of yield strength is not considered by these regulations. Only in shipbuilding classification societies offer a bonus for high strength steels in fatigue calculations. However, the rules are based on older data sets and also the quality of cutting processes has increased during the last decades. Based on the fatigue tests recommended FAT curves are compared with the results. Initial tests show that even untreated specimens of S355 steel grade can reach results above the highest recommended curve FAT-140. That leads to the assumption that often-applied lower curves such as FAT-100 are too conservative for current production processes with high surface qualities. To evaluate the fatigue behavior of those details calculations of different edge details such as grinded radii or milled chamfers are presented. Within the tests different steel grades from S235 to S460 are considered.  Also the effect of surface roughness and residual stresses caused by the thermal cutting are taken into account. Goal of the study is to present applicable FAT curves to be used for a reasonable assessment of fatigue related design.

Presenting Author: Jan-Hendrik Grimm Institute for Ship Structural Design and Analysis, Hamburg University of Technology

Authors:

Jan-Hendrik Grimm Institute for Ship Structural Design and Analysis, Hamburg University of Technology
Hubertus Von Selle Institute for Ship Structural Design and Analysis, Hamburg University of Technology
Moritz Braun Institute for Ship Structural Design and Analysis, Hamburg University of Technology
R. U. Franz Von Bock Und Polach Institute for Ship Structural Design and Analysis, Hamburg University of Technology
Sören Ehlers Institute for Ship Structural Design and Analysis, Hamburg University of Technology
Jonas Hensel University of Technology Chemnitz
Juliana Diniz E Castro Institute of Joining and Welding, University of Braunschweig
Ann-Christin Hesse Institute of Joining and Welding, University of Braunschweig
Klaus Dilger Institute of Joining and Welding, University of Braunschweig