Experimental investigation on the effect of low temperatures on the fatigue strength of welded steel joints

Abstract

There are an increasing number of liquefied natural gas ships and oil tankers that are intended for navigation in ice and cold climates, and as such, there is a necessity to assess the risk of fatigue damage to these ships. A significant aspect of the fatigue assessment is the performance of steels when subject to low temperatures. This paper presents the results of an investigation on the fatigue strength of welded steel joints at low temperatures and discusses some of the associated issues. The paper presents the results of cyclic tension fatigue testing of welded specimens made from AH36 and DH32 steel grades under room and cold temperature conditions. Nominal fatigue curves for these specimens and crack lengths as a function of loading cycle number are also provided. The fatigue strength of welded specimens of DH32 and AH36 steel grades has been obtained. The data can be used for the evaluation of the fatigue life of ship structures manufactured from the specified steel grades and can be used for establishing whether measures need to be taken to reduce the risk of fatigue damage in the structural elements of ships trading in cold climates.

Keywords:

• fatigue
• low temperatures
• welded steel joints
• crack propagation
• ship structures

Acknowledgements

The assistance of the Krylov Shipbuilding Research Institute and those who participated in the experimental investigation are gratefully acknowledged. The authors also gratefully acknowledge the support and contributions of Lloyd's Register colleagues for their invaluable technical assistance. The authors also wish to thank the management of Lloyd's Register for permission to publish this paper. The views expressed are those of the authors alone and do not necessarily represent the policy of Lloyd's Register or Krylov Shipbuilding Research Institute.

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