Publications Repository - Gdańsk University of Technology

In the shipbuilding industry, the risk of brittle fractures is relatively high because some units operate in arctic or subarcticzones and use high thickness (up to 100 mm) steel plates in their structures. This risk is limited by employing certifiedmaterials with a specific impact strength, determined using the Charpy method (for a given design temperature) and byexercising control over the welding processes (technology qualification, production supervision, and non-destructive tests).However, for offshore constructions, such requirements may prove insufficient. For this reason, regulations employed inconstructing offshore structures require conducting crack tip opening displacement (CTOD) tests for steel and weldedjoints with thicknesses exceeding 40 mm for high tensile strength steel and 50 mm for other steel types. Since classificationcodes do not accept the results of CTOD tests conducted on specimens of sub-sized dimensions, the problem of theoreticallymodelling the steel construction destruction process is of key importance, as laboratory tests for notched elements ofconsiderable thickness (100 mm and higher) are costly and problems stemming from high loads and a wide range ofrecorded parameters are not uncommon. The aim of this research is to find a relationship between material thickness andCTOD value, by establishing and verifying a numerical model that allows recalculating a result obtained on a sub-sizespecimen to a full- size specimen for a ductile fracture mode. This work presents results and conclusions from numericalmodelling and compares them with laboratory test results of the elastic-plastic properties of high thickness steel, typicallyused in offshore applications.

Authors

• dr inż. Jakub Kowalski link open in new tab ,
• prof. dr hab. inż. Janusz Kozak link open in new tab