Research on behaviour of butt-welded joints with imperfections Static and dynamic behaviour Vladimir Stojmanovski, MSc Centre for Research, Development and Continuous Education – CIRKO, LLC Inspection Body for Pressure Equipment, Metal Structures and Cableways Skopje, Republic of Macedonia vladimir.stojmanovski@gmail.com Prof. Zoran Bogatinovski, PhD / Prof. Viktor Stojmanovski, PhD Ss Cyril and Methodius University in Skopje Faculty of Mechanical Engineering - Skopje Skopje, Republic of Macedonia zoran.bogatinovski@mf.edu.mk viktor.stojmanovski@mf.edu.mk Abstract—Due to discontinuities from various imperfections found on the outer contour of the welded joint, there is irregular stress distribution in the joint with elevated peaks. The influence of these peaks cannot be precisely estimated during the calculation of the joint. In practice, the solution of the problem, in order to prevent the existence of such imperfections, lays in establishment of rigorous criteria prescribed by the regulation. Sometimes there is a question whether these rigorous criteria are reasonable due to the fact that they directly influent the costs of the welded structure. On the other side, in some separate cases as far as there is discontinuity, it is very likely that during the reparation the situation might worsen, particularly if there is a location where the reparation is hard to be made. Considering these facts, in some cases, it is necessary to make judgment whether there is need to make reparation on the discontinuities found on the outer contour during the examination. The purpose of this paper is to endorse the influence of the discontinuities on the capacity of the welded joint in order to make appropriate judgment. Keywords—welded joint, butt-weld, quality assessment, imperfection, material testing, static testing, dynamic testing, FEA. I. INTRODUCTION The behaviour of butt welds with discontinuity of the outer contour caused by various imperfections 1 is subject of analysis in this paper. Various test-samples (plates) from materials S355J2G3 (material 1) and S235JR (material 2) are welded for the testing. The selected materials are commonly used for the production of welded structures. For the test, various imperfections are simulated in the welds of the plates. Standard test-samples for mechanical examination are formed from the plates. Static load tests of the basic material and the welded joints are performed for all considered cases. 1 see Table 3 For some characteristic cases dynamic test was performed too. Stress distribution with real dimensions of the models and defects was analysed with Finite Element Method using ALGOR software. II. BASIC MATERIAL Chemical composition and mechanical properties of the used materials gained from the material tests are presented in Table 1 and Table 2. From the test results it may be concluded that chemical composition and mechanical properties meet the requirements of the standard EN 10025 for both examined materials. TABLE I. CHEMICAL COMPOSITION TABLE II. MECHANICAL PROPERTIES Scientific Cooperations International Workshops on Engineering Branches 8-9 August 2014, Koc University, ISTANBUL/TURKEY 261