| Abstract [eng] |
Stress distribution and fatigue analysis of complex welded structures are time-consuming and complicated procedures. Fatigue experiments of these complex structures might be expensive or even not possible. So, using the finite element analysis technique, stress information can be collected at a critical region of the complex models which includes steel bridges, pressure vessels, tanks, marine, and offshore structures. The structural stress of the model might vary with a sudden change in the model's shape, which might be at fillets, chamfers, and weld joints. The probability of failure occurs at the weld joints is higher, especially at the weld toe region. The structural stresses at the weld joint can predict the fatigue life of the entire model. The complex models might have hundreds and thousands of welded joints, thus, fatigue calculation with finite element analysis is the only solution to calculate the life of the entire model. Fatigue analysis of welded joints required complete information about the critical region of the structure. The fatigue life depends upon the stress distribution and stress concentration factors at the welded joint which can determine using special approaches in the finite element analysis. One of the fundamental goals of fatigue design is to extrapolate structural stresses at the weld toe region without a weld notch effect, which is possible with the help of finite element analysis. It might capture membrane and bending structural stresses of the weldments. This paper shows the design of a surge tank with the analysis of publications and design codes, and sub-modelling techniques in finite element analysis, which is a model reduction technique that allowed to concentrate on a critical region of the structure. The reliability of the model reduction technique is verified with deformation graphs at different notch radius, through-thickness, and along the surface of the model. Based on the model reduction technique, different fatigue assessment methods are compared using local approaches and studied recent development approaches to find the effectiveness of each fatigue assessment method. |
