박용 디젤 발전기세트의 베이스프레임 용접부 피로강도평가

Designers are often perplexed with choosing a proper S-N curve for a specific welded joint although a number of organizations have already proposed many curves for different welded joints and guidelines for them. This situation becomes worse in strain measurement because the number of installing strain gauges is restricted and designers want to check more possible weak points. In this study, various fatigue design curves for welded joints are compared and applied to the fatigue strength evaluation of baseframe for marine generator set. Strain measurement has been carried out for the operating condition. Strain measuring points are determined according to the hot spot stress approach. One-point and two-point extrapolation methods are used in order to calculate the hot spot stress. S-N curves suitable for one-point and two-point extrapolation methods have been proposed for a rational design of welded joints, and applied to the fatigue strength evaluation of the baseframe using the measured data.