基于表面外推的热点应力法平板焊趾疲劳分析研究

Study on Fatigue Analysis of Welded Toes of Plate Structures Using Hot Spot Stress Method Based on Surface Extrapolation

针对传统名义应力整体法在焊接板结构疲劳分析应用中的实际困难,全面介绍和分析应用于海洋结构工程领域的基于表面外推的热点应力局部法。对热点应力法基本原理、热点应力表面外推确定技术、热点局部区域有限元建模原则、应力梯度影响热点应力修正、多轴应力疲劳考虑及热点应力S-N曲线选用等内容进行详细论述,总结出基于表面外推的热点应力局部法在实际工程各环节的合理实施方式及适用的设计数据,并明确了其局限性。由于板梁焊接结构的相似性,故认为广泛应用于海洋结构工程中基于表面外推的热点应力疲劳分析方法在铁道行业桥梁、机车车辆等领域有参考和借鉴价值。

In view of the practical difficulty of the traditional nominal stress global approach applied in fatigue analysis of welded plate steel structures, the hot spot stress local method based on surface extrapolation developed in marine structural engineering was introduced comprehensively. The basic principle of the hot spot stress method, surface extrapolation determination technique of the hot spot stress, FE modeling rules of the local hot spot region, correction method of the hot spot stress under the stress gradient influence, consideration of multi-axle stress fatigue and selection of the hot spot stress S-N curve are expounded in detail. Rational application of the hot spot stress local method based on surface extrapolation in each step of practical engineering and the appropriate design data were summarized, the potential limitations were also revealed. Considering the similarities among the welded plate ＆ girder structures, wide application of the hot spot stress fatigue analysis method based on surface extrapolation in marine structures has practical reference for railway applications such as bridges, rolling stock and so on.