摘要
在基于疲劳裂纹扩展理论的疲劳评估方法中需要确定疲劳热点,并准确求解热点处裂纹应力强度因子。论文将CCS在规范中规定的疲劳评估节点分为四类:1典型对接接头和T型接头焊趾处,2趾端底板,3趾端肘板,4垂直三构件相交角点。分别使用三维有限元技术求解第一类、第二类、第三类节点的应力强度因子修正系数并和BS7910公式对比。结果表明:第一类节点与BS7910公式吻合良好;第二类节点裂纹扩展在趾端范围内时应力强度因子修正系数较BS7910公式大,超过趾端范围内时,应力强度因子修正系数发生突变快速下降并逐渐趋近于1;第三类节点应力强度因子修正系数在整个范围内较BS7910公式大。第二类构件、第三类构件应力强度因子修正系数和BS7910公式误差都很大。为此,分别对第二、三类节点提出了各自的修正公式,它们和有限元计算结果吻合良好。
In the fatigue crack growth theory based fatigue assessment method, fatigue hot spots need to be identified and stress intensity factor of crack should be determined accurately. In this paper, fatigue assessment nodes defined in CCS Standard are divided into four categories： weld toe of butt-joints and T-joints, bottom plate of bracket toe, bracket plate of bracket toe, and intersection point of three perpendicular components. The SIFs of surface cracks at the first three categories are analyzed with 3D FEA and compared with the results of SIF magnification factors calculated with equations recommended in BS7910.The results show that the SIF magnification factors of surface crack at fn＇st category is close to that of BS7910, while the results of second and third categories are quite different from BS7910. Correction formulas are proposed respectively for second and third categories, and the results show well agreement with that from FEA.
出处
《中国造船》
EI
CSCD
北大核心
2015年第1期27-40,共14页
Shipbuilding of China
