基于有限元方法和两对Paris疲劳裂纹扩展公式，考虑裂纹表层对裂纹扩展的阻碍影响，研究拉伸载荷作用下平板表面裂纹和对接接头纵向及横向表面裂纹扩展特性.结果表明：对接接头纵向表面裂纹在裂纹初始扩展阶段迅速向极扁长型发展，最终形状为扁长型；平板表面裂纹与对接接头横向表面裂纹扩展规律相似，在裂纹初始扩展阶段迅速向极近半圆形发展，最终形状为近半圆形；在裂纹扩展过程中，对接接头纵向表面裂纹长度方向上的扩展快于平板表面裂纹和对接接头横向表面裂纹长度方向上的扩展.
Behavior of the butt welded joint and plate surface crack propagation under tension load is studied by using finite element analysis and two coupled Paris fatigue growth laws in consideration of the retardation of the crack growth on surface layer. Results show that the butt welded joint longitudinal surface crack shapes change quickly into extremely shallowlong crack at the initial propagation phase and finally into shallowlong crack, while the plate surface crack shape and the butt welded joint transverse crack shapes change quickly into extremely near semicircular crack and finally into near semicircular crack. The butt welded joint longitudinal surface crack propagation rates are faster than those of plate surface crack and butt welded joint transverse crack.
［1］HOSSEINI A, MAHMOUD M A. Evaluation of stress intensity factor and fatigue growth of surface cracks in tension plates［J］. Eng Fract Mech, 1985, 22:957-974.
［2］MAHMOUD M A, HOSSEINI A. Assessment of stress intensity factor and aspect ratio variability of surface cracks in bending plates［J］. Eng Fract Mech, 1986, 24:207-221.
［3］NEWMAN J C, RAJU I S. An empirical stress intensity factor equation for the surface crack［J］. Eng Fract Mech, 1981, 15:185-192.
［4］ SMITH R A, COOPER J F. A finite element model for the shape development of irregular planar cracks［J］. Int J Pres Ves Piping, 1989, 36:315-326.
［5］ LIN X B, SMITH R A. Finite element modeling of fatigue crack growth of surface cracked plates［J］. Eng Fract Mech, 1999, 63:523-540.
［6］ 吴志学.表面裂纹疲劳扩展形状演化预测［J］.应用力学学报,2010,27(4):783-786.
WU Zhixue. Prediction of aspect ratio variation of surface cracks under fatigue loading［J］. Chinese Journal of Applied Mechanics, 2010, 27(4):783-786.(in Chinese)
［7］WU S X. Shape change of surface during fatigue growth［J］. Eng Fract Mech, 1985, 22:897-913.
［8］李良碧,罗广恩,王自力.潜艇结构锥柱结合壳损伤容限研究［J］.船舶力学,2006,10(1):92-97.
LI Liang-bi, LUO Guang-en, WANG Zi-li. Study on damage tolerance of submarine conecylinder pressure shell structure［J］. Journal of Ship Mechanics, 2006,10(1):92-97.(in Chinese)
［9］FUCHS H O, STEPHENS R I. Metal fatigue in engineering［M］. New York: John Wiley & Sons, 1980.
［10］杨秉宪.微小裂纹的发生与扩展［J］.北京航空学院学报,1984(2):67-75.
YANG Bing-xian. Initiation and growth of small cracks［J］.Journal of Beijing University of Aeronautics and Astronautics,1984(2):67-75.(in Chinese)
［11］黄如旭.高强钢结构表面裂纹扩展特性研究［R］.无锡:中国船舶科学研究中心科技报告,2013.
