应用夏波希模型估算海洋石油钢结构疲劳寿命的试验研究

AN EXPERIMENTAL STUDY ON FATIQUE LIFE ESTIMATION OF OFFSHORE STEEL STRUCTURES WITH CHABOCHE' S MODEL

基于损伤力学的理论和方法,书夏波希疲劳损伤数学模型应用于海洋石油钢结构的疲劳寿命估算.对国产海洋用钢15MnVNb的表面裂纹试样在拉-弯载荷联合作用下,进行了疲劳损伤试验,提出了损伤因子的测量方法及疲劳损伤特性参数的计算方法.根据常幅疲劳试验结果,计算出了15MnVNb材料损伤特性参数,并给出了疲劳寿命估算的表达式.通过模拟海浪载荷的随机疲劳试验,验证了夏波希模型.疲劳寿命的理论计算结果与试验结果的相对误差约为7％,说明两者吻合较好.

Chaboche' s mathematical model of fatigue damage was used for the first time to estimate the fatigue life of offshore steel structures based upon the therory of damage mechanics. Through fatigue experiments of surface crack specimens of China-made offshore steel 15MnVNb under tension-bending loads, the measurement method of damage factors and the calculation method of fatigue damage parameters were derived. According to the result of the constant amplified fatigue experiments, the damage parameters of 15MnVNb steel and the formulas of fatigue life estimation were also obtained. Chabche' s model was examined by rendom fatigue experiments under a simulated sea were load. The relative error of estimated life and experimental life is approximately 7%.