摘要
压力容器等大型结构的安全性与初始裂纹的位置及尺寸、材料性能参数等不确定因素有关。概率断裂力学方法将不确定性参量作为随机变量处理,可较好地减小不确定因素对结构完整性评定的影响。本文对含表面半椭圆形裂纹平板进行了拉弯组合载荷作用下的概率断裂力学分析,估算了含表面半椭圆形裂纹平板在拉弯联合加载下裂纹尖端的应力强度因子及J积分值。失效准则考虑了基于线弹性的断裂韧性KIc准则及基于弹塑性的裂纹阻力JIc准则,将裂纹深度、材料性能等参数作为随机变量,采用Monte-Carlo方法计算了不同拉弯组合载荷作用下裂纹板的失效概率,对比分析了不同失效准则及不同拉弯组合系数下裂纹板的失效概率。
Background： The uncertainties of input parameters in an deterministic structural integrity assessment of pressure vessels may affect the assessment results. This can be improved by performing probability facture mechanics （PFM） analysis. Purpose： This work investigates the effect of uncertainties of load, defect size, fracture toughness and failure criteria on the failure probability of semi-elliptical surface cracks in plates under combined tension and bending. Methods： The correction factor method provided by EPRI is used to estimate the stress intensity factor （SIF）. The J-integral values at the deepest point of the surface crack tip are evaluated using the reference stress method and the globe limit load solution developed by Goodall ＆ Webster and Lei. PFM analysis is performed with considering the uncertainty of crack size, yield strength and fracture toughness and Monte-Carlo （MC） simulation is used to calculate the failure probability. Results： Failure probability increases with increase of load level, Lr, for all load ratio values considered in this work for a given failure criterion. However, the failure probability based on the elastic-plastic fracture criterion is higher than that based on the linear elastic fracture criterion for a given load lever, Lr. Conclusions： The load level and the failure criteria have significant effect on the failure probability. However, the load ratio makes a little contribution to the failure probability for a given failure criterion.
出处
《核技术》
CAS
CSCD
北大核心
2013年第4期176-181,共6页
Nuclear Techniques
基金
"十二五"国家科技支撑计划项目(2011BAK06B02-03)资助
