摘要
从弹塑性断裂力学角度出发,进行了回收轻薄型金属10F沸腾钢多角度下的Ⅰ/Ⅱ复合断裂试验;利用数字图像相关技术,通过对裂纹尖端区域的数字图像比对分析,计算了复合裂纹稳定扩展的临界COD值(δC1)和临界CTOA(ΨC1),尝试用其作为一种断裂参数来描述10F沸腾钢的断裂韧性,并分析了Ⅰ/Ⅱ复合裂纹扩展路径。结果表明:在同种边界条件下,Ⅰ型裂纹体能承受的荷载最大;加载角度在45°时承载能力最小。Ⅰ/Ⅱ复合型和纯Ⅱ型裂纹的扩展路径从启裂开始,都表现为Ⅰ型裂纹主导的扩展。在各加载角度下,裂纹扩展到一定长度后,ΨC在一定范围内能保持相对稳定。Ⅰ/Ⅱ复合型和纯Ⅱ型裂纹的启裂点不在预裂纹尖端,而在裂尖一定距离处。δC1可反映10F沸腾钢材料的断裂韧性,其分量δC1,Ⅰ和δC1,Ⅱ反映裂纹扩展的复合度。
By elastic-plastic fracture mechanics,the mixed mode Ⅰ/Ⅱ fracture tests of thin sheet metal 10F rimmed steel were conducted under different loading angles.Digital image correlation technique was applied to analyze the crack tip region.The value of critical COD（δC1） and critical CTOA（ψC1） was calculated for stable mixed mode crack extension,and tried to be used as fracture parameters to describe the fracture toughness of 10F rimmed steel.The path of crack extension under mixed mode fracture was analyzed.The results show that：under the same boundary conditions and different loading angles,the maximum load-carrying capacity occurs at pure mode Ⅰ;the load-carrying capacity at the angle of 45° is minimum.For mixed mode Ⅰ /Ⅱ and pure mode Ⅱ,the crack extension is dominated by pure mode Ⅰ.Under any loading angle,追C remained relatively stable is in a certain range after crack growing to a certain length.The initial crack point is not at the crack tip for both mixed mode Ⅰ /Ⅱ and pure mode Ⅱ,but in the distance near the crack tip.The δC1 can reflect the fracture toughness of 10F rimmed steel materials and its components δC1. Ⅰ and δC1. Ⅱ can reflect the mixed degree of stable crack extension.
出处
《热加工工艺》
CSCD
北大核心
2013年第24期60-63,共4页
Hot Working Technology
基金
国家自然科学自然基金项目(50974068)
