摘要
虽然径向压缩含内单边裂纹的圆环型试样已有学者进行了分析,但在该试样上增加有益于加载的平台,就形成了新的试样——圆孔内单边裂纹平台巴西圆盘(holed single cracked flattened Brazilian disc,HSCFBD),并对其进行了研究.此外,对圆孔内(双边)裂纹平台巴西圆盘(holed cracked flattened Brazilian disc,HCFBD)做了进一步研究.通过有限元分析,对含有不同内外半径比、无量纲裂纹长度、平台角的HSCFBD和HCFBD的无量纲应力强度因子Y进行了全面标定,给出Y的曲线和拟合公式,拟合公式计算结果与数值标定结果相对误差在±1.39%以内.分析了试件形状参数对应力强度因子的影响:内外半径比越大,平台角越小,无量纲应力强度因子越大.根据应力强度因子的变化规律,推荐了适合测试Ⅰ型断裂韧度的HSCFBD和HCFBD的参数.进行了HCFBD的初步试验,还用国际岩石力学学会建议的人字形切槽巴西圆盘做了对比试验.
Previously the circular ring specimen containing an inner single radial crack subjec- ted to diametrically compressive loading had been studied, here it was modified with a pair of parallel flattened facets, which were beneficial to loading, to form a new-type specimen the holed single cracked flattened Brazilian disc （HSCFBD）. In addition, the holed （double） cracked flattened Brazilian disc （HCFBD） was further investigated. The dimensionless stress in- tensity factors of HSCFBD and HCFBD with different inner-radius-to-outer-radius ratios, differ- ent dimensionless crack lengths and different flattened angles, were comprehensively calibrated through fmite element simulation, and the curve-fitting formulas of the factor were given. The relative errors between the fitting formulas and the numerical calibration results were within ~ I. 39%. The effects of geometric factors on the dimensionless stress intensity factor were also analyzed. The results show that the dimensionless stress intensity factor increases with the in- ner-radius-to-outer-radius ratio, and decreases with the flattened angle. According to the varying law of the stress intensity factor, the specimen parameters of HSCFBD and HCFBD were recommended for testing the mode-I fracture toughness. The preliminary test of HCFBD speci- mens was carried out for a sand stone, and the comparative test of CCNBD specimens sugges- ted by the International Society for Rock Mechanics was also conducted.
出处
《应用数学和力学》
CSCD
北大核心
2015年第1期16-30,共15页
Applied Mathematics and Mechanics
基金
国家自然科学基金(51179115)
教育部博士点基金(20130181130013)~~
