摘要
用平台巴西圆盘试样在一次试验中同时测定脆性岩石的弹性模量E、拉伸强度ts和张开型断裂韧度IcK。根据应力分析的结果和Griffith 强度准则,为了保证试样在加载过程中由中心部位起裂,平台对应的加载角必须大于一个临界值(a2≥20°),并以此条件确定平台的最小相对宽度。理论分析表明,可以根据记录的载荷-位移破坏全过程曲线(包括最大载荷之后过程的记录),由初始直线段确定E,由最大载荷确定ts,由紧随其后的最小载荷确定IcK。给出E,ts和IcK相应的计算公式,公式中的关键参数由严格的有限元分析标定。还给出了一些基于弹性力学的近似解析公式,它们的精度也用有限元分析做了验证,因此,利用这些公式所得的结果是可靠的。
The flattened Brazilian disk specimen was proposed to determine elastic modulus E, tensile strength σt and opening mode fracture toughness KIc for brittle rocks in one test simultaneously. According to the results of stress analysis and Griffith's strength criteria, in order to guarantee crack initiation at the center of the specimen, the loading angle must be greater than critical value (2α≥20°), and hence the minimum relative value of flatten width should be decided accordingly. Based on the recorded load-displacement curve of the specimen's whole fracture process (including the recorded process after the maximum load), the theoretical analysis shows that E can be determined by the initial linear section, σt can be determined by the maximum load, and KIc by the minimum load immediately subsequent to the maximum load. The relevant formulas for the calculation of E, σ, KIc were presented, and the key coefficients in these formulas were calibrated by strict finite element analysis. Some approximate analytical formulas based on the mechanics of elasticity were also provided, and their accuracy is demonstrated by the finite element analysis Hence the results obtained from these formulas are reliable.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2002年第9期1285-1289,共5页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金资助项目(19872046)。
关键词
弹性模量
拉伸强度
断裂韧度
平台巴西圆盘试样
有限元
近似解析公式
Analysis
Cracks
Elastic moduli
Finite element method
Fracture toughness
Specimen preparation
Tensile strength
