摘要
证明了在普通试验机上加载,机身形变um=f(u)/Km和力P作用端位移a=u+um=u+f(u)/Km都是岩样形变u的函数.据此,正确写出了以原点为起点试验机-岩样系统的势函数,正确求得岩样有大于零的微形变du(>0)而系统处于准静态时的平衡方程.由此平衡方程导得的系统动力失稳起始点j和终止点s的位置,可以返回到岩样荷载-形变曲线上,在这两点处的曲线斜率f′(uj),f′(us)相同,它们的绝对值等于机身刚度Km,由此得到的f′(uj)+Km=0即为岩样失稳的Cook刚度判据.以岩样形变u为变量,给出机身弹性应变能变化率曲线,用解析与几何方式阐明了岩样动力失稳瞬间试验机释放的应变能量值.
It is proved that the deformation of machine body um= f（u）/Km and the displacement a=u｜um =u＋f（u）/Km of the point on which the force P acts are functions about the deformation of rock sample u. Accordingly, the potential function of test machine-rock sample system is written out exactly when the origin point is set out as starting point, and the equilibrium equation is exactly obtained when rock sample occurs tiny distortion du（〉0） while system keeps on quasi-static state. According to this equilibrium equation, the obtained positions of starting point j and halting point s when system is in dynamic failure can be backtracked to curve of rock sample load-deformation. On the two points, the curve has the same slopes f＇（ui） and f＇（us）, whose absolute values ate equal to stiffness Km of machine body, and thus the obtained relation formula f＇（uj ）＋Kin = 0 is also Cook stiffness criterion of rock sample failure. By using deformation u of rock sample as variable, the curve of change rate of elastic strain energy about machine body is given out and strain energy value released by test machine with dynamic failure of rock sample is illustrated by the ways of analytics and illustration.
出处
《青岛理工大学学报》
CAS
2008年第1期1-6,共6页
Journal of Qingdao University of Technology
基金
山东省自然科学基金资助项目(Y2005-A03)
山东省教委重点资助项目(G04D15)
关键词
普通试验机
势函数
准静态形变
平衡方程
应变能变化率
能量释放量
ordinary test machine
potential function
quasi-static deformation
equilibrium equation
strain energy change rate
energy releasing amount
