Creep Rupture Process Research Articles

Influence of grain boundary sliding on material failure in the tertiary creep range

In the later stages of a creep rupture process, a number of micro-cracks form at grain boundary facets normal to, or nearly normal to, the maximum principal tensile stress. Then the grains can be pulled apart by a mechanism involving grain boundary sliding together with dislocation creep of the grains. An axisymmetric model problem is formulated, by which some features of this final separation process can be studied, and the model is analysed numerically. Free sliding on the grain boundaries is assumed, and different boundary conditions are used in the analyses to simulate a variety of situations. The calculated times for separation by this process of grain boundary sliding are compared with times required for cavitation on grain boundary facets.

Hole growth in plane viscous creep including interaction effects

A basis is presented for modeling the creep rupture process in terms of cavity growth by viscous creep deformation. It is shown that hole interactions must be included in the analysis in order to establish a rupture criterion. A technique introduced by Berg to study the growth of single holes is extended to treat two-hole geometries. The initial displacement rates for the case of two circular holes are calculated and interaction effects are examined.

Erratum: “Statistical Aspects of Fracture in Concrete, II. Statistical Relationship between Fracture and Creep Properties of Portland Cement Mortar in Bending”

Bending creep-rupture tests have been made over a time range from 0.1 to 10 4 seconds on a large number of standard mortar specimens. The observed creep curves consist of the three stages of transient, steady-state, and accelerating creep, and each creep stage can be interpreted as a kind of stochastic process from a statistical point of view. A new rheological model based on the Eyring theory of absolute reaction rates accounts quantitatively for the stress dependence of the transition probability densities for these creep stages, as well as for the time law of the creep-rupture process.

Statistical Aspects of Fracture in Concrete, II. Statistical Relationship between Fracture and Creep Properties of Portland Cement Mortar in Bending

Bending creep-rupture tests have been made over a time range from 0.1 to 10 4 seconds on a large number of standard mortar specimens. The observed creep curves consist of the three stages of transient, steady-state, and accelerating creep, and each creep stage can be interpreted as a kind of stochastic process from a statistical point of view. A new rheological model based on the Eyring theory of absolute reaction rates accounts quantitatively for the stress dependence of the transition probability densities for these creep stages, as well as for the time law of the creep-rupture process.