Assessment of creep damage and residual creep life of a cast HP 40 Nb Mod. Reformer tube was performed, wherein the experimental Larson–Miller diagram and area fraction of creep voids were adopted. The state of damage of the tube in service was metallographically analyzed by using light and electron microscopy. Samples from the serviced reformer furnace tube were cut and prepared for void exami...

Despite decades of intensive research, an entirely satisfactory constitutive relation for creep in concrete is still unavailable, even for working stress levels [I]. The rate-type creep laws with internal variables [2], although rather effective for numerical creep analysis of large structural systems, seem to be incapable of describing the aging phenomena without at least partially violating s...

Orientation and temperature dependence of yield stress or CRSS (Critical Resolved Shear Stress) and tension/compression anisotropy of the yield stress or CRSS have been shown by Shah and Duhl (1), Heredia and Pope (2), and Miner et al. (3). Tension/compression asymmetry in the yield strength of Ni-based superalloys has been explained in terms of the “core width effect” (4). Shah and Duhl (5) ob...

The stress-induced yielding scenario of colloidal gels is investigated under rough boundary conditions by means of rheometry coupled with local velocity measurements. Under an applied shear stress σ, the fluidization of gels made of attractive carbon black particles dispersed in a mineral oil is shown to involve a previously unreported shear rate response γ dot above(t) characterized by two wel...

pavement permanent deformations due to lack of shear strength in mixture are a major reason of rutting. any simple test to determine mixtures resistance to permanent deformation isn’t distinguished in the 1st level of superpave mix design method and prevalent methods for evaluating mixture rut resistance are expensive and time-consuming. two aggregate types, gradations, asphalt cements and fill...

Plate-type heat exchangers are anticipated to be used in the next-generation nuclear industry, and solid-state diffusion welding is a critical technology for building plate-type with high integrity. In this study, we manufactured weldment evaluated its creep behavior. Microscopic analysis revealed that Al-rich oxides were developed along interface, significantly impeding grain-boundary movement...

Tensile creep of concrete at early ages is one of the important factors that affect the stress of restrained and partly restrained concrete. But only few data are available on tensile creep of concrete. The effect of ground slag on tensile creep was studied using lever-type tensile creep tester. Early age tensile basic creep of concrete loaded at the age of 3 days was researched. Results show t...

Creep strain experiments on uncemented reservoir sands suggest that the time-dependent component of deformation can be modeled using linear viscoelasticity theory. The standard approach to solving for the values of the appropriate model parameters is to fit creep strain data as a function of time. However, by writing the creep compliance function in terms of strain-rate rather than strain, it i...

The deformation of structural alloys presents problems for power plants and aerospace applications due to the demand for elevated temperatures for higher efficiencies and reductions in greenhouse gas emissions. The materials used in such applications experience harsh environments which may lead to deformation and failure of critical components. To avoid such catastrophic failures and also incre...

In this paper, ratcheting behavior of beams subjected to mechanical cyclic loads at elevated temperature, using the rate dependent Chaboche unified viscoplastic model with combined kinematic and isotropic hardening theory of plasticity, is investigated. A precise and general numerical scheme, using the incremental method of solution, is developed to obtain the cyclic inelastic creep and plastic...