During the recent decades, the design and construction of underground spaces into rock salt have been particularly regarded for storing petroleum fluids, natural gas, and compressed air energy, and also for disposing nuclear and chemical wastes. The rock salt hosting such spaces will be subjected to various types of monotonic/cyclic, short-term/long-term stresses during the construction and/or ...

During the flood development in an oil field, the creep characteristic of mudstone is one of the important factors causing casing damage. In this study, based on the theory of fractional order differential and taking into account the creep damage evolution rules, a fractional nonlinear creep-damage model is proposed to reflect the instantaneous deformation in loading processes and the accelerat...

The tensile creep and creep-recovery behavior of a unidirectional Sic-fiher/Si,N,-matrix composite was investigated at 1200°C in air. A primary objective of the study was to determine how various sustained and cyclic creep loading histories would influence the creep rate, accumulated creep strain, and the amount of strain recovered upon specimen unloading. The key results obtained from the inve...

Ti–6Al–4V foams are produced by the expansion of pressurized argon pores trapped in billets created by powder metallurgy. Pore expansion during thermal cycling (840–1030 C, which induces transformation superplasticity in Ti–6Al–4V) improves both the foaming rate (by reducing the flow stress) and the final porosity (by delaying fracture of the pores and subsequent escape of the gas), as compared...

The ultimate objective of this research project is to develop creep damage constitutive equations for low Cr-Mo alloy and its weldment under low stress (0.2-0.4 yield stress, ��). This paper summarizes a critical analysis on the cavity nucleation and growth and the deformation mechanisms and creep damage evolution characteristics at low stress with temperature ranging from 450 °C to 650 °C, in ...

-The densification of a porous intermetallic alloy (Ti-14wt%AI-21wt%Nb) during the final stage of densification has been investigated under various states of stress and compared with the predictions of current models for densification by power-law creep. The experiments generally confirm the model predictions that the densification rate is a sensitive function of the stress state. Experimentall...

We report on the successful realization of a contactless, non-perturbing, displacement-measuring system for characterizing the surface roughness of polymer materials used in tribological applications. A single, time-dependent, scalar value, dubbed the collective micro-asperity deformation, is extracted from the normal-displacement measurements of normally loaded polymer samples. The displacemen...

Some exploratory work on creep and inverse creep in nylon 6 monofilament, polyester multifilament yarn and wool and cotton spun yarns has been presented. It is observed that the extent of creep and inverse creep differs from material to material and depends on the initial stress. Cotton shows minimum inverse creep while nylon shows maximum inverse creep. Wool and polyester have intermediate inv...

We determined the impact of creep feed provision and type on pre- post-weaning growth performance piglets. At 2 wk post farrow, litters (n = 50) were given no or provided a simple feed, complex both until weaning at ∼28 d. Creep regardless type, resulted in increased (P < 0.05) piglets final week pre-weaning immediate post-weaning, which was not maintained end nursery period. Piglets showed ...