Creep rupture assessment is a significant issue in the field of high-temperature structural integrity. In this paper, creep 3D pressure pipelines with volumetric defects subjected to cyclic thermo-mechanical loadings done using direct numerical approach within framework stress compensation method (SCM). For calculation limit, an extended shakedown analysis scheme yield strength correction essen...

Optimal structural design under creep conditions, initiated over 20 years ago, brings a fairly larg~ variety of problems, interesting both from theoretical and engineering point of view. Existence of the time factor leads to optimization for a prescribed lifetime and the number of independent variables in governing equations increases by one. Practical importance is connected with design of met...

Creep phenomenon in rock engineering plays a key role in development of underground spaces as they must be stable enough for a long period of time. Current research involved designing and manufacturing of a new creep testing machine. The equipment is capable to perform simultaneous light-duty creep tests on more than one cylindrical rock samples at a very low cost.To evaluate the equipment’s pe...

Modelling of the long-term creep damage and lifetime is very challenging due to their strong stress level dependence. Aiming at developing a set constitutive equations suitable for service, research was carried out in modelling minimum strain rate, cavitation rupture, coupling between deformation. Firstly, based on driven concept, cavity nucleation model growth were calibrated together using hi...

Long term tensile creep studies were conducted on binary NiAl in the temperature range 700-1200 K with the objectives of characterizing and understanding the creep mechanisms. Inverse and normal primary creep curves were observed depending on stress and temperature. It is concluded that the primary creep of NiAl is limited by dislocation mobility. The stress exponent for creep, n, decreased fro...

Operating structural components experience complex loading conditions resulting in 3D stress states. Current design practice estimates multiaxial creep rupture life by mapping a general state of to uniaxial correlation using effective measures. The data supporting the development measures are nearly always only and biaxial, as tests not widely available. This limitation means current must extra...

One of the yet unresolved engineering problems is forecasting the creep lives of weldment in a pragmatic way with sufficient accuracy. There are number of obstacles to circumvent including: complex material behavior, lack of accurate knowledge about the creep material behavior specially about the heat affected zones (HAZ),accurate and multi-axial creep damage models, etc. In general, creep life...

For nickel-based single crystal superalloy DD6 (AECC Beijing Institute of Aeronautical Materials, Beijing, China) material, a method for predicting creep rupture time was proposed based on newly defined equivalent stress method. An anisotropic model describing the orientation-dependent behavior and lifetime proposed. The subroutine written model. stability improved by adjusting iterative algori...