The temperature and von Mises stress distributions of the rotor during a startup-running-shutdown-natural cool process were numerically studied using ABAQUS and the damage caused by the interaction of creep and fatigue was subsequently computed and discussed.
The combination of high temperatures and low stresses typically places failure for monolithic ceramics in the creep regime. The objective of this work is to present a design methodology for predicting the lifetimes of structural components subjected to multiaxial creep loading.
A unified ductility criterion for fatigue–creep life prediction is presented based on the static fracture toughness exhaustion and dissipated cyclic strain energy density of high temperature components. It provides a general failure criterion for both low and high cycle fatigue regimes. The effects of mean stress, creep and loading waveform on fatigue life are incorporated into this criterion.
The developed multiaxial system for a mission includes evaluation of transient metal temperatures, corresponding elastic and inelastic strains, creep strains, and subsequently creep/fatigue lives. The calculations are performed using the ductility exhaustion method.
Current research on the creep life prediction of a film-cooling hole structure still remains in an initiating stage. With the boom in the aviation industry, there is an urgent need to propose a new method to predict the creep lives of film-cooling hole structures and investigate the creep mechanism deeply.
L. Zhao, N. Alang and K. Nikbin, Investigating creep rupture and damage behaviour in notched P92 steel specimen using a microscale modelling approach, Fatigue & Fracture of Engineering Materials & Structures, 41, 2, (456-472), (2017).
The multiaxial fatigue life prediction was carried out according to von Mises's equivalent theory. The results from the prediction showed that the equivalent strain range can be served as the valid mechanics for predicting multiaxial high temperature and low cyclic fatigue life.
model for creep life prediction operating at high temperature and subjected to an elastic-plastic-creep deformation. 2. Creep Life Assessment Methods 2.1. Reference Stress Method. The reference stress method describes the inelastic response of structures. The method has been developed to enable simplified assessment
The objective of this paper is to present a creep life prediction methodology based on a modified form of the Kachanov-Rabotnov continuum damage mechanics (CDM) theory. In this theory, the uniaxial creep rate is described in terms of stress, temperature, time, and the current state of material damage.
It is observed that KR cannot predict the creep deformation, damage, and rupture life of nickel base superalloys accurately using one set of constants for all the stress levels. The Sinh model exhibits a superior ability to predict the creep behavior using one set of constants for all the stress levels.
This creep life prediction methodology was preliminarily added to the integrated design code named Ceramics Analysis and Reliability Evaluation of Structures/Creep (CARES/Creep), which is a postprocessor program to commercially available finite element analysis (FEA) packages.
for creep life prediction under multiaxial state of stress. The average hardness near to notch root was more in comparison with regions away from the notch root and shallow notch was found exhibit more hardness in comparison with sharper notch. Keywords AUSC Multiaxial creep Finite element analysis Life prediction Hardness measurement
through simulated experiments and the same have been predicted by applying multiaxial creep damage rule recommended in RCC-MR. Further, the permissible lives of such structures under reactor conditions have been extrapolated applying a Larson Miller Parameter. 3 CREEP-FATIGUE DAMAGE LIFE PREDICTION OF PFBR COMPONENTS
Deterministic and Probabilistic Creep and Creep Rupture Enhancement to CARES/Creep: Multiaxial Creep Life Prediction of Ceramic Structures Using Continuum Damage Mechanics and …
Calculations of creep damage under conditions of strain control are often carried out using either a time fraction approach or a ductility exhaustion approach. In practice, calculations of creep damage are further complicated by the presence of multiaxial states of stress.
n −1 3 § σ vm · σ ij' ε c ij = A¨ ¸ (6) 2 ©1− ω ¹ 1−ω χ Bσ rep ω = (7) (1 − ω )φ The creep rupture life of the steel under multiaxial state of stress has been predicted based on the representative stress associated with creep damage using FE analysis coupled with creep damage mechanics. 8 Presentation of multiaxial creep ...
Abstract. Over the past ten years significant progress has been made towards reliable methods for creep life assessment. Through development and application, methods are now at a stage at which their technical viability is established and the cost benefits are proven at the plant operation, maintenance, and strategic planning levels.
The developed multiaxial system for a mission includes evaluation of transient metal temperatures, corresponding elastic and inelastic strains, creep strains and subsequently creep/fatigue lives. The calculations are performed using the ductility exhaustion method.
Liu, Y., Mahadevan, S., Multiaxial High-Cycle Fatigue Life Prediction of Isotropic and Anisotropic Materials. 46th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics & Materials Conference, Austin, TX, April 2005.
A model for creep life prediction of thin tube using strain energy density as a function of stress triaxiality under quasistatic loading employing elastic-creep & elastic-plastic-creep deformation
Brian Dyson. Department of Materials, Imperial College of Science, Technology and Medicine, Prince Consort Road, London SW7 2BP, England
Accurate deformation modeling and life prediction of these structures only achieved with an accurate understanding of how this and other key alloys behave under complex conditions. This research conveys a proposed methodology that can be used to apply creep and plasticity constitutive models that correlate with experimental data. Several
Oct 23, 1998· Deterministic and Probabilistic Creep and Creep Rupture Enhancement to CARES/Creep: Multiaxial Creep Life Prediction of Ceramic Structures Using Continuum Damage Mechanics and the Finite Element Method
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This paper discusses an evaluation method of creep-fatigue lives of YH61 single crystal superalloy under multiaxial loading at high temperature. Three types of creep-fatigue tests were performed using three types of the single crystalsuperalloy specimens at 1173K. They were push-pull tests using solid bar specimens, tension-torsion tests using hollow cylinder specimens and biaxial tension ...
This creep life prediction methodology was preliminarily added to the integrated design code named Ceramics Analysis and Reliability Evaluation of Structures/Creep (CARES/Creep), which is a ...
The characteristics that make composites, especially glass fiber-reinforced and wood/epoxy composites, suitable for wind turbine blades are low density, good mechanical properties, excellent corrosion resistance, tailorability of material properties, and versatility of fabrication methods. Although ...
The computer program CARES/LIFE calculates the time-dependent reliability of monolithic ceramic components subjected to thermomechanical and/or proof test loading. This program is an extension of the CARES (Ceramics Analysis and Reliability Evaluation of Structures) computer program. CARES/LIFE ...
The connection failures will be analyzed using progressive ply failure techniques to predict leakage. Once the analytical models are shown to provide an accurate prediction of failure, the models will be used to evaluate alternative connection geometry and material parameters that may be of interest.
TOUGHENED CERAMICS LIFE PREDICTION Final Technical Report (880R2 1 749) ... The following is a summary of accomplishments that occurred under the Toughened Ceramic Life prediction Program: ... included uniaxial and multiaxial strength, fatigue and creep testing of silicon carbide, silicon nitride and alumina ceramics.
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