All Outputs (54)

The effect of phase angle on crack growth mechanisms under thermo-mechanical fatigue loading (2020)
Journal Article

© 2020 Elsevier Ltd The current paper describes TMF crack growth behaviour in an advanced nickel-based superalloy. Changes in behaviour are examined which occur as a function of the phase angle between applied stress and temperature. The fractography... Read More about The effect of phase angle on crack growth mechanisms under thermo-mechanical fatigue loading.

Thermomechanical fatigue in 9-12Cr steels: Life prediction models and the effect of tensile dwell periods (2019)
Journal Article

This paper is concerned with the assessment of life prediction models for thermomechanical fatigue (TMF), with specific application to P91 steel. A program of TMF tests, including dwell periods, are performed to determine the role of thermomechanical... Read More about Thermomechanical fatigue in 9-12Cr steels: Life prediction models and the effect of tensile dwell periods.

The development of a novel technique for small ring specimen tensile testing (2018)
Journal Article

The wide scale use of small specimens in routine testing programs could significantly reduce material resource requirements (factors of 10 are easily achievable). This is a major benefit to situations where there is not enough material to manufacture... Read More about The development of a novel technique for small ring specimen tensile testing.

A neural network approach for determining spatial and geometry dependent Green's functions for thermal stress approximation in power plant header components (2018)
Journal Article

The trend in power generation to operate plant with a greater frequency of on/partial/off load conditions creates several concerns for the long term structural integrity of many high temperature components. The Green's function method has been used f... Read More about A neural network approach for determining spatial and geometry dependent Green's functions for thermal stress approximation in power plant header components.

Effect of post processing on the creep performance of laser powder bed fused Inconel 718 (2018)
Journal Article

In this study, the creep performance of laser powder bed fusion manufactured Inconel 718 specimens is studied in detail and compared with conventional hot-rolled specimens alongside as-built then heat-treated and as-built then hot-isostatic pressed s... Read More about Effect of post processing on the creep performance of laser powder bed fused Inconel 718.

The Prediction of isothermal cyclic plasticity in 7175-T7351 aluminium alloy with particular emphasis on thermal ageing effects (2018)
Journal Article

Rapid thermal ageing has been observed in the literature for certain aerospace aluminium alloys under conditions which are foreseeable in their intended component applications. While several experimental programs have explored this phenomenon in the... Read More about The Prediction of isothermal cyclic plasticity in 7175-T7351 aluminium alloy with particular emphasis on thermal ageing effects.

A case study investigation into the effects of spatially dependent convection coefficients on the fatigue response of a power plant header component (2018)
Journal Article

Societal and environmental pressures are forcing thermal power plant operators to deviate greatly from the generation strategies of the past. The application of high frequency start up/shut down/partial load cycles to components that may well be outs... Read More about A case study investigation into the effects of spatially dependent convection coefficients on the fatigue response of a power plant header component.

The influence of shot peening on the fatigue response of Ti-6Al-4V surfaces subject to different machining processes (2018)
Journal Article

Machining processes are known to drastically impact the performance and lifetime of a component subjected to fatigue in service. Therefore, understanding the effect of manufacturing processes on surface integrity is vital to determine their suitabili... Read More about The influence of shot peening on the fatigue response of Ti-6Al-4V surfaces subject to different machining processes.

Creep behaviour of inconel 718 processed by laser powder bed fusion (2018)
Journal Article

Additive manufacturing lends itself well to the manufacture of aerospace parts due to the high complexity and small volume of many components found in modern aero engines. By exploiting additive manufacturing design freedoms, enhanced part functional... Read More about Creep behaviour of inconel 718 processed by laser powder bed fusion.

Staged thermomechanical testing of nickel superalloys produced by selective laser melting (2017)
Journal Article

The creep performance of additively manufactured components remains an issue before additive manufacturing can be put fully implemented. In this study, Inconel 718 two-bar specimens are produced by selective laser melting and subjected to a ‘staged’... Read More about Staged thermomechanical testing of nickel superalloys produced by selective laser melting.

Small ring testing of high temperature materials (2017)
Journal Article

In service components such as steam pipes, pipe branches, gas and steam turbine blades, etc. which operate in engineering applications such as power plant, aero-engines, chemical plant etc., can operate at temperatures which are high enough for creep... Read More about Small ring testing of high temperature materials.

Practical considerations of the use of cross-weld and compact tension specimens’ creep data (2016)
Journal Article

This article gives an overview of the use of cross-weld and compact tension specimen modelling and analyses data to characterise creep behaviour of the high-temperature components. Cross-weld and compact tension specimens are used to describe creep c... Read More about Practical considerations of the use of cross-weld and compact tension specimens’ creep data.

Micromechanical finite element modelling of thermo-mechanical fatigue for P91 steels (2016)
Journal Article

In this paper, the cyclic plasticity and fatigue crack initiation behaviour of a tempered martensite ferritic steel under thermo-mechanical fatigue conditions is examined by means of micromechanical finite element modelling. The crystal plasticity-ba... Read More about Micromechanical finite element modelling of thermo-mechanical fatigue for P91 steels.

A comparison of simple methods to incorporate material temperature dependency in the Green’s function method for estimating transient thermal stresses in thick-walled power plant components (2016)
Journal Article

The threat of thermal fatigue is an increasing concern for thermal power plant operators due to the increasing tendency to adopt “two-shifting” operating procedures. Thermal plants are likely to remain part of the energy portfolio for the foreseeable... Read More about A comparison of simple methods to incorporate material temperature dependency in the Green’s function method for estimating transient thermal stresses in thick-walled power plant components.

Cyclic thermomechanical testing of 316 stainless steel (2015)
Journal Article

Materials used for components such as power plant steam pipes, gas turbines discs and die forming machinery can be subject to combinations of extreme loading and temperature conditions. In addition, the materials can contain or develop cracks. Once a... Read More about Cyclic thermomechanical testing of 316 stainless steel.

Cyclic viscoplasticity testing and modeling of a service-aged P91 steel (2014)
Journal Article

A service-aged P91 steel was used to perform an experimental program of cyclic mechanical testing in the temperature range of 400 °C–600 °C, under isothermal conditions, using both saw-tooth and dwell (inclusion of a constant strain dwell period at t... Read More about Cyclic viscoplasticity testing and modeling of a service-aged P91 steel.

High temperature, low cycle fatigue characterization of P91 weld and heat affected zone material (2014)
Journal Article

The high temperature low cycle fatigue behavior of P91 weld metal (WM) and weld joints (cross-weld) is presented. Strain-controlled tests have been carried out at 400 °C and 500 °C. The cyclic behavior of the weld material (WM) and cross-weld (CW) sp... Read More about High temperature, low cycle fatigue characterization of P91 weld and heat affected zone material.

A Basis for Selecting the Most Appropriate Small Specimen Creep Test Type (2014)
Journal Article

Many components in conventional and nuclear power plant, aero-engines, chemical plant etc., operate at temperatures which are high enough for creep to occur. These include plain pipes, pipe bends, branched pipes etc., the manufacture of such componen... Read More about A Basis for Selecting the Most Appropriate Small Specimen Creep Test Type.

A unified viscoplastic model for high temperature low cycle fatigue of service-aged P91 steel (2014)
Journal Article

The finite element (FE) implementation of a hyperbolic sine unified cyclic viscoplasticity model is presented. The hyperbolic sine flow rule facilitates the identification of strain-rate independent material parameters for high temperature applicatio... Read More about A unified viscoplastic model for high temperature low cycle fatigue of service-aged P91 steel.

Pragmatic optimisation methods for determining material constants of viscoplasticity model from isothermal experimental data (2013)
Journal Article

A procedure to estimate material constants for the unified Chaboche viscoplasticity model from experimental data has been published elsewhere; however several critical assumptions are made to enable this and potential numerical problems can limit the... Read More about Pragmatic optimisation methods for determining material constants of viscoplasticity model from isothermal experimental data.