Category: Fatigue

Creep, Fatigue

Computational modeling of creep-based fatigue as a means of selecting lead-free solder alloys

The primary aim of this investigation was to understand the effect of temperature fluctuations on a number of various solder materials namely SAC105, SAC305, SAC405 and Sn–36Pb–2Ag. To achieve this objective, three different classic joint assemblies (a ball joint, a test specimen joint and finger lead joint) were modeled which provided the foundation for the creep and fatigue behaviors simulation. Anand’s viscoplasticity as a constitutive … Continue reading Computational modeling of creep-based fatigue as a means of selecting lead-free solder alloys

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Environmental, Fatigue, Nickel, Peening, Superalloys

Factors affecting the corrosion fatigue life in nickel based superalloys for disc applications

The nickel based superalloy 720Li is employed in the gas turbine due to its mechanical performance at elevated temperature. A comprehensive assessment of the materials behaviour under representative service conditions is reported to address the drive for ever increasing temperatures and more arduous environmental exposure. Fatigue experiments have been performed in an air and air/SOx environment at 700 ∘C containing a mixed salt as a contaminant. … Continue reading Factors affecting the corrosion fatigue life in nickel based superalloys for disc applications

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Fatigue, Nickel, Peening, Superalloys

Influence of shot peening on high-temperaturecorrosion and corrosion-fatigue of nickel basedsuperalloy 720Li

High-temperature corrosion fatigue, a combination of corrosion with a fatigue cycle, is an emerging generic issue affecting power generation and aero gas turbine engines and has the potential to limit component life. Historically, surface treatments, such as shot peening have been used to improve component life and have been optimised for fatigue response. Research into optimisation of shot peening techniques for hot corrosion and high-temperature … Continue reading Influence of shot peening on high-temperaturecorrosion and corrosion-fatigue of nickel basedsuperalloy 720Li

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Composites, Creep, Fatigue

Mechanical characterisation of a fibre reinforced oxide/oxide ceramic matrix composite

Monotonic tension, fatigue and creep experiments were conducted on an oxide/oxide ceramic matrix composite over the range of temperature 20–1200°C. The role of continuous fibre reinforcement, differential thermal expansion, stress redistribution interactions between fibres and matrix and the influence of inherent processing defects are all considered when describing the deformation and ultimate mechanical failure of these systems.   D.T. Di Salvoa, E.E. Sacketta, R.E. Johnstona, … Continue reading Mechanical characterisation of a fibre reinforced oxide/oxide ceramic matrix composite

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Fatigue, Nickel, Superalloys

The use of coupled nonlocal damage-plasticity to predict crack growth in ductile metal plates

A nonlocal coupled damage-plasticity model is presented for predicting crack growth within plates made from a ductile metallic alloy. The damage law is explicitly defined in terms of the accumulated nonlocal plastic strain ensuring efficient numerical implementation. On the basis of this model, a UMAT for the finite element (FE) package ABAQUS (implicit) is developed. Thin plates of different geometries were modelled and analysed using … Continue reading The use of coupled nonlocal damage-plasticity to predict crack growth in ductile metal plates

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Fatigue, Nickel, Superalloys

Microstructure and Mechanical Properties of an Advanced Nickel-Based Superalloy in the as-HIP Form

This study evaluates the suitability of as-hot isostatically pressed (HIP) RR1000 for non-critical applications in aero-engine components. RR1000, an advanced powder nickel-based superalloy, was developed for disc rotor components in aero-engines. For these critical applications, the consolidated alloy powder particles are extruded to break down carbide and oxide networks, known as prior particle boundaries (PPBs), and to refine the structure into a fine grain size … Continue reading Microstructure and Mechanical Properties of an Advanced Nickel-Based Superalloy in the as-HIP Form

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Fatigue, Nickel, Superalloys

Crack growth in the creep-fatigue regime under constrained loading of thin sheet combustor alloys

Damage tolerant lifing methodologies are an essential requirement to support the safe and reliable operation of combustors in the modern gas turbine aero-engine. These static components experience a wide range of temperature superimposed upon a complex stress field resulting from their geometrical form. Features such as seam welds, injector ports and cooling hole arrays could potentially initiate and subsequently interact with fatigue cracks, while the … Continue reading Crack growth in the creep-fatigue regime under constrained loading of thin sheet combustor alloys

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Fatigue, Titanium

Domestic object damage and fatigue behaviour of an advanced gamma TiAl alloy

Laboratory simulated domestic object damage (DOD) was imposed on aerofoil style specimens manufactured from a latest generation gamma titanium aluminide. The form of the impact sites was characterised in detail before assessment under fatigue loading at room temperature and 650°C. A reduction in fatigue strength due to the presence of DOD was shown to be sensitive to the projectile impact energy but independent of test … Continue reading Domestic object damage and fatigue behaviour of an advanced gamma TiAl alloy

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Fatigue, Nickel, Peening, Superalloys

Surface topography and the impact on fatigue performance

Areal characterization was applied to plain fatigue specimens manufactured from a nickel-based superalloy, Alloy 720Li, to determine the impact of machined/finished surface topography on fatigue performance of this material. Samples were subjected to fatigue testing in the as-turned and shot peened conditions to study the interaction between residual stresses and topography in influencing the fatigue performance. The turning process was deliberately manipulated to produce three … Continue reading Surface topography and the impact on fatigue performance

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Fatigue, Nickel, Superalloys

Surface Roughness, Areal Topographic Measurement, and Correlation to LCF Behavior in a Nickel-Based Superalloy

Surface roughness often determines fatigue performance of advanced engineering components making definition of this parameter essential subsequent to manufacture. Traditionally, topography measurements employ an average amplitude parameter, Ra, obtained from a two-dimensional contact measurement. This parameter, however, is highly localised making it relatively unreliable. This study attempts to correlate areal (3D) topographic, measurements with the low cycle fatigue (LCF) performance defined for a nickel-based superalloy … Continue reading Surface Roughness, Areal Topographic Measurement, and Correlation to LCF Behavior in a Nickel-Based Superalloy

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