An alternative approach to estimating the parameters of a generalised Grey Verhulst model: An application to steel intensity of use in the UK

Being able to forecast time series accurately has been quite a popular subject for researchers both in the past and at present. However, researchers have resorted to various forecasting models that have different mathematical backgrounds, such as statistical time series models, causal econometric models, artificial neural networks, fuzzy predictors, evolutionary and genetic algorithms. In this paper, a brief review of a relatively new approach, known … Continue reading An alternative approach to estimating the parameters of a generalised Grey Verhulst model: An application to steel intensity of use in the UK

Development of a high temperature flow stress model for AerMet 100 covering several orders of magnitude of strain rate

Constant strain rate, constant velocity and Hopkinson Pressure Bar compression tests were carried out on AerMet 100 martensitic steel between 1130 °C and 1250 °C spanning strain rates from 0.01 s−1 to 4000 s−1. The results were used to generate a predictive flow stress model over the entire range of test conditions. The effect of initial austenite grain size on flow stress was found to follow the Hall–Petch relationship. … Continue reading Development of a high temperature flow stress model for AerMet 100 covering several orders of magnitude of strain rate

Insights into microstructural interfaces in aerospace alloys characterised by atom probe tomography

Atom probe tomography (APT) is becoming increasingly applied to understand the relationship between the structure and composition of new alloys at the micro- and nanoscale and their physical properties. Here, we use APT datasets from two modern aerospace alloys to highlight the detailed information available from APT analysis, along with potential pitfalls that can affect data interpretation. The interface between two phases in a Ti–6Al–4V … Continue reading Insights into microstructural interfaces in aerospace alloys characterised by atom probe tomography

Prediction of fatigue lives at stress raising features in a high strength steel

The fatigue properties of the high strength stainless steel CSS42L have been evaluated under strain and stress controlled conditions. The results have been used to derive a predictive approach based on the Walker strain equation. Accurate predictions are obtained for VCN and DEN specimens although the lower stress concentration RCN specimen is shown to compare more readily with plain specimen stress controlled data. The difference in fatigue life between … Continue reading Prediction of fatigue lives at stress raising features in a high strength steel

The changing constants of creep: A letter on region splitting in creep lifing

This letter explores the issues surrounding the use of region splitting as a means to improve current creep lifing techniques.  The history of the technique is discussed briefly and its current implementation by major research groups discussed in more detail.  An example of novel or non-traditional region splitting is also explored with its first known application to nano-creep.  The issues surrounding region splitting when considered … Continue reading The changing constants of creep: A letter on region splitting in creep lifing

Prediction of fatigue lives at stress raising features in a high strength steel

The fatigue properties of the high strength stainless steel CSS42L have been evaluated under strain and stress controlled conditions. The results have been used to derive a predictive approach based on the Walker strain equation. Accurate predictions are obtained for VCN and DEN specimens although the lower stress concentration RCN specimen is shown to compare more readily with plain specimen stress controlled data. The difference in fatigue life between … Continue reading Prediction of fatigue lives at stress raising features in a high strength steel

Long-Term Creep Data Prediction for Type 316H Stainless Steel

Impressive data sets have been produced for 316H stainless steel (18Cr–12Ni–Mo with up to 0.08C) by the National Institute for Materials Science (NIMS), Japan, to reveal the dependencies on stress and temperature of the high-temperature creep and creep fracture behavior of nine batches of tube, six of bar and two of plate. Using these long-term property values, the stresses to produce failure in 100,000 h at various plant exposure … Continue reading Long-Term Creep Data Prediction for Type 316H Stainless Steel