A creep-fatigue life prediction model considering multi-factor coupling effect

A creep-fatigue life prediction model based on a novel creep damage evaluation method (NCDEM) considering the multi-factor coupling effect is presented in this paper. Further, to verify the validity and practicability, the creep-fatigue life of GH4169 at 650 °C is calculated to compare with the experimental results. Ultimately, the prediction results are respectively compared with those of the creep-fatigue life prediction models based on the time fraction method (TFM), ductility exhaustion method (DEM), and strain energy density exhaustion method (SEDEM). Consequently, the prediction results are distributed in ±1.5 times dispersion band, which elucidates the creep-fatigue life prediction model proposed based on the NCDEM has the best ability.

Corrosion-Fatigue Life Prediction Modeling for RC Structures under Coupled Carbonation and Repeated Loading

The coupled action of concrete carbonation and repeated loading strongly influences the safety of reinforced concrete (RC) structures and substantially reduces service life. A novel corrosion-fatigue life prediction model for RC structures under coupled carbonation and repeated loading was developed. The effect of fatigue damage on concrete carbonation and carbonation-induced corrosion rate was considered, and the acceleration of fatigue damage accumulation due to reinforcement corrosion was considered in this approach. The proposed corrosion-fatigue life prediction model was illustrated by a 6 m-span RC slab in a simply supported slab bridge for the highway, and the effects of traffic frequency, overloading, carbonation environment grade, and environmental temperature and relative humidity on corrosion-fatigue life were discussed. The results indicate that the proposed model can predict the corrosion-fatigue life of RC structures simply and conveniently. Traffic frequency, overloading, carbonation environment grade, and environmental temperature and relative humidity can decrease the corrosion-fatigue life of the RC slab by up to 66.86%, 58.90%, 77.45%, and 44.95%, respectively. The research is expected to provide a framework for the corrosion-fatigue life prediction of RC structures under coupled carbonation and repeated loading.

A combined low and high cycle fatigue life prediction model considering the crack closure effect of micro-defects based on the continuous damage mechanics

In this study, a combined low and high cycle fatigue (CCF) life prediction model, which considers the crack closure effect (CCE) of micro-defects, is proposed based on the continuous damage mechanics. The CCF life prediction model is decomposed into three sub-models: the low cycle fatigue (LCF), high cycle fatigue (HCF) under the maximum stress of LCF (HCFLM), and their coupled damage models. The CCE is considered by taking one CCE parameter into the HCFLM sub-model. The experimental CCF data of K403 full-scale turbine blades under different vibration stresses is used to verify the accuracy of the proposed model to compare with other life prediction models. The prediction life from the proposed model falls within the 2 times of scatter band compared with the experimental results. Further, there are the different damage evolution forms at different vibration stresses. When the vibration stress is below 64.48MPa, the CCF damage mainly is caused by the LCF damage. However, while the vibration stress is higher than 64.48MPa, the HCFLM damage plays a major role in the CCF damage accumulation, and it is predicted that the CCF damage of the first stage serration on the K403 turbine blades is mainly from LCF.

Battery life prediction method based on DE-GWO-LSTM

Aiming at the problem of inaccurate prediction results of lithium-ion battery life, a lithium-ion battery life prediction model based on hybrid algorithm is designed. The position of grey wolf algorithm is updated by differential evolution algorithm, which improves the population diversity and avoids premature stagnation of the algorithm. The GWO-LSTM model and DE-GWO-LSTM model are compared and analyzed by using NASA data. The proposed DE-GWO-LSTM can well conduct global search and local search, and improve the prediction performance to a certain extent.

Lifetime Assessment for Multiaxial High-Cycle Fatigue Using Twin-Shear Unified Yield Criteria

In this paper, a life prediction model associated with maximum principal stress and equivalent shear amplitude based on twin-shear unified yield criterion for multiaxial high-cycle fatigue is proposed. The equivalent shear amplitude is the normalized format of the equivalent shear amplitude based on clusters of yield criteria embodying Tresca and the linearization of Huber-von Mises, extending the application to metallic materials. Simultaneously, the effect of mean stress on multiaxial high-cycle fatigue is considered in the proposed model. As an assessment of the new prediction model, the criterion is compared with experimental data of aluminum alloy LY12CZ and carbon structural steel SM45C published in the relevant literature, which shows that most of the data are located within an error range of less than two times the data and are in good agreement with the experiment. Moreover, the proposed model is also compared with other models, such as McDiarmid, Liu, and Freitas, to validate its competitiveness.