Purpose–In view of the difficulty in determining the key parameters d in the Corten-Dolan model,based on the introduction of small loads,damage degrees and stress states to the Corten-Dolan model and the existing imp...Purpose–In view of the difficulty in determining the key parameters d in the Corten-Dolan model,based on the introduction of small loads,damage degrees and stress states to the Corten-Dolan model and the existing improved model,the sequential effects of the adjacent two-stage load were further considered.Design/methodology/approach–Two improved Corten-Dolan models were established on the basis of modifying the parameter d by two different methods,namely,increasing stress ratio coefficient as well as considering the effects of loading sequence and damage degree as independent influencing factors respectively.According to the test data of the welded joints of common materials(standard 45 steel),alloy materials(standard 16Mn steel)and Q235B steel,the validity and feasibility of the above two improved models for fatigue life prediction were verified.Findings–Results show that,compared with the traditional Miner model and the existing Corten-Dolan improved model,the two improved models have higher prediction accuracy in the fatigue life prediction of welding materials whether under two-stage load or multi-stage load.Originality/value–Because the mathematical expressions of the models are relatively simple and need no multi-layer iterative calculation,it is convenient to predict the fatigue life of welded structure in practical engineering.展开更多
The numerical solutions for uncertain viscoelastic problems have important theo- retical and practical significance. The paper develops a new approach by combining the scaled boundary finite element method （SBFEM） a...The numerical solutions for uncertain viscoelastic problems have important theo- retical and practical significance. The paper develops a new approach by combining the scaled boundary finite element method （SBFEM） and fuzzy arithmetic. For the viscoelastic problems with zero uncertainty, the SBFEM and the temporally piecewise adaptive algorithm is employed in the space domain and the time domain, respectively, in order to provide an accurate semi- analytical boundary-based approach and to ensure the accuracy of discretization in the time domain with different sizes of time step at the same time. The fuzzy arithmetic is used to address the uncertainty analysis of viscoelastic material parameters, and the transformation method is used for computation with the advantages of effectively avoiding overestimation and reducing the computational costs. Numerical examples are provided to test the performance of the proposed method. By comparing with the analytical solutions and the Monte Carlo method, satisfactory results are achieved.展开更多
基金the National Natural Science Foundation of China(10802015)the Joint Fund of Natural Science Foundation of Liaoning Province(2015020119)+1 种基金the Liaoning Province Graduate Education and Teaching Reform Research Project(2017)the Liaoning Province Transformation and the Innovation and Entrepreneurship Education Project(2017).
文摘Purpose–In view of the difficulty in determining the key parameters d in the Corten-Dolan model,based on the introduction of small loads,damage degrees and stress states to the Corten-Dolan model and the existing improved model,the sequential effects of the adjacent two-stage load were further considered.Design/methodology/approach–Two improved Corten-Dolan models were established on the basis of modifying the parameter d by two different methods,namely,increasing stress ratio coefficient as well as considering the effects of loading sequence and damage degree as independent influencing factors respectively.According to the test data of the welded joints of common materials(standard 45 steel),alloy materials(standard 16Mn steel)and Q235B steel,the validity and feasibility of the above two improved models for fatigue life prediction were verified.Findings–Results show that,compared with the traditional Miner model and the existing Corten-Dolan improved model,the two improved models have higher prediction accuracy in the fatigue life prediction of welding materials whether under two-stage load or multi-stage load.Originality/value–Because the mathematical expressions of the models are relatively simple and need no multi-layer iterative calculation,it is convenient to predict the fatigue life of welded structure in practical engineering.
文摘The numerical solutions for uncertain viscoelastic problems have important theo- retical and practical significance. The paper develops a new approach by combining the scaled boundary finite element method （SBFEM） and fuzzy arithmetic. For the viscoelastic problems with zero uncertainty, the SBFEM and the temporally piecewise adaptive algorithm is employed in the space domain and the time domain, respectively, in order to provide an accurate semi- analytical boundary-based approach and to ensure the accuracy of discretization in the time domain with different sizes of time step at the same time. The fuzzy arithmetic is used to address the uncertainty analysis of viscoelastic material parameters, and the transformation method is used for computation with the advantages of effectively avoiding overestimation and reducing the computational costs. Numerical examples are provided to test the performance of the proposed method. By comparing with the analytical solutions and the Monte Carlo method, satisfactory results are achieved.
