Since the traditional Miner rule ignores the influence of the load sequence on the fatigue life, the fuzzy rules are used to analyze the fuzziness of the fatigue damage caused by the stress nearby the fatigue limit un...Since the traditional Miner rule ignores the influence of the load sequence on the fatigue life, the fuzzy rules are used to analyze the fuzziness of the fatigue damage caused by the stress nearby the fatigue limit under different load sequences. The improved fuzzy Miner rule can reflect the influence of the load sequence on the fatigue life. Results of the example show that the prediction error can be reduced from 61.6% to 21.7%.展开更多
To investigate the relation between material＇s cychc plastic behaviour and fatigue crack growth, a new model is proposed. The model incorporated the two intrinsic properties of material＇ s cyclic plastic and crack ...To investigate the relation between material＇s cychc plastic behaviour and fatigue crack growth, a new model is proposed. The model incorporated the two intrinsic properties of material＇ s cyclic plastic and crack tip＇ s deformation dislocation to interpret fatigue crack threshold. The relation between material＇ s cyclic hardening parameters （cyclic hardening amplitude and cyclic hardening rate） and fatigue threshold is studied. Fatigue threshold is determined based on the dislocation-free zone （DFZ） model, the theory of cohesive zone and the cyclic deformation behaviour. The results show that fatigue threshold increases with the decrease of the amplitude of cyclic hardening and is independent of cyclic hardening rate, but fatigue crack growth rate increases with the increase of cyclic hardening rate.展开更多
In this paper, we propose a pre-processing method for the detection of wire-rope signals. This is necessary because of the lack of processing methods that are currently employed. First, we investigated the one-dimensi...In this paper, we propose a pre-processing method for the detection of wire-rope signals. This is necessary because of the lack of processing methods that are currently employed. First, we investigated the one-dimensional discrete morphological and wavelet transform. Then, we developed a pre-processing model that is based on the morphological wavelet-filtering algorithm. We then proposed a modified morphology filtering algorithm. We also designed an experiment platform for wire-rope detection.Eight levels of localized flaws(LFs) and damage were formed in the wire-rope specimen. We performed a series of experimental studies, and the results show that the proposed method can effectively filter the drift signal. The signal-to-noise ratio of the new filtering algorithm was over 26 d B. The signal-to-noise ratio of the existing method is less than 15 d B, and the noise-signal ratio of the new filtering algorithm has improved by 73%. Based on our results, the filtering effect of the proposed method is better than that of the present method. This study has great significance and practical value in engineering applications.展开更多
基金the National Natural Science Foundation of China(60472118)~~
文摘Since the traditional Miner rule ignores the influence of the load sequence on the fatigue life, the fuzzy rules are used to analyze the fuzziness of the fatigue damage caused by the stress nearby the fatigue limit under different load sequences. The improved fuzzy Miner rule can reflect the influence of the load sequence on the fatigue life. Results of the example show that the prediction error can be reduced from 61.6% to 21.7%.
基金Sponsored by the Fundamental Research Foundation of Harbin Engineering University(Grant No.HEUFT07007)
文摘To investigate the relation between material＇s cychc plastic behaviour and fatigue crack growth, a new model is proposed. The model incorporated the two intrinsic properties of material＇ s cyclic plastic and crack tip＇ s deformation dislocation to interpret fatigue crack threshold. The relation between material＇ s cyclic hardening parameters （cyclic hardening amplitude and cyclic hardening rate） and fatigue threshold is studied. Fatigue threshold is determined based on the dislocation-free zone （DFZ） model, the theory of cohesive zone and the cyclic deformation behaviour. The results show that fatigue threshold increases with the decrease of the amplitude of cyclic hardening and is independent of cyclic hardening rate, but fatigue crack growth rate increases with the increase of cyclic hardening rate.
基金the National Natural Science Foundation of China (No. 51404276)the Fundamental Research Funds for the Central Universities (Nos. 2014QJ01 and 2015QJ04)
文摘In this paper, we propose a pre-processing method for the detection of wire-rope signals. This is necessary because of the lack of processing methods that are currently employed. First, we investigated the one-dimensional discrete morphological and wavelet transform. Then, we developed a pre-processing model that is based on the morphological wavelet-filtering algorithm. We then proposed a modified morphology filtering algorithm. We also designed an experiment platform for wire-rope detection.Eight levels of localized flaws(LFs) and damage were formed in the wire-rope specimen. We performed a series of experimental studies, and the results show that the proposed method can effectively filter the drift signal. The signal-to-noise ratio of the new filtering algorithm was over 26 d B. The signal-to-noise ratio of the existing method is less than 15 d B, and the noise-signal ratio of the new filtering algorithm has improved by 73%. Based on our results, the filtering effect of the proposed method is better than that of the present method. This study has great significance and practical value in engineering applications.
