The cyclic void growth model (CVGM) based on microscopic fracture mechanism is an effective method to analyze and predict ultra-low cycle fatigue (ULCF) fracture. In this method, the void growth index and damage degradation parameters are important parameters to control the crack propagation process. Due to the influence of production technology, the void growth index and damage degradation parameters of different batches of steels are often unfixed, which leads to the insufficient accuracy of the ultra-low cycle fatigue fracture analysis. In order to solve this problem, smooth round bar, smooth notch round bar and notch samples were used to carry out experiments, the ultra-low cycle fatigue characteristics of steel were studied, and the cracking mechanism and damage evolution law of the samples were explored. Secondly, the VUSDFLD program based on the cyclic void growth model was written, and the finite element analysis was carried out based on the results of test to calibrate the void growth index and damage degradation parameters. Finally, the ultra-low cycle fatigue fracture of notched samples was studied, the crack initiation and crack propagation rates were analyzed, and the ultra-low cycle fatigue fracture life of the samples was predicted. The results show that the fracture process of ultra-low cycle fatigue matches well with the experimental results, which is suitable for the prediction of ultra-low cycle fatigue fracture life.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |