To study the impact of V-notch radius on the mechanical properties of TA15 titanium alloy,tensile,stress-rupture,fatigue tests and fracture analysis are conducted on both smooth specimens and those with varing V-notch radii. By using the finite element method,the distribution of the stress-strain field at the notch is analyzed,the relationship between the stress-strain field and the notch strength,stress-rupture time,fatigue life and fracture behaviour of TA15 titanium alloy are further investigated. The results show that under static loading,as the notch radius decreases from 0.85 mm to 0.15 mm,both the tensile strength and stress-rupture time of TA15 titanium alloy increase,while the proportion of the shear-plastic zone in fracture decreases. Stress triaxiality around the notch initially increases and then decreases as it extends inward from the root of the notch,as determined by finite element analysis. The fracture originates from the peak position of stress triaxiality (near the notch root). During the prolonged stress-rupture tests,stress redistribution around the notch occurrs,resulting in a strengthening effect at the notch. Under dynamic loading,the fracture surface of the notched specimen exhibits multi-source crack propagation. Different stress concentrations and gradients around the notch result in varying degrees of fatigue damage. As the notch radius decreases,the size of the critical fatigue damage area decreases,effective stress increases,leading to a decrease in fatigue life and the proportion of crack propagation zones.
| 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 |