To evaluate the bolt-connection reliability of the integrated aluminum alloy frame for commercial vehicles, this study adopts a systematic method including torque statistics after fatigue test, Brinell hardness test of mounting surfaces, ultimate torque verification test of threaded connection pairs, and anti-loosening test under road load spectrum. The results show that after 1.5×105 cycles of sinusoidal fatigue loading, the residual-torque retention rates of all critical connection points are higher than 70%; the hardness of mounting surfaces ranges from 65 to 115 HBW with uneven distribution and an average value of about 86.5 HBW. The equivalent Brinell hardness is converted from test data obtained using an impact ball with a diameter of 3 mm and an impact energy of 11 mJ, and the connection point of the lower control arm has the lowest hardness; the safety factors for M12~M18 bolt connections are no less than 1.55; under road-load-spectrum loading, the maximum attenuation rates of torque and axial force are 15.3% and 14.9%, respectively.
| 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 |