![](https://lstatic.shangxueba.com/sxbzda/h5/images/m_q_title.png)
[主观题]
由三根钢管构成的支架如图所示。钢管的外径为d = 30 mm,内径为d = 22 mm,长度 l = 2.5 m,材料为q235钢,e = 206 gpa,sp = 200 mpa,ss = 235 mpa,a = 304mpa,b = 1.12 mpa。在支架的顶点三杆铰接。若取稳定安全因数nst = 3,试求许可载荷f。
由三根钢管构成的支架如图所示。钢管的外径为D = 30 mm,内径为d = 22 mm,长度 l = 2.5 m,材料为Q235钢,E = 206 GPa,sp = 200 MPa,ss = 235 MPa,a = 304MPa,b = 1.12 MPa。在支架的顶点三杆铰接。若取稳定安全因数nst = 3,试求许可载荷F。
![](https://lstatic.shangxueba.com/sxbzda/h5/images/tips_org.png)