?????????????
?й????е?????????
1.????????s??
???????????????????????????????????????????????????????????????????????????????Σ????????????????????????????????С?????????????
??Ps???????s??????????Fo?????????????????????s =Ps/Fo(MPa)??MPa???????????N??????/mm2????MPa=106Pa??Pa???????=N/m2??
??????????????
????????????????????????????????10??25?????????????3570?/?????????????30?/???????8????????????????????????130?/???10????????????????????????????????????????????????????????????С?
?????????????
16*2200*8000 78??
20*2200*10300 32??
25*2200*12050 90??
30*2200*8000 98??
??6??4???????8*1810*8000??q420q??????????????
