???????????????
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1.????????s??
???????????????????????????????????????????????????????????????????????????????Σ????????????????????????????????С?????????????
??Ps???????s??????????Fo?????????????????????s =Ps/Fo(MPa)??MPa???????????N??????/mm2????MPa=106Pa??Pa???????=N/m2??
????????
??????????г????????????????????????????????????????????????????????????л?????????????????????????硢?????????????????????
???????????????
8??2000??8000 42??
8??2000??8000 21??
10??1800??8000 32??
10??1800??8000 80??
10??2000??8000 21??
10??2000??8000 52??
?????????55*55??q550qd?????????????????
