???????????
??????????????
????????е???????????????10??28??,?й????????Э??(?????и?Э??)???鳤??????????????и?Э??????????????????,?????????????????????λ????,?????????????????????????????????,??????????????,?????????????????????????,????????????????
?????????????
?й????е?????????
1.????????s??
???????????????????????????????????????????????????????????????????????????????Σ????????????????????????????????С?????????????
??Ps???????s??????????Fo?????????????????????s =Ps/Fo(MPa)??MPa???????????N??????/mm2????MPa=106Pa??Pa???????=N/m2??
?绯??й???16*1800*8m??q690qd????????????????????
