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?????κ??????(????)?????????:

      ?????????λ: kg/m(???/??) & lb/ft(??/???)

?????÷???????

                ??????

                  (??+??)??2??3.14-????????0.02466= kg/m

                 ?????:

                     kg/m = (Oc - 4Wt) * Wt * 0.00785               

                     Oc???????????Wt??????

                     ??????Oc=4*a            

                     ??????Oc=2a+2b a,b????

?????????????????????? ??????????4x???x(???-???)x7.85 

???????У???????????????????λ???????????????????????ó???????????????????????λ?? 

??????30x30x2.5????????????????????????????????????? 

????4x2.5x(30-2.5)x7.85=275x7.85=2158.75??????2.16????

??????????????????????λ???4x???x(???-???)???????????????????????????????????λ???????????????????????7.85????ó????????????????λ????????