??????????????????????????
??????????????????????????????亸??????????????????????????
???????????????????????????????λ???о???????????????????????????????????????????о?????????l2?????????????????????????????????????l1???????????????????????????????????
????ab/2=l1/r1=l2/r2
?????????????r2??????????????????????l1??l2??????????l2???????????????????
????Mel=Ebso3/12r2
???????????????????
???????Mpl=af(T1)bso2/4
????E-?????????
????b-???????
????so——??????
????af(T1)——???????????????
??????????
????r2=Eso/3kf(T1)(6-48)
????????l2=l0.2+??l???????22????????????????????
????l0.2=r2sin(ab/2)(6-49)
??????????????l???(6-55)???
??????l=al??T¯lh(6-50)
??????С?T¯-?????lh????????x??????so?????????????????????????????AP1????????v1????????pcp??p?????????cp????????????????????
??????T¯=AP1??2cppsov1lh(6-51)
???????(6-50)???(6-51)?????
??????l=alAP1psov1/2cp
?????????????????????????????п???????????????????
???????(6-49)???(6-52)???????l0.2???????????l2.
????l2=r2sin(ab/2)+f’alAP1??2cppsovl(6-53,
???????f’——????2?????????????????
?????????????????????o??1???????0.5-0.9??????棬1??????2??????????f’???????l????????棬??????????2??????f’????С???
?????