• 2022-06-14
    图示桁架有:FN1=FN2=FN3= 0。https://p.ananas.chaoxing.com/star3/origin/7755ae2c01506409997cd5592302bd81.png
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    • 0

      图示对称桁架在正对称荷载作用下,杆1、2、3、4的内力为:( )[img=363x216]17e4440a1f6e057.png[/img] A: FN1 = FN2 = 0,FN3 = FN4≠0 B: FN1 = FN2≠0,FN3 = FN4 = 0 C: FN1 = FN2≠0,FN3 = FN4≠0 D: FN1 = FN2 = FN3 = FN4 = 0

    • 1

      如图所示,杆件受力P作用,分别用FN1、FN2、FN3和σ1、σ2、σ3表示截面I-I、II-II、III-III上的轴力和正应力,则有( )。[img=305x79]180384ec9172fcd.png[/img] A: FN1>FN2>FN3 B: σ1>σ2>σ3 C: FN3>FN1>FN2 D: σ3>σ1>σ2

    • 2

      图示等直杆两端固定。设AC、CD、DB三段的轴力分别为FNl、FN2,FN3,则() A: FNl=FN3=-P,FN2=0 B: FNl=FN3<0,FN2>0 C: FN1=FN2=FN3=0 D: FNl=FN3=0, FN2=P

    • 3

      图示桁架中,1、2杆的内力为:[img=259x195]17e0adda6464218.jpg[/img] A: FN1>;0,FN2>;0 B: FN1<;0,FN2<;0 C: FN1 = -FN2 D: FN1 = FN2 = 0

    • 4

      图示桁架中,FN1=FN2=FN3=0[img=849x424]1803dac89de1d4c.jpg[/img]