• 2022-06-30
    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