应力 T O max p p 强度条件、≤[a max A ≤[z] 变形 △l O EA E 刚度条件 180 max max ≤[] G p应力 强度条件 变形 刚度条件 p I T   = p max W T  = [ ] p max   W T A FN  = [ ] N,max   A F EA F l l N  = E   = GI p Tl  = [ ] π 180 p max  max  =    GI T