P Q(θ) C A θ O N(θ) M(θ)
NA 2?Pcos??Psin(??)444?2?Q(?)?NAsin??Pcos(??)?Psin??Pcos(??)
444?2?M(?)?NA?a(1?cos?)?Pasin(??)?Pa(1?cos?)?Pasin(??)444N(?)??NAcos??Psin(??)??(3) 画弯矩图
AC弧段内，弯矩单调递增；
??22M()?Pa(1?)?0.104Pa
442CB弧段内：令
M(?)?0: 求极值
2?Pa(1?cos?)?Pasin(??)?0 ???53.2o 44dM(?)?0 ??116.6o M(?)??0.437PR d?画弯矩图
0.104Pa -0.437Pa 上海理工大学 力学教研室 15