area of rudder 舵面积 g!yC_o-Z+l!M3b4L0area of safe operation 安全工作区CAD门户0hE9gk"e.H1UM]x area of section 横断面积 l&FGqqz'h5K0area of section 横剖面面积 R,sH/t-t#vp0area of section 剖面面积CAD门户F@9Vn}j area of sections 截剖面面积曲线图 AD|n!NAwRj1E0area of stress concentration 应力集中区 c.?&H9z0B