A.使計(jì)算應(yīng)力小于實(shí)際應(yīng)力 B.使計(jì)算應(yīng)力等于實(shí)際應(yīng)力 C.使計(jì)算應(yīng)力和實(shí)際應(yīng)力相近 D.使計(jì)算應(yīng)力大于實(shí)際應(yīng)力