正方形等截面立柱，受纵向压力F作用。当力F作用点由A移至B时，柱内最大压应力的比值<img height="39" src="https://nimg.ppkao.com/2018-08/longzhengxuan/201808221659448897.jpg?sign=415d327c8e164281bf8662295a52bf46&t=62d52137" style="width: 43px; height: 51px;" width="38" />有（）<img height="244" src="https://nimg.ppkao.com/2018-08/longzhengxuan/2018082217003451624.jpg?sign=de7e702e23df7c17b597af2aa3a13878&t=62d52137" style="width: 147px; height: 166px;" width="133" />