如下图所示的圆截面悬臂梁,若其他条件不变,而直径增加一倍,则其最大正应力是原来的( )。 A. mg src="https://cdn.shuashuati.com/imgs/9a0f7f08076028af57865a8981fc5018.png"> B. 1/8倍 B.8倍 C.2倍 D.1/4倍
【单选题】As for a hydraulic vane pump, which of the following is in contact with the vanes during working: (1)the rotor; (2)the pump shaft; (3)the external surface of the housing.