一.引言当長矩形板在垂直於板面的均佈荷重作用下,離板的兩狭邊的稍遠部分將彎曲為一柱面。由於兩長邊連結於固定的鉸支座,所以不能自由移动,因而在荷重作用下板的兩端同時承受拉力。於是在板的截面內除彎曲應力外,還有均佈的張應力。因這拉力所生的撓矩與垂直於板面的荷重所生的撓矩方向相反,所以有助於板的强度。並且,板的撓度愈大,這板的兩端的拉力所增長板强度的效果也愈大。為了减少板的最大正应力,可使板有一適當的初彎曲。丁摩辛柯(Timoshenko)教授會以正弦 I. INTRODUCTION When a long rectangular plate is subjected to a uniform load perpendicular to the plate surface, the part farther from the two narrow sides of the plate will be bent into a cylinder. Since the two long sides are connected to the fixed hinge support, they cannot move freely, so that both ends of the plate are subjected to tension at the same time under the load. In addition to the bending stress in the cross-section of the plate, there is also a uniform tensile stress. The bending moment due to this pulling force is opposite to the bending moment generated by the load perpendicular to the plate surface, so it contributes to the strength of the plate. Also, the greater the deflection of the plate, the greater the effect of the tensile force at both ends of the plate to increase the plate strength. In order to reduce the maximum normal stress of the plate, the plate may be given a proper initial bend. Professor Timoshenko will sine