Polar coordinates极坐标 The position of a point P in polar coordinates is defined by the radial coordinate r and the angular coordinateθ. 一点P的极坐标用径向坐标r和角坐标θ表示 P(r,0) displacements:位移:urue strains:应变:
Section 12.1 Introduction and Assumptions 引言和假定 a plate is a body bounded by two closely spaced parallel planes and one or more prismatical surfaces normal to the planes