⑩天掌 Teaching Plan on Advanced Mathematics 小矩形片的压力元素为dP=2rx√R2-x2r 端面上所受的压力 R P=b 2r--x R y」、R2-x2d(R2-x2) 0 R R 2 y R 3 3Tianjin Polytechnic University Teaching Plan on Advanced Mathematics 小矩形片的压力元素为 dP x R x dx 2 2 = 2 − 端面上所受的压力 P x R x dx R 2 2 0 =  2 − ( ) 2 2 0 2 2 R x d R x R = −  − − ( ) R R x 0 3 2 2 3 2       = − − . 3 2 3 R  =