Formule momento dinerzia

Pagina 1

Useful Moment of Inertia Formulas Note: In the table below, the overbar indicates the moment of inertia is taken about an axis that passes through the centroid, denoted as ‘C’. Parallel axis theorems are: 2 AdII xx  2 AdII yy  yxAII xyxy  Here, A is the area of the shape, d is the distance from the centroidal axis to the desired parallel axis, and yx are the x and y distances of the centroid from the origin of the desired coordinate frame. Rectangle: 3 12 1 bhI x  3 3 1bhI x  hbI y 3 12 1 hbI y 3 3 1 0yxI Area = bh Triangle: 3 36 1 bhI x  3 12 1 bhI x  72 )2( 2hsbbI xy  bhArea 2 1 Circle: 4 4 1 rII yx  0yxI 2rArea  Semi-circle: 4 8 1 rII yx  4 ' 9 8 8 rI x       0yxI 2 2rArea  Ellipse: 3 4 1 abI x  baI y 3 4 1  0yxI abArea  y x y` x` b h C b/2 h/2 b h x x` C h/3 s C r y x C r y x 4r/3π x` C r y x a b