Cross-Sectional Properties of Areas

Center of Gravity

a point of balance where the tendency of forces to rotate one side of an object are countered by equal and opposite forces located on the other side of the object

Centroid

the center of gravity for a two-dimensional shape

Composite Shapes

refers to a combination of 2 or more structural shapes that compose a structural member’s cross section

Moment of Inertia

a mathematical concept that incorporates the effect of cross sectional shape and orientation to study the strength of a structural member

Parallel Axis Theorem

a mathematical method by which the moment of inertia of a shape with respect to its centroidal axis can be transferred to a prescribed parallel axis which is normally the centroidal axis of the composite shape

Radius of Gyration

defined as the square root of the moment of inertia divided by the cross sectional area of the shape; a shape factor that measures the resistance to bending about a defined axis