Ch.6 Properties of Sections Flashcards
Most section properties are aligned with the axes of the ___
cross-section
What are the units of inertia?
(unit of length)^4
What is the name for the center of gravity of an object of uniform density?
Centroid
What is a centroid?
Center of gravity of an object of uniform density
What is the equation for a centroid?
where dx and dy are the distance along the matching axis of the centroid from the chosen reference origin of on the object
Find the centroid of this object from its component parts
What is a mathematical expression that describes the relative location of material in a cross section?
Moment of Inertia
What is a moment of inertia?
Relative location of material in a cross-section. It resists bending stress and deflection
What is another name for moment of inertia?
Second moment
What is moment of inertia a measure of?
Cross-sectional stiffness
How would one find the Moment of Inertia of Hollow Shapes?
If the centroids of two shapes coincide, you may subtract the moment of inertia of the void from the moment of inertia of the overall body. THIS IS CALLED THE NEGATIVE AREA METHOD