The moment of inertia is one of the most important properties of the structural element, which largely determines the engineer’s choice of section. It is also known as the second moment of the field.

The word inertia has meanings such as inertia and inertia. The moment of inertia of a body corresponds to the resistance of the engineering element against stresses such as torsion and bending in the geometric design. In fact, most people think of the following picture when it comes to the moment of inertia. Comparison of the resistance of a beam against the same load that is influenced by its design in two different positions.

As shown in the diagram, some shapes are better at resisting bending than others. Obviously, the orientation of the shape also affects the bending. In a way it roughly shows why the long part of the beam should be placed vertically.

Columns, beams, and most other structural elements have cross sections similar to I, H, C shapes. This situation brings with it some question marks:

- Why aren’t these elements made of fully filled simple geometries (square, circle, etc.)?
- Which principles are used to decide on the geometry to be chosen in the design of a structural element?

In order to find answers to these questions, it will be useful to explain the event numerically. So let’s examine the three different sections below:

*Three Different Sections to Explain the Importance of Moment of Inertia in Engineering Designs*

- Let’s consider three different sections for the RS beam as above, A, B and C. If we calculate that they are all made of the same material, the total cross section areas are equal. The masses of the objects per unit length are also equal.
- Which section shape is used for the beam with vertical force P, shown on the right, causes less internal stress and deflection?
- The answer is related to the beam’s Moment of Inertia around the x-axis. Since most of the areas in section A are further away from the x-axis, this section has the greatest moment of inertia. Therefore, less stress and deflection occurs.

Moment of inertia, the second moment of a name field, although it may change section according to specifications, we think of the engineering construction element for rectangular cross- **bh ****3**** /12** is one of the proof and calculation methods