That's because we can consider the beam to bend vertically along the beam span (or experience a bending moment around the x-axis) and laterally along the beam span (or bend around the y-axis). Notice how there are two values for the moment of inertia. Using the formulas that you can also see in our moment of inertia calculator, we can calculate the values for the moment of inertia of this beam cross-section as follows: To further understand this concept, let us consider the cross-section of a rectangular beam with a width of 20 cm and a height of 30 cm. The moment of inertia also varies depending on which axis the material is rotating along. The moment of inertia depends on the dimensions of the material's cross-section. The moment of inertia represents the amount of resistance a material has to rotational motion. On the other hand, to determine the moment of inertia for a particular beam cross-section, you can visit our moment of inertia calculator. You can learn more about the modulus of elasticity by checking out our stress calculator.

This difference in the values of modulus of elasticity shows that concrete can only withstand a small amount of deflection and will experience cracking sooner than steel. Concrete's modulus of elasticity is between 15-50 GPa (gigapascals), while steel tends to be around 200 GPa and above. The higher a material's modulus of elasticity, the more of a deflection can sustain enormous loads before it reaches its breaking point. The modulus of elasticity depends on the beam's material. We can define the stiffness of the beam by multiplying the beam's modulus of elasticity, E, by its moment of inertia, I. Calculating beam deflection requires knowing the stiffness of the beam and the amount of force or load that would influence the bending of the beam.

Moment of inertia calculation t beam