What is Plastic Section Modulus?
Plastic Section Modulus (PSM) is a measure of the resistance of a cross-section of a beam or other structural member to bending. It is equal to the moment of inertia of the section divided by the distance from the neutral axis to the outermost fiber of the cross-section. It is also known as plastic modulus or plastic moment of inertia. It is an important factor in the design of structures which must resist bending.
PSM is the most important factor in determining the strength of an I-beam. It is used to calculate the amount of bending that a beam can withstand before it fails. It is also used to determine the amount of stress that can be applied to a beam before it becomes permanently deformed. PSM can also be used to calculate the amount of load that a beam can carry safely.
How to Calculate Plastic Section Modulus of an I Beam
Calculating the Plastic Section Modulus of an I-beam is not a difficult task, but it does require a basic understanding of the principles of mechanics. The first step is to determine the Moment of Inertia (MOI) of the cross-section of the beam. This can be done by measuring the width, height and thickness of the cross-section and using the formula for MOI.
Once the MOI has been determined, the next step is to divide the MOI by the distance from the neutral axis to the outermost fiber of the cross-section. This value is the Plastic Section Modulus. The formula for calculating Plastic Section Modulus is MOI/d, where d is the distance from the neutral axis to the outermost fiber.
Example of Calculation
To illustrate how to calculate the Plastic Section Modulus of an I-beam, let us consider a simple example. Suppose we have an I-beam with a cross-sectional area of 10 cm2 and a Moment of Inertia of 40 cm4. Suppose also that the distance from the neutral axis to the outermost fiber is 2 cm. In this case, the Plastic Section Modulus can be calculated as follows:
PSM = MOI/d = 40 cm4/2 cm = 20 cm3
Conclusion
The Plastic Section Modulus of an I-beam can be calculated by dividing the Moment of Inertia of the cross-section of the beam by the distance from the neutral axis to the outermost fiber of the beam. This value is an important factor in the design of structures which must resist bending and is used to calculate the amount of load that a beam can safely carry. The example provided in this article illustrates how to calculate the Plastic Section Modulus of an I-beam.