Compressive Stress

Compressive stress is the force that is responsible for the deformation of the material such that the volume of the material reduces. It is the stress experienced by a material which leads to a smaller volume. High compressive stress leads to failure of the material due to tension.

When compressive stress is applied to the brittle materials, these materials fracture as there is a sudden release of the stored energy. When the compressive stress is applied to the ductile materials, they compress, and there is no failure.

There are three ways to deform a solid with the help of external force:

1. When a solid body is stretched by applying two equal forces normal to the cross-sectional area, the resistive force developed per unit area is known as tansile stress
2. When a solid body is compressed, restoring force is developed due to an externally applied force. That restoring force per unit cross-sectional area is known as compressive stress.
3. When a solid body is exposed to two equal and opposite forces parallel to the cross-sectional area, the tangential force that is developed per unit area is known as tangential or shearing stress.

Unit of Compressive Stress:

The SI unit of compressive stress is Pascal (Pa)

Dimension:

Its dimensional formula is [ML-1T-2].

Difference between Tensile Stress and Compressive Stress

Tensile stress

• Tensile stress results in elongation of the material
• Tensile stress is due to the application of an external stretching force

Compressive Stress

• Compressive stress results in the shortening of the material
• Compressive stress is due to the application of external compressive force

Working Principle of Compressive Stress

When a material is subjected to a compressive force, it experiences:

• Elastic Deformation – The material returns to its original shape after the force is removed (within the elastic limit).
• Plastic Deformation – The material undergoes permanent deformation if the stress exceeds the yield strength.
• Fracture or Failure – If the compressive stress surpasses the material's ultimate strength, it may crack, buckle, or break.
• Mathematically, compressive stress (σ\sigmaσ) is given by

Sigma =F/A

Where:

• F = Applied force (N)
• A = Cross-sectional area(M)

Applications of Compressive Stress

Compressive stress plays a vital role in various industries, including:

1. Building & Construction – Used to test the strength of materials like concrete, bricks, and steel.
2. Automobile Industry – Ensures components like pistons and suspension systems can withstand stress.
3. Bridges & Dams – Structures designed to handle compressive forces efficiently.
4. Manufacturing – Used in processes like forging, pressing, and stamping metals.
5. Aerospace Engineering – Materials undergo compressive stress tests to ensure durability in extreme conditions.

Advantages of Compressive Stress in Engineering

? Improves Structural Integrity – Ensures buildings, bridges, and roads can withstand loads. ? Enhances Material Strength – Testing helps in selecting the right materials for construction.

? Prevents Failure & Accidents – Compressive testing ensures safety in various industries. ? Supports Efficient Design – Helps engineers optimize structures for maximum load-bearing capacity.

? Cost-Effective – Reduces material wastage by ensuring proper material selection.