Stress-Strain Curve of Different Materials

Materials can be classified into two categories based on the Stress-Strain curve,

• Brittle Materials
• Ductile Materials

Brittle Materials

Brittle Materials are those materials, which can fracture without any warning or plastic deformation. Glass, Ceramic, Cast iron, Concrete, and some types of Plastics are examples of brittle materials.

• Similar to ductile materials, brittle materials initially undergo elastic deformation when subjected to an applied load.
• Unlike ductile materials, brittle materials typically do not exhibit a distinct yield point on the stress-strain curve.
• Once the applied stress exceeds a certain threshold, the brittle material undergoes sudden and catastrophic failure without any significant plastic deformation.
• The stress-strain curve for brittle materials ends abruptly at the point of fracture, where the material breaks into two or more pieces.
• Brittle materials typically have a high modulus of elasticity (Young’s modulus), indicating that they are stiff and rigid.

Ductile Materials

Ductile materials are those materials, which can undergo a large amount of plastic deformation such as stretching, bending, or compressing, without breaking apart. Ductile materials can be formed into any shape without losing their structural integrity. Metals, Polymers, Rubber, and Composite materials are examples of Ductile Materials.

• The stress-strain curve follows a linear relationship between stress (σ) and strain (ε) within a certain range known as the elastic region.
• The elastic limit or proportional limit is the maximum stress that a material can withstand without permanent deformation.
• At the yield point, the material transitions from elastic deformation to plastic deformation.
• Beyond the yield point, the stress-strain curve enters the plastic deformation region, where the material undergoes permanent or irreversible deformation.

Related Articles

• Stress, Strain and Elastic Potential Energy
• Elasticity and Plasticity 
• Difference Between Stress and Pressure
• Modulus of Rigidity

Stress-Strain Curve is a very crucial concept in the study of material science and engineering. It describes the relationship between stress and the strain applied on an object. We know that stress is the applied force on the material, and strain, is the resulting change (deformation or elongation) in the shape of the object. For example, when force (stress) is applied to the spring, its length changes under that stress. But as stress is removed, spring came to its initial position.

Stress-Strain curve provides insights into the different materials under different levels of stress. This can help engineers design more efficient and strong structures. In this article, we will learn about, stress, strain, and the relationship between them and others in detail.