Concepts to Remember on Mechanical Properties of Solids for JEE and CBSE Board Exams:

Stress-Strain Curve:

• Graphical representation of stress vs. strain.
• Provides information about the material’s behavior under applied force.

Young’s Modulus (Y):

• Represents the stiffness of a material.
• Ratio of stress to strain in the elastic region.
• Higher Y indicates greater rigidity.

Breaking Strength:

• Maximum stress a material can withstand before failure.
• Ultimate strength or tensile strength at the breaking point.

Tensile Strength:

• Maximum stress a material can withstand under tensile force.
• Measures resistance to stretching or pulling forces.

Compressive Strength:

• Maximum stress a material can withstand under compressive force.
• Measures resistance to squeezing or crushing forces.

Shear Strength:

• Maximum shear stress a material can withstand before failure.
• Measures resistance to sliding forces.

Elastic Modulus:

• General term for moduli that measure the stiffness of a material.
• Includes Young’s modulus, shear modulus, and bulk modulus.

Plastic Deformation:

• Permanent deformation of a material beyond its elastic limit.
• Occurs when stress exceeds the material’s yield strength.

Brittle Fracture:

• Sudden and complete failure of a material with little or no plastic deformation.
• Occurs when stress exceeds the material’s ultimate tensile strength.

Ductile Fracture:

• Gradual and localized failure of a material with significant plastic deformation.
• Occurs when stress exceeds the material’s yield strength but below the ultimate tensile strength.

Fatigue Failure:

• Failure of a material due to repeated or fluctuating stresses below the material’s ultimate tensile strength.

Creep:

• Time-dependent deformation of a material under sustained stress.
• Occurs when stress exceeds a certain threshold for a prolonged period.

Hardness:

• Resistance of a material to permanent deformation or indentation.
• Measured using various hardness tests, such as Brinell, Vickers, or Rockwell.

Toughness:

• Ability of a material to absorb energy before failure.
• Area under the stress-strain curve up to the point of failure.

Resilience:

• Ability of a material to store and release elastic energy.
• Area under the stress-strain curve up to the elastic limit.