JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech IV Year DESIGN AND SELECTION OF ENGINEERING MATERIALS Previous Question Paper (July - 2021 - R16)

Engineering materials are categorized based on their atomic structure and bonding, which dictate their mechanical, thermal, and electrical properties:

• Metals and Alloys: Characterized by metallic bonding, these materials exhibit high thermal and electrical conductivity, ductility, and strength. They are typically opaque and possess a crystalline structure.
• Ceramics: Composed of metallic and non-metallic elements with ionic or covalent bonding. They are known for high hardness, high melting points, excellent chemical resistance, and brittleness.
• Polymers: Large molecular chains held by covalent bonds and weak van der Waals forces. They exhibit low density, low thermal and electrical conductivity, and high flexibility or elasticity.
• Composites: Engineered combinations of two or more distinct materials to achieve properties not possible with individual components, such as high strength-to-weight ratios and tailored stiffness.

The relationship between Young's modulus (E), shear modulus (G), and Poisson's ratio (υ) for an isotropic material is given by the formula:

Given:

E = 120 GPa

υ = 0.342

Substituting the values into the equation:

The shear modulus of copper is approximately 44.71 GPa.