Numerical methods & Viscoelastic models of Elastomers — Summer 2024

Astring has a diameter of 1 cm and the original length of 2 m. The string is pulled by a force of 200 N. Determine the change in length of the string. Young’s modulus of the string = 5 × 109 N/m2

Two liters of water, when subjected to a pressure of 10 atmospheres, are compressed by 1.013 cc. Find the Compressibility of water

Distinguish between bulk modulus and young modulus.

Mention the properties of typical elastomers.

Discuss the structure of an ideal elastomers.

Explain the elasticity of a network and derive its equation.

Amild steel wire of radius 0.5 mm and length 3 m is stretched by a force of 49N. Calculate: (a) longitudinal stress (b) longitudinal strain (c) elongation produced in the body is Yfor steel is 2.1 × 1011 N/m2.

Explain the term viscoelasticity with suitable example.

Define the term Viscosity and write its nomenclature.

Discuss in detail about the Viscosity theory.

Give the difference between stress relaxation and stress retardation.

Write the phenomena of viscous flow with suitable example.

Discuss in detail about the capillary viscometer.

Derive the hook’s model equation for elastic material.

Explain the maxwell model and give its disadvantages.

Apolystyrene sample of 0.02/m2 cross-sectional area is subjected to a creep load of 105 N. The load is removed after 30 s. assuming that the Maxwell element accurately describes the behavior of polystyrene and that viscosity is 5 × 1010 P, while Young’s modulus is 5 × 105 psi, calculate: (a) The compliance, (b) The deformation recovered on the removal of the dead load & (c) The permanent

Define terms: (i) Toughness (ii) Brittleness (iii)Ductility

Give the importance of Deborah number.

Derive the equation for creep experiment for Voight model. P.T .O

What is the Tg of butadiene-styrene copolymer containing 10 vol% styrene?

Give the difference between pseudoplastic fluid and dilatant fluid.

Discuss in detail about the factors affecting glass transition temperature.

Toluene behaves as a plasticizer for polystyrene. Estimate Tg of a polystyrene sample containing 20 vol% toluene.

Distinguish between thixotropic fluid and rheopectic fluid.

Discuss in detail about states of aggregation.