Temperature Stress and its Factors

Temperature stress refers to the stress induced in a material due to changes in temperature. It occurs when there is a difference in temperature across a material, causing it to expand or contract. The factors that affect temperature stress include the coefficient of linear expansion, temperature rise, and modulus of elasticity.

1. Coefficient of Linear Expansion

The coefficient of linear expansion (α) is a material property that quantifies how much a material expands or contracts per unit length when the temperature changes. It is defined as the fractional change in length per unit change in temperature. The coefficient of linear expansion varies for different materials and is typically given in units of per degree Celsius (°C).

When a material is subjected to a temperature change, it expands or contracts according to its coefficient of linear expansion. This expansion or contraction can induce stress in the material, especially when it is constrained or bonded to other materials. The magnitude of the temperature stress is directly proportional to the coefficient of linear expansion of the material.

2. Temperature Rise

The temperature rise is the actual change in temperature experienced by a material. When the temperature of a material increases or decreases, it expands or contracts accordingly. This expansion or contraction can result in temperature stress.

A higher temperature rise leads to a greater difference in temperature across the material, which in turn leads to higher temperature stress. Therefore, the temperature rise is an important factor that contributes to the overall temperature stress experienced by a material.

3. Modulus of Elasticity

The modulus of elasticity (E) is a fundamental property of a material that quantifies its stiffness or ability to deform under stress. It is defined as the ratio of stress to strain within the elastic limit of the material. The modulus of elasticity is a measure of how much a material can withstand deformation without permanent damage.

When a material is subjected to temperature stress, it undergoes thermal expansion or contraction. This expansion or contraction induces strain in the material. The modulus of elasticity determines how the material responds to this strain. A higher modulus of elasticity indicates that the material is stiffer and can withstand larger temperature stresses without significant deformation.

Conclusion

In conclusion, the temperature stress experienced by a material is influenced by the coefficient of linear expansion, temperature rise, and modulus of elasticity. The coefficient of linear expansion determines the extent of expansion or contraction, the temperature rise determines the magnitude of the temperature difference, and the modulus of elasticity determines the material's ability to withstand the induced strain. Therefore, all three factors (1, 2, and 3) contribute to the temperature stress, making option 'D' the correct answer.

C