Thermal Stress In Constrained Rod — the NEET Physics formula with its derivation, variables, validity constraints and worked solver.
Thermal Stress in Constrained Rod This formula applies specifically to a material rod that is prevented from undergoing free thermal expansion or contraction. The free thermal strain ( thermal ) developed due to temperature change is T . When the rod is constrained, the actual strain ( ) is forced to zero. The stress ( ) required to counteract this strain is given by Hooke's Law: = Y . Substituting the thermal strain into Hooke's Law yields the thermal stress: = Y T . Y > 0 (Young's Modulus must be positive) > 0 (Coefficient of thermal expansion must be positive) Forgetting the constraint condition (the formula only applies if expansion is prevented). Confusing the coefficient of linear expansion ( ) with the coefficient of volume expansion. Assuming the stress is proportional to the absolute temperature (T) rather than the change in temperature ( T ).