Theoretical and Experimental Studies of the Dynamic Process of Thermal Expansion

The exact solutions of a set of non-linear differential equations with limiting conditions describing the anharmonic vibration of a one-dimensional lattice have been obtained. The thermal expansion coefficient of the lattice and the characteristic time of thermal expansion process were found and physical interpretations given. Some experimental results of thin metal foils could be taken as an evidence for the theoretical prediction. These results also tell us that, for high-speed heating, thermal stress exists even in the case of uniform temperature and free expanding, though it relaxes rapidly.