Abstract：The assumption of materials' incompressibility was amended to compressibility when the effect of temperature change on the volume of polymer materials was taken under consideration. Theoretical research is conducted on the popcorn void crack phenomenon of polymer materials with neo-Hookea feature under the effect of hygro-thermal during reflow soldering. Using the theory of finite deformation, an general analytical solution relating the void growth to the vapor presser and thermal stress is obtained when the temperature change cause the material volume change. The general analytical solution will include the analytical solution of the material with incompressibility. The analysis results show that：Considering the effect of volume expansion of polymer materials, the critical load will be increased. If the expansion coefficient is smaller, the effect of volume expansion on the evolution of the void will be less. Using the incompressible hypothesis is reasonable when the temperature variation range is small.
2013, Vol. 34 
