Based on the field theoretical approach developed by physical mesomechanics and recent analysis on the associated gauge field, deformation of solid-state materials is formulated as a linear transformation of infinitesimal line elements in a deforming object. This formalism is capable of describing all stages of deformation including fracture on the same theoretical basis. The elastic and plastic stages are differentiated by whether the transformation is global or local. From the gauge invariance of the transformation and the least action principle applied to the gauge field, dynamics of plastic deformation is obtained being characterized as decaying, transverse wave behavior of the displacement field. Fracture is characterized as the final stage of deformation where the material becomes totally dissipative and the displacement wave decays completely. Optical interferometric experiment has been carried out to analyze in-plane displacement of a metal specimen under tensile loading. The result of analysis indicates that the plastic deformation and fracture criteria derived from the present formalism are able to reveal the transition from the elastic to plastic stage and predict the initiation of crack growth.