Simple-shear deformation is essential to the study of the time-dependent rheological behavior of materials in atomistic and/or molecular terms, for the change in shape under simple shear is not accompanied by any change in volume. A novel test specimen with double-shear geometry is proposed for the study of viscoelastic and elastoplastic deformation and how of ceramic materials at elevated temperatures, The external load is applied to the specimen in compressive mode, which overcomes several difficulties in high-temperature testing, In order to scrutinize the reliability, reproducibility, and the self-consistency of experimental results obtained in the double-shear geometry, the linear viscoelastic deformation and flow of soda-lime glass are examined at temperatures greater than the glass transition point. It is concluded on the basis of experimental observation that the double-shear geometry proposed in the present study produces ideal simple-shear deformation at elevated temperatures in a relatively easy way and will provide an important tool for characterizing the high-temperature deformation and how of ceramic materials.
