Abstract: The atomic scale model and mechanical properties of SiO2 aerogels was simulated and calculated based on the principle of molecular dynamics .The results indicates that the structure is mainly nano-clusters and connected skeleton structure is difficult to form when the density is 0 .078 g/cm3 .The distribution of silica oxygen elements has been extended to a connected amorphous skeleton structure when the density is 0.172 g/cm3 and above.The stress-strain relationships curve were figured out by applying strains on the different density cell , and the elastic modulus was obtained in different elastic range.The simulation results shows that the elastic modulus is linear with the density .The elastic modulus changes from 0.1265 MPa to 0.7889 MPa when density ranges from 0.078 g/cm3 to 0.443 g/cm3 .

Key words: The atomic scale model and mechanical properties of SiO2 aerogels was simulated and calculated based on the principle of molecular dynamics .The results indicates that the structure is mainly nano-clusters and connected skeleton structure is difficult to form when the density is 0 .078 g/cm3 .The distribution of silica oxygen elements has been extended to a connected amorphous skeleton structure when the density is 0.172 g/cm3 and above.The stress-strain relationships curve were figured out by applying strains on the different density cell , and the elastic modulus was obtained in different elastic range.The simulation results shows that the elastic modulus is linear with the density .The elastic modulus changes from 0.1265 MPa to 0.7889 MPa when density ranges from 0.078 g/cm3 to 0.443 g/cm3 .