1. State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and Engineering Tsinghua University Beijing 100084 China
2. School of Engineering Brown University Providence RI 02912 USA
3. Centre for Advanced Mechanics and Materials CNMM Applied Mechanics Laboratory Department of Engineering Mechanics Tsinghua University Beijing 100084 China
4. Woodruff School of Mechanical Engineering Georgia Institute of Technology Atlanta GA 30332 USA