Structural damage detection based on improved frequency change ratio Jian WANG, Huan JIN, Xiao MA, Bin ZHAO, Zhi YANG, Yaduo LIU, Yi WANG and Xian WANG MATEC Web Conf., 272 (2019) 01010 Published online: 13 March 2019 DOI: 10.1051/matecconf/201927201010