Free vibration of the bi-dimensional functionally grated (2D-FG) nanobeams Ngoc Anh Le Thi, Duc Hieu Tran, Ngoc Lan Vu Thi, An Ninh Vu Thi and Dinh Kien Nguyen E3S Web Conf., 496 (2024) 02004 Published online: 12 March 2024 DOI: 10.1051/e3sconf/202449602004