Hung, T.Q., Tu, T.M. and Duc, D.M. 2021. Free vibration of piezoelectric FGM sandwich beam with porous core embedded in thermal environment and elastic foundation. Journal of Science and Technology in Civil Engineering (JSTCE) - HUCE. 15, 4 (Oct. 2021), 15-28. DOI:https://doi.org/10.31814/stce.huce(nuce)2021-15(4)-02.