ANALYSIS OF FUNCTIONALLY GRADED SANDWICH BEAMS UNDER HYGRO – THERMO – MECHANICAL LOADS By NGUYEN BA DUY DISSERTATION Submitted to Ho Chi Minh City University of Technology and Education in partial fullfillment of the requirements for the degree of Doctor of Philosophy 2019 MAJOR : ENGINEERING MECHANICS Ho Chi Minh City, September 2019 ANALYSIS OF FUNCTIONALLY GRADED SANDWICH BEAMS UNDER HYGRO – THERMO – MECHANICAL LOADS By NGUYEN BA DUY DISSERTATION Submitted to Ho Chi Minh City University of Technology and Education in partial fullfillment of the requirements for the degree of Doctor of Philosophy 2019 MAJOR : ENGINEERING MECHANICS Ho Chi Minh City, September 2019 THE PhD THESIS HAS BEEN COMPLETED AT: HO CHI MINH CITY UNIVERSITY OF TECHNOLOGY AND EDUCATION PhD thesis is protected in front of EXAMINATION COMMITTEE FOR PROTECTION OF DOCTORAL THESIS HO CHI MINH CITY UNIVERSITY OF TECHNOLOGY AND EDUCATION, Date month year ORIGINALITY STATEMENT I hereby declare that this submission is my own work and to the best of my knowledge it contains no materials previously published or written by another person, or substantial proportions of material which have been accepted for the award of any other degree or diploma at Ho Chi Minh City University of Technology and Education (HCMUTE) or any other educational institution, except where due acknowledgement is made in the thesis Any contribution made to the research by others, with whom I have worked at HCMUTE or elsewhere, is explicitly acknowledged in the thesis I also declare that the intellectual content of this thesis is the product of my own work, except to the extent that assistance from others in the project’s design and conception in style, presentation and linguistic expression is acknowledged Date………………………… Signed………………………… ACKNOWLEDGEMENTS My thanks go to many people who provided great support and had an important role in this research I would like to express my gratitude to my supervisor, Assoc Prof Nguyen Trung Kien, and co-supervisors Prof Vo Phuong Thuc of the Northumbria University for their continuous support and valuable guidance throughout this research I had also the opportunity to work with people in GACES of HCMUTE Therefore, my acknowledgments are extended to Prof Nguyen Hoai Son and Nguyen Ngoc Duong for his technical guidance and training Dr Nguyen Van Hau is thanked for his comment and discussion on functionally graded materials (FGM) My thanks also go to Le Quoc Cuong who helped and provided me a useful matlab Thank you to everyone else who help me with this research Last but not least, I wish to profoundly thank my parents, my wife, my son and my sister for their unconditional love and unlimited support Without their encouragement, I would not have been able to overcome many difficulties and challenges during this research ... critical buckling load ( N c ) of FG sandwich beams 96 r N ) of FG sandwich beams 97 c r Table 3.23 Non-dimensional critical buckling load ( Ncr ) of FG sandwich beams 98 Table 3.24 Non-dimensional... 3.24 Non-dimensional critical buckling load ( Ncr ) of FG sandwich beams 99 V Table 3.25 Non-dimensional fundamental frequency ( ) of FG sandwich beams with various boundary conditions (Type C)... critical buckling load ( N ) of FG sandwich beams with various boundary conditions (Type C) 102 Table 3.27 The first three non-dimensional frequencies of FG sandwich beams .103 Table 4.1: