Thermal expansion behaviors of sandwich structures reinforced by carbon nanotubes using an improved higher-order model

By using carbon nanotubes (CNTs) to reinforce face sheets, mechanical performance of sandwich structures can be significantly improved. However, thermal expansion behaviors of sandwich structures reinforced by the CNTs are rarely studied in published literature. For a sandwich structure under uniform temperature rise, this is a typical three-dimensional (3D) issue as transverse normal deformation plays an important role. To study such issue, a novel higher-order model for the functionally graded (FG) sandwich plates has been developed, in which continuity conditions of transverse shear stresses at interfaces have been enhanced by considering the functionally graded alteration of material properties in the face sheets. After performance of the proposed model is verified by the 3D elasticity solutions and the 3D-FEM results, present model is extended to predict thermal response of sandwich plates reinforced by the CNTs. Moreover, the influence law of the CNTs on thermal behaviors has been investigated, in which volume fractions of the CNTs have a significant impact on thermal behaviors, and stiffness of sandwich structures can be obviously improved by changing the distributing profiles of the CNTs along thickness. However, the stresses display the sudden change along thickness direction of face sheets, which are harmful to structural safety. Therefore, before the CNTs are utilized to improve stiffness of sandwich structure, it is very necessary to predict thermal behaviors of sandwich structures by using an accurate and efficient model. This work can provide an effective model to design distributing profiles of the CNTs according to engineering requirements.