Thermoelastic properties of sandwich materials with pin-reinforced foam cores  

作　　者：LU TianJian1,LIU Tao2,3 & DENG ZiChen2,4 1 MOE Key Laboratory of Strength and Vibration,School of Aerospace,Xi’an Jiaotong University,Xi’an 710049,China 2 Department of Engineering Mechanics,Northwestern Polytechnical University,Xi’an 710072,China 3 Department of Engineering,University of Cambridge,Cambridge CB2 1PZ,UK 4 State Key Laboratory of Structural Analysis of Industrial Equipment,Dalian University of Technology,Dalian 116024,China 

出　　处：《Science China(Technological Sciences)》2008年第12期2059-2074,共16页中国科学（技术科学英文版）

基　　金：the National Basic Research Program of China(Grant No.2006CB601202);the National Natural Science Foundation of China(Grant Nos.10572111,10632060);the National 111 Project of China(Grant No.B06024);the National High Technology Research Development Program(Grant No.2006AA03Z519);the NPU Foundation for Fundamental Research,the Open Foundation of State Key Laboratory of Structural Analysis of Industrial Equipment(Grant No.GZ0701);the NPU Foundation for Scientific Innovation

摘　　要：Pin-reinforced foam is a novel type of sandwich core materials formed by inserting pins(trusses) into a foam matrix to create a truss-like network reinforced foam core.Upon loading,the pins deform predominantly by local stretching whilst the deformation of foam is governed by local bending.This paper presents a theoretical study on the thermoelasticity of pin-reinforced foam sandwich cores.To calculate the effective thermoelastic properties of pin-reinforced foam cores,the energy-based homogenization approach is employed to develop a micromechanics-based model,calibrated by the existing experimental data.It is found that the stiffness of the sandwich core is mainly governed by pin reinforcements:the foam matrix contributes little to sandwich stiffness.Compared with traditional foam cores without pin reinforcements,the changes in inplane thermal expansion coefficients are not vigorous as a result of pin reinforcements,while the through-thickness thermal expansion coefficient changes significantly.It is also demonstrated that it is possible to design materials with zero or negative thermal expansion coefficients under such a context.Pin-reinforced foam is a novel type of sandwich core materials formed by inserting pins (trusses) into a foam matrix to create a truss-like network reinforced foam core. Upon loading, the pins deform predominantly by local stretching whilst the deformation of foam is governed by local bending. This paper presents a theoretical study on the thermoelasticity of pin-reinforced foam sandwich cores. To calculate the effective thermoelastic properties of pin-reinforced foam cores, the energy-based homogenization approach is employed to develop a micromechanicsbased model, calibrated by the existing experimental data. It is found that the stiffness of the sandwich core is mainly governed by pin reinforcements: the foam matrix contributes little to sandwich stiffness. Compared with traditional foam cores without pin reinforcements, the changes in in-plane thermal expansion coefficients are not vigorous as a result of pin reinforcements, while the throughthickness thermal expansion coefficient changes significantly. It is also demonstrated that it is possible to design materials with zero or negative thermal expansion coefficients under such a context.

关 键 词：SANDWICH PANEL pin REINFORCEMENT analytical solutions HOMOGENIZATION THERMOELASTICITY thermal expansion 

分 类 号：TB383.4[一般工业技术—材料科学与工程]