Applied Mathematics and Mechanics (English Edition) ›› 2020, Vol. 41 ›› Issue (12): 1821-1832.doi: https://doi.org/10.1007/s10483-020-2691-7

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Thermal-induced snap-through buckling of simply-supported functionally graded beams

Yongyong XI1, Qiang LYU1, Nenghui ZHANG1,2, Junzheng WU1   

  1. 1. School of Mechanics and Engineering Science, Shanghai University, Shanghai 200444, China;
    2. Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai Institute of Applied Mathematics and Mechanics, Shanghai University, Shanghai 200072, China
  • Received:2020-08-03 Revised:2020-10-18 Published:2020-11-21
  • Contact: Nenghui ZHANG E-mail:nhzhang@shu.edu.cn

Abstract: The instability of functionally graded material (FGM) structures is one of the major threats to their service safety in engineering applications. This paper aims to clarify a long-standing controversy on the thermal instability type of simply-supported FGM beams. First, based on the Euler-Bernoulli beam theory and von Kármán geometric nonlinearity, a nonlinear governing equation of simply-supported FGM beams under uniform thermal loads by Zhang's two-variable method is formulated. Second, an approximate analytic solution to the nonlinear integro-differential boundary value problem under a thermal-induced inhomogeneous force boundary condition is obtained by using a semiinverse method when the coordinate axis is relocated to the bending axis (physical neutral plane), and then the analytical predictions are verified by the differential quadrature method (DQM). Finally, based on the free energy theorem, it is revealed that the symmetry breaking caused by the material inhomogeneity can make the simply-supported FGM beam under uniform thermal loads occur snap-through postbuckling only in odd modes; furthermore, the nonlinear critical load of thermal buckling varies non-monotonically with the functional gradient index due to the stretching-bending coupling effect. These results are expected to provide new ideas and references for the design and regulation of FGM structures.

Key words: functionally graded beam, simply-supported boundary, buckling, thermal load, snap-though, free energy theorem

2010 MSC Number: 

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