Abstract:

Folding-brazing is one of the efficient methods for fabricating X-type lattice sandwich structures.How-ever,it can cause thermal residual stress.Current researches have ignored the effect of the thermal residual stresson the structural stability.In this paper,a finite element method is adopted to simulate the buckling behavior of theX-type lattice sandwich structure in the state of compression under the thermal residual stress,and the effects of thebrazing temperature drop and the plate thickness are taken into account.The results show that (1) raising the platethickness helps to increase the buckling critical load of the structure and enlarge the plastic fluid zone of the struc-ture in the state of buckling; (2) in general,the pre-buckling behavior of the structure consists of linear and non-linear deformations; (3) the thermal residual stress can strengthen the linear deformability but weaken the non-linear deformability,and it has little effect on the buckling critical load; and (4) both raising the dropping range ofthe brazing temperature and decreasing the plate thickness can enhance the thermal residual stress effect.

Key words: X-type lattice sandwich, nonlinearity, buckling, thermal stress, numerical simulation