Keywords: auxetic shell, functionally graded material, buckling, elastic-plastic, external pressure, dome.

Metallic auxetics are likely to be porous and until recently it would be impossible to have several layers of distinctly different, yet auxetic, layers to be merged. A very recent development of an auxetic substrate film capable of bonding different porous layers, made it possible to research gradually changing material properties through the wall thickness in shell structures. This paper studies the effect of functionally graded layers on the buckling of externally pressurised domes. Six-layer auxetic shell has larger buckling pressures for dominant presence of auxetic material. The opposite happens when the content of auxetic is diminished. There is virtually no effective stress jump between internal layers. The stress jump between top and bottom surfaces in 2-layer shell are seven times larger than in six-layers with functionally graded Young’s modulus and Poisson’s ratio. It is also noted that there is no difference between apex load deflections curves between 2-layer (50 percent steel and 50 percent auxetic) and graded six-layer dome. All comparisons are made for geometrically identical shells with elastic perfectly plastic modelling of material. The yield point was kept constant and was not subject of grading through the wall thickness.

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