found there furthermore the configuration of void structures 50 shown in fig3 and 4 removes less material than is removed when using conventional elliptical slots this results in a material structure which is less likely to crack and is less porous reduced porosity is desirable for applications such as a combustor liner that requires a controlled level of porosity to control the flow of air through the combustor liner wall reduced porosity is also desirable in other gas turbine applications such as turbine seal segments or blade tracks or any component whose functions include maintaining a pressure differential or metering air flow the configurations for u201c barbell u201d void structures 50 shown in fig5 a to 5d depict variations for void structures in which the void structures are formed with slot portions connecting pairs of round or oblong holes rather than the elliptical or oblong slots typically used in the manufacture of materials that exhibit auxetic characteristics the slot portion may be straight or curved the length and width of the slot portion the diameter of the holes the shape of the holes i e round oblong elliptical other variations and the spacing between slots can be varied to achieve the desired combination of auxetic behavior stress reduction.