Finite Element Analyzing of the Effect of Crack on Mechanical Behavior of Honeycomb and Re-entrant Structures

Authors : Berkay ERGENE, Bekir YALÇIN

Pages : 1015-1025

Doi:10.2339/politeknik.534103

View : 51 | Download : 19

Publication Date : 2020-12-01

Article Type : Research Paper

Abstract :Developments in technology require the new materials, lighter and more efficient structures and also new manufacturing methods. In this study, after doing researches about topology optimization, regular honeycomb and re-entrant structures; the regular honeycomb and re-entrant structures were designed, and then Ti-6Al-4V material was chosen for these structures in finite element insert ignore into journalissuearticles values(FE); analyzing. The three different rib thickness values insert ignore into journalissuearticles values(t); of 1 mm, 1.5 mm and 2 mm were assigned for honeycomb and re-entrant structures in FE analyses. Also, the crack was created on the models, and then 2-D FE analyses were done for both cracked and un-cracked honeycomb and re-entrant structures under tensile forces through y axis. Afterwards, the effect of crack on stress intensity factor, stresses, strains and displacement were obtained and characterized the auxetic behavior of the regular honeycomb and re-entrant structures. Furthermore, increase in rib thickness decreases stress and strains for each structure. Moreover, re-entrant structures have negative Poisson’s ratio due to their geometric properties and the notable effect of crack on the equivalent stress in re-entrant was emerged in comparison with honeycomb structure.  As a result, the only possible fracture in honeycomb for thickness of 1 mm might be observed owing to stress intensity factor obtained from analyses bigger than fracture toughness of honeycomb structure.    
Keywords : Auxetic behavior, crack, negative Poissons ratio, stress intensity factor

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