Size effects on the in-plane mechanical behavior of hexagonal honeycombs

Abstract

Abstract In-plane uniaxial compression tests were experimented on seven kinds of honeycomb specimens with different sizes (cell numbers) under the loading rate of 10 mm/min, in order to investigate the size effects on four important mechanical parameters (the curve modulus, initial collapse stress, densification strain, and plateau stress) of the honeycomb structure. The results show that the curve modulus of honeycombs decreases with decrease in specimen size, indicating that the curve modulus in in-plane direction is sensitive to size. In addition, the initial collapse stress in x 2-direction as well as energy absorption efficiency in x 1-direction is slightly sensitive to the specimen size. However, the other mechanical parameters of honeycomb show significant size independence. The weak boundary cells are used to explain size effects on the in-plane mechanical behavior of honeycomb. Consequently, the minimum specimen size of hexagonal honeycomb specimens for measuring the effective in-plane mechanical properties of a bulk honeycomb is determined according to these results.