Buckling resistance of ultra-low-density carbon fiber curved-wall honeycomb based on stretching process

Although honeycomb is a kind of lightweight structural material with great potential, its specific strength is not always able to meet the requirements, especially in the weight-sensitive field. Inspired by the bionic idea of cuttlebone, the curved-wall configuration design is proposed to strengthen the buckling impedance of honeycomb, which can effectively prevent the premature occurrence of buckling failure mode induced by thin walls. Compared with the straight-wall honeycomb materials of the same geometric size, the probability of buckling failure in curved-wall honeycomb materials proposed in this paper is reduced by more than 22 %. Moreover, to achieve the preparation of curved-wall configuration, a processing strategy that uses stretching process to prepare ultralight carbon fiber honeycomb (Carbcomb) material is firstly introduced. Compared to the Hexcel Corporation's aluminum honeycomb with a density of 21 kg/m³, for the Carbcomb, the specific compressive strength and specific shear strength along both the L and W directions respectively improved by 57 %, 61 % and 77 %. In addition, the minimum density of fabricated Carbcomb (14.6 kg/m³) is less than that of the Hexcel's products (16 kg/m³), and the research findings fill the gap of the carbon fiber honeycomb material in low density areas (10 ∼ 30 kg/m³). More importantly, this process which does not require much manual operation can effectively avoid the problems of unstable mechanical properties, difficult mass production and high preparation cost of the existing carbon fiber structural parts. This curved-wall configuration design and fabricated approach widens the potential of carbon fiber honeycomb as a structural material, and makes it possible for lower cost and higher efficiency in aerospace and transportation applications.