In-Plane Thermal Characterization of Fiberglass/Phenolic Honeycomb Core through an Experimental-Numerical Approach

Anisotropic hyperelastic constitutive modeling of in-plane finite deformation responses of commercial composite hexagonal honeycombs

“…Moreover, as deformations increase, two geometric phenomena including densification (at which point the cell walls start closing up within their longitudinal direction) under tensile-dominated loads and shear instability (at which point the double-thickness cell walls rotate in the opposite direction) under compressive-dominated loads may respectively result in stiffening and softening responses of the honeycomb core, thereby resulting in the observed bi-modular behavior. These phenomena are depicted in Figure 2 for two widely used composite hexagonal honeycombs in the aerospace industry [17,20].…”

“…In-plane nonlinear elastic responses under large compressive and tensile loadings: (a) HRP-C fiberglass/phenolic honeycomb core [20] and (b) Nomex hexagonal honeycomb core [17]. …”

“…In a previous study by the authors [18,20], the in-plane uniaxial tension and compression behavior of a commercial HRP-C fiberglass/phenolic hexagonal cell honeycomb core was investigated using experiments and numerical models. The authors reported a non-linear stress-strain response owing to mechanisms affected by the presence of node-bond fillets under tension and dominated by cell instabilities under compression.…”

“…Schematic of core-forming process alongside illustration of core cell deformations on convex and concave sides of core in (L-W) plane with its dominant failure modes [23,24]. …”

“…During the core-forming process, node bond failures [23,24] due to separation of the adjacent ribbons are the dominant failure mode of the core, as illustrated in Figure 6. Numerical simulations of the core-forming processes would be desirable to minimize the hitherto trial-and-error approach used to achieve complex-shaped cores without node bond failures.…”