Compressive properties and parametric study of fiber-reinforced negative stiffness honeycomb with thin-walled inclined beam

Negative stiffness (NS) honeycombs exhibit exceptional energy absorption and high reusability but face manufacturing limitations due to complex curved geometries. This study proposes a simplified straight-beam NS honeycombs fabricated via 3D printing using carbon fiber reinforced polyamide (PA/CF) filaments. By optimizing beam angles (θ=100º-110º), the structure approximates the deformation process and force-displacement response of classical curved-beam NS while achieving 70% higher energy absorption at θ=100º. Quasi-static cyclic compression tests demonstrated excellent repeatability with 44-62% energy attention after four cycles and elastic recovery. Finite element analysis well validated experiments and revealed that vertical beam thickness dominated peak force, while crossbeam stabilized the deformation. These findings suggested that the reusable damping and self-locking effect (θ > 105º) of NS honeycomb would enable rapid force dissipation in building foundations, and the tunable stiffness with controlled vertical beam thickness energy absorption also enable applications in biomedical implants (e.g. load-adaptive spinal cages) and surgical tools requiring impact-absorbing precision. Therefore, this work establishes PA/CF-based straight-beam NS honeycombs as scalable solutions for tunable, reusable energy-absorbing devices.