Crash absorbers are structural devices used in automotive with the aim of reducing the severity of impacts. Conventional crash absorbers dissipate the kinetic energy of the collision by irreversible deformation, and need to be replaced afterwards to restore safety of the structure, highly increasing cost and inconvenience of the system. The aim of this experimental thesis was to design and manufacture a reusable crash absorber , able to regain functionality after compression. The work was based on the concept of Negative Stiffness Honeycomb, with the objective of improving the performance, reliability and cost effectiveness with respect to previously published studies in the literature based on a similar concept. The multi-step experimental process led to the realization of three different prototypes, in series as a result of critical evaluation of their performance. The first and second iteration model were made in Nylon PA 6/66 3D printed by FDM, while the last one was laser cut by Stainless Steel AISI 304. The first iteration model was characterized by a simple bidimensional configuration, while the second and third iteration models featured a novel three-dimensional modular design , through which an increased stability in dynamic compressions as well as less complex manufacturing and assemble process were obtained The second and third models were tested under dynamic compression, reaching performance results higher in terms of absolute value of peak force and energy dissipation with respect to previous literature studies. If confirmed in further larger studies, this thesis work could represent a relevant advancement in the field of crashworthiness. In fact, negative stiffness honeycomb could become a viable alternative in those contexts where conventional crash absorbers are not convenient for practical applications involving repeated impacts or when substitution of the device is made complex by environmental and economic factors, with the final result of reducing cost, time and work associated to the replacement of the deformed safety device after the collision.