A deformable structure, such as a panel or a shock absorber, for absorbing energy from a mechanical and/or acoustic impact. The structure comprises an inner core and one or more external layers covering the inner core. The inner core comprises a set of first segments having a positive Poison's ratio and second segments having a negative Poisson's ratio. The first and second segments are arranged alternately and joined to one another so that the deformation received by one first segment is transmitted to an adjacent second segment and vice versa.