Deformable structure for absorbing energy from a mechanical and/or acoustic impact comprising an inner core and one or more external layers covering the inner core, - the inner core comprising a set of first segments having a geometric configuration with positive Poisson's ratio and second segments having a geometric configuration with negative Poisson's ratio; - said first and second segments (25, 35) being arranged alternately and joined between them so that the deformation received by one first segment can be transmitted to an adjacent second segment and vice versa; - said first and second segments (25, 35) being formed by a plurality of interconnected walls (27, 37) delimiting therebetween hollow cells (29, 39) arranged transversely to an expected direction of said impact; - said first and second segments (25, 35) being arranged alternately and the ends of the interconnected walls (27, 37) of two adjacent segments being joined so that the deformation received by one first segment can be transmitted to an adjacent second segment and vice versa; - the inner core being arranged between two external layers (17, 19) as a panel prepared to receive said impact, being the upper and lower adjacent ends of the interconnected walls (27, 37) of all first and second segments (25, 35) joined to said two external layers (17, 19) or the inner core being formed by a stack of alternated first and second segments (25, 35) oriented in the expected direction of the impact, as a shock absorber, and covered by an external layer being joined to it all the contiguous ends of the interconnected walls (27, 37) of said first and second segments (25, 35); characterized in that: when the inner core is arranged between two external layers (17, 19) as a panel prepared to receive said impact, the deformable structure further comprises in the inner core additional damping elements arranged in a direction parallel to the expected direction of said impact and joined to the external layers (17, 19) or when the inner core is formed by a stack of alternated first and second segments (25, 35) oriented in the expected direction of the impact, as a shock absorber, the deformable structure further comprises in the inner core additional damping elements arranged in a direction perpendicular to the expected direction of said impact and attached to the external layer. - the inner core comprising a set of first segments having a geometric configuration with positive Poisson's ratio and second segments having a geometric configuration with negative Poisson's ratio; - said first and second segments (25, 35) being arranged alternately and joined between them so that the deformation received by one first segment can be transmitted to an adjacent second segment and vice versa; - said first and second segments (25, 35) being formed by a plurality of interconnected walls (27, 37) delimiting therebetween hollow cells (29, 39) arranged transversely to an expected direction of said impact; - said first and second segments (25, 35) being arranged alternately and the ends of the interconnected walls (27, 37) of two adjacent segments being joined so that the deformation received by one first segment can be transmitted to an adjacent second segment and vice versa; - the inner core being arranged between two external layers (17, 19) as a panel prepared to receive said impact, being the upper and lower adjacent ends of the interconnected walls (27, 37) of all first and second segments (25, 35) joined to said two external layers (17, 19) or the inner core being formed by a stack of alternated first and second segments (25, 35) oriented in the expected direction of the impact, as a shock absorber, and covered by an external layer being joined to it all the contiguous ends of the interconnected walls (27, 37) of said first and second segments (25, 35);