An electromechanical actuator (10), comprising a movable member (14) provided with connecting means (20) and translationally movable with respect to a frame (12), and an energy absorbing-dissipating structure (28, 30) located on a strain path between said connecting means (20) and said frame (12) and comprising a porous capillary matrix (40) having an apparent porosity and an associated liquid (42) having a wetting angle higher than 90 degrees relative to said matrix (40) and selected such that part of said liquid (42) penetrates the pores of said matrix (40), when said chamber is subjected to a pressure equal to or higher than a first pressure level P1, and is spontaneously rejected off the pores of said matrix (40) by capillary action, when said structure is subjected to a pressure lower than a second pressure level P2 itself lower than said first pressure level P1.