With the aim of decreasing CO2 emissions, car producers’ efforts are focused, among others, on reducing the weight of vehicles yet preserving the overall vibrational comfort. To do so, new lightweight materials combining high stiffness and high (passive) damping are sought. For panels essentially loaded in bending, sandwich composites made of two external metallic stiff layers and an inner polymeric (i.e. absorbing) core are broadly used. In the present work, the performances of such sandwich structures are enhanced by optimizing their damping behavior according to their use. More precisely, spatial patterning through selective UV irradiation of the viscoelastic properties of the silicone elastomeric layer is obtained based on a recently published UV irradiation selective technique [1]. Initially developed to modulate the elastic property gradient in Liquid Silicone Rubber (LSR) membranes, the procedure is now generalized to control the viscoelastic behavior of Room Temperature Vulcanization (RTV) silicone. Since the Young’s modulus and damping factor of the polymeric material are triggered by the UV irradiation dose, the resulting vibration response of the sandwich composite, made of aluminum skins and RTV silicone core, can be accordingly tuned. [1] Stricheret al. (2016). “Light‐Induced Bulk Architecturation of PDMS Membranes,” Macromol. Mater. Eng. 301(10), 1151-1157.