A simulation-driven design approach to the manufacturing of stiff composites with high viscoelastic damping

Materials with enhanced vibration damping properties are of ever-growing technological interest. The ability of a material to limit mechanical vibrations, indeed, not only may extend its service life, but also reduces its susceptibility to mechanical noise generation. The selection and design of damping structural materials usually aims to maximize the loss coefficient, while sacrificing the stiffness, to achieve the proper vibration damping capability. In this work, we overcome this typical stiffness tradeoff by geometrically confining thin viscoelastic layers between stiff thicker ones in a layered composite, thus enhancing its viscoelastic shear response. The preparation of the composite is guided by a simple design methodology based on the effective properties of its homogenized counterpart. An optimal design window, defined for the viscoelastic volume fraction, directs the manufacturing of the composite. This approach allows to manufacture composites that exhibit enhanced damping properties, with over three orders of magnitude increase of loss coefficient and less than one order of magnitude decrease of stiffness compared to the constituent stiff material. Such materials might find applications in fields where high stiffness is required but a damping component is necessary to avoid the build-up of dangerous vibrational modes: from the aerospace industry to the design of "silent" infrastructures.