Composite materials for damping acoustic vibrations

A method of producing an article for damping vibrations by constrained layer damping, the article comprising:

• a first constraining layer,
• a second constraining layer, and
• a damping layer disposed between the first and second constraining layers,
• wherein the first and second constraining layers each independently comprise a fibre-reinforced composite material comprising one or more fibre(s) and a polymer composition;
• wherein the first and second constraining layers each independently have a thickness from 1.5 to 5 mm;
• wherein the damping layer comprises a viscoelastic material;
• wherein the damping layer has a thickness from 1 to 10 mm;
• and
• wherein the article has a thickness from 6 to 50 mm;
• wherein the method comprises the step of:
• (i) providing the damping layer, said damping layer having a first and second surface;
• (ii) disposing one or more fibre(s) on the first and second surfaces of said damping layer;
• (iii) infusing the damping layer and/or one or more fibre(s) with a polymer composition;
• and
• (iv) curing said polymer composition to form the fibre-reinforced composite material of the first and second composite layers.