A vibration damping insert (46) configured to seat within a cell (40) of a cellular structure (35) and to span the cell cavity (44). The insert (46) comprises a first portion (48) formed of a first material and a second portion (50) formed of a second material having lower stiffness than the first material. The first portion (48) is arranged to constrain deformation of the second portion (50) to be in a predetermined direction. The invention also comprises a vibration damping body (34) comprising a cellular structure (35) formed of a plurality of tessellating cells (40) and a vibration damping insert (46) as described. The vibration damping insert (46) is mounted in at least one of the cells (40) in the cellular structure (35). The invention also comprises a method of manufacturing a vibration damping body (34).
