Abstract: A composite multi-axial impact protection liner for a helmet is provided that reduces rotational acceleration, rotational strain rate, and rotational strain that cause concussions. In a protective helmet so equipped, one or more layers of fluid polymer, including strain thinning and strain thickening polymers, are positioned between the wearer's head and a hard helmet shell. The liner offers greater injury protection, performance, and personal comfort using the rate dependent and combined effect of strain thinning and strain thickening of fluid polymer layers.

Abstract: A composite multi-axial impact protection liner for a helmet is provided that reduces rotational acceleration, rotational strain rate, and rotational strain that cause concussions. In a protective helmet so equipped, one or more layers of fluid polymer, including strain thinning and strain thickening polymers, are positioned between the wearer's head and a hard helmet shell. The liner offers greater injury protection, performance, and personal comfort using the rate dependent and combined effect of strain thinning and strain thickening of fluid polymer layers.