Abstract: A vibration damping structure includes a panel which is a structure and a damping member joined to the panel. The damping member has a plurality of joined portions joined to a mating surface of the panel through respective joined surfaces in the X direction, and a plurality of spacing portions recessed toward the side opposite to the panel in the Z direction between adjacent joined portions. The damping member is formed such that the damping member is higher in damping than the panel and a resonance frequency of the damping member is formed such that it is substantially the same as a primary resonance frequency of the panel.

Abstract: Floor panel vibration is reduced by suppressing a mode in which an entire region surrounded by a plurality of frame members in a floor panel vibrates. Vehicle-body framework members having closed cross-section structures, and a panel member to which vibration is transmitted from an engine or/and a suspension via the vehicle-body framework members are provided. The panel member includes a flange portion having a planar shape on its outer peripheral edge and to which the vehicle-body framework members are joined along the panel outer peripheral edge; a curved surface portion that is curved such that a place closer to a panel central side bulges out more to a lower side in a continuous manner from a panel-central-side edge portion of the flange portion; and a flat surface portion that extends to the panel central side from the panel-central-side edge portion of the curved surface portion in a continuous manner.

Abstract: A vibration damping structure includes a panel which is a structure and a damping member joined to the panel. The damping member has a plurality of joined portions joined to a mating surface of the panel through respective joined surfaces in the X direction, and a plurality of spacing portions recessed toward the side opposite to the panel in the Z direction between adjacent joined portions. The damping member is formed such that the damping member is higher in damping than the panel and a resonance frequency of the damping member is formed such that it is substantially the same as a primary resonance frequency of the panel.

Abstract: Floor panel vibration is reduced by suppressing a mode in which an entire region surrounded by a plurality of frame members in a floor panel vibrates. Vehicle-body framework members having closed cross-section structures, and a panel member to which vibration is transmitted from an engine or/and a suspension via the vehicle-body framework members are provided. The panel member includes a flange portion having a planar shape on its outer peripheral edge and to which the vehicle-body framework members are joined along the panel outer peripheral edge; a curved surface portion that is curved such that a place closer to a panel central side bulges out more to a lower side in a continuous manner from a panel-central-side edge portion of the flange portion; and a flat surface portion that extends to the panel central side from the panel-central-side edge portion of the curved surface portion in a continuous manner.