Vehicle-body structure for vehicle
A reinforcing body is disposed in a closed cross sectional portion constituted by one or more vehicle body components. The reinforcing body is provided with a joining portion to be joined to the vehicle body components. The joining portion includes hard connecting portions connected to the vehicle body components in an abutting state, and a soft connecting portion connected to the vehicle body components via a vibration damping member. The storage shear rigidity (KB′) of the vibration damping member is set in the range: 800 N/mm<KB′<57500 N/mm.
1. A vehicle body structure for a vehicle, which includes one or more vehicle body components constituting a closed cross sectional portion, the vehicle body structure comprising:
a reinforcing body disposed in the closed cross sectional portion, wherein
the reinforcing body includes a joining portion to be joined to the vehicle body component,
the joining portion includes a hard connecting portion connected to the vehicle body component in an abutting state, and a soft connecting portion connected to the vehicle body component via a vibration damping member,
the vibration damping member is formed in such a manner that a storage shear rigidity KB′ thereof satisfies a requirement: 800 N/mm<KB′<57500 N/mm, and
the storage shear rigidity KB′ is function of parameters which includes
an area of a surface of the vibration damping member in contact with the vehicle body component,
a thickness of the vibration damping member in a direction orthogonal to the contact surface, and
a storage shear rigidity modulus of the vibration damping member.
2. The vehicle body structure for a vehicle according to claim 1 , wherein
the vibration damping member is formed in such a manner that the storage shear rigidity KB′ thereof satisfies a requirement: 2200 N/mm<KB′<20000 N/mm.
3. The vehicle body structure for a vehicle according to claim 2 , wherein
the storage shear rigidity KB′ is expressed by:
KB′=G′×Ab/Tb
where
Ab is an area of a surface of the vibration damping member in contact with the vehicle body component,
Tb is a thickness of the vibration damping member in a direction orthogonal to the contact surface, and
G′ is a storage shear rigidity modulus of the vibration damping member.
4. The vehicle body structure for a vehicle according to claim 3 , wherein
the joining portion is formed of a plurality of flange portions, each of which includes a surface facing an inner surface of the vehicle body component,
one of the flange portions constitutes the soft connecting portion, and
the remaining flange portions constitute the hard connecting portion.
5. The vehicle body structure for a vehicle according to claim 1 , wherein
the storage shear rigidity KB′ is expressed by:
KB′=G′×Ab/Tb
where
Ab is an area of a surface of the vibration damping member in contact with the vehicle body component,
Tb is a thickness of the vibration damping member in a direction orthogonal to the contact surface, and
G′ is a storage shear rigidity modulus of the vibration damping member.
6. The vehicle body structure for a vehicle according to claim 5 , wherein
the joining portion is formed of a plurality of flange portions, each of which includes a surface facing an inner surface of the vehicle body component,
one of the flange portions constitutes the soft connecting portion, and
the remaining flange portions constitute the hard connecting portion.
7. The vehicle body structure for a vehicle according to claim 2 , wherein
the joining portion is formed of a plurality of flange portions, each of which includes a surface facing an inner surface of the vehicle body component,
one of the flange portions constitutes the soft connecting portion, and
the remaining flange portions constitute the hard connecting portion.
8. The vehicle body structure for a vehicle according to claim 1 , wherein
the joining portion is formed of a plurality of flange portions, each of which includes a surface facing an inner surface of the vehicle body component,
one of the flange portions constitutes the soft connecting portion, and
the remaining flange portions constitute the hard connecting portion.