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US 12,358,559 B2Granted
Vehicle body structural member and method for designing vehicle body structural member
AssigneeNippon Steel Corporation
InventorMasahiko Abe
Life of this patent
Estimating the term…
Abstract
This vehicle body structural member is a vehicle body structural member (1) extending in a longitudinal direction, wherein, in at least a portion thereof in the longitudinal direction, a cross-section perpendicular to the longitudinal direction satisfies the Expressions (1) to (3). σ cr > σ y Expression ( 1 ) σ cr = k π 2 Et 2 12 ( 1 - v 2 ) b f 2 Expression ( 2 ) k = 4. exp ( - 28 R 1 t b f b ) Expression ( 3 )
Claims8
A vehicle body structural member extending in a longitudinal direction thereof,
- wherein, in at least a portion in the longitudinal direction, a cross-section perpendicular to the longitudinal direction comprises:
- a maximum radius of curvature curved portion having the maximum radius of curvature R1 in units of mm among a plurality of curved portions;
- a reference flat portion having the longest cross-sectional length br in units of mm among plane portions, which are connected to the maximum radius of curvature curved portion, and whose end portions on sides opposite to end portions connected to the maximum radius of curvature curved portion are connected to the curved portions whose centers of circles of curvature are on the same side as a centroid of the cross-section with respect to the cross-section;
- and
- a small radius of curvature curved portion having a radius of curvature R2, which is less than or equal to 50% of the radius of curvature R1 of the maximum radius of curvature curved portion in units of mm,
- wherein the small radius of curvature curved portion is disposed on a side opposite to the reference flat portion with a reference line interposed therebetween, which passes through the centroid of the shape of the cross-section and is a straight line parallel to the reference flat portion,
- wherein the following Expressions (1) to (3) are satisfied,
- [
- Math
- .
- 1
- ]
- σ
- cr
- >
- σ
- y
- Expression
-
- (
- 1
- )
- [
- Math
- .
- 2
- ]
- σ
- cr
- =
- k
-
- π
- 2
-
- Et
- 2
- 12
-
- (
- 1
- -
- v
- 2
- )
-
- b
- f
- 2
- Expression
-
- (
- 2
- )
- [
- Math
- .
- 3
- ]
- k
- =
- 4.
- exp
-
- (
- -
- 28
-
- R
-
- 1
-
- t
- b
- f
-
- b
- )
- Expression
-
- (
- 3
- )
- here,
- σcr:
- an elastic buckling stress of the reference flat portion in units of MPa
- σy:
- a yield stress of the reference flat portion in units of MPa
- k:
- a buckling stress coefficient
- E:
- Young's modulus of the portion forming the reference flat portion in units of MPa
- t:
- a sheet thickness of the portion forming the reference flat portion in units of mm
- ν:
- Poisson's ratio of the portion forming the reference flat portion
- bf:
- a cross-sectional length of the reference flat portion in units of mm
- R1:
- a radius of curvature of the maximum radius of curvature curved portion in units of mm
- b:
- the maximum external dimension of a cross-section in a direction along the reference line in the cross-section in units of mm, and
- wherein the vehicle body structural member is a hollow tubular member extending in the longitudinal direction.
100 more elements
A method comprising:
- forming a vehicle body structural member having, in at least a portion in the longitudinal direction, a cross-section perpendicular to the longitudinal direction that comprises:
- a maximum radius of curvature curved portion having the maximum radius of curvature R1 in units of mm among a plurality of curved portions;
- a reference flat portion having the longest cross-sectional length br in units of mm among plane portions, which are connected to the maximum radius of curvature curved portion, and whose end portions on sides opposite to end portions connected to the maximum radius of curvature curved portion are connected to the curved portions whose centers of circles of curvature are on the same side as a centroid of the cross-section with respect to the cross-section;
- and a small radius of curvature curved portion having a radius of curvature R2, which is less than or equal to 50% of the radius of curvature R1 of the maximum radius of curvature curved portion in units of mm,
- wherein the small radius of curvature curved portion is disposed on a side opposite to the reference flat portion with a reference line interposed therebetween, which passes through the centroid of the shape of the cross-section and is a straight line parallel to the reference flat portion,
- wherein the vehicle body structural member is made to satisfy the following Expressions (1) to (3),
- [
- Math
- .
- 5
- ]
- σ
- cr
- >
- σ
- y
- Expression
-
- (
- 1
- )
- [
- Math
- .
- 6
- ]
- σ
- cr
- =
- k
-
- π
- 2
-
- Et
- 2
- 12
-
- (
- 1
- -
- v
- 2
- )
-
- b
- f
- 2
- Expression
-
- (
- 2
- )
- [
- Math
- .
- 7
- ]
- k
- =
- 4.
- exp
-
- (
- -
- 28
-
- R
-
- 1
-
- t
- b
- f
-
- b
- )
- Expression
-
- (
- 3
- )
- here,
- σcr:
- an elastic buckling stress of the reference flat portion in units of MPa
- σy:
- a yield stress of the reference flat portion in units of MPa
- k:
- a buckling stress coefficient
- E:
- Young's modulus of the portion forming the reference flat portion in units of MPa
- t:
- a sheet thickness of the portion forming the reference flat portion in units of mm
- ν:
- Poisson's ratio of the portion forming the reference flat portion
- bf:
- a cross-sectional length of the reference flat portion in units of mm
- R1:
- a radius of curvature of the maximum radius of curvature curved portion in units of mm
- b:
- the maximum external dimension of a cross-section in a direction along the reference line in the cross-section in units of mm, and
- wherein the vehicle body structural member is a hollow tubular member extending in the longitudinal direction.
99 more elements
Dependencies are inferred from the claim text.