WO2021166988A1 - 車体構造部材及び車体構造部材の設計方法 - Google Patents

車体構造部材及び車体構造部材の設計方法 Download PDF

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Publication number
WO2021166988A1
WO2021166988A1 PCT/JP2021/006055 JP2021006055W WO2021166988A1 WO 2021166988 A1 WO2021166988 A1 WO 2021166988A1 JP 2021006055 W JP2021006055 W JP 2021006055W WO 2021166988 A1 WO2021166988 A1 WO 2021166988A1
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Prior art keywords
curvature
radius
cross
reference plane
structural member
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Ceased
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PCT/JP2021/006055
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English (en)
French (fr)
Japanese (ja)
Inventor
雅彦 阿部
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Nippon Steel Corp
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Nippon Steel Corp
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Priority to CN202180014846.9A priority Critical patent/CN115103795B/zh
Priority to US17/798,908 priority patent/US12358559B2/en
Priority to EP21757748.5A priority patent/EP4108546A4/en
Priority to JP2022501957A priority patent/JP7243913B2/ja
Publication of WO2021166988A1 publication Critical patent/WO2021166988A1/ja
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D21/00—Understructures, i.e. chassis frame on which a vehicle body may be mounted
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D25/00—Superstructure or monocoque structure sub-units; Parts or details thereof not otherwise provided for
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D29/00—Superstructures, understructures, or sub-units thereof, characterised by the material thereof
    • B62D29/007—Superstructures, understructures, or sub-units thereof, characterised by the material thereof predominantly of special steel or specially treated steel, e.g. stainless steel or locally surface hardened steel
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D65/00—Designing, manufacturing, e.g. assembling, facilitating disassembly, or structurally modifying motor vehicles or trailers, not otherwise provided for
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T30/00—Transportation of goods or passengers via railways, e.g. energy recovery or reducing air resistance
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/12—All metal or with adjacent metals
    • Y10T428/12292—Workpiece with longitudinal passageway or stopweld material [e.g., for tubular stock, etc.]

Definitions

  • This disclosure relates to a vehicle body structural member and a method for designing a vehicle body structural member.
  • the present application claims priority based on Japanese Patent Application No. 2020-025171 filed in Japan on February 18, 2020, the contents of which are incorporated herein by reference.
  • a vehicle body structural member a hollow member formed of a steel plate and having a predetermined cross-sectional shape has been used.
  • These vehicle body structural members are required to be lightweight and to have a sufficient load capacity when an impact such as a collision is applied. Therefore, in recent years, a high-strength steel plate having high strength may be used as a material.
  • Patent Document 1 describes a technique for bending a surface subject to compressive deformation outward in order to realize a member having high axial compressive bending strength in a vehicle body structural member subject to axial compressive bending deformation. ing.
  • Patent Document 1 only bends the shape of the surface subject to compression deformation to the outside convexly among the cross-sectional shapes of the member, and the cross-sectional shape including the plane continuous with the curved surface is the entire member.
  • the effect on bending strength is not considered.
  • thinning and increasing the strength of the material used for the vehicle body structural member can reduce the elastic buckling stress of the member. For this reason, elastic buckling may occur before the yield stress of the material is reached at a portion that receives a bending load, particularly a flat surface portion, which may reduce the bending strength.
  • conventional techniques, including the technique described in Patent Document 1 do not set the cross-sectional shape of the member from such a viewpoint.
  • an object of the present invention is to provide a new and improved vehicle body structural member capable of ensuring a high bending strength and a design method thereof. It is in.
  • the first aspect of the present disclosure is a vehicle body structural member extending in the longitudinal direction, and a cross section perpendicular to the longitudinal direction is a unit among a plurality of curved portions in at least a part of the longitudinal direction.
  • the maximum radius of curvature curved portion having the maximum radius of curvature R1 in mm and the end portion connected to the maximum radius of curvature curved portion and opposite to the end connected to the maximum radius of curvature curved portion are circles of curvature.
  • the maximum curvature It has a small radius-curved portion having a radius of curvature R2 that is 50% or less of the radius of curvature R1 in a unit mm of the radius-curved portion, and the small radius-curved portion passes through the centroid of the shape of the cross section.
  • It is a vehicle body structural member that is arranged on the opposite side of the reference plane portion with a reference line that is a straight line parallel to the reference plane portion in between, and satisfies the following equations (1) to (3).
  • the cross section may be present at 50% or more of the total length in the longitudinal direction.
  • the vehicle body structural member according to (1) or (2) above may further satisfy the following equation (4).
  • the tensile strength of the reference plane portion may be 1180 MPa or more.
  • the radius of curvature R1 may be 15 mm or more.
  • the thickness of the reference plane portion may be 0.4 to 1.6 mm.
  • a second aspect of the present disclosure is a vehicle body structural member extending in the longitudinal direction, wherein a cross section perpendicular to the longitudinal direction is a unit among a plurality of curved portions in at least a part of the longitudinal direction.
  • the maximum radius of curvature curved portion having the maximum radius of curvature R1 in mm and the end portion connected to the maximum radius of curvature curved portion and opposite to the end connected to the maximum radius of curvature curved portion are circles of curvature.
  • the maximum curvature It has a small radius-curved portion having a radius of curvature R2 that is 50% or less of the radius of curvature R1 in a unit mm of the radius-curved portion, and the small radius-curved portion passes through the centroid of the shape of the cross section.
  • FIG. 1A is a cross-sectional view taken along the line AA of FIG. 1A. It is sectional drawing which shows the cross section perpendicular to the longitudinal direction of the vehicle body structural member 1A which concerns on the modification.
  • FIG. 5 is a cross-sectional view showing a cross section perpendicular to the longitudinal direction of the vehicle body structural member 1A'according to the modified example. It is sectional drawing which shows the cross section perpendicular to the longitudinal direction of the vehicle body structural member 1A ′′ which concerns on the modification. It is sectional drawing which shows the cross section perpendicular to the longitudinal direction of the vehicle body structural member 1B which concerns on a modification.
  • FIG. 1A is a cross-sectional view taken along the line AA of FIG. 1A. It is sectional drawing which shows the cross section perpendicular to the longitudinal direction of the vehicle body structural member 1A which concerns on the modification.
  • FIG. 5 is a cross-sectional view showing a cross section perpendicular to the longitudinal direction of the vehicle body structural
  • FIG. 5 is a cross-sectional view showing a cross section perpendicular to the longitudinal direction of the vehicle body structural member 1B'according to the modified example. It is a perspective view which shows the automobile skeleton as an example to which a structural member is applied. It is a figure which shows typically an example of the cross section perpendicular to the longitudinal direction of the vehicle body structural member which concerns on Example.
  • the material axis direction of the vehicle body structural member that is, the direction in which the axis extends is referred to as the longitudinal direction.
  • the direction along the surface of the top plate portion may be referred to as the width direction
  • the direction perpendicular to the longitudinal direction and the width direction may be referred to as the vertical direction.
  • the "cross-sectional length” means a length along the circumferential direction in a cross section perpendicular to the longitudinal direction of the vehicle body structural member.
  • the "center of gravity” means the center of gravity in a cross section perpendicular to the longitudinal direction of the vehicle body structural member.
  • the direction away from the center of gravity is defined as the outward direction, and the direction toward the center of gravity is defined as the inward direction.
  • the "planar portion” means a linear portion in a cross section perpendicular to the longitudinal direction of the vehicle body structural member, specifically, a portion having a radius of curvature larger than the maximum external dimension of the cross section.
  • the maximum external dimension is the longest distance between the extension line of one flat surface portion and the intersection point of each extension line of the two flat surface portions extending from the curved portion to the flat surface portion. Means.
  • the "curved portion” is a portion of the cross section perpendicular to the longitudinal direction of the vehicle body structural member, excluding the flat portion, that is, a portion having a radius of curvature equal to or less than the maximum external dimension of the cross section, and is outward or inside of the vehicle body structural member. It means an arc-shaped part that is convex in the direction. Therefore, the R stop means the boundary between the flat surface portion and the curved portion.
  • the radius of curvature of the curved portion can be obtained as follows. That is, in a cross section perpendicular to the longitudinal direction of the vehicle body structural member, two R stops and a bending center point located equidistant along the surface from the two R stops on the curved portion of the surface. Find 3 points. By obtaining the curvature from these three points by a known mathematical method, the radius of curvature of the curved portion can be obtained.
  • the surface is the outer surface of the bent plate material.
  • the radius of curvature of the flat portion can also be obtained by the same calculation method as the radius of curvature of the curved portion.
  • structural member 1 (hereinafter, referred to as structural member 1) according to the first embodiment of the present disclosure will be described.
  • FIG. 1A is a perspective view showing the structural member 1 according to the present embodiment as an example.
  • the structural member 1 is a structural member of the vehicle body, in other words, a skeleton member.
  • the car body is, for example, the car body of an automobile.
  • the structural member 1 is a hollow tubular member extending in the longitudinal direction.
  • the structural member 1 can be formed by applying various known processing techniques to a plate material such as a steel plate.
  • the structural member 1 may be formed by forming a blank material into a predetermined shape by cold or hot press working and joining the ends.
  • the structural member 1 preferably has a tensile strength of 1180 MPa or more, more preferably 1500 MPa or more in the reference plane portion 13 described later.
  • the plate material may be, for example, a steel plate of 0.4 mm or more and 1.6 mm or less from the viewpoint of shock absorption characteristics and weight reduction required for the structural member 1.
  • the material of the material plate may be a metal such as aluminum in addition to steel.
  • FIG. 1B shows a cross section perpendicular to the longitudinal direction (AA cross section of FIG. 1A) in the central portion of the structural member 1 in the longitudinal direction.
  • the structural member 1 has a cross section perpendicular to the longitudinal direction, which is formed by four curved portions 14 and four flat portions 12.
  • a curved portion having the maximum radius of curvature in a cross section perpendicular to the longitudinal direction is defined as a “maximum radius of curvature curved portion”. Therefore, in the structural member 1 according to the present embodiment, of the four curved portions 14 shown in FIG. 1B, the curved portion having the maximum radius of curvature R1 in the unit mm is the maximum radius of curvature curved portion 11.
  • the maximum radius of curvature curved portion 11 has higher rigidity against out-of-plane deformation caused by compressive stress than the flat surface portion 12, so that the portion has higher rigidity against bending load and is less likely to be elastically buckled. Is.
  • the radius of curvature R1 is preferably 1/4 or more of the maximum external dimension b.
  • the radius of curvature R1 may be 15 mm or more.
  • the radius of curvature R1 is preferably 1/2 or less of the maximum external dimension b.
  • the end of the cross section is connected to the R stops at both ends of the maximum radius of curvature curved portion and is opposite to the end connected to the maximum radius of curvature curved portion, and the center of the circle of curvature is the cross section.
  • the center of the figure is defined as a "reference plane portion", which is the plane portion having a larger cross-sectional length among the plane portions connected to the curved portion on the same side with respect to the cross section.
  • the cross-sectional length of the flat surface portion 12 connected to the R stop Q1 is longer than the cross-sectional length of the flat surface portion 12 connected to the R stop Q2.
  • the plane portion 12 connected to the R stop Q1 is the reference plane portion 13.
  • the reference flat surface portion 13 is a flat surface portion of the two flat surface portions 12 connected to the curved portion 11 having the maximum radius of curvature, whichever is prone to elastic buckling due to a bending load. Therefore, the smaller the cross-sectional length b f of the reference plane portion 13, the more the elastic buckling in the vicinity of the reference plane portion 13 can be suppressed.
  • cross-sectional length b f of the reference plane 13 45 mm or less when the following thickness 1.0mm ultra 1.6 mm, when the following thickness 0.8mm ultra 1.0mm 28 When it is 1 mm or less and the plate thickness is 0.8 mm or less, it is preferably 22.5 mm or less.
  • the cross-sectional length b f of the reference plane portion 13 is too small, the total cross-sectional length (total circumference length) of the structural member 1 cannot be secured, so that the cross-sectional coefficient decreases.
  • the cross-sectional length b f of the reference plane portion 13 is preferably 5 mm or more.
  • the cross-sectional length b f of the reference plane portion 13 is 22.5 mm or less when the plate thickness is more than 1.0 mm and 1.6 mm or less, 14.1 mm or less when the plate thickness is more than 0.8 mm and 1.0 mm or less, and the plate thickness is 0. When it is 8 mm or less, it is preferably 11.3 mm or less.
  • the reference line L shown in FIG. 1B is a straight line that passes through the center of gravity P of the cross-sectional shape and is parallel to the reference plane portion 13.
  • the radius of curvature is 50% or less of the radius of curvature R1 (mm) of the maximum radius of curvature curved portion 11 on the side opposite to the reference plane portion 13 with the reference line L in between.
  • Two small radius of curvature curved portions 15 having R2 (mm) are arranged.
  • the small radius of curvature curved portion 15 is a portion where the distance from the reference line L of the two R stops to the closer R stop is larger than that of the maximum radius of curvature curved portion 11, and the degree of contribution to the bending rigidity is large. ..
  • the structural member 1 When the structural member 1 receives a bending load such that the reference plane portion 13 is inside the bend, the region where the reference plane portion 13 exists is the compression side and the region on the opposite side is tensioned with reference to the reference line L. Side bending stress is generated.
  • the reference plane portion 13 that receives the bending load so as to be inside the bending is referred to as a load receiving surface.
  • the small radius of curvature curved portion 15 has a radius of curvature R2 which is 50% or less of the radius of curvature R1 in the unit mm of the maximum radius of curvature curved portion 11, so that the cross section of the curved portion 15 suppresses elastic buckling on the compression side. As a whole, high bending rigidity can be ensured. Therefore, the structural member 1 according to the present embodiment can exhibit excellent bending strength by providing the reference plane portion 13 at a portion where an input of a bending load is expected due to a collision or the like.
  • the structural member 1 can secure a high bending strength by having the maximum radius of curvature curved portion 11 and the small radius of curvature curved portion 15.
  • the small radius of curvature curved portion 15 is on the opposite side of the reference plane portion 13 with the reference line L in between, and the longer the distance from the reference line L, the greater the bending strength.
  • the structural member 1 can secure a high bending strength when the following equations (1) and (2) are satisfied.
  • ⁇ cr Elastic buckling stress in the unit MPa of the reference plane portion 13
  • ⁇ y Yield stress in the unit MPa of the reference plane portion 13
  • k Buckling stress coefficient
  • E Young in the unit MPa of the portion forming the reference plane portion 13.
  • Ratio t Plate thickness in unit mm of the portion forming the reference plane portion 13
  • b f of the portion forming the reference plane portion 13 Cross-sectional length of the reference plane portion 13 in unit mm.
  • Equation (2) shows the elastic buckling stress ⁇ cr of the reference plane portion 13. Therefore, by satisfying the equation (1), in other words, the elastic buckling stress ⁇ cr of the reference plane portion 13 is larger than the yield stress ⁇ y, so that the strength of the material is not generated without causing the elastic buckling of the reference plane portion 13. It can be said that the characteristics can be reasonably utilized and high bending strength can be secured.
  • (2) has a Young's modulus E of the reference plane 13, the plate thickness t, and, as the Poisson's ratio ⁇ is large, also elastic seat reference plane 13 as sectional length b f of the reference plane 13 is smaller This is a calculation formula newly found and derived by the present inventor regarding the relationship with the increase in the bending stress ⁇ cr.
  • the buckling stress coefficient k is a value determined from the differential equation of buckling of the flat plate and the eigenvalues obtained by the bending shape satisfying the differential equation, and is obtained by the following equation (3).
  • R1 Maximum radius of curvature
  • the radius of curvature b in the unit mm of the curved portion 11 The maximum external dimension in the unit mm of the cross section in the direction along the reference line L in the cross section.
  • the radius of curvature of the other curved portions in the cross section is also 0 mm due to the definition of the maximum radius of curvature curved portion. .. Therefore, since the reference plane portion is sandwiched by the ridge line having a radius of curvature of 0 mm, it can be assumed that the constraint condition of the reference plane portion is the constraint condition of free rotation and translational fixation. In this case, the buckling stress coefficient is 4.0.
  • the radius of curvature R1 of the maximum radius of curvature curved portion 11 is designed to be large to some extent in order to improve the axial compressive force as in the structural member 1 according to the present embodiment, it is adjacent to the maximum radius of curvature curved portion 11.
  • the present inventor has noted that the translation of the widthwise end of the reference plane portion 13 is not completely fixed. Then, the present inventor has found that a more accurate elastic buckling stress ⁇ cr can be calculated by setting the true buckling stress coefficient k of the reference plane portion 13 to be lower than 4.0.
  • the present inventor further pursued research, and the buckling stress coefficient k is the radius of curvature R1 at the unit mm of the maximum radius of curvature curved portion 11 and the unit mm of the portion forming the reference plane portion 13. It was found that there is a correlation between the plate thickness t, the cross-sectional length b f of the reference plane portion 13 in the unit mm, and the length of the reference line L in the cross section in the unit mm, and the equation (3) was derived. When the constraint condition of the reference plane portion is free to rotate and free to translate, the buckling stress coefficient is 0.425. Therefore, when the value of the buckling stress coefficient k obtained by the equation (3) is less than 0.425, the value of k may be set to 0.425.
  • the value of 90% of the elastic buckling stress ⁇ cr is larger than the yield stress ⁇ y. That is, it is preferable that the structural member 1 further satisfies the following equation (4).
  • FIG. 7 is a diagram showing an automobile skeleton 2 as an example to which a structural member is applied.
  • the structural member may constitute the automobile skeleton 2 as a cabin skeleton or a shock absorbing skeleton.
  • Examples of application of the structural members according to the present disclosure are Roof Center Reinforce 201, Roof Side Rail 203, B Pillar 207, Side Sill 209, Tunnel 211, A Pillar Lower 213, A Pillar Upper 215, Kick Clean Force 227, Floor Cross Member 229. , Under lean force 231 and front header 233 and the like.
  • examples of application of the structural member according to the present disclosure as a shock absorbing skeleton include a rear side member 205, an apron upper member 217, a bumperin force 219, a crash box 221 and a front side member 223.
  • the structural member according to the present disclosure may be applied to a door impact beam or the like as a reinforcing material provided inside the door of an automobile. In short, the structural member of the present disclosure can be applied as long as it is a site where a bending load can act.
  • the structural member 1 When the structural member 1 is used as a skeleton member of a vehicle body in this way, the structural member 1 has a high bending strength, so that deformation at the time of a collision can be reduced. In addition, the deformability is also improved, and the inside of the skeleton can be protected.
  • the structural member 1 described above has a closed cross section having a tubular cross section perpendicular to the longitudinal direction, but has a cross section perpendicular to the longitudinal direction as in the structural member 1A according to the modified example shown in FIG. It may be a member having a substantially hat-shaped open cross section.
  • a cross section perpendicular to the longitudinal direction constitutes a substantially hat-shaped open cross section by four curved portions 14A and five flat portions 12A. ..
  • the flat surface portion 12A having one end free end may be referred to as a flange portion, and the flat surface portion 12A connected to the flange portion via the curved portion 14A is referred to as a vertical wall portion.
  • the flat surface portion 12A connected to the vertical wall portion via the curved portion 14A at the end portion of the vertical wall portion opposite to the end portion connected to the flange portion is referred to as a top plate portion.
  • the curved portion 14A having the maximum radius of curvature R1 in the unit mm among the four curved portions 14A is the maximum radius of curvature curved portion 11A.
  • the radius of curvature of two of the four curved portions 14A is the maximum.
  • one of the two curved portions 14A is regarded as the maximum radius of curvature curved portion 11.
  • the flat surface portion 12A connected to the R stop Q2 at the end of the maximum radius of curvature curved portion 11A the other end on the opposite side to the end connected to the R stop Q2 has the center of the curvature circle as the center of cross section P. It is connected to the curved portion 14A on the opposite side of the cross section. Therefore, of the flat surface portions 12A connected to the R stops Q1 and Q2 at both ends of the maximum radius of curvature curved portion 11A, the flat surface portion 12A having the larger cross-sectional length is the reference flat surface portion 13A.
  • the reference plane portion 13A is a plane portion 12A connected to the R stop Q1 of the maximum radius of curvature curved portion 11A.
  • the reference plane portion 13A is the top plate portion.
  • the reference line L shown in FIG. 2 is a straight line that passes through the center of gravity P having a cross-sectional shape perpendicular to the longitudinal direction of the structural member 1A and is parallel to the reference plane portion 13A.
  • the structural member 1A has a radius of curvature R2 that is 50% or less of the radius of curvature R1 in the unit mm of the maximum radius of curvature curved portion 11A on the side opposite to the reference plane portion 13A with the reference line L in between. Two small radius of curvature curved portions 15A are arranged.
  • the small radius of curvature curved portion 15A is a portion having a larger bending strength than the maximum radius of curvature curved portion 11A. Therefore, when the structural member 1A receives a bending load, bending stress is likely to occur in which the region where the reference plane portion 13A exists is on the compression side and the region on the opposite side is on the tension side with reference to the reference line L. .. Further, the small radius of curvature curved portion 15A is also a portion that exhibits excellent bending resistance by having a radius of curvature R2 that is 50% or less of the radius of curvature R1 in the unit mm of the maximum radius of curvature curved portion 11A.
  • the structural member 1A can exhibit excellent bending strength by providing the reference plane portion 13A at a portion where an input of a bending load is expected due to a collision or the like.
  • the structural member 1A can secure a high bending strength when the above equations (1) to (3), preferably the above equations (1) to (4) are satisfied. Become.
  • the flat surface portion 12A' which is the vertical wall portion is longer than the cross-sectional length of the flat surface portion 12A' which is the top plate portion, the flat surface portion 12A'which is the top plate portion is Reference plane portion 13A'.
  • a part of the flat surface portion 12A'' serving as the top plate portion may have a recess 16 as in the structural member 1A'' according to the modified example shown in FIG. ..
  • the planes arranged on both sides of the recess 16 in the width direction are collectively regarded as one plane portion 12A'' here.
  • the curved portion and the flat portion constituting the concave portion 16 are not included in the curved portion and the flat portion in the present disclosure.
  • the cross section perpendicular to the longitudinal direction constitutes an open cross section by four curved portions 14A ′′ and five flat surface portions 12A ′′.
  • the reference plane portion 13A'' is a plane portion 12A'' connected to the R stop Q1 of the maximum radius of curvature curved portion 11A''.
  • the reference line L shown in FIG. 4 is a straight line that passes through the center of gravity P having a cross-sectional shape perpendicular to the longitudinal direction of the structural member 1A ′′ and is parallel to the reference plane portion 13A ′′.
  • the structural member 1A'' is also 50% or less of the radius of curvature R1 in the unit mm of the maximum radius of curvature curved portion 11A'' on the side opposite to the reference plane portion 13A'' with the reference line L in between.
  • Two small radius of curvature curved portions 15A'' having a radius of curvature R2 are arranged. Further, also in the structural member 1A'', similarly to the structural member 1, a high bending strength is ensured when the above equations (1) to (3), preferably the above equations (1) to (4) are satisfied. It will be possible.
  • the reference plane portion 12A' structural member 1A ' having a recess 16 in the top plate portion continuous with the maximum curvature radius curved portion 11A of the'''.
  • the distance from the flat R stop Q1 to the flat R stop Q3 connected to the maximum radius of curvature curved portion 11A ′′ in the recess 16 is replaced with b f'.
  • the maximum external dimension b in the unit mm of the cross section in the direction along the reference line L in the above equation (4) is set to the reference plane portion 12A''.
  • the steel plate 100 may be joined to the flat surface portion 12B which is a flange portion as in the structural member 1B according to the modified example shown in FIG.
  • a hat type member 100A or the like may be joined instead of the steel plate 100.
  • the cross section perpendicular to the longitudinal direction constitutes a closed cross section by eight curved portions 14B'and ten flat surfaces 12B'.
  • the curved portion 14B' having the maximum radius of curvature R1 in the unit mm among the eight curved portions 14B' is the maximum radius of curvature curved portion 11B'.
  • the radius of curvature of two of the eight curved portions 14B' is the maximum.
  • one of the two curved portions 14B' is the maximum radius of curvature curved portion 11B'.
  • the other end on the side opposite to the end connected to the R stop Q1 has the center of the curvature circle as the center of cross section P. It is connected to the curved portion 14B'on the same side with respect to the cross section.
  • the other end on the opposite side to the end connected to the R stop Q2 has the center of curvature P as the center of the cross section. Is connected to the curved portion 14B'on the opposite side of the cross section. Therefore, of the two flat surface portions 12B'consisting with the R stops Q1 and Q2 at both ends of the maximum radius of curvature curved portion 11B', the other end is curved to the opposite side (inward direction) from the maximum radius of curvature curved portion 11B'.
  • the flat surface portion 12B'connected to the curved portion 14B' is the reference flat surface portion 13B'.
  • the reference plane portion 13B' is a plane portion 12B' connected to the R stop Q1 of the maximum radius of curvature curved portion 11B'.
  • the reference line L shown in FIG. 6 is a straight line that passes through the centroid P having a cross-sectional shape perpendicular to the longitudinal direction of the structural member 1B'and is parallel to the reference plane portion 13B'.
  • the radius of curvature which is 50% or less of the radius of curvature R1 in the unit mm of the maximum radius of curvature curved portion 11B' on the side opposite to the reference plane portion 13B'with the reference line L in between.
  • Two small radius of curvature curved portions 15B'having R2 are arranged.
  • the small radius of curvature curved portion 15B' is a unit mm of the maximum radius of curvature curved portion 11B'arranged on the opposite side of the reference plane portion 13B'with the reference line L in between.
  • the four curved portions 14B' having a radius of curvature R2 that is 50% or less of the radius of curvature R1 in the above, each of the two curved portions 14B'farthest from the reference line L.
  • the structural members 1, 1A, 1A', 1A ", 1B, 1B' according to the first embodiment have a uniform cross-sectional shape over the entire length, but do not have a uniform cross-sectional shape over the entire length. It is also preferable that the portion of the cross section satisfying the equations (1) to (3), preferably the equations (1) to (4) is present in a part of the total length in the longitudinal direction. More preferably, the portion of the cross section satisfying the equations (1) to (3), preferably the equations (1) to (4) is present in 50% or more of the total length in the longitudinal direction, and 80% or more. Is more preferable.
  • the structural member 1 according to the first embodiment has one maximum radius of curvature curved portion 11, but may have a plurality of maximum radius of curvature curved portions 11 as shown in FIGS. 2 to 6, for example. In that case, any one can be regarded as the maximum radius of curvature curved portion 11.
  • the structural member 1 according to the first embodiment has two small radius of curvature curved portions 15, but may have at least one small radius of curvature curved portion 15.
  • the structural member 1 according to the first embodiment has two flat surface portions connected to the maximum radius of curvature curved portion 11, but may have one flat surface portion connected to the maximum radius of curvature curved portion 11. That is, one end of the maximum radius of curvature curved portion 11 may be directly connected to the other curved portion or may be a free end. In that case, one plane portion connected to the maximum radius of curvature curved portion 11 is the reference plane portion 13.
  • a second embodiment of the present disclosure is a method of designing a structural member.
  • the design method according to the present embodiment is the design method for the structural member according to the first embodiment, and the structural member is designed so as to satisfy the equations (1) to (3).
  • the cost required for the design can be suppressed by changing the cross-sectional shape and material of the structural member and design changes such as adding a reinforcing member so as to satisfy the formulas (1) to (3). It becomes possible.
  • the length was 184.0 mm and the uniform cross section was formed from a steel plate having a plate thickness of 1.0 mm, a tensile strength of 1180 MPa, a yield stress of ⁇ y943 MPa, a Poisson's ratio of 0.3, and a Young's modulus of 206000 MPa. Numerical analysis was performed on the hollow member having the above, and the bending strength was evaluated.
  • the shape of the cross section perpendicular to the longitudinal direction of 1 has an outer shape (maximum outer dimension) b of 46.0 mm, and the radius of curvature of each of the four corners is 2.0 mm (that is, the maximum).
  • the maximum radius of curvature R1 was changed to 18.0 mm, and the radius of curvature R2 of the two corners on the tension side was changed to 8.5 mm, and numerical analysis was performed.
  • the maximum radius of curvature R1 was changed to 18.0 mm, and the radius of curvature R2 of the two corners on the tension side was changed to 9.5 mm, and numerical analysis was performed.
  • the length of the reference plane b f are different values, respectively.
  • Experiment No. 4 in which the radii of curvature of the four curved portions are equal. Based on the bending strength of No. 1, Experiment No. The case where the bending proof stress was larger than the bending proof stress of No. 1 was B, and the case where the bending proof stress was the largest was A. The case where the bending strength was smaller than the bending strength of 1 was evaluated as C, and A and B were used as acceptance criteria.
  • the bending strength was calculated by the following method. That is, a pure bending analysis for rotating the end of the member is performed to obtain a bending moment M-deflection angle ⁇ diagram, and the deflection angle ⁇ is 0 rad. ⁇ ⁇ 0.1 rad.
  • the maximum value of the bending moment M in the range of is defined as the bending proof stress.
  • the deflection angle ⁇ is the angle formed by the axis of the member before deformation and the axis of the deformed member at both ends in the longitudinal direction of the member.
  • a shell element was used as an element constituting the member, the element type was a perfect integration element, and five integration points were provided in the plate thickness direction.
  • the element size of the flat portion was 2.0 mm ⁇ 2.0 mm, and the element size of the curved portion was 2.0 mm ⁇ 0.7 mm.
  • the physical property type of the material constituting the member was a multi-linear approximate isotropic elasto-plastic body, and the equivalent stress-equivalent composition strain relationship obtained from the result of the tensile test of the 1180 MPa class steel sheet was defined. This yield stress was 943 MPa. In this analysis, the initial fraud was ignored.

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  • Mechanical Engineering (AREA)
  • Manufacturing & Machinery (AREA)
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  • Structural Engineering (AREA)
  • Body Structure For Vehicles (AREA)
PCT/JP2021/006055 2020-02-18 2021-02-18 車体構造部材及び車体構造部材の設計方法 Ceased WO2021166988A1 (ja)

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CN202180014846.9A CN115103795B (zh) 2020-02-18 2021-02-18 车身构造部件以及车身构造部件的设计方法
US17/798,908 US12358559B2 (en) 2020-02-18 2021-02-18 Vehicle body structural member and method for designing vehicle body structural member
EP21757748.5A EP4108546A4 (en) 2020-02-18 2021-02-18 Vehicle body structural member and method for designing vehicle body structural member
JP2022501957A JP7243913B2 (ja) 2020-02-18 2021-02-18 車体構造部材及び車体構造部材の設計方法

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EP4108546A4 (en) 2023-08-09
CN115103795B (zh) 2024-07-19
EP4108546A1 (en) 2022-12-28
US20230093164A1 (en) 2023-03-23
JP7243913B2 (ja) 2023-03-22

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