JP2014065411A - Panel component evaluation method, panel component evaluation device, and method of manufacturing automobile panel component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a panel component evaluation method that enables tensile rigidity on or near a character line to be easily evaluated in trial manufacture of a designed automobile panel component.SOLUTION: Tensile rigidity of an automobile panel component is predicted on the basis of the plate thickness of the automobile panel component, curvature radii R1 and R2 of convex and concave surfaces 4 and 5 configuring a character line, an aperture angle θ of the character line, and the product of logarithms of the curvature radii R1 and R2 of the curved surfaces 4 and 5.

Description

  The present invention relates to a panel component evaluation method and a panel component evaluation apparatus applied when manufacturing automotive panel components such as door panels, hood panels, and roof panels. The present invention also relates to a method for manufacturing automotive panel components such as door panels, hood panels, and roof panels.

  Generally, automotive panel components such as door panels are manufactured by press-molding a metal plate such as a steel plate. One of the characteristics required for such automotive panel parts is tension rigidity. For the purpose of increasing the rigidity rigidity and design, it has traditionally been possible to arrange creases called character lines on the panel parts. Has been done.

The improvement effect of the tension rigidity by arranging the character line is better. However, since there is no means to predict the tension stiffness when the character line is arranged, conventionally, the prototype panel component is prototyped, the stiffness of the prototype panel component is measured, and the measured value Is compared with the target value to judge the quality of the prototype. In this case, if the measured value of the tension stiffness is lower than the target value, it is necessary to start over from the design or arrange a reinforcing member on the back side of the panel part. There is a problem that it takes time. In addition, the method of securing reinforcement rigidity by arranging a reinforcing member on the back side of the automotive panel component has a problem of inhibiting the weight reduction of the automotive panel component.
By the way, Patent Literature 1 and Patent Literature 2 describe a technique for predicting rigidity from the shape of a panel component. Patent Document 3 describes a technique for predicting dent rigidity as a load resistance in a load direction of a plate member when a load is applied to a predetermined point of the plate member.

Japanese Patent No. 3786171 JP-A-7-33048 JP 2011-158270 A

However, the techniques described in Patent Document 1 and Patent Document 2 have a problem that it is difficult to predict the tension rigidity of a portion where the panel shape is rapidly changing, such as a character line.
Further, the technique described in Patent Document 3 has a problem in that the rigidity of the character line itself cannot be predicted because the position of the character line is used as a variable in order to predict the dent rigidity.

  The present invention has been made in view of the above-described problems, and can easily evaluate the tension rigidity on the character line or in the vicinity of the character line when the designed automotive panel component is prototyped. An object is to provide an evaluation method and a panel component evaluation apparatus. Another object of the present invention is to provide a method for manufacturing an automotive panel component capable of shortening the time required from designing the automotive panel component to mass production and reducing the cost. It is said.

  In order to achieve the above object, the invention of claim 1 is a panel component evaluation method for evaluating an automotive panel component having a character line composed of a convex curved surface and a concave curved surface. The tension rigidity of the automotive panel part is predicted based on a plate thickness, a radius of curvature of the convex curved surface and the concave curved surface, and an opening angle of the character line.

The invention of claim 2 is characterized in that the tension rigidity of the automotive panel part is predicted from the following equation.
P ′ = P ₀ ′ × (t ² / g) × (h × Rt + i)
However,
P ': Tension rigidity (N / mm)
P ₀ ′: P ₀ ′ = (a × α + b) × (180−θ) ² + (c × β + d) × (180−θ) + (e × γ + f),
α: α = ln (R1) × ln (R2),
β: β = (ln (R2)) ² / ln (R1),
γ: γ = (ln (R1)) ² / ln (R2),
θ: Character line opening angle (°),
R1, R2: curvature radius (mm) of the convex curved surface and the concave curved surface constituting the character line of the automotive panel part,
t: Thickness (mm) of automotive panel parts,
Rt: radius of curvature of the vertex of the character line (mm),
ai: Constants.

The invention of claim 3 is a panel component evaluation apparatus for evaluating an automotive panel component having a character line composed of a convex curved surface and a concave curved surface, wherein a logarithm product of the curvature radii of the convex curved surface and the concave curved surface is obtained. A logarithmic product computing unit for computing, the logarithmic product calculated by the logarithmic product computing unit, the thickness of the panel member for the automobile, the opening angle of the character line, and the radius of curvature of the apex of the character line And a tension rigidity calculating section for calculating the tension rigidity of the panel component.
The invention according to claim 4 compares the predicted value of the tension stiffness predicted by the method according to claim 2 with a target value, and after the predicted value of the tension stiffness reaches the target value or more, It is characterized by making a prototype.

According to the first to third aspects of the present invention, it is possible to easily evaluate the tension rigidity on the character line or in the vicinity of the character line when the designed automotive panel part is prototyped.
According to invention of Claim 4, it is not necessary to repeat trial manufacture of the panel component for motor vehicles until the tension rigidity of the panel component for motor vehicles reaches a target value. Therefore, it is possible to shorten the period required from the design of the automotive panel part to the mass production and to reduce the cost.

It is a figure which shows an example of the panel component for motor vehicles. It is a figure which shows the finite element analysis model of the panel component for motor vehicles shown in FIG. It is a figure which shows the AA 'cross section of FIG. It is a figure which shows a load-displacement curve when a cylindrical indenter is pressed on the character line of the panel member for motor vehicles. It is a figure which shows schematic structure of the panel component evaluation apparatus which concerns on one Embodiment of this invention. It is a figure which shows one Embodiment of the manufacturing method of the panel component for motor vehicles based on this invention. It is a figure for demonstrating the period required from the completion of the design of the panel component for motor vehicles at the time of applying a conventional method to mass production. It is a figure for demonstrating the period required from the completion | finish of design of the panel component for motor vehicles at the time of applying this invention to mass production. It is a perspective view which shows an example of the door panel for motor vehicles. It is a top view of the door panel for motor vehicles shown in FIG. It is a figure which shows an example of the method of measuring the tension rigidity of the door panel shown in FIG. It is a figure which shows an example of the reinforcement member arrange | positioned at the back surface side of a door panel. It is a figure which shows the arrangement position of the reinforcement member shown in FIG. It is a top view which shows an example of the character line of the door panel shown in FIG. It is a figure for demonstrating the curvature radius of a convex curved surface and a concave curved surface in case the character line of the panel component for motor vehicles is comprised from a convex curved surface and a concave curved surface.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram illustrating an example of an automobile door panel. An automotive panel component 1 shown in FIG. 1 has a character line 2 and a handle emboss 3. The character line 2 is composed of a convex curved surface 4 and a concave curved surface 5.
Here, as a combination of the two curved surfaces constituting the character line 2, there are three types of convex curved surface and convex curved surface, convex curved surface and concave curved surface, concave curved surface and concave curved surface, but in one embodiment of the present invention, As shown in FIG. 1, the character line 2 is made up of a convex curved surface 4 and a concave curved surface 5.

2 is a diagram showing a finite element analysis model of the automotive panel component shown in FIG. 1, FIG. 3 is a diagram showing a cross section taken along the line AA ′ of FIG. 2, and FIG. 4 is a diagram when pressing a cylindrical indenter on the character line FIG. 2 is a diagram showing a load-displacement curve, and the present inventors made a finite element analysis model shown in FIG. 2 in order to investigate the correlation between the shape dimension of the automotive panel part and the tension rigidity.
Specifically, the curvature radius R1 of the convex curved surface 4 and the curvature radius R2 of the concave curved surface 5 shown in FIG. 3 are 500 mm to 3000 mm, the opening angle θ of the character line 2 shown in FIG. 3 is 165 ° to 175 °, and FIG. A finite element analysis model in which the curvature radius Rt of the vertex of the character line shown is 5 mm to 60 mm, the thickness t of the automotive panel part is varied in the range of 0.55 mm to 0.8 mm, and the projected area of the entire model is 1100 mm × 800 mm Was made.

The opening angle of the character line referred to here is an angle formed by two tangents 6a and 6b at the boundary between the radius of curvature of the vertex of the character line and the curved surfaces 4 and 5. Further, the curvature radius of the character line apex portion is the curvature radius of the curved surface portion between the convex curved surface 4 and the concave curved surface 5.
For example, when the convex curved surface 4 has a uniform convex shape within a range of 150 mm perpendicular to the character line and the concave curved surface 5 has a uniform concave shape within a range of 150 mm perpendicular to the character line, for example, FIG. As shown in Figure 3, the vertex of the character line (points A and a), the point 150 mm vertically away from the character line (points C and c), and the point 75 points vertically away from the character line (points B and b) Can be defined as the radius of curvature of the convex curved surface 4 and the concave curved surface 5. Here, the reason why the positions of points C and c are 150 mm vertically away from the character line is that even if the curvature changes at a position 150 mm or more away from the character line, it does not affect the rigidity of the character line. It is.

  The finite element analysis model shown in FIG. 2 was produced by using HyperMesh from Altair. The mesh size of the analysis model was 0.5 mm near the character line, 5 mm at the panel edge, and a size that smoothly connected the mesh in the middle. Moreover, the element was made into the translational constraint on the four sides of the analysis model using the shell element.

Next, the inventors produce an analytical model that imitates a cylindrical indenter having a diameter of 45 mm, and press this model on the character line of the model shown in FIG. 2 to thereby obtain a load-displacement curve shown in FIG. It was created. As a result of analyzing the inclination of the load-displacement curve when the automotive panel component is displaced from 0.0 mm to 0.5 mm as the tensile stiffness, the tensile stiffness P ′ (N / mm) of the automotive panel component is expressed by the following equation: The knowledge that it can be predicted from. In addition, LS-DYNA ver971d R3.2.1 was used for the analysis, and the static implicit method was used.
P ′ = P ₀ ′ × (t ² / g) × (h × Rt + i) (1)
However,
P ₀ ′: P ₀ ′ = (a × α + b) × (180−θ) ² + (c × β + d) × (180−θ) + (e × γ + f),
α: α = ln (R1) × ln (R2),
β: β = (ln (R2)) ² / ln (R1),
γ: γ = (ln (R1)) ² / ln (R2),
θ: Character line opening angle (°),
R1, R2: curvature radius (mm) of the convex curved surface and the concave curved surface constituting the character line of the automotive panel part,
t: Thickness (mm) of automotive panel parts,
Rt: radius of curvature of the vertex of the character line (mm),
ai: Constants.

The constants a to i in Equation (1) vary depending on the shape of the indenter used for the test, but are obtained by testing and analysis.
FIG. 5 is a diagram showing a schematic configuration of a panel component evaluation apparatus according to an embodiment of the present invention. The panel component evaluation apparatus 51 shown in FIG. 5 includes a plate thickness t, a convex curved surface 4 and a concave curved surface of an automotive panel component. 5 is the logarithm product (ln () of the curvature radii R1 and R2 input to the input section 52 and the input section 52 for inputting the radius of curvature R1 and R2, the opening angle θ of the character line and the curvature radius Rt of the character line vertex. R1) × ln (R2)), a logarithmic product calculation unit 53, and a tension stiffness calculation for calculating the stiffness of an automotive panel part from the formula (1) based on the logarithmic product calculated by the logarithmic product calculation unit 53 Part 54.

The panel component evaluation apparatus 51 includes a comparison unit 55 that compares the tension stiffness calculated by the tension stiffness calculation unit 54 with a target value, and an output unit 56 that outputs a comparison result of the comparison unit 55.
FIG. 6 is a diagram showing an embodiment of a method for manufacturing an automotive panel component according to the present invention. Automotive panel parts such as door panels are manufactured through design, design, and prototyping. In an embodiment of the present invention, as shown in FIG. If it is performed in S2, the process proceeds to Step S3, and the tension rigidity P ′ of the automotive panel part is predicted from the equation (1).

In this case, the panel component evaluation apparatus shown in FIG. 5 shows the plate thickness t of the automotive panel component, the curvature radii R1, R2 of the convex curved surface 4 and the concave curved surface 5, the curvature radius Rt of the character line apex, and the opening angle θ of the character line. When input to the input unit 52 of 51, the tension stiffness P ′ is calculated by the tension stiffness calculation unit 54 of the panel component evaluation apparatus 51.
If the tension stiffness P ′ is predicted in step S3, the process proceeds to step S4, and the predicted value of the tension stiffness P ′ is compared with the target value. Here, if the predicted value of the tension stiffness P ′ is smaller than the target value, the process returns to step S2, and the automotive panel component is designed again so that the tension stiffness P ′ is equal to or greater than the target value. On the other hand, if the predicted value of the tension stiffness P ′ is equal to or greater than the target value, the process proceeds to step S5, and a prototype of the automotive panel component is produced.

  In order to accurately predict the tension stiffness P ′, the radii of curvature R1 and R2 of the convex curved surface 4 and the concave curved surface 5 are preferably 500 mm or more and 3000 mm or less, and the opening angle θ of the character line 2 is 165 ° or more. It is desirable that it is 175 degrees or less. The curvature radius Rt of the character line apex is preferably 5 mm or more and 100 mm or less, and the plate thickness t is preferably 0.5 mm or more and 1.2 mm or less.

  As described above, by predicting the tension stiffness P ′ of the automotive panel part from the formula (1) before making the prototype of the automotive panel part, Alternatively, it is possible to easily evaluate the tension stiffness in the vicinity of the character line, and it is not necessary to repeat trial manufacture of the automotive panel component until the tension stiffness of the automotive panel component reaches a target value.

  Therefore, compare the predicted stiffness stiffness value with the target value, and prototype the automotive panel component after the predicted stiffness stiffness reaches the target value. Thus, it is possible to obtain an automotive panel component having high tension rigidity without requiring many periods and costs. When manufacturing automotive panel parts, conventionally, as shown in FIG. 7, after design, proceed to design and trial production, determine the stiffness stiffness through trial production, if there is not enough characteristics, return to design and design, Correction is required. At this time, since a mold correction or the like is required, a loop of “redesigning → mold correction → prototype” generally requires a period of two months or more. Furthermore, even if this loop is turned, the tension stiffness is not known until the trial production is performed again. Therefore, it is necessary to continue the loop of “Redesign → Mold correction → Trial production” until the tension stiffness reaches the expected value. . If the loop is rotated three times, the period required from the end of design to mass production is about 24 months.

  On the other hand, by applying one embodiment of the present invention, as shown in FIG. 8, it is possible to estimate the tension rigidity at the stage where the panel shape is determined, that is, at the stage of design and design. In this way, from the loop of “Redo design → Die correction → Prototype”, which was necessary when the tension stiffness did not meet the expected value, the mold correction and prototyping process, which required time and effort, was required. Omitting and only “redesigning” is required.

Therefore, when the present invention is applied, if the loop is rotated three times, the period required from the end of the design to the mass production is about 19 months from the end of the design to the mass production. It becomes possible to shorten the period by 21% compared with the case where it passes. Accordingly, it is possible to reduce the man-hours for mold correction and the like.
Moreover, since it is not necessary to arrange a reinforcing member on the back side of the automotive panel component to ensure the rigidity of the tension, it is possible to reduce the weight of the automotive panel component.

Example 1
In addition, it is possible to reduce the weight of the panel component by effectively arranging the character line on the panel component using the embodiment of the present invention.
As an example of an automotive panel part, a door panel having a thickness of 0.7 mm is shown in FIGS. As a material of the door panel, a steel plate having a tensile strength of 340 MPa (elastic modulus: 210 GPa, yield strength: 235 MPa, tensile strength: 345 MPa, total elongation: 40%) was used. The tension stiffness of the door panel 7 shown in FIGS. 9 and 10 was measured by the method shown in FIG. That is, a cylindrical rubber indenter 8 having a diameter of 45 mm was pressed against point A on the door panel 7 (see FIG. 10), and the displacement at point A at this time was measured with a displacement meter 9. The tension stiffness when the displacement at point A was 0.5 mm was measured with the load cell 10. As a result, the measured value of the tension rigidity of the door panel 7 (plate thickness 0.7 mm) was 40 N / mm.

  Considering the weight reduction of the panel parts by setting the plate thickness to 0.60 mm while maintaining the tension rigidity. In order to reduce the plate thickness, the tension stiffness of the panel parts is reduced. If no countermeasure is taken, the tension stiffness at point A is 30 N / mm, which does not meet the target. Therefore, measures are essential. Possible measures include a method of arranging a reinforcing member behind the point A (conventional method) and a method of arranging a character line using the present invention (invention method).

When arranging the reinforcing member, for example, the reinforcing member 11 having the dimensions shown in FIG. 12 (soft steel plate; elastic modulus: 210 GPa, yield strength: 170 MPa, tensile strength: 290 MPa, total elongation: 48%) is placed at the position shown in FIG. When arranged, the tension stiffness was 60 N / mm. This has achieved the goal, but the tension stiffness is unnecessarily increased. Further, the weight is increased by inserting the reinforcing member 11, and the weight reduction effect due to the reduction of the thickness of the door panel is reduced.
Although it is possible to reduce the size of the reinforcing member 11 and to aim for appropriate tension rigidity, trial and error is required, and a long time is required. Further, even if the size can be reduced, the fact that the reinforcing member 11 must be inserted is not changed, and the lightening effect by reducing the plate thickness cannot be maximized.

  On the other hand, when one embodiment of the present invention is applied, it is not necessary to arrange a reinforcing member on the back side of the door panel. The curvature radius of the door panel shown in FIG. 10 in the arrow direction was 1500 mm. The curvature radii R1 and R2 of the convex curved surface 4 and the concave curved surface 5 constituting the character line are R1 = 1500 mm, R2 = 1000 mm, the plate thickness t is 0.60 mm, the target tension stiffness P ′ is 40 N / mm, Table 1 By substituting the values shown in (1) as the values of constants a to i, a relational expression between the opening angle θ of the character line and the radius of curvature Rt of the character line apex can be obtained.

When the radius of curvature Rt of the character line apex is 10 mm, the tension angle at point A can be made higher than the target without adding a reinforcing member by setting the opening angle θ of the character line to 175 ° or less. It became.
Table 2 shows the results when the opening angle θ of the character line is 175 ° and the character line 2 is arranged at the position shown in FIG.

  By using one embodiment of the present invention, it can be seen that the weight can be efficiently reduced without impairing the tension rigidity.

DESCRIPTION OF SYMBOLS 1 ... Automotive panel component 2 ... Character line 3 ... Embossing for a handle 4 ... Convex curved surface 5 ... Concave curved surface 6a, 6b ... Tangent 7 ... Door panel 8 ... Rubber indenter 9 ... Displacement meter 10 ... Load cell 51 ... Panel component evaluation apparatus 52 ... Input unit 53 ... Logarithmic product calculation unit 54 ... Tension stiffness calculation unit 55 ... Comparison unit 56 ... Output unit

Claims (4)

  A panel component evaluation method for evaluating an automotive panel component having a character line composed of a convex curved surface and a concave curved surface, the plate thickness of the automotive panel component, the curvature radius of the convex curved surface and the concave curved surface, A panel component evaluation method for predicting a tension rigidity of the automotive panel component based on an opening angle of the character line. The panel component evaluation method according to claim 1, wherein the tension rigidity of the automotive panel component is predicted from the following equation.
P ′ = P ₀ ′ × (t ² / g) × (h × Rt + i)
However,
P ': Tension rigidity (N / mm)
P ₀ ′: P ₀ ′ = (a × α + b) × (180−θ) ² + (c × β + d) × (180−θ) + (e × γ + f),
α: α = ln (R1) × ln (R2),
β: β = (ln (R2)) ² / ln (R1),
γ: γ = (ln (R1)) ² / ln (R2),
θ: Character line opening angle (°),
R1, R2: curvature radius (mm) of the convex curved surface and the concave curved surface constituting the character line of the automotive panel part,
t: Thickness (mm) of automotive panel parts,
Rt: radius of curvature of the vertex of the character line (mm),
ai: Constants.   A panel component evaluation apparatus for evaluating an automotive panel component having a character line composed of a convex curved surface and a concave curved surface, and a logarithmic product computing unit for computing a logarithmic product of the radius of curvature of the convex curved surface and the concave curved surface. The rigidity of the automotive panel component is determined based on the logarithmic product calculated by the logarithmic product calculation unit, the plate thickness of the automotive panel component, the opening angle of the character line, and the curvature radius of the apex portion of the character line. A panel component evaluation apparatus comprising: a tension rigidity calculation unit for calculating.   A predicted value of tension stiffness predicted by the method according to claim 2 is compared with a target value, and the automotive panel part is prototyped after the predicted value of tension stiffness reaches a target value or more. Manufacturing method for automotive panel parts.

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