JP2007033067A - Method of estimating dent rigidity - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To appropriately acquire dent rigidity from information in a design drawing as to a dent rigidity estimation method for calculating displacement of a plate member at a measurement point in a loading direction when imposing a load on the plate member made of metal at its measurement point. <P>SOLUTION: The area of a stress effect domain, which is defined around the measurement point P1 when a load is imposed on the measurement point P1, is calculated as a flexure area B1. Displacement of the plate member at the measurement point P1 in the loading direction is calculated from the curvature of the plate member at the measurement point P1, the plate thickness of the plate member at the measurement point P1, the material quality of the plate member P1, and the flexure area B1, based on a prescribed relational expression. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is, for example, a metal plate member such as an outer plate of a vehicle such as a passenger car, an outer plate of a household appliance, a metal door outer plate or a panel, and when a load is applied to a measurement point of the plate member, The present invention relates to a method for calculating a displacement of a plate member in a load direction of a measurement point.

For example, in a vehicle such as a passenger car, in a metal outer plate (plate member) such as a door or an engine hood, the outer plate in the load direction of the measurement point when a load is applied to the measurement point of the outer plate (plate member) ( The displacement of the plate member may be obtained as dent rigidity.
So far, in the latter half of vehicle development, for example, when the prototype vehicle is completed, a load is actually applied to the measurement point of the outer plate (plate member) of the prototype vehicle, and the outer plate (plate in the load direction of the measurement point) The dent stiffness was obtained by actually measuring the displacement of the member.

As described above, in the latter half of the vehicle development (for example, when the prototype vehicle is completed), it is often inconvenient to obtain the dent stiffness (when the prototype vehicle is completed, there is a part where the dent stiffness is not sufficient). When it is discovered, it takes time to change the design later, and in recent years, there is a desire to be able to determine the dent rigidity in the first half of vehicle development (for example, when the design drawing is completed). is there.
As a result, in the first half of vehicle development (for example, when the design drawing is completed), as a method for predicting dent stiffness, a method for predicting dent stiffness from information on the design drawing is considered. There has been proposed a method for calculating a displacement in the load direction of a measurement point by obtaining a predetermined relational expression based on the curvature, the thickness of the measurement point of the plate member, and the material of the plate member (see, for example, Patent Document 1).

JP 2000-249636 A

Here, as described in the above-mentioned [Background Art], the applicant of the present invention uses the curvature of the measurement point of the plate member, the plate thickness of the measurement point of the plate member, and the material of the plate member as the factors representing the rigidity of the plate member. As a result of trying to obtain a predetermined relational expression by multiple regression analysis etc., the dent stiffness obtained by actually applying a load to the measurement point of the plate member tends to be different from the obtained predetermined relational expression was gotten.
As a result, in the method of predicting dent rigidity from information in the design drawing, the factor representing the rigidity of the plate member is insufficient with only the curvature of the measurement point of the plate member, the plate thickness of the measurement point of the plate member, and the material of the plate member. It is possible that
An object of the present invention is to appropriately obtain the dent rigidity when the dent rigidity is predicted from the information of the design drawing as a dent rigidity prediction method.

[I]
(Constitution)
The first feature of the present invention resides in the following configuration in the dent stiffness prediction method.
The area of the stress-affected region defined around the measurement point when a load is applied to the measurement point is calculated as a twill area. The displacement in the load direction of the measurement point is calculated based on a predetermined relational expression based on the curvature of the measurement point of the plate member, the plate thickness of the measurement point of the plate member, the material of the plate member, and the deflection area.

(Function)
For example, in the case of a metal outer plate (plate member) such as a door of a vehicle such as a passenger car or an engine hood, when the load is actually applied to the measurement point of the plate member, the displacement in the load direction of the measurement point is small, but the measurement There is a part where a relatively wide area around the point is displaced in the load direction, or the displacement of the measurement point in the load direction is large, but a relatively narrow area around the measurement point is displaced in the load direction. The applicant of the present invention has found that there is a difference in the deformation state of the plate member around the measurement point depending on the portion of the plate member. The applicant of the present invention also confirmed that there is a difference in such deformation state by CAE analysis.
Thereby, the applicant of the present invention expected that the deformation state of the plate member around the measurement point would be effective as a factor representing the rigidity of the plate member.

  As described above, when a load is actually applied to the measurement point of the plate member, the displacement of the measurement point in the load direction is small, but there is a portion where a relatively wide area around the measurement point is displaced in the load direction. Or the displacement of the measurement point in the load direction is large, but there is a portion in which a relatively narrow area around the measurement point is displaced in the load direction. The deformation state of the plate member corresponds to the area that is displaced around the measurement point when a load is applied to the measurement point, and the stress effect defined around the measurement point when the load is applied to the measurement point I found that it was the area of the region.

Therefore, as in the first feature of the present invention, the applicant of the present invention calculates the area of the stress-affected region defined around the measurement point when a load is applied to the measurement point as a trumpet area. Using the curvature of the plate member measurement point, the plate thickness of the plate member measurement point, the material of the plate member, and the deflection area as factors representing the rigidity of the plate member, a predetermined relational expression was obtained by multiple regression analysis or the like (Dent Rigidity prediction method). Then, when the dent rigidity obtained by actually applying a load to the measurement point of the plate member was compared with the obtained predetermined relational expression, a result in which both were sufficiently matched was obtained.
Thus, according to the first feature of the present invention, based on the predetermined relational expression, the curvature of the measurement point of the plate member, the plate thickness of the measurement point of the plate member, the material of the plate member, and the deflection area are extracted from the design drawing. Thus, the displacement (dent rigidity) of the measurement point in the load direction can be appropriately calculated at the stage of the design drawing.

(The invention's effect)
According to the first feature of the present invention, in addition to the curvature of the measurement point of the plate member, the thickness of the measurement point of the plate member, and the material of the plate member, it is defined around the measurement point when a load is applied to the measurement point. By adding the area of the stress-affected area as a wrinkle area, a dent stiffness prediction method that can appropriately determine the dent stiffness from the information of the design drawing was obtained.
As a result, the dent stiffness can be appropriately determined in the first half of development, and the dent stiffness can be appropriately evaluated, thereby preventing the development delay due to the delay in the evaluation of the dent stiffness. become able to.

[II]
(Constitution)
The second feature of the present invention resides in the following configuration in the dent stiffness prediction method of the first feature of the present invention.
The stress-affected area is defined based on the singular point of the degree of change in stress.

(Function)
According to the second feature of the present invention, the “action” described in the preceding item [I] is provided in the same manner as the first feature of the present invention, and in addition to this, the following “action” is provided.
According to the second feature of the present invention, the wrinkle area is defined by a singular point of the degree of change in stress (for example, a point where the degree of change in stress suddenly changes).
Thus, according to the second feature of the present invention, when a stress-affected region spreads from the measurement point to the periphery when a load is applied to the measurement point, a singular point of the degree of change in stress (exists around the measurement point) In this case, it is considered that the stress propagation is interrupted and the stress-affected region ends, and therefore, the wrinkle area (stress-affected region) can be clearly defined based on the singular point of the degree of change in stress.

(The invention's effect)
According to the second feature of the present invention, the “effect of the invention” described in the preceding item [I] is provided in the same manner as the first feature of the present invention. In addition, the following “effect of the invention” is provided. ing.
According to the second feature of the present invention, it is possible to clearly define a wrinkle area (stress-affected region) based on a singular point of the degree of change in stress, and to appropriately determine the dent rigidity from the information of the design drawing. As a result, the calculation accuracy of the dent stiffness prediction method was improved.

[III]
(Constitution)
The third feature of the present invention resides in the following configuration in the dent stiffness prediction method of the second feature of the present invention.
One of the portion of the plate member around the measurement point having a curvature different from the curvature of the measurement point of the plate member, and the joint point between the support member provided on the back surface side of the plate member and the back surface of the plate member or Both are included as singular points of the degree of change in stress.

(Function)
According to the third feature of the present invention, as in the second feature of the present invention, the “action” described in the preceding paragraphs [I] and [II] is provided. In addition, the following “action” is provided. Yes.
According to the third feature of the present invention, the portion of the plate member around the measurement point has a curvature portion different from the curvature of the measurement point of the plate member, and the support member provided on the back side of the plate member and the back surface of the plate member The joint point becomes a singular point of the degree of change in stress, and these are described as clear information on the design drawing and are easy to grasp clearly from the design drawing. can do.

(The invention's effect)
According to the third feature of the present invention, the “effect of the invention” described in the preceding paragraphs [I] and [II] is provided in the same manner as the second feature of the present invention. In addition, the following “effect of the invention” is provided. Is provided.
According to the third feature of the present invention, the portion of the plate member around the measurement point has a curvature portion different from the curvature of the measurement point of the plate member, and the support member provided on the back side of the plate member and the back surface of the plate member This makes it possible to accurately calculate the deflection area, and to properly determine the dent stiffness from the design drawing information, thereby improving the calculation accuracy of the dent stiffness prediction method. did it.

[IV]
(Constitution)
A fourth feature of the present invention resides in the following configuration in the dent stiffness prediction method of the second or third feature of the present invention.
When a predetermined distance is set outward along the plate member from the measurement point, and the singular point of the stress change degree is more than the predetermined distance from the measurement point, the position of the predetermined distance is changed to the singular point of the stress change degree. Let it be a point.

(Function)
According to the fourth feature of the present invention, the “action” described in the preceding paragraph [I] [II] [III] is provided in the same manner as the second or third feature of the present invention. It has “action”.
For example, if the singular point of the degree of change in stress as described in the previous section [II] [III] is far away from the measurement point, the wrinkle area may be calculated as a very large value. It can be considered that the dent stiffness cannot be calculated properly due to the wrinkle area.
According to the fourth feature of the present invention, if the singular point of the degree of change in stress is more than a predetermined distance from the measurement point, the position of the predetermined distance is set as the singular point of the degree of change in stress. There is no such thing as a larger value.

(The invention's effect)
According to the fourth feature of the present invention, the “effect of the invention” described in the preceding item [I] [II] [III] is provided as in the second or third feature of the present invention. The “effect of the invention” is provided.
According to the fourth feature of the present invention, it is possible to avoid a situation in which the dent stiffness is not calculated as an unnecessarily large value, and the dent stiffness cannot be appropriately calculated. The calculation accuracy of the method could be improved.

[V]
(Constitution)
A fifth feature of the present invention resides in the following configuration in any one of the dent stiffness prediction methods of the second to fourth features of the present invention.
Three or more singular points of the degree of change in stress are set, and the area of the polygonal plate member having the singular point of the degree of change in stress as a vertex is calculated as a wrinkle area.

(Function)
According to the fifth aspect of the present invention, in addition to any one of the second to fourth aspects of the present invention, the “action” described in the preceding paragraphs [I] to [IV] is provided. It has the following “actions”.
As described in the previous section [II], when defining the deflection area by a singular point of the degree of change in stress and calculating the deflection area, for example, the shape of the deflection area is formed by a combination of a plurality of curves. , Tawami area calculation may be difficult.

  According to the fifth feature of the present invention, since the area of the polygonal plate member having the singular point of the degree of change in stress as the apex is calculated as the wrinkle area, the shape of the wrinkle area is formed by a combination of a plurality of straight lines. Can be easily calculated (for example, by dividing the wrinkle area into a plurality of triangles and quadrilaterals, and calculating and summing the areas of the divided triangles and quadrilaterals, it is easy to calculate the wrinkle area. be able to).

(The invention's effect)
According to the fifth feature of the present invention, the “effect of the invention” described in the preceding paragraphs [I] to [IV] is provided as in any one of the second to fourth features of the present invention. In addition, the following “effects of the invention” are provided.
According to the fifth feature of the present invention, it is possible to easily calculate the area of wrinkles, and to appropriately determine the dent stiffness from the information of the design drawing, thereby improving the calculation accuracy of the dent stiffness prediction method. I was able to increase it.

[VI]
(Constitution)
A sixth feature of the present invention resides in the following configuration in the dent stiffness prediction method of the first feature of the present invention.
When the support member provided on the back surface side of the plate member and the back surface of the plate member are joined so as to surround the measurement point, the area of the plate member region joined so as to surround the measurement point To do.

(Function)
According to the sixth feature of the present invention, the “action” described in the preceding item [I] is provided similarly to the first feature of the present invention, and in addition to this, the following “action” is provided.
When the support member is provided on the back surface side of the plate member and the support member and the back surface of the plate member are bonded, the plate member may be bonded so as to surround the measurement point. In such a state, when a stress is applied to the measurement point and the stress-affected region spreads from the measurement point to the surrounding area, stress propagation occurs at the boundary between the joined portion and the outer unjoined portion. Since it is considered that the stress-affected region is terminated, the area of the plate member region joined so as to surround the measurement point can be clearly defined as a wrinkle area (stress-affected region).

(The invention's effect)
According to the sixth feature of the present invention, the “effect of the invention” described in the preceding item [I] is provided in the same manner as the first feature of the present invention. In addition, the following “effect of the invention” is provided. ing.
According to the sixth aspect of the present invention, it becomes possible to clearly define the deflection area (stress-affected area) by the area of the area of the plate member joined so as to surround the measurement point. Rigidity can be calculated appropriately, and the calculation accuracy of the dent stiffness prediction method has been improved.

  As shown in FIGS. 1 and 2, in the door 1 of a passenger car which is an example of a vehicle, when the door 1 is opened, the index finger to the little finger are placed below the door grip 2, and the outer plate 3 of the door 1 is placed. The door grip 2 may be pulled and operated to release a door lock mechanism (not shown) while the door grip 2 is pushed slightly upward with a thumb, and then the door 1 is opened.

  As described above, when the door 1 is opened, the outer plate of the door 1 is pressed in a state where the upper part of the door grip 2 of the outer plate 3 (corresponding to a metal plate member) of the door 1 is pushed with the thumb. (Dent stiffness prediction method) (longitudinal curvature RT1 and transverse curvature RY1, plate thickness T1, ultimate YP value Y1) The relational expression D1) regarding the displacement H1 of the outer plate 3 of the door 1 in the load direction of the deflection area B1 and the measurement point P1 will be described as follows.

[1] Longitudinal curvature RT1 and transverse curvature RY1
As shown in FIGS. 1 and 2, a measurement point P1 is set at a portion slightly above the door grip 2 in the outer plate 3 of the door 1, and a longitudinal curvature RT1 (see FIG. 2) at the measurement point P1 of the outer plate 3 of the door 1 is set. 1) (curvature in the vertical direction of the paper surface) and lateral curvature RY1 (curvature in the horizontal direction of the paper surface in FIG. 1) are obtained from the information on the design drawing. In this case, as shown in FIG. 4, when a load (load) is applied to a measurement point of a predetermined plate member (predetermined material and plate thickness), the curvature at the measurement point increases (as the curvature radius increases). The correlation that the dent rigidity is increased (the displacement of the plate member in the load direction at the measurement point is reduced) is required in advance.

[2] Thickness T1
As shown in FIGS. 1 and 2, the plate thickness T1 at the measurement point P1 of the outer plate 3 of the door 1 is obtained from the information on the design drawing. In this case, as shown in FIG. 5, when a load (load) is applied to a measurement point of a predetermined plate member (predetermined material and curvature), the dent rigidity increases as the plate thickness at the measurement point increases ( The correlation that the displacement of the plate member in the load direction of the measurement point is reduced) is obtained in advance.

[3] Ultimate YP value Y1 (corresponding to the material of the outer plate 3 of the door 1)
As shown in FIG.1 and FIG.2, the material used for the outer plate | board 3 of the door 1 is calculated | required from the information of a design drawing. In the material used for the outer plate 3 of the door 1, as shown in FIG. 6, a stress / strain graph (load / stress graph) is required, and the upper yield of the material used for the outer plate 3 of the door 1 is obtained. The point is obtained as the reached YP value Y1 at the measurement point P1 of the outer plate 3 of the door 1, and the upper yield point (by the various treatments such as the heat treatment applied to the material used for the outer plate 3 of the door 1) The reached YP value Y1) changes from high to low. In this case, as shown in FIG. 7, when a load (load) is applied to a measurement point of a predetermined plate member (predetermined curvature and plate thickness), the displacement of the measurement point in the load direction is obtained in advance. The correlation that the dent rigidity becomes higher (the displacement of the plate member in the load direction at the measurement point becomes smaller) as the arrival YP values T11, Y12, Y13 are larger is obtained in advance.

[4] Wrinkle area B1
As shown in FIGS. 1 and 3, when the measurement point P <b> 1 is set at a portion slightly above the door grip 2 in the outer plate 3 of the door 1, the door grip is positioned below the measurement point P <b> 1 of the outer plate 3 of the door 1. 2 is provided (a separate member from the outer plate 3 of the door 1), and the press line 5 of the outer plate 3 of the door 1 is present above the measurement point P1 of the outer plate 3 of the door 1. is doing. On the back side of the outer plate 3 of the door 1, support as a reinforcement of the door 1 is provided behind (to the left of the drawing in FIG. 1) and forward (to the right of the drawing in FIG. 1) the measurement point P <b> 1 of the outer plate 3 of the door 1. The members 7 and 8 are provided, and the support members 7 and 8 and the back surface of the outer plate 3 of the door 1 are joined by the mastic agents 9 and 10.

  In this case, as shown in FIGS. 1 and 3, the longitudinal curvature of the boundary portion 6 between the door grip unit 4 and the outer plate 3 of the door 1 and the vertical curvature of the press line 5 are measured by the outer plate 3 of the door 1. Since this is different from the longitudinal curvature RT1 at the point P1, the boundary portion 6 between the door grip unit 4 and the outer plate 3 of the door 1 and the press line 5 are set as singular points of the degree of change in stress (the outer plate of the door 1). When the longitudinal curvature RT1 (curvature radius) at 3 measurement points P1 is equal to or less than ½ of the lateral curvature RY1 (curvature radius), it is set as a singular point of the degree of change in stress). Thereby, in the boundary portion 6 between the door grip unit 4 and the outer plate 3 of the door 1, a portion located below the measurement point P1 of the outer plate 3 of the door 1 is set as a singular point A1, and in the press line 5, A portion located above the measurement point P1 of the outer plate 3 of the door 1 is set as a singular point A2.

As shown in FIGS. 1 and 3, the joint point (mastic agent 9) between the support member 7 and the back surface of the outer plate 3 of the door 1 is set as a singular point of the degree of change in stress. At a joint point (mastic agent 9) with the back surface of the outer plate 3 of the door 1, a portion closest to the measurement point P1 of the outer plate 3 of the door 1 is set as a singular point A3. The joint point (mastic agent 10) between the support member 8 and the back surface of the outer plate 3 of the door 1 is set as a singular point of the degree of change in stress. At the joint point (mastic agent 10), a portion closest to the measurement point P1 of the outer plate 3 of the door 1 is set as a singular point A4.
In this case, at the junction point (mastic agent 9, 10) between the support members 7, 8 and the back surface of the outer plate 3 of the door 1, the center of the junction point (center of the application range of the mastic agent 9, 10) is the singular point A3. , A4, or the portion farthest from the measurement point P1 of the outer plate 3 of the door 1 can be set as the singular points A3, A4.

  As shown in FIG. 3, when four singular points A1 to A4 are set, the distance between the measurement point P1 of the outer plate 3 of the door 1 and the singular point A1 exceeds a predetermined distance (for example, 50 mm). The position of a predetermined distance from the measurement point P1 of the outer plate 3 of the door 1 toward the singular point A1 is set as the singular point A1. Similarly, if the distance between the measurement point P1 of the outer plate 3 of the door 1 and the singular points A2, A3, A4 exceeds a predetermined distance (for example, 50 mm), the singular point A2 from the measurement point P1 of the outer plate 3 of the door 1 will be described. , A3, A4, the positions at a predetermined distance are set as singular points A2, A3, A4.

  As shown in FIG. 3, the singular points A2 and A3, the singular points A2 and A4, the singular points A1 and A3, and the singular points A1 and A4 are connected by a straight line, and the rectangular door has four singular points A1 to A4 as vertices. 1 area of the outer plate 3 is set. A triangular area BB1 formed by the measurement point P1 and singular points A2 and A3 of the outer plate 3 of the door 1, a triangular area BB2 formed by the measurement point P1 and singular points A1 and A4 of the outer plate 3 of the door 1, A triangular area BB3 formed by the measurement point P1 of the outer plate 3 of the door 1 and the singular points A1 and A3, and a triangular area BB4 formed by the measurement point P1 of the outer plate 3 of the door 1 and the singular points A2 and A4. Calculate the total of the areas BB1 to BB4 of the four triangles. Thereby, the total of the areas BB1 to BB4 of the four triangles is set as the area of the stress-affected region defined around the measurement point P1 when a load is applied to the measurement point P1, and is calculated as the wrinkle area B1. .

[5] Relational expression D1
The longitudinal curvature RT1 and lateral curvature RY1 at the measurement point P1 of the outer plate 3 of the door 1 obtained as described in [1] to [4] above, and the plate thickness at the measurement point P1 of the outer plate 3 of the door 1 T1, the reached YP value Y1 of the outer plate 3 of the door 1 at the measurement point P1, and the deflection area B1 are explanatory variables (factors representing the rigidity of the outer plate 3 of the door 1), and the displacement of the measurement point P1 in the load direction A multiple regression analysis was performed using H1 as an objective variable, and the following relational expression D1 could be obtained.

(Relational expression D1) Log (H1) = Log (RT1 ^ (C1) * RY1 ^ (C2) * B1 ^ (C3) * (T1 * Y1) ^ (C4)) + C5
H1: Displacement of the outer plate 3 of the door 1 in the load direction at the measurement point P1 RT1: Longitudinal curvature at the measurement point P1 of the outer plate 3 of the door 1 RY1: Lateral curvature at the measurement point P1 of the outer plate 3 of the door 1 T1: Thickness at the measurement point P1 of the outer plate 3 of the door 1 Y1: Reached YP value at the measurement point P1 of the outer plate 3 of the door 1 C1, C2, C3, C4, C5: Constant “^” is a factorial Means.
The bottom of Log is “e”.

As described above, when the opening operation of the door 1 is performed, the upper part of the door grip 2 on the outer plate 3 of the door 1 is pushed with the thumb, and the upper side of the door grip 2 on the outer plate 3 of the door 1 is slightly pushed. The dent rigidity (displacement H1 of the outer plate 3 of the door 1 in the load direction at the measurement point P1) can be obtained from the information in the design drawing (not shown) by the relational expression D1.
In this case, dent rigidity (displacement H1 of the outer plate 3 of the door 1 in the load direction of the measurement point P1) obtained by actually applying a load to the measurement point P1 of the outer plate 3 of the door 1 and a relational expression D1 are obtained. In comparison, a result was obtained in which both were well matched (no multi-collinearity (VIF), for example, a multiple correlation coefficient of 0.92 and a degree of freedom adjusted contribution of 0.82).

[First Alternative Embodiment of the Invention]
In the above-mentioned [Best Mode for Carrying Out the Invention], instead of the deflection area B1 shown in [4] and FIG. 3, the deflection area B1 may be calculated as shown in FIG.
As shown in FIG. 8, a relatively wide support member (not shown) is provided on the back side of the outer plate 3 of the door 1 as a reinforcement of the door 1, and the mastic agent 11 is applied over a relatively wide range. Thus, the support member and the back surface of the outer plate 3 of the door 1 are joined over a relatively wide range by the mastic agent 11 so as to surround the measurement point P1 of the outer plate 3 of the door 1. In this case, the application area of the mastic agent 11 is calculated as a wrinkle area B1.

  In the state shown in FIG. 8, the mastic agent 11 is not applied over a relatively wide range, but the mastic agent 11 is linear (mastic agent 11 so as to surround the measurement point P1 of the outer plate 3 of the door 1. Is applied in a closed loop line shape and the inner side is not coated with the mastic agent 11), the area of the portion surrounded by the mastic agent 11 is calculated as a thigh area B1.

[Second Embodiment of the Invention]
In the above-mentioned [Best Mode for Carrying Out the Invention] [First Alternative Embodiment], the dent rigidity of the slightly upper portion of the door grip 2 in the outer plate 3 of the door 1 is shown in the design drawing (not shown). (Dent stiffness prediction method) (relational expression D1) is shown in the above item [5], but also in the engine hood (not shown) of a passenger car and the back door of a hatchback type passenger car. The same relational expression as the relational expression D1 described is obtained (however, the values of the constants C1, C2, C3, C4 and C5 are different).

[Third Another Embodiment of the Invention]
As described in [Best Mode for Carrying Out the Invention] [First Alternative Embodiment of the Invention], when the door 1 is opened, the door grip 2 on the outer plate 3 of the door 1 is slightly opened. When the displacement H1 of the outer plate 3 of the door 1 in the load direction of the measurement point P1 is obtained in a state where the upper part is pushed with the thumb, the door in the outer plate 3 of the door 1 is obtained based on this by the following relational expression D2. It is possible to obtain the dent rigidity in a state where the upper part of the grip 2 is pushed by the palm.

(Relational formula D2) Z1 = C11 × H1 + C12 × T1 × Y1 + C13 × RT1 + C14 × RY1 + C15
Z1: Discrimination value H1: Displacement of the outer plate 3 of the door 1 in the load direction at the measurement point P1 RT1: Longitudinal curvature at the measurement point P1 of the outer plate 3 of the door 1 RY1: Measurement point P1 of the outer plate 3 of the door 1 T1: Thickness at the measurement point P1 of the outer plate 3 of the door 1 Y1: Ultimate YP value at the measurement point P1 of the outer plate 3 of the door C11, C12, C13, C14, C15: Constant

  As described above, the discriminant value Z1 is obtained by the relational expression D2, and the discriminant value Z1 is compared with the set value Z2, thereby pushing the portion slightly above the door grip 2 on the outer plate 3 of the door 1 with the palm of the hand. The dent stiffness at can be evaluated (whether or not a displacement in the load direction occurs can be predicted).

[Fourth Embodiment of the Invention]
In the above-mentioned [third alternative embodiment of the invention], the dent rigidity in the state in which the portion of the door grip 2 on the outer plate 3 of the door 1 slightly above the door grip 2 is pushed with the palm of the hand is determined from the information on the design drawing (not shown). Although a method of obtaining (dent rigidity prediction method) (relational expression D2) is shown, the same relational expression as the relational expression D2 is obtained also in an engine hood (not shown) of a passenger car and a back door of a hatchback type passenger car. (However, the values of the constants C11, C12, C13, C14, and C15 are different).

[Fifth Embodiment of the Invention]
In the above-mentioned [Best Mode for Carrying Out the Invention] [First Alternative Embodiment of the Invention] to [Fourth Alternative Embodiment of the Invention], the following configuration may be adopted.
When obtaining the relational expressions D1 and D2, not only the multiple regression analysis but also the relational expressions D1 and D2 may be obtained using a neural network or various statistical methods.

  Instead of the four singular points A1 to A4, three singular points may be set, or five or more singular points may be set. Only the part of the curvature different from the curvature of the measurement point of the plate member in the part of the plate member around the measurement point is set as a singular point of the degree of change in stress, or a support member provided on the back side of the plate member Only the joint point with the back surface of the plate member may be set as a singular point of the degree of change in stress.

  As a singular point of the degree of change in stress, in addition to the part of the curvature different from the curvature of the measurement point of the plate member and the joint point between the support member provided on the back surface side of the plate member and the back surface of the plate member, A portion where the plate thickness changes, a portion where an opening exists, a portion subjected to spot welding, or the like may be set. Rather than adopting the upper yield point (reached YP value Y1) as the material of the plate member, it is a yield that takes into account work hardening: work hard (WH) (0.2% proof stress) and bake hardening: bake hard (BH). Points may be adopted.

Instead of fixing the predetermined distance (see [4] in the previous section) to a constant value, the predetermined distance may be changed depending on the portion of the plate member that sets the measurement point, and the predetermined distance depends on the direction from the measurement point. (For example, in FIG. 3, in the direction from the measurement point P1 of the outer plate 3 of the door 1 to the singular points A1 and A2, the predetermined distance is set to 50 mm, for example, and the outside of the door 1 is changed. In the direction from the measurement point P1 of the plate 3 to the singular points A3 and A4, the predetermined distance is set to 80 mm, for example).
The present invention can be applied not only to an outer plate of a vehicle such as a passenger car but also to an outer plate of a household electric appliance, a metal plate member such as an outer plate or panel of a metal door.

Perspective view slightly above the door grip on the door skin Rear view of the door grip slightly above the door grip Side view showing the area of wrinkles slightly above the door grip on the outer skin of the door The figure which shows the relationship between the dent rigidity in the measuring point of a predetermined board member (predetermined material and board thickness), and the curvature in a measuring point The figure which shows the relationship between the dent rigidity in the measurement point of a predetermined board member (predetermined material and curvature), and the board thickness in a measurement point Diagram showing stress / strain graph (load / stress graph) for materials used for door skins The figure which shows the relationship between the load (load) applied to the measurement point of a predetermined plate member (predetermined curvature and plate thickness), the displacement in the load direction of the measurement point, and the upper yield point (reached YP value). The side view which shows a wrinkle area in the slightly upper side of the door grip in the outer plate | board of a door regarding 1st another form of implementation of invention.

Explanation of symbols

3 Plate member A1, A2, A3, A4 Singular point of degree of change of stress B1 Tall area D1 Predetermined relational expression H1 Displacement of plate member in load direction of measurement point P1 Measurement point RT1, RY1 Curvature of measurement point of plate member T1 Thickness of plate member measurement point Y1 Material of plate member

Claims (6)

In the dent rigidity prediction method for calculating the displacement of the plate member in the load direction of the measurement point when a load is applied to the measurement point of the metal plate member,
Calculate the area of the stress-affected area defined around the measurement point when a load is applied to the measurement point,
Based on a predetermined relational expression, the displacement of the measurement point in the load direction is calculated based on the curvature of the measurement point of the plate member, the thickness of the measurement point of the plate member, the material of the plate member, and the deflection area. Dent stiffness prediction method.   The dent stiffness prediction method according to claim 1, wherein the stress-affected region is defined based on a singular point of a degree of change in stress.   One of the portion of the plate member around the measurement point having a curvature different from the curvature of the measurement point of the plate member, and the joint point between the support member provided on the back surface side of the plate member and the back surface of the plate member or The dent stiffness prediction method according to claim 2, wherein both are included as singular points of the degree of change in the stress.   When a predetermined distance is set outward from the measurement point along the plate member, and the singular point of the degree of change in the stress is separated from the measurement point beyond the predetermined distance, the position of the predetermined distance is changed to the stress. The dent stiffness prediction method according to claim 2, wherein the dent stiffness is a singular point of degree.   The number of the singular points of the change degree of the stress is set to three or more, and the area of the polygonal plate member having the singular point of the change degree of the stress as a vertex is calculated as the wrinkle area. The dent stiffness prediction method according to any one of the above.   When the support member provided on the back surface side of the plate member and the back surface of the plate member are joined so as to surround the measurement point, the area of the plate member joined so as to surround the measurement point The dent rigidity prediction method according to claim 1, wherein the area is an area.

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