JP6967823B2 - Deformation analysis method of the material to be pressed - Google Patents

Description

The present invention relates to a method for analyzing deformation of a material to be pressed.

For example, press molding is generally used in the manufacturing process of panel-shaped parts such as steel plates used for automobile bodies. In the parts obtained by press molding (hereinafter referred to as press parts) as described above, springback usually occurs not a little at the time of mold opening due to the residual stress generated at the time of press molding (particularly at the time of mold clamping). Since this springback can cause poor dimensional accuracy, deformation during press molding is predicted in advance by numerical analysis using FEM (finite element method), and countermeasures are being studied (for example, Patent Document 1). reference).

Japanese Unexamined Patent Publication No. 2013-198927

By the way, as described above, when analyzing the deformation during press forming, the pressed material is analyzed as an analysis condition so that a predetermined stress distribution (residual stress distribution) is generated in the pressed material in the mold-molded state depending on the conditions. It may be desirable to give a given stress distribution to. In this case, as a method of applying a predetermined stress distribution to the analysis model of the material to be pressed, a method of applying by displacement or load is common, but in case of displacement or load, the orientation is added to the size. Since it is necessary to specify information as well, there is a problem that the amount of calculation becomes enormous.

In view of the above circumstances, in the present invention, it is a technical problem to be solved that deformation analysis at the time of press molding can be performed in a short time.

The solution to the above problems is achieved by the deformation analysis method of the material to be pressed according to the present invention. That is, this analysis method is a method of analyzing the deformation of the material to be pressed when the material to be pressed is mold-opened from the state of being molded with the press mold, and is pressed when a thermal load is applied to the material to be pressed. A correlation acquisition step to acquire the correlation between the stress distribution generated in the material and the thermal load, and the analysis model of the pressed material by substituting the stress distribution generated in the pressed material in the molded state with the thermal load based on the correlation. It is characterized by having a heat load applying step and a deformation analysis step for analyzing the deformation of the analysis model of the material to be pressed when the mold is changed from the mold-clamped state to the mold-opened state.

As described above, in the analysis method according to the present invention, the stress distribution actually generated based on factors other than heat such as the press load in the mold-clamped state of press molding is replaced with the thermal load in the analysis to analyze the material to be pressed. I tried to give it to the model. In this type of press molding, there is a certain correlation between the stress distribution generated in the material to be pressed when a heat load is applied to the material to be pressed, that is, when heat is applied in the mold-clamped state, and the heat load. Be done. Therefore, based on this correlation, a predetermined thermal load is applied to the analysis model of the material to be pressed so that the desired stress distribution to be applied occurs in the material to be pressed in the molded state. As a result, since it is sufficient to specify only the magnitude of heat, the amount of calculation can be significantly reduced as compared with the conventional case. Therefore, accurate deformation analysis can be performed while shortening the time required for deformation analysis of the material to be pressed.

Further, in the deformation analysis method of the material to be pressed according to the present invention, in the correlation acquisition step, the stress distribution generated in the basic shape model when a heat load is applied to the basic shape model of the material to be pressed is calculated and calculated by analysis. The correlation between the stress distribution and the thermal load may be obtained.

As described above, the stress distribution when a thermal load is applied to the basic shape model of the material to be pressed can be obtained by a simple analysis. Therefore, the correlation between the above-mentioned stress distribution and the thermal load can be obtained in a short time, and thereby the time required for the deformation analysis of the material to be pressed can be further shortened. Further, since the above-mentioned analysis is performed for the purpose of acquiring the correlation (tendency) between the stress distribution and the thermal load, it does not have to be an analysis model that faithfully reproduces the shape of the material to be pressed (actually). There is no particular problem in terms of analysis accuracy (even if the model is simpler than the shape of).

Further, in the deformation analysis method of the material to be pressed according to the present invention, the analysis model of the material to be pressed may be formed by a solid model having a plurality of solid elements in the thickness direction.

In this way, by forming the analysis model of the material to be pressed with a solid model having a plurality of solid elements in the thickness direction thereof, for example, a thermal load is applied to the solid elements forming the surface of the material to be pressed to form a mold. It is possible to reproduce the stress distribution generated in the material to be pressed in the tightened state. Therefore, it is possible to reproduce an accurate stress distribution in the thickness direction of the material to be pressed, which makes it possible to further improve the accuracy of the deformation analysis. Of course, in the present invention, the stress distribution generated in the material to be pressed by the mold clamping is substituted by the thermal load and applied, so that even when a solid model having a plurality of solid elements in the thickness direction is used, the stress distribution is applied. Accurate deformation analysis can be performed while suppressing the increase in calculation time.

As described above, according to the present invention, it is possible to carry out deformation analysis during press molding in a short time.

It is a flowchart which shows the flow of the deformation factor analysis method and the design method of the pressed part which concerns on one Embodiment of this invention. It is a flowchart which shows the flow of the deformation analysis method of the pressed part which concerns on one Embodiment of this invention. (A) is an exact size model of the pressed part to be the target of the present deformation analysis, and (b) to (d) are specific examples of the deformation mode that can occur in the pressed part by press forming. It is a figure which listed the specific example of the deformation mode which can occur in the press part of a predetermined shape by press molding. It is a figure which listed the concrete example of the factor stress distribution which becomes the occurrence factor of each deformation mode. It is a figure which showed the example of the factor stress distribution which becomes the occurrence factor of each deformation mode schematically. It is a main part perspective view which concerns on an example of the case where the exact size model shown in FIG. 2 is made of solid elements. It is a front view of the main part which shows the state which applied the factor stress distribution by the thermal load to the positive dimension model shown in FIG. 7. It is a graph which shows the correlation between a stress distribution and a thermal load. It is a graph which shows the contribution degree of each occurrence factor to one deformation mode. It is a graph which shows the contribution degree of each occurrence factor to other deformation modes. It is a schematic diagram which shows the procedure of the stress analysis method at the time of press molding which was performed conventionally.

Hereinafter, the contents of the deformation factor analysis method of the pressed part according to the embodiment of the present invention and the design method of the pressed part using the analysis result will be described with reference to the drawings.

FIG. 1 shows a procedure of a design method for a pressed part according to the present embodiment. As shown in FIG. 3, this design method includes an exact size model creation step S1 for creating an exact size model of a pressed part, a deformation mode setting step S2 for setting a plurality of deformation modes that can occur in the pressed part, and a deformation mode. Factor stress setting step S3 that sets the factor stress that causes the occurrence of Based on the deformation analysis result obtained in the above, an evaluation step for evaluating the influence of the generating factors on each deformation mode, here, a contribution specifying step S5 for specifying the number of generating factors contributing to each deformation mode and the contribution degree thereof. It is provided with a contribution reflection step S6 for designing a pressed part by reflecting the influence of the generation factor on each deformation mode, here, the contribution of each generation factor to each deformation mode in the exact size model.

Further, as shown in FIG. 2, the deformation analysis step S4 has a correlation with the correlation acquisition step S41 for acquiring the correlation between the stress distribution generated in the pressed component and the thermal load when a thermal load is applied to the pressed component. Based on this, the heat load application step S42, in which the stress distribution generated in the pressed part in the mold-clamped state is replaced by the heat load and applied to the exact size model of the pressed part, and the pressed part when the mold-clamped state is changed to the mold-opened state. A deformation analysis step S43 for analyzing the deformation of the exact size model is provided. The pressed part referred to here corresponds to the material to be pressed according to the present invention, and the exact size model of the pressed part corresponds to the analysis model of the material to be pressed according to the present invention. Hereinafter, each step will be described in order.

(S1) Exact size model creation step In this step, an exact size model of the pressed part to be the target of deformation analysis is created. In the present embodiment, the pressed part is composed of a plate-shaped member and has a cross-sectional hat shape as shown in FIG. 3A, for example. Therefore, a three-dimensional analysis model is created so that the exact size model 10 of the pressed part also has a cross-sectional hat shape. The exact size model 10 of the pressed part referred to here means an analysis model having the drawing dimensions of the pressed part at the time before the start of the present analysis method.

(S2) Deformation Mode Setting Step In this step, a plurality of deformation modes that may occur in the pressed part by press forming are set. Here, when selecting a specific deformation mode, past knowledge or data (stress analysis, basic experiment) related to press molding of pressed parts of the same shape but different material or similar shape (including simple shape) and the same material. It is better to do it based on the academic verification results related to the press molding. For example, as shown in FIG. 3A, as a deformation mode that can occur when a pressed part having a cross-sectional hat shape is press-molded, as shown in FIG. 4, the warp of the vertical wall portion 11 (first deformation). Mode M1), opening of the vertical wall portion 11 (second deformation mode M2), warpage of the upper wall portion 12 (third deformation mode M3), splashing of the flange portion 14 (fourth deformation mode M4), and the like. Can be mentioned.

The warp of the vertical wall portion 11 here means a mode in which the left and right vertical wall portions 11 are bent and deformed in a direction away from each other, for example, as shown in FIG. 3 (b). Further, the opening of the vertical wall portion 11 is such that the vertical wall portion 11 and the vertical wall portion 11 are opened in a direction in which the angle between the inner surface of the vertical wall portion 11 and the inner surface of the upper wall portion 12 increases, as shown in FIG. It means a mode in which the corner portion (first corner portion 13) connecting the wall portion 12 is deformed. Further, the warp of the upper wall portion 12 means a mode in which the upper wall portion 12 connected to the left and right vertical wall portions 11 bends and deforms along the longitudinal direction thereof, for example, as shown in FIG. 3 (d).

Of course, depending on the shape of the pressed part that forms the cross-sectional hat shape, for example, although not shown, other deformation modes such as twisting (twisting around the virtual axis along the longitudinal direction) and bending of the entire pressed part can be further set. You may.

(S3) Factor stress setting step In this step, the factor stress that is the cause of each deformation mode, here, the factor stress distribution is set for each deformation mode. Here, when setting the factor stress distribution that is a specific factor, as in the deformation mode, past knowledge or data related to press molding of pressed parts with the same shape but different material or similar shape and the same material, etc. It is better to do it based on the academic verification results related to the press molding. For example, as shown in FIG. 4, when a plurality of deformation modes M1 to M4 that may occur when a pressed part having a cross-sectional hat shape is press-molded, a factor F1 for generating each deformation mode M1 (M2 to M4) is set. The factor stress distribution that becomes (F2 to F5) can be set. Specifically, as shown in FIG. 5, for the first deformation mode M1 related to the warp of the vertical wall portion 11, the stress difference between the front and back surfaces of the vertical wall portion 11 is the first generation factor F1 (factor stress distribution). ). Further, for the second deformation mode M2 related to the opening of the vertical wall portion 11, the front-back stress difference of the first corner portion 13 can be mentioned as the second generation factor F2 (factor stress distribution). Further, for the third deformation mode M3 related to the warp of the upper wall portion 12, the stress difference between the front and back surfaces of the upper wall portion 12 and the stress difference between the upper wall portion 12 and the flange portion 14 are set to the third and fourth, respectively. Factors of occurrence F3, F4
It can be mentioned as (factor stress distribution). Further, for the fourth deformation mode M4 related to the splash of the flange portion 14, the fifth generation of the front and back stress difference of the corner portion (second corner portion 15) connecting the vertical wall portion 11 and the flange portion 14 is generated. It can be mentioned as a factor F5 (factor stress distribution).

As shown in FIG. 6, for example, the stress difference between the front and back surfaces of the vertical wall portion 11 (first factor F1) is such that the outer surface 11a side is pulled in the longitudinal direction with respect to the neutral shaft 11c of the vertical wall portion 11. It means a stress distribution in which stress σ + and compressive stress σ− are generated in the longitudinal direction on the inner surface 11b side. The same stress distribution is meant for other factors F2 to F5.

Of course, as described above, when other deformation modes such as twisting and bending of the entire pressed part are further set for the pressed part having a cross-sectional hat shape, the factor stress that causes these other deformation modes ( Factor stress distribution) may be set individually.

(S4) Deformation analysis step In this step, deformation analysis of the regular size model 10 is performed when the factor stress (factorial stress distribution) that causes each deformation mode is independently applied to the regular size model 10. For example, when a plurality of deformation modes M1 to M4 shown in FIG. 4 and factor stress distributions (generation factors F1 to F5) shown in FIG. 5 are set, a factor that becomes the first generation factor F1 with respect to the exact size model 10. A stress distribution (see FIG. 6) is applied independently, and the deformation of the positive size model 10 at that time is analyzed (deformation analysis for the first deformation mode M1). Further, the factor stress distribution (see FIG. 5) that becomes the second generation factor F2 is independently applied to the regular size model 10 and the deformation of the regular size model 10 at that time is analyzed (second deformation mode M2). Deformation analysis for). Further, the factor stress distributions (see FIG. 5) that are the third and fourth generation factors F3 and F4 are independently applied to the exact size model 10 and the deformation of the exact size model 10 at that time is analyzed (). Deformation analysis for the third deformation mode M3). Further, the factor stress distribution (see FIG. 5) that becomes the fifth generation factor F5 is independently applied to the regular size model 10 and the deformation of the regular size model 10 at that time is analyzed (fourth deformation mode M4). Deformation analysis for). In short, the deformation analysis of the exact size model 10 is performed for the number of deformation modes set in step S2 (if two or more generation factors can be set for one deformation mode, the number of the generation factors).

Here, in the present embodiment, the factor stress distribution is applied to the positive size model 10 by a thermal load (thermal load application step S42). The factor stress distribution referred to here corresponds to the stress distribution according to the present invention. Further, in this case, for example, as shown in FIG. 7, the exact size model 10 as an analysis model is formed by a solid model having a plurality of solid elements 21 to 23 in the thickness direction thereof, and a specific solid element (here, here,) is formed. By applying a thermal load to the solid elements 22, 23) on the surface side in the thickness direction forming the surface of the pressed component, the factor stress distribution that becomes the generation factors F1 to F5 of each deformation mode M1 to M4 is reproduced. At this time, a thermal load may be applied while the solid element 21 located on the center side in the thickness direction of the positive size model 10 is restrained.

Specifically, as shown in FIG. 8, positive heat 24 is applied (heated) to the node 22a of the solid element 22 located on one side of the front and back sides of the positive size model 10 in the mold-clamped state of press molding. Then, by applying (cooling) negative heat 25 to the node 23a of the solid element 23 located on the other side of the front and back, a desired heat load is applied to a predetermined portion of the exact size model 10 and press molding is performed. It is possible to reproduce a predetermined stress distribution (factorial stress distribution) in the mold clamping state. For example, the solid element 22 located on one side of the front and back constitutes the inner surface 11b (see FIG. 6) of the vertical wall portion 11, and the solid element 23 located on the other side of the front and back constitutes the outer surface 11a of the vertical wall portion 11 (FIG. 6). By applying positive heat 24 to the node 22a of the solid element 22 and applying negative heat 25 to the node 23a of the solid element 23, the stress distribution shown in FIG. 6 is applied in the mold clamping state. (Factor stress distribution), that is, a factor stress distribution (front and back stress difference of the vertical wall portion 11) which is the first generation factor F1 of the first deformation mode M1 shown in FIG. 3B can be imparted. When the solid element 21 on the center side in the thickness direction is constrained, the above-mentioned factor stress distribution is applied in a state where the node 21a of the solid element 21 is also constrained. After applying the factor stress distribution in this way, the deformation of the exact size model 10 when the mold is changed from the mold-clamped state to the mold-opened state is analyzed (deformation analysis step S43).

As for the magnitude of the heat 24, 25 (heat load) applied at this time, the heat load is applied to the regular size model 10 or the analysis model (basic shape model) having a shape obtained by further simplifying the regular size model 10 in advance. The correlation between the stress distribution and the thermal load can be acquired by analysis (correlation acquisition step S41), and can be set based on the correlation. In this type of press molding, as shown in FIG. 9, there is a tendency that a linear correlation is observed between the stress distribution and the thermal load when a thermal load is applied to a pressed component composed of plate-shaped members. Therefore, it is possible to replace the easily assumed factor stress distribution with a thermal load.

(S5) Contribution degree specifying step In this step, based on the deformation analysis result of the exact size model 10 obtained in the deformation analysis step S4, the number of generation factors contributing to each deformation mode and each generation factor to each deformation mode are determined. Identify the degree of contribution. For example, in the deformation analysis step S4, when the factor stress distribution that becomes the generation factor F1 of the first deformation mode M1 shown in FIG. A first transformation mode M1 (primary transformation mode) occurs, and another transformation mode (eg, a secondary transformation mode such as the second transformation mode M2), and in some cases yet another transformation mode (eg, a third transformation mode). Deformation mode M3 and other tertiary deformation modes) may occur. In this case, the degree of contribution of the generation factors (for example, the first to fourth generation factors F1 to F4) of each deformation mode M1 to M3 is specified from the deformation amount of the exact size model 10 related to each deformation mode M1 to M3. Specifically, one deformation analysis result obtained by the analysis is decomposed into deformation amounts for each of the deformation modes M1 to M3, and the corresponding generation factors F1 to F4 are based on the magnitude of the decomposed deformation amount. Calculate the contribution.

Similarly, regarding the deformation analysis results when the factor stress distribution that becomes the factors F2 to F5 of the other deformation modes M2 to M4 is applied to the positive dimension model 10, the number of factors that cause the deformation modes that are found to occur, And its contribution. In this way, with respect to the deformation analysis results of the exact size model 10 obtained for all the generation factors, the number of generation factors that contributed to the deformation and the degree of contribution thereof are specified. For example, in the deformation analysis result for one deformation mode shown in FIG. 10, the contribution of the generation factor A is the highest, and the contribution of the generation factor B is relatively low. On the other hand, in the deformation analysis results for the other deformation modes shown in FIG. 11, it can be seen that the contribution of the generation factor B is the highest, followed by the contribution of the generation factor A. From this, it can be clearly understood that the factor that causes one deformation mode contributes as the factor that causes another deformation mode, and the degree of contribution thereof. Further, the number and types of generation factors contributing to each deformation mode (for example, 3 types in the deformation mode shown in FIG. 10 and 4 types in the deformation mode shown in FIG. 11) can be known at a glance. From the above, it becomes possible to elucidate (at least the tendency) of the deformation mechanism (at least the tendency) of the pressed part according to the exact size model 10 at the time of press molding. It should be noted that FIGS. 10 and 11 are merely exemplified as one of the methods for expressing the distribution of the degree of contribution based on the deformation analysis result, and each of the generation factors A to E and the generation factors F1 to F5 shown in FIG. 5 are illustrated. There is no direct relationship with.

(S6) Contribution reflection step (redesign step)
In this step, the influence of each generation factor (contribution degree in this case) on each deformation mode obtained by the above steps S1 to S5 is reflected in the exact size model 10 to design (redesign) the pressed part. .. Specifically, since the contribution of the cause is known for each deformation mode, the exact size model 10 is supported so that the factor stress distribution that causes each cause becomes as small as possible according to the contribution. Change the shape of the part. Specific examples of the shape change include addition of a seat surface and addition of a bead according to the deformation mode. Alternatively, increasing the plate thickness (including overlapping of plate-shaped portions) for the purpose of improving rigidity can be mentioned.

Further, when a plurality of generation factors influence each other's corresponding deformation modes, it is preferable to carry out individual design changes according to the degree of contribution of each generation factor to the deformation mode. This makes it possible to offset the deformation and prevent the product (pressed parts) after press molding from being deformed.

As described above, in the deformation analysis method of the press part according to the present invention, the stress distribution actually generated based on an external factor such as the press load in the mold clamping state of the press molding is replaced with the heat load in the analysis of the press part. It was added to the analysis model (actual size model 10) of. In this type of press molding, between the stress distribution generated in the pressed material when a heat load is applied to the material to be pressed (here, the pressed part), that is, when heat is applied in the mold-clamped state, and the heat load. Has a certain correlation (see FIG. 9). Therefore, based on this correlation, a predetermined heat load is applied to the exact size model 10 as an analysis model of the pressed parts so that the desired stress distribution to be applied occurs in the pressed parts in the mold-clamped state. As a result, since it is sufficient to specify only the magnitude of heat, the amount of calculation can be significantly reduced as compared with the conventional case. Therefore, the time required for deformation analysis of the pressed part can be shortened.

Further, in the deformation factor analysis method for the pressed part according to the present embodiment, a plurality of deformation modes (for example, the first to fourth deformation modes M1 to M4 shown in FIG. 4) that may occur in the pressed part by press molding, and each deformation. Factor stress distributions that are the factors that cause the modes (for example, the first to sixth factors F1 to F5 shown in FIG. 5) are set for each deformation mode, and these factor stress distributions are independently applied to the exact size model 10 of the pressed part. Deformation analysis of the exact size model 10 when it is applied is performed, and based on the deformation analysis result, the influence of the generation factors on each deformation mode, specifically, the number of generation factors contributing to each deformation mode, and each deformation mode I tried to specify the contribution of each cause of. This makes it possible to obtain the following effects.

That is, conventionally, in the deformation analysis during press molding, for example, as shown in FIG. 12, the mold clamping is performed from the state where the material 1a to be pressed is arranged between the press molds 2 and 3 (see FIG. 12A). Press molding is performed by performing stress analysis of the materials to be pressed 1a to 1c in the order of each step from the performed state (see FIG. 12 (b)) to the state in which the mold is opened (FIG. 12 (c)). Later deformation (see FIG. 12 (d)) was predicted. Therefore, the material to be pressed 1c (pressed parts in this case) after press molding has a residual stress distribution caused by mold clamping and deformation after mold opening caused by this residual stress distribution (for example, after the above-mentioned press molding). The difference between the shape 1c and the normal shape 1c', etc.) was obtained as only one result.

On the other hand, in the deformation factor analysis method according to the present embodiment, the deformation generated in the pressed part by press molding is a plurality of deformations for each part or simple deformations (for example, a plurality of deformations shown in FIGS. 3B to 3D). It was decided to decompose and evaluate the deformation modes M1, M2 ...). Further, in order to quantitatively evaluate the evaluation, the factor stress distribution that causes each deformation mode M1, M2 ... It was decided to apply it to the exact size model 10 (see FIG. 3A) of the pressed parts of the above, and to perform deformation analysis of the exact size model 10. Then, based on the deformation analysis result, the number of generation factors contributing to each deformation mode M1, M2 ... And the degree of contribution of each generation factor to each deformation mode M1, M2 ... were specified. In this way, by assigning the factor stress distribution that causes each deformation mode and analyzing the deformation analysis result of the exact size model 10 at that time, the factor that causes one deformation mode is the other deformation mode. It is possible to objectively evaluate the effect (contribution) on the factors that cause it. Therefore, by performing the above-mentioned deformation analysis for all parts and all types of deformation modes of the exact size model 10 of the pressed parts, the deformation factors of the entire pressed parts are systematically identified, organized and grasped (visualized). ) (See FIGS. 10 and 11). This makes it possible to take appropriate measures for each part type. In addition, since the contribution rate of each generation factor is clarified for each deformation mode, it is possible to easily take measures according to each deformation mode. In addition, if the deformation factors that cause dimensional accuracy defects can be clarified at the product drawing stage, for example, the correct size model 10 will be redesigned by incorporating in advance the countermeasure effect of dimensional accuracy defects and the risk of secondary defects. Therefore, it is possible to improve the degree of completion of the drawing in a short period of time. Therefore, it is possible to design stamped parts at low cost. Of course, if the deformation factor at the time of press molding is clarified, it is possible to easily apply the measures based on the above-mentioned analysis results to similar parts even if the parts type is changed.

In addition, since these factor stress distributions correspond to the deformation mode, which is a simple deformation, high reproduction accuracy can be obtained even when the factor stress distribution is reproduced by applying a thermal load, which makes it accurate. It becomes possible to perform analysis. Of course, since the pressed parts are formed in a thin-walled shape such as a plate, it is easy to apply positive and negative heats 24 and 25 to the front and back surfaces to reproduce a predetermined stress distribution.

Further, in the present embodiment, the exact size model 10 as an analysis model is formed by a solid model having a plurality of solid elements 21 to 23 in the thickness direction thereof, and a specific solid element (here, a solid on the surface side in the thickness direction) is formed. By applying a thermal load to the elements 22 and 23), the factor stress distribution that becomes the generation factors F1 to F5 of each deformation mode M1 to M4 is reproduced. In this way, by creating the exact size model 10 with a solid model having a plurality of solid elements in the thickness direction, it is possible to reproduce an accurate stress distribution in the thickness direction. Of course, by substituting the stress distribution with a thermal load and applying it to the exact size model 10, it is possible to perform accurate deformation analysis while suppressing the calculation time.

Although one embodiment of the present invention has been described above, the deformation analysis method of the material to be pressed according to the present invention may adopt a configuration other than the above as long as it does not deviate from the gist thereof.

For example, in the above embodiment, the exact size model 10 as an analysis model is formed by a solid model having three solid elements 21 to 23 in the thickness direction thereof (see FIG. 7), and heat is applied to the specific solid elements 22 and 23. The case where a load is applied is illustrated, but of course it is also possible to adopt a solid model having another form. For example, although not shown, the exact size model 10 can be formed by a solid model having two solid elements (three nodes) in the thickness direction thereof, or having four or more solid elements in the thickness direction. It can also be formed with a solid model. However, if the number of solid elements in the thickness direction is too large, the advantage of substituting the stress distribution with a thermal load (reduction of calculation time) may be lost. It is better to set the number of solid elements in the thickness direction in consideration of the allowable calculation time. Of course, if there is no particular problem in terms of analysis accuracy, a shell model may be adopted instead of the solid model.

Further, in the above embodiment, the case where the pressed part having a cross-sectional hat shape is targeted for analysis has been described (see FIG. 3 and the like), but of course, the pressed part having a form other than the cross-sectional hat shape (pressed). It is possible to apply the present invention to materials). That is, it is possible to apply the deformation analysis method according to the present invention to a material to be pressed having an arbitrary shape as long as it can be press-molded.

Further, in the above embodiment, in the deformation analysis step S4 of the deformation factor analysis method at the time of press forming, the factor stress distribution that causes each deformation mode is measured by heat (thermal load) with respect to the exact size model 10 of the pressed part. Although the case of giving as an alternative is illustrated, of course, the present invention can be applied to other deformation analysis methods. That is, as long as the stress distribution occurs in the material to be pressed in the molded state, it is possible to substitute the stress distribution other than the factor stress distribution with the thermal load according to the present invention and impart it to the analysis model.

In addition, regardless of the type of press molding, for example, in addition to cold press molding, this is also used when press molding is performed on a work (material to be pressed) in a heated state such as warm press molding or hot press molding. Of course, the invention can be applied.

1a to 1c Pressed material 2, 3 Press mold 10 Correct size model of pressed parts 11 Vertical wall part 11c Neutral shaft 12 Upper wall part 13 First corner part 14 Flange part 15 Second corner part 21 to 23 Solid elements 21a to 23a Nodes F1-F5, A to E Generation factors M1 to M4 Deformation mode S1 Full size model creation step S2 Deformation mode setting step S3 Factor stress setting step S4 Deformation analysis step S41 Correlation acquisition step S42 Thermal load application step S43 Deformation analysis step S5 Contribution Degree specific step (evaluation step)
S6 Contribution reflection step (redesign step)

Claims (3)

It is a method of analyzing the deformation of the material to be pressed when the material to be pressed is opened from the state of being molded with a press mold.
A correlation acquisition step for acquiring a correlation between the stress distribution generated in the pressed material when a heat load is applied to the pressed material and the heat load.
Based on the correlation, the heat load applying step of substituting the stress distribution generated in the pressed material in the mold clamping state with the heat load and applying the heat load to the analysis model of the pressed material,
A deformation analysis method for a material to be pressed, comprising a deformation analysis step for analyzing the deformation of the analysis model of the material to be pressed when the mold is changed from the mold-clamped state to the mold-opened state. In the correlation acquisition step, the stress distribution generated in the basic shape model when a thermal load is applied to the basic shape model of the material to be pressed is calculated by analysis, and the correlation between the calculated stress distribution and the thermal load is acquired. The method for analyzing deformation of the material to be pressed according to claim 1. The deformation analysis method for a material to be pressed according to claim 1, wherein the analysis model for the material to be pressed is formed by a solid model having a plurality of solid elements in the thickness direction.

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