WO2014157013A1 - Simulation method, preform substrate manufacturing method, preform manufacturing method, simulation device, preform substrate, preform, fiber-reinforced plastic molding, and simulation program - Google Patents

Abstract

The simulation device: acquires a first preliminary cutting pattern by simulating the behavior of a reinforcing fiber substrate on the basis of the shaping characteristics thereof when shaped in a shaping mold; trims unnecessary portions from the first preliminary cutting pattern; acquires a second preliminary cutting pattern by simulating the behavior of the reinforcing fiber substrate, which is the first preliminary cutting pattern that has been trimmed and spread open, when shaped; forms incisions in the second preliminary cutting pattern; acquires a third preliminary cutting pattern by simulating the behavior of the reinforcing fiber substrate, in which incisions have been made in the second preliminary cutting pattern and the pattern spread open, when shaped; and generates a preform cutting pattern by cutting off at least one region in the overlapping regions of the third preliminary cutting pattern and spreading the pattern open.

Description

Simulation method, preform substrate manufacturing method, preform manufacturing method, simulation apparatus, preform substrate, preform, fiber-reinforced plastic molded body, and simulation program

The present invention relates to a simulation method, a preform substrate manufacturing method, a preform manufacturing method, a preform method for generating a cut pattern before forming a preform substrate of a fiber reinforced plastic molded body using a reinforcing fiber substrate. The present invention relates to a simulation apparatus that generates a cut pattern before shaping of a reforming base material, a preform base material, a preform, a fiber-reinforced plastic molded body, and a simulation program.

Fiber reinforced plastics (hereinafter referred to as FRP) that use carbon fiber or glass fiber as reinforced fiber are widely used in various fields such as aircraft use, general industrial use, and sports use because of their high specific strength and specific modulus. It's being used.

As a typical manufacturing method of FRP, a prepreg base material in which a reinforcing fiber is impregnated with a matrix resin in advance is used, and a molded body in which the prepreg base materials are stacked one by one is heated and pressurized in an autoclave to be cured. There is a so-called autoclave molding method. However, the production of FRP using an autoclave has problems that the molding cost is high and the productivity is low. In order to solve such problems in prepreg molding, a resin transfer molding molding method (hereinafter referred to as RTM molding method) has been put into practical use. In the RTM molding method, a precursor (referred to as a preform) of an FRP molded body in which a resin-impregnated dry reinforcing fiber base (typically a continuous fiber fabric) is shaped into a predetermined shape is placed on a mold. Then, after the whole is covered with a bag film or a mold, the inside of the bag film or the mold is evacuated and the resin is injected and cured. The RTM molding method is lower in cost and superior in productivity than the conventional autoclave molding method using a prepreg.

However, in the manufacture of this preform, defective shaping such as wrinkles and tension generated when a reinforcing fiber base material is shaped for a complicated three-dimensional shape having many corners and irregularities becomes a problem. ing. Moreover, the easiness along the type | mold at the time of shaping also changes with kinds of reinforcement fiber base material. For this reason, methods for preparing and shaping a base material that has been cut in advance have been studied in the past when shaping a reinforcing fiber base material that is actually used into a mold.

For example, in Patent Document 1, it is proposed that a base material portion that forms a portion to be cut out and removed after molding is formed by shaping by cutting. Patent Document 2 proposes preparing and shaping a reinforcing fiber base material that is cut into a predetermined shape and cut into a box shape having a bottom surface portion and a side surface portion. In Patent Document 3, it is proposed that shaping is performed by preparing a base material in which a notch is formed and devising the pressing order in shaping for a shape having a large curvature.

However, in any of the above methods, the target shape is limited, and when shaping into a new shape, it is necessary to design a preform by repeating trial manufacture many times while actually cutting in the base material. Such a trial-and-error preform design requires a great deal of cost and manpower.

Measures using computer simulation can be considered as a technique for avoiding the trial-and-error method as described above. Conventionally, clothing simulation is known as a simulation technique for shaping a three-dimensional shape (see, for example, Patent Document 4). However, this method is intended to reproduce fabric wrinkles and stretches, and is not applicable to the manufacture of preforms for FRP molded bodies for the purpose of improving wrinkles and stretches.

JP 2009-12297 A JP 2011-167936 A Japanese Patent No. 4022222 JP 2000-3383 A

The present invention has been made in view of the above, and in the manufacture of preforms of FRP molded bodies, the cost for molds and base materials is greatly reduced at the examination stage, and labor-saving work that has been done manually is saved. The object is to provide a simulation method, a preform manufacturing method, a preform manufacturing method, a simulation apparatus, a preform substrate, a preform, a fiber-reinforced plastic molded body, and a simulation program To do.

In order to solve the above-described problems and achieve the object, a simulation method according to the present invention is a computer that generates a cut pattern before forming a reinforcing fiber base material constituting a preform of a fiber-reinforced plastic molded body by simulation. Is a simulation method executed by reading out the shaping characteristics of the reinforcing fiber base material from the storage unit and simulating the behavior when the reinforcing fiber base material is shaped into a shaping mold based on the shaping characteristics A first preliminary cut pattern acquiring step for acquiring a first preliminary cut pattern thereby, a trim step for trimming unnecessary portions from the first preliminary cut pattern acquired in the first preliminary cut pattern acquisition step, and the trim Reinforced fiber base developed from the first preliminary cut pattern trimmed in steps The second preliminary cut pattern acquisition step of acquiring the second preliminary cut pattern by simulating the behavior when forming the shape into the shaping mold, and the second preliminary cut pattern acquisition step of acquiring the second preliminary cut pattern An incision forming step for forming an incision according to the shaping characteristic with respect to the preliminary cut pattern, and a reinforcing fiber base material in which the second preliminary cut pattern in which the incision is formed in the incision formation step is developed is the shaping mold. In the third preliminary cut pattern acquisition step of acquiring the third preliminary cut pattern by simulating the behavior when shaping into the third preliminary cut pattern, and the third preliminary cut pattern acquired in the third preliminary cut pattern acquisition step By cutting and unfolding at least one of the wrapped areas It characterized by having a a cut pattern generating step of generating a cutting pattern for the preform.

A simulation apparatus according to the present invention is a simulation apparatus for generating a cut pattern before shaping of a reinforcing fiber base material constituting a preform of a fiber reinforced plastic molded body by simulation, and the shaping characteristics of the reinforcing fiber base material Is read out from the storage unit, and the first preliminary cut pattern acquisition unit acquires the first preliminary cut pattern by simulating the behavior when the reinforcing fiber base is shaped into the shaping mold based on the shaping characteristics A trim portion for trimming unnecessary portions from the first preliminary cut pattern acquired by the first preliminary cut pattern acquisition portion, and a reinforcing fiber base material developed from the first preliminary cut pattern trimmed by the trim portion The second preliminary cut pattern is simulated by simulating the behavior when forming the mold into the shaping mold A second preliminary cut pattern acquisition unit to be acquired, a cut formation unit for forming a cut corresponding to the shaping characteristic with respect to the second preliminary cut pattern acquired by the second preliminary cut pattern acquisition unit, and the cut The 3rd preliminary cut pattern which acquires the 3rd preliminary cut pattern by simulating the behavior at the time of shaping the reinforcing fiber base which developed the 2nd preliminary cut pattern in which the formation part formed the cut into the shaping type A cut pattern that generates a cut pattern for a preform by cutting and developing at least one of the overlapped areas in the cut pattern acquisition unit and the third preliminary cut pattern acquired by the third preliminary cut pattern acquisition unit And a generating unit.

The simulation program according to the present invention includes a computer that generates a cut pattern before shaping of a reinforcing fiber base constituting a preform of a fiber reinforced plastic molded body by simulation, and stores the shaping characteristics of the reinforcing fiber base. The first preliminary cut pattern obtaining step for obtaining the first preliminary cut pattern by simulating the behavior when shaping the reinforcing fiber base into the shaping mold based on the shaping characteristics; A trim step for trimming unnecessary portions outside the product from the first preliminary cut pattern acquired in the first preliminary cut pattern acquisition step, and a reinforcing fiber base material developed from the first preliminary cut pattern trimmed in the trim step By simulating the behavior when shaping the mold into the shaping mold A second preliminary cut pattern acquisition step for acquiring two preliminary cut patterns, and a cut for forming a cut corresponding to the shaping characteristic with respect to the second preliminary cut pattern acquired in the second preliminary cut pattern acquisition step A third preliminary cut pattern by simulating a forming step and a behavior when forming the reinforcing fiber base material in which the second preliminary cut pattern having the cut formed in the notch forming step is developed into the shaping mold A pre-cut by cutting and unfolding at least one of the overlapping regions in the third pre-cut pattern acquisition step acquired in the third pre-cut pattern acquisition step and the third pre-cut pattern acquisition step Cut pattern generation step for generating patterns Characterized in that to execute, when.

The present invention is suitably used for manufacturing a preform which is a precursor of an FRP molded body, and simulates a base material cut pattern required for shaping a reinforcing fiber base material into an arbitrary three-dimensional shape. This is a method for producing a preform using the cut pattern and using the created cut pattern. According to the present invention, it is possible to significantly reduce the examination cost and work load by the conventional trial and error method.

FIG. 1 is a flowchart relating to a preform manufacturing method according to the first embodiment of the present invention. FIG. 2 is a load-displacement curve when a load is applied in the shear direction of the reinforcing fiber base. FIG. 3 is a diagram showing shear deformation of the reinforcing fiber base material. FIG. 4 is a perspective view of a shaping mold according to the first embodiment of the present invention. FIG. 5 is a view showing a reinforcing fiber base according to the first embodiment of the present invention. FIG. 6 is a perspective view showing a first preliminary cut pattern shape according to the first embodiment of the present invention. FIG. 7 is a diagram showing fiber orientation at the start of shaping in the vicinity of one corner of the shaping mold according to the first embodiment of the present invention. FIG. 8 is a diagram showing a product end and a trim line on the first preliminary cut pattern according to the first embodiment of the present invention. FIG. 9 is a diagram showing a second preliminary cut pattern shape obtained by trimming and developing the first preliminary cut pattern according to the first embodiment of the present invention. FIG. 10 is a perspective view of a second preliminary cut pattern obtained by trimming the first preliminary cut pattern according to the first embodiment of the present invention and re-shaping with the developed base material. FIG. 11 is an enlarged view of a corner portion of a second preliminary cut pattern shape obtained by trimming the first preliminary cut pattern according to the first embodiment of the present invention and re-shaped with the developed base material. FIG. 12 is a diagram in which the first preliminary cut pattern according to the first embodiment of the present invention is trimmed and cut into a shaped second preliminary cut pattern shape and developed. FIG. 13 is a diagram showing the overlap of the base material in the corner portion of the third preliminary cut pattern shape according to the first embodiment of the present invention. FIG. 14 is a diagram in which an excess base material is cut out and developed at the corner portion of the third preliminary cut pattern shape according to the first embodiment of the present invention. FIG. 15 is a block diagram showing a functional configuration of the simulation apparatus according to the first embodiment of the present invention. FIG. 16 is a view showing a reinforcing fiber base according to the second embodiment of the present invention. FIG. 17 is a diagram showing a preform cut pattern created in the second embodiment of the present invention. FIG. 18 is a view showing a reinforcing fiber base according to the third embodiment of the present invention. FIG. 19 is an enlarged view of a corner portion of the second preliminary cut pattern shape obtained by trimming the first preliminary cut pattern according to the third embodiment of the present invention and re-shaped with the developed base material. FIG. 20 is a diagram showing the configuration of a preform cut pattern obtained in the third embodiment of the present invention. FIG. 21 is a diagram schematically showing a state in which shaping is started in the simulation method according to the fourth embodiment of the present invention. FIG. 22 is a perspective view showing a first preliminary cut pattern shape according to the fourth embodiment of the present invention. FIG. 23 is a diagram showing the configuration of a preform cut pattern obtained in the fourth embodiment of the present invention. FIG. 24 is a perspective view of a shaping mold according to the embodiment of the present invention. FIG. 25 is a top view of the shaping mold according to the embodiment of the present invention. FIG. 26 is a perspective view at the start of shaping according to the embodiment of the present invention. FIG. 27 is a diagram showing a preform cut pattern created in Example 1 of the present invention. FIG. 28 is a diagram showing a preform cut pattern created in Example 2 of the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. It should be noted that the drawings are schematic and may differ from actual ones. Further, it is needless to say that due to the schematic drawings, there may be included portions having different dimensional relationships and ratios between the drawings.

(First embodiment)
FIG. 1 shows a flowchart relating to a method for manufacturing a preform of an FRP molded body according to the first embodiment of the present invention.

First, in step S1, data is acquired regarding the shaping characteristics of the reinforcing fiber base material used for the preform. The reinforcing fiber substrate used for the production of the preform in the present invention is characterized in that the reinforcing fibers are oriented in a biaxial orthogonal direction. Such a reinforcing fiber base material is hardly deformed even when a load is applied in the direction in which the reinforcing fibers are oriented, but has a characteristic that a large deformation occurs when a load is applied in the shear direction in which the reinforcing fibers are not oriented. . In evaluating the formability of the reinforcing fiber base, it is necessary to consider such omnidirectional characteristics.

せ ん 断 Shear characteristics are particularly important in evaluating the formability of a reinforcing fiber substrate. A picture frame method and a bias extension method are known as methods for quantifying the shear characteristics of the reinforcing fiber substrate. In the picture frame method, a square frame is fixed to the frame so that the reinforcing fibers of the reinforcing fiber base material cut into the square are oriented at 0 degrees or 90 degrees when the sides of the frame are 0 degrees and 90 degrees. The relationship between the load and the shear deformation is obtained by applying a tensile load on the diagonal line and causing the base material to undergo a shear deformation. Further, the bias extension method is to grip the short side so that the reinforcing fibers are oriented at 45 ° and −45 ° when the long side of the base material cut into a rectangle is 0 ° and the short side is 90 °. The relationship between the load and the shear deformation is obtained by applying a tensile load and causing the substrate to undergo shear deformation.

FIG. 2 shows a general load-displacement curve when a tensile load is applied in the shear direction in a reinforcing fiber substrate in which reinforcing fibers are arranged in two-axis orthogonal directions. In the load-displacement curve 1, the load gradually increases in the region 2 immediately after the load is applied. In this region 2, the frictional force between the reinforcing fiber bases generated by deformation due to the tensile load appears as a load. Next, when the reinforcing fiber starts to slide, the region moves to a region 3 where shear deformation proceeds with almost no increase in load. When the load is continuously applied, the region 4 is increased in an exponential manner. In the region 4, the reinforcing fibers are strongly bound to each other, and the reinforcing fibers cannot easily move. When a load is further applied, the load increases due to the tightening and deformation of the reinforcing fiber, and the deformation cannot be absorbed in the surface, so that the surface is deformed and wrinkles are generated. This wrinkle becomes an excessive base material in an actual preform and remains as a shaping defect. Therefore, it can be said that the point 5 at which wrinkles start to occur is the limit point of shaping. The present invention is characterized in that the shear angle of the reinforcing fiber base at the shaping limit point 5 is evaluated as the shear rocking angle.

FIG. 3 schematically shows shear deformation of the reinforcing fiber base material. When the reinforcing fiber base material undergoes shear deformation, the shape 11 before deformation is changed to the shape 12. The fiber orientation 13 of the reinforcing fiber base indicates the orientation after deformation, and before the deformation, the orientation is 45 degrees and −45 degrees with respect to the load direction 14. A displacement amount 15 indicates a displacement amount of the evaluation point 16 after the deformation of the reinforcing fiber base material after the deformation, and an angle 17 is an angle formed by the load direction 14 and the fiber orientation 13 of the reinforcing fiber base material after the deformation. The angle 17 can be obtained from the picture frame test and the bias extension test described above. When this angle 17 is θ (°), the shear angle α (°) of the reinforcing fiber base can be obtained by equation (1).
α = 90-2θ (°) (1)
Accordingly, α at the shaping limit point 5 shown in FIG. 2 is the shear rocking angle.

In addition, the tensile properties in the fiber direction that are the characteristics of the reinforcing fiber base material, the bending characteristics that show the drapeability of the base material, the friction characteristics between the mold and the base material, and the friction characteristics between the base material layers when shaping with two or more layers It is preferable to obtain in advance in order to accurately evaluate the formability.

FIG. 4 shows a shaping mold used in the embodiment of the present invention. The shaping mold 20 shown in the figure has side surfaces 22a, 22b, 22c, 22d on a base surface 21, and further toward the upper surface 23, four corners 24a, 24b, 24c, 24d and four sides 25a, Cores having the same curvature (radius: R) are assembled to 25b, 25c, and 25d.

FIG. 5 shows a reinforcing fiber substrate used in the first embodiment of the present invention. In the reinforcing fiber base 30 shown in the figure, the lattice line 31 represents the fiber orientation, and the direction 32 is the 0 degree direction.

The reinforcing fiber used for the reinforcing fiber base is not particularly defined, but carbon fiber, glass fiber, aramid fiber, polyparaphenylene benzobis oxazole (PBO) fiber, and the like can be used. Of these, one or a combination of two or more may be used. The weaving structure is a structure in which continuous fibers are arranged in two directions, and may be plain weave, twill, satin weave, woven weave, etc., or NCF (non-crimp fabric). From the viewpoints of handleability and cost, plain weave and twill weave are preferably used.

Further, it is also possible to use a reinforced fiber base material in which a low melting point resin is previously attached to one side or both sides. There are no particular restrictions on the resin to be attached, but examples include thermosetting resins such as epoxy resins, thermoplastic resins such as acrylic resins and nylon resins, and they may be used singly or in combination. . The resin form may be powder or liquid. The amount to be adhered is not particularly limited, but it is preferably such that it exhibits a necessary fixing force when the preform is shaped and does not hinder resin impregnation in molding.

Prediction of shapeability in the present invention is characterized in that the shape formation characteristics acquired in step S1 are defined as physical property data in the reinforcing fiber base material and simulated by a finite element method. Steps S2 to S8 described below are processes by simulation.

In step S2, a simulation for shaping the reinforcing fiber base 30 shown in FIG. 5 into the shaping mold 20 shown in FIG. 4 is performed. It is assumed that the reinforcing fiber base 30 shown in FIG. 5 has a sufficient size for shaping the core shape of the shaping mold 20 shown in FIG. 4 and has not been processed such as cutting. The reinforcing fiber base 30 shown in FIG. 5 is arranged with the longitudinal direction 26 of the core of the shaping mold 20 shown in FIG. The positioning of the base material may be at any position, such as the geometric center of the shaping mold or the area that does not require deformation of the base material for shaping, but it is constrained so that the base material does not translate or rotate during shaping. It is preferable. In addition, you may make it perform the process of step S2 based on the data previously acquired as a shaping characteristic of the reinforced fiber base material 30 instead of using the shaping characteristic acquired by step S1.

FIG. 6 is a diagram showing a first preliminary cut pattern which is a result obtained by the simulation in step S2. In the first preliminary cut pattern 33 shown in the figure, wrinkles 35 are generated at the corner portion 34. FIG. 7 is an enlarged view of the vicinity of one corner 24a of the shaping mold 20 shown in FIG. 4, and shows a fiber orientation 41 at the start of shaping of the reinforcing fiber base 30 in the corner 24a. As shown in FIG. 7, when the reinforcing fiber base 30 is disposed in the shaping mold 20, the fibers are oriented at 0 degrees or 90 degrees on the side surfaces 22 a and 22 b with respect to the 0-degree direction 42. However, the orientation angles 44a and 44b of the two lattice lines 31 perpendicular to each other of the reinforcing fiber base 30 with respect to the vertex line 43 of the corner 24a are 45 degrees and −45 degrees. Therefore, when shaping, the reinforcing fiber base material 30 hardly extends in the direction along the side surfaces 22a and 22b, but the base material greatly extends along the vertex line 43 of the corner 24a. Therefore, the first preliminary cut pattern after shaping has a shape as shown in FIG. 6, and a region exceeding the shear locking angle of the base material is generated in the corner portion 34, and the ridge 35 remains.

In step S3, the first preliminary cut pattern obtained in step S2 is referred to, and an extra base material that is surely out of the product after shaping is trimmed by simulation. FIG. 8 is a view of the first preliminary cut pattern 33 of FIG. 6 as viewed from the upper surface (arrow view in the direction of arrow A). The product end 51 and the trim line 52 on the first preliminary cut pattern 33 are shown in FIG. Show. When trimming at the very end of the product end 51, there is a possibility that the base material is insufficient with respect to the product shape when actually shaping due to a change in behavior or variation during shaping due to trimming. Accordingly, the trim line 52 preferably has a margin of about 10 mm to 100 mm with respect to the product end 51 after shaping, although it depends on the size and shape of the product.

In step S4, the first preliminary cut pattern trimmed in step S3 is developed and a shaping simulation is performed. Since the load applied to the base material during shaping changes due to the trimming, step S4 is performed for the purpose of confirming the influence. FIG. 9 is a diagram showing the base material shape obtained by developing the trimmed first preliminary cut pattern, where the lattice lines 61 are fiber orientations and the direction 62 is the 0 degree direction.

FIG. 10 is a diagram showing the shape of the second preliminary cut pattern when the base material 60 (first preliminary cut pattern after trimming) shown in FIG. 9 is shaped again into the shaping mold 20 shown in FIG. It is. In the second preliminary cut pattern 63 shown in the figure, the fold 65 is still generated at the corner portion 64. The positioning at the time of shaping is preferably the same as that of the base material before trimming so that the influence of trimming can be confirmed. In the second preliminary cut pattern obtained in step S4, there is no shortage of the substrate with respect to the product shape (step S5: Yes), and there is a region exceeding the shear locking angle in the second preliminary cut pattern ( In step S6: Yes), the simulation process proceeds to step S7 described later.

Note that, in the second preliminary cut pattern obtained in step S4, if a substrate shortage occurs with respect to the product shape (step S5: No), the process returns to step S3 and the trim is performed again. In addition, in the second preliminary cut pattern obtained in step S4, if there is no substrate shortage with respect to the product shape (step S5: Yes), the second preliminary cut pattern must have a region exceeding the shear locking angle. If the second preliminary cut pattern obtained in step S4 is developed as a final preform cut pattern (step S11), the process proceeds to step S10 described later.

In step S7, a cut is formed by simulation in a region where surplus base material is generated and becomes wrinkled in the product. In the present invention, the shear rocking angle is used as an index when forming the cut. FIG. 11 is an enlarged view of the corner portion 64 of the second preliminary cut pattern 63 obtained in step S4 shown in FIG. 10, and clearly shows a region exceeding the shear locking angle. Specifically, the region 71 in FIG. 11 is a region exceeding the shear locking angle. In step S7, first, a shear line is released by making a cut line 72 in the region 71 to form a cut. The incision line 72 is preferably placed at a location that is a starting point for the out-of-plane deformation of the substrate in that the shear deformation of the second preliminary cut pattern can be released. Moreover, it is preferable to cut | disconnect the area | region where the shear angle is large among the area | regions 71 which exceed a shear rocking angle, and open | release the shear deformation of a base material. That is, it is preferable to insert the cut line 72 so that the region 71 is equally divided from the midpoint 74 of the outer peripheral line 73 of the region 71 exceeding the shear locking angle.

In step S8, the second preliminary cut pattern in which the cut is formed in step S7 is developed, a shaping simulation is performed, and a third preliminary cut pattern is acquired. FIG. 12 is a development of the second preliminary cut pattern in which cuts are formed. The base material 80 (second preliminary cut pattern after the cut is formed) shown in the figure is developed in a state where the cuts 81a, 81b, 81c, and 81d are inserted in the portions corresponding to the corner portions. In FIG. 12, the lattice lines 82 are fiber orientations. The present invention is characterized in that the base material is arranged with the direction 83 as the 0 degree direction, and the base material cuts 81a, 81b, 81c and 81d are simulated without considering the contact between the cut edges. FIG. 13 is an enlarged view of the corner portion of the third preliminary cut pattern after the simulation in step S8. As shown in FIG. 13, the base material overlaps at the corner portion, and the first edge 92 a and the second edge 92 b in the overlap region 91 intersect during the shaping. By not considering the contact between the first edge 92a and the second edge 92b of the cut when performing the simulation, the cut edges intersect and overlap without interfering with each other. It is possible to accurately grasp whether it is.

In step S9, the base material for the overlap region 91 of the third preliminary cut pattern is cut out and developed to obtain a preform cut pattern. About how to cut out the base material in the overlap region 91, it is only necessary that the base material corresponding to the area of the region 91 can be removed. 13 may be cut from both sides of the first edge 92a and the second edge 92b, or may be cut from only one of the edges. However, when cutting from only one of the edges, the shearing deformation of the base material on the edge side that has not been cut remains large, so from the viewpoint of dispersing the shearing deformation, the first edge 92a and the first edge 92a It is preferable to cut from both sides of the second edge 92b. In particular, in order to disperse the shear deformation substantially evenly, it is more preferable to cut the base material for a substantially uniform area from both sides of the cutting edge.

Fig. 14 shows the preform cut pattern. In step S9, by removing the excess base material from the third preliminary cut pattern and developing it, a preform cut pattern 100 having notches 101a, 101b, 101c, and 101d at the four corners is formed. The preform cut pattern 100 is output as CAD (Computer Aided Design) data, for example, and displayed on the display unit 1003.

Through the above steps S1 to S9, it is possible to obtain a preform cut pattern in which generation of wrinkles during shaping is suppressed and the amount of base material used is minimized. Also, perform a simulation again with the preform cut pattern obtained as necessary to check whether defects such as wrinkles and gaps between cutting edges remain, and if so, go back to any step. It is also possible to start over from the middle. For example, if a substrate shortage occurs after step S8, the process may return to step S7 to perform a process such as cutting off with a little overlap.

Finally, in step S10, a preform is obtained by applying the preform cut pattern obtained through steps S1 to S9. Thus, a preform having no wrinkles or overlap can be obtained. A preform shaping method is not particularly limited, and a simple press, a multistage press, a hand lay-up, or the like is applied. It can be arbitrarily selected depending on the size and shape of the preform and the required quality. If the result of actual shaping does not meet the requirements, it is possible to make corrections in the field or retroactively.

FIG. 15 is a block diagram illustrating a functional configuration of a simulation apparatus that is an apparatus capable of executing the simulation method according to the present embodiment. A simulation apparatus 1001 shown in the figure has an input unit 1002 realized using a user interface such as a keyboard, a mouse, and a touch panel, and a display panel made of liquid crystal or organic EL (Electro Luminescence), and displays various information. A display unit 1003 for storing, a storage unit 1004 for storing various types of information including information for performing a simulation, and a control unit 1005 for controlling the operation of the simulation apparatus 1001.

The storage unit 1004 includes a shaping information storage unit 1041 that stores shaping information such as shear characteristics, tensile characteristics, bending characteristics, and friction characteristics between layers when a plurality of layers are stacked, a simulation program according to the present embodiment, and a predetermined OS. And a program storage unit 1042 for storing various programs including a program for starting the program. The storage unit 1004 is configured using a RAM (Random Access Memory) and a ROM (Read Only Memory).

The control unit 1005 is realized by using a CPU (Central Processing Unit) or the like, and is connected to each component of the simulation device 1001 to be controlled via a bus line. The control unit 1005 includes a first preliminary cut pattern acquisition unit 1051, a trim unit 1052, a second preliminary cut pattern acquisition unit 1053, a cut formation unit 1054, a third preliminary cut pattern acquisition unit 1055, and a cut pattern generation unit. 1056.

The first preliminary cut pattern acquisition unit 1051 reads the shaping characteristic of the reinforcing fiber base material from the shaping information storage unit 1041 and simulates the behavior when the reinforcing fiber base material is shaped into the shaping mold. 1 preliminary cut pattern is acquired.

The trim unit 1052 trims unnecessary portions outside the product from the first preliminary cut pattern acquired by the first preliminary cut pattern acquisition unit 1051.

The second preliminary cut pattern acquisition unit 1053 performs the second preliminary cut by simulating the behavior when the reinforcing fiber base material developed from the first preliminary cut pattern trimmed by the trim unit 1052 is formed into a shaping mold. Get the pattern.

The cut forming unit 1054 forms a cut corresponding to the shaping characteristic with respect to the second preliminary cut pattern acquired by the second preliminary cut pattern acquisition unit 1053.

The third preliminary cut pattern acquisition unit 1055 simulates the behavior when the reinforcing fiber base material on which the second preliminary cut pattern in which the cut forming unit 1054 has formed the cut has been formed into a shaping mold. Get the preliminary cut pattern.

The cut pattern generation unit 1056 generates a preform cut pattern by cutting out and developing one of the overlapping regions in the third preliminary cut pattern acquired by the third preliminary cut pattern acquisition unit 1055.

The simulation apparatus 1001 having the above configuration may be realized using one computer (electronic computer) or may be realized using a plurality of computers. In the latter case, it is possible to perform processing in cooperation with each other while transmitting and receiving data via a communication network such as the Internet.

The simulation program according to the present embodiment may be recorded on a computer-readable recording medium such as a hard disk, a flash memory, a CD-ROM, a DVD-ROM, or a flexible disk and widely distributed.

According to the first embodiment of the present invention described above, a preform can be manufactured by significantly reducing the cost and labor required for the study from the trial-and-error method performed in the conventional field. Is possible. In addition, since a change in product thickness due to wrinkles and overlap can be eliminated, a uniform preform with a uniform thickness can be obtained.

(Second Embodiment)
A second embodiment of the present invention will be described with reference to FIGS. FIG. 16 is a diagram showing a reinforcing fiber base used in the second embodiment of the present invention. In the reinforcing fiber base 110 shown in FIG. 16, the lattice lines 111 indicate the fiber orientation, and the direction 112 indicates the 0 degree direction. Using the shaping mold 20 of FIG. 4, the other conditions are the same as in the first embodiment, and the same steps S1 to S10 are performed, thereby obtaining a preform cut pattern. FIG. 17 is a diagram showing a preform cut pattern obtained in the present embodiment. The preform cut pattern 120 shown in FIG. 17 includes eight cutouts 121a, 121b, 121c, 121d, 121e, 121f, 121g, and 121h. By applying the preform cut pattern 120 and shaping, a preform free of wrinkles and overlap can be manufactured.

As can be seen from a comparison between FIG. 14 and FIG. 17, when the shape is formed by changing the orientation angle with respect to the shaping mold, the number and position of the cutouts of the preform cut pattern change, and the cut when the preform is shaped. It can be said that the butted edge butting position changes depending on the fiber orientation. Therefore, when forming by laminating a plurality of layers, by changing the orientation angle of the fiber in each layer, it is possible to eliminate the overlap of the notch edge butting positions, and suppress the strength reduction due to the overlapping of the butting positions. Can do.

Note that the configuration of the simulation apparatus according to the present embodiment is the same as the configuration of the simulation apparatus 1001 described in the first embodiment.

(Third embodiment)
A third embodiment of the present invention will be described with reference to FIGS. FIG. 18 is a diagram showing a reinforcing fiber base used in the third embodiment of the present invention. In the reinforcing fiber base 200 shown in FIG. 18, the lattice line 201 represents the fiber orientation, and the direction 202 is the 0 degree direction.

3rd Embodiment is another embodiment at the time of arrange | positioning a reinforced fiber base material so that it may become the same fiber orientation as 1st Embodiment. From step S1 to step S4 in FIG. 1, the second preliminary cut pattern is obtained through the same process as step S1 to step S4 of the first embodiment. FIG. 19 is an enlarged view of the corner portion of the second preliminary cut pattern obtained in step S4. A region 205 shown in FIG. 19 indicates a region exceeding the shear locking angle. The processes in step S5 and step S6 are the same as in the first embodiment.

In the third embodiment, in step S7, as shown by the broken line in FIG. 19, the points 207a and 207b at both ends of the outer peripheral line 206 of the region 205 exceeding the shear locking angle are extended along the boundaries 208a and 208b of the region 205. Make an incision.

When forming the cut along the boundaries 208a and 208b, if the region is within a shear locking angle of −10 degrees, even if there is a cut outside the region 205 exceeding the shear locking angle, a temporary effect can be obtained. It is preferable that a part of the region 205 exceeds the shear locking angle because the concentration of shear deformation can be reduced. More preferably, as shown in FIG. 19, incisions may be made along the boundaries 208a and 208b of the region 205 from points 207a and 207b at both ends of the outer peripheral line 206 of the region 205 exceeding the shear locking angle.

As shown in FIG. 19, by forming the cuts along the boundaries 208a and 208b, the region 205 exceeding the shear locking angle is extended to both sides along the direction indicated by the arrows 209a and 209b, that is, along the corners. Can be effectively mitigated. Further, the cut may be made on one side of the boundary 208a, 208b of the region 205 exceeding the shear locking angle, but it is preferable to make the cut on both sides because the concentration of shear deformation can be effectively reduced.

Steps S8 to S11 are the same as in the first embodiment. FIG. 20 is a diagram showing a configuration of a preform cut pattern obtained in the present embodiment. The preform cut pattern 210 shown in the figure has eight notches 211a, 211b, 211c, 211d, 211e, 211f, 211g, and 211h. By applying the preform cut pattern 210 and shaping, a preform having no wrinkles or overlap can be manufactured.

Note that the configuration of the simulation apparatus according to the present embodiment is the same as the configuration of the simulation apparatus 1001 described in the first embodiment.

(Fourth embodiment)
The fourth embodiment of the present invention is characterized by manufacturing a preform composed of a plurality of layers. In the following description, a case where a preform is manufactured by simultaneously shaping three layers will be mainly described, but the number of layers to be laminated is not limited to this.

The outline of the process of the preform manufacturing method according to this embodiment is the same as that of the first embodiment. That is, the process of the preform manufacturing method according to the present embodiment is performed according to the flowchart shown in FIG. Hereinafter, an outline of a preform manufacturing method will be described focusing on differences in processing from the first embodiment.

FIG. 21 is a diagram schematically showing a state in which shaping is started in step S2. In the present embodiment, a simulation is performed assuming that the reinforcing fiber bases 200, 110, and 30 are stacked on the shaping mold 20 in order from the bottom, and shaping is performed at the same time. In the present embodiment, the behavior during shaping is simulated assuming that the influence of interlayer friction during shaping is small.

FIG. 22 is a diagram showing a first preliminary cut pattern obtained by the simulation in step S2. The first preliminary cut pattern 300 shown in the figure is a simulation result obtained when the reinforcing fiber base materials 30, 110, and 200 are simultaneously shaped.

The subsequent steps S3 to S8 are the same except that the simulation is performed with the three reinforcing fiber bases 30, 110, and 200 overlapped.

In step S9, a preform cut pattern of each reinforcing fiber substrate is obtained. FIG. 23 is a diagram showing the structure of the preform cut pattern obtained in step S9. Preform cut patterns 100 ′, 120 ′, and 210 ′ shown in FIG. 23 are preform cut patterns obtained from the reinforcing fiber substrates 30, 110, and 200, respectively. In the present embodiment, as the shaping condition, a shaping condition with a small influence of interlayer friction that is deformed while repeatedly contacting and leaving adjacent layers is applied. Therefore, the preform cut patterns 100 ′, 120 ′, and 210 ′ have substantially the same shape as the preform cut patterns 100, 120, and 210 obtained in the first, second, and third embodiments, respectively. In addition, under conditions where the influence of inter-layer friction is not negligible, where adjacent layers are deformed while always in contact with each other during shaping, a preform cut pattern different from that obtained with a single layer is obtained for each layer. It is done. The present invention can also be applied to shaping conditions in which the influence of such interlayer friction cannot be ignored.

Note that the configuration of the simulation apparatus according to the present embodiment is the same as the configuration of the simulation apparatus 1001 described in the first embodiment.

In the fourth embodiment of the present invention described above, a preform cut pattern having different cut formation positions is obtained from a reinforcing fiber base having the same lattice line orientation direction. Can be eliminated, and a drop in strength due to notch concentration at the same position during lamination can be suppressed.

Note that the method of stacking the reinforcing fiber bases shown in FIG. 21 is merely an example, and the stacking order can be arbitrarily changed. Also, the number of stacked layers and the combination of the orientation directions of the lattice lines can be changed as appropriate.

Further, the trimming method in step S3, the notch forming method in step S7, and the overlap region cutting method in step S9 are not limited to those described above. If it can be avoided, it may be executed by other methods.

In addition, when a preform composed of a plurality of layers is formed in the present embodiment, it may be formed one layer at a time instead of forming in a lump in a state where a plurality of layers are laminated as described above.

According to the present invention, it is possible to manufacture a preform by significantly cutting the cost and the amount of work required for the study from the trial and error method that has been performed in the conventional field. In addition, since a change in product thickness due to wrinkles and overlap can be eliminated, a uniform preform with a uniform thickness can be obtained. Further, the present invention is not limited to the above-described embodiment, and can be applied to any product shape.

In the present invention, it is also possible to use a reinforcing fiber base impregnated with a semi-cured resin. In this case, a condition corresponding to the impregnation of the semi-cured resin may be added as a shaping condition for performing the simulation.

Specific examples of the present invention are shown below. In addition, this invention is not limited by the Example demonstrated below.

FIG. 24 is a perspective view showing a configuration of an aluminum shaping mold used in the examples. 25 is a view in the direction of arrow B in FIG. 24 (top view of the shaping mold). The shaping mold 400 shown in FIGS. 24 and 25 has four corners 402a and 402b of a rectangular parallelepiped having a length of 240 mm, a width of 160 mm, and a height of 50 mm on a base surface 401 of 400 mm × 400 mm and a height of 20 mm. 402c and 402d are provided with R of 10 mm (R10), 20 mm (R20), 30 mm (R30), and 40 mm (R40), respectively, and further, gradually changing fillets 404a, 404b, 404c, and 404d are placed on four sides of the upper surface 403. It has a shape that smoothly connects each corner. A 360 mm × 360 mm reinforcing fiber base is formed on the shaping mold 400 to produce a preform.

The reinforcing fiber substrate used is carbon fiber woven fabric CO6343B manufactured by Toray Industries, Inc. (woven structure: plain weave, fabric weight: 198 g / m ² , reinforcing fiber: T300B-3K, elastic modulus: 230 GPa, strength: 3530 MPa, fineness: 198 tex. , Filament number: 3,000).

Fig. 26 shows the state at the start of shaping. The reinforcing fiber base 406 is arranged on the shaping mold 400, positioned at any five points on the upper surface of the core, and an acrylic plate 405 having a hole of 400 mm × 400 mm, a thickness of 10 mm, and a core outer shape + 2 mm in the center. It is shaped by pushing straight in parallel to the base surface 401. The fiber orientation of the reinforcing fiber base 406 was positioned so that any one side of the base surface was 0 degrees and 0 degrees and 90 degrees, and the simulation was performed by a finite element method.

(Example 1)
FIG. 27 is a diagram showing a preform cut pattern created by executing the simulation method according to the first embodiment as Example 1 of the present invention. Since the shaping mold 400 used in this example has different R at each corner, the shape of the preform cut pattern 410 shown in FIG. 27 is also different at each corner. That is, in the preform cut pattern 410, notches 411a, 411b, 411c, and 411d having different shapes were formed at the corners of R10, R20, R30, and R40, respectively.

As a result of actually creating and shaping the preform cut pattern shape obtained by simulation, a slight overlap remained in the portion shaped at the R10 corner 401a, requiring simple correction, but shaping at the other corners. It was possible to obtain a good preform with no gap at the shape of the cut portion and no gap at the notch edge butting position.

The time required from the start of the study to the production of the preform is about half a day, and the substrate used is only one substrate of 360 mm × 360 mm used for creating the cut pattern for the preform. When the same work was carried out by the conventional trial and error method, the work time was one day and 6 sheets of 360 mm x 360 mm were required until a preform without a gap at the position where the wrinkles and notched edges were abutted. The effect of the present invention could be confirmed. In addition, if it is shaped into a more complex shape or shaped in multiple layers, the trial and error method requires more labor, time, cost for studying the mold and the base material, and the effect of the present invention is effective. You can expect even more.

(Example 2)
FIG. 28 is a diagram showing a preform cut pattern created by executing the simulation method according to the second embodiment as Example 2 of the present invention. Since the shaping mold 400 has a different R at each corner, the shape of the preform cut pattern 500 shown in FIG. 28 is also different at each corner. That is, in the preform cut pattern 500, cutouts 501a and 501b are formed at the corner of R10, cutouts 501c and 501d are formed at the corner of R20, cutouts 501e and 501f are formed at the corner of R30, and R40. The cutouts 501g and 501h were formed at the corners. The notches 501a to 501h have different shapes.

As a result of actually creating and shaping the preform cut pattern shape obtained by simulation, it was possible to obtain a good preform with no gap at the notch edge butt position.

(Example 3)
In Example 3 of the present invention, the preform cut pattern 410 (see FIG. 27) obtained in Example 1 and the preform cut pattern 500 (see FIG. 8) obtained in Example 2 are overlapped to form Example 1. And 2 were formed in the same mold (shaped mold 400). As a result of shaping, it was possible to obtain a good preform having no gap at the notch edge of each layer.

From the results shown in Examples 1 to 3, the effect of the present invention could be confirmed. For Examples 1 and 2, the time required from the start of the study to the production of the preform was about half a day, and the substrate used was one substrate for each layer of 360 mm × 360 mm used to create the preform cut pattern. Only. When the same work was carried out by the conventional trial and error method, the working time was one day until a preform having no gap was formed at the butting position of the wrinkles and notched edges in each example, and two layers of 360 mm × 360 mm In total, about 6 substrates were required, and the effects of the present invention could be confirmed. In addition, if it is shaped into a more complicated shape, the trial and error method requires more labor, time, cost for studying the mold and the base material, and the effect of the present invention can be further expected.

1: Load-displacement curve 2: Initial shear deformation region of base material 3: Intermediate shear deformation region of base material 4: Shear locking region of base material 5: Forming limit point 11: Shape before base material shear deformation 12: Base Shape 13 after material shear deformation: Fiber orientation after base material shear deformation 14: Load direction 15: Displacement amount due to base material shear deformation 16: Displacement evaluation point 20, 400: Shaping mold 21: Shaping base surface 22a 22b, 22c, 22d: shaping mold side surface 23: shaping mold upper surface 24a, 24b, 24c, 24d: shaping mold corners 25a, 25b, 25c, 25d: shaping mold upper surface 4 sides 26: shaping Shape 0 degree direction 30, 110, 200: Reinforcement fiber base material 31, 61, 82, 111: Reinforcement fiber base material fiber orientation 32, 62, 83, 112: Reinforcement fiber base material 0 degree direction 33: No. 1 preliminary cut pattern 34: first preliminary pattern 34 Cut pattern corner portions 35, 65: ridge 41: fiber orientation at the start of shaping 42: 0 degree direction of reinforcing fiber base 43: corner vertex line 44a, 44b: corner vertex line and reinforcing fiber substrate Angle 51: Product end 52 on the first preliminary cut pattern 52: Trim line 60 on the first preliminary cut pattern 60: Base material (first preliminary cut pattern after trimming)
63: Second preliminary cut pattern 64: Corner portion 71 of second preliminary cut pattern: Shear rocking angle excess region 72: Cut line 73: Outer line of shear locking angle excess region 74: Outer line of shear locking angle excess region Midpoint 80: base material (second preliminary cut pattern after forming the cut)
81a, 81b, 81c, 81d: cut 91: overlap region 92a, 92b: cut edge 100, 100 ′, 120, 120 ′, 210, 210 ′, 410, 500: preform cut patterns 101a, 101b, 101c, 101d, 121a, 121b, 121c, 121d, 121e, 121f, 121g, 121h, 211a, 211b, 211c, 211d, 211e, 211f, 211g, 211h, 411a, 411b, 411c, 411d, 501a, 501b, 501c, 501d, 501e, 501f, 501g, 501h: notch 1001: simulation device 1002: input unit 1003: display unit 1004: storage unit 1005: control unit 1041: shaping information storage unit 1042: program storage unit 105 : First preliminary cut pattern acquisition unit 1052: trim portion 1053: second preliminary cut pattern acquisition unit 1054: cut forming unit 1055: third preliminary cut pattern acquisition unit 1056: cut pattern generator

Claims (20)

1. A simulation method executed by a computer that generates a cut pattern before shaping of a reinforcing fiber base constituting a preform of a fiber-reinforced plastic molded body by simulation,
   A first preliminary cut pattern is obtained by reading out the shaping characteristics of the reinforcing fiber base from the storage unit and simulating the behavior when shaping the reinforcing fiber base into a shaping mold based on the shaping characteristics. A first preliminary cut pattern acquisition step to be acquired;
   A trim step for trimming unnecessary portions from the first preliminary cut pattern acquired in the first preliminary cut pattern acquisition step;
   The second preliminary cut for obtaining the second preliminary cut pattern by simulating the behavior when the reinforcing fiber base material developed from the first preliminary cut pattern trimmed in the trim step is shaped into the shaping mold A pattern acquisition step;
   An incision forming step of forming an incision according to the shaping characteristic with respect to the second preliminary cut pattern acquired in the second preliminary cut pattern acquisition step;
   A third preliminary cut pattern is obtained by simulating the behavior when forming the reinforcing fiber base, which has developed the second preliminary cut pattern in which the cut is formed in the cut forming step, into the shaping mold. 3 preliminary cut pattern acquisition steps;
   A cut pattern generation step for generating a preform cut pattern by cutting and developing at least one of the overlapping regions in the third preliminary cut pattern acquired in the third preliminary cut pattern acquisition step;
   A simulation method characterized by comprising:
2. The shaping properties include shear properties,
   The simulation method according to claim 1, wherein the notch forming step forms a notch in a region exceeding a shear locking angle of the reinforcing fiber base.
3. In the notch forming step, in the region exceeding the shear locking angle including the line from the midpoint of the reinforcing fiber substrate exceeding the shear locking angle of at least one of the reinforcing fiber bases in the outer peripheral line of the second preliminary cut pattern, 3. The simulation method according to claim 2, wherein the notch is formed so as to divide the region into two equal parts.
4. The method for producing a preform according to claim 2 or 3, wherein the shaping characteristic includes a tensile characteristic in a fiber direction of the reinforcing fiber base and an out-of-plane bending characteristic of the reinforcing fiber base.
5. The third preliminary cut pattern acquisition step is simulated without considering the self-contact of the reinforcing fiber substrate,
   The simulation according to any one of claims 1 to 4, wherein the cut pattern generation step cuts the reinforcing fiber base material in an overlapping region by forming the cut as an extra base material. Method.
6. The at least one step of the trim step, the second preliminary cut pattern acquisition step, the cut formation step, the third preliminary cut pattern acquisition step, and the cut pattern generation step is executed a plurality of times. 6. The simulation method according to any one of 1 to 5.
7. The method for producing a preform according to any one of claims 1 to 6, wherein the reinforcing fiber base is oriented in two directions in which the reinforcing fibers are orthogonal to each other.
8. The simulation method according to any one of claims 1 to 7, further comprising a display step of displaying the cut pattern generated in the cut pattern generation step.
9. 2. The preform cut pattern is generated by developing the second preliminary cut pattern when the second preliminary cut pattern does not have a region exceeding the shear locking angle. Simulation method.
10. The simulation method according to any one of claims 1 to 9, wherein a simulation of each step in a state where a plurality of the reinforcing fiber base materials are laminated is executed.
11. The simulation method according to any one of claims 1 to 10, wherein the reinforcing fiber base material is impregnated with a semi-cured resin.
12. A preform substrate prior to shaping the preform is obtained by cutting the reinforcing fiber substrate according to the preform cut pattern generated by the simulation method according to any one of claims 1 to 11. A method for producing a preform substrate, characterized by comprising:
13. A method for producing a preform, wherein the preform is produced by shaping the preform substrate produced by the method for producing a preform substrate according to claim 12 into the shaping mold. .
14. 14. The preform manufacturing method according to claim 13, wherein a plurality of preform base materials having different incisions are stacked and collectively shaped.
15. A simulation device for generating a cut pattern before shaping of a reinforcing fiber base constituting a preform of a fiber reinforced plastic molded body by simulation,
    A first preliminary cut pattern is obtained by reading out the shaping characteristics of the reinforcing fiber base from the storage unit and simulating the behavior when shaping the reinforcing fiber base into a shaping mold based on the shaping characteristics. A first preliminary cut pattern acquisition unit to be acquired;
    A trim section for trimming unnecessary portions from the first preliminary cut pattern acquired by the first preliminary cut pattern acquisition section;
    The second preliminary cut that acquires the second preliminary cut pattern by simulating the behavior when the reinforcing fiber base developed from the first preliminary cut pattern trimmed by the trim portion is shaped into the shaping mold. A pattern acquisition unit;
    A notch forming unit for forming a notch according to the shaping characteristic with respect to the second preliminary cut pattern acquired by the second preliminary cut pattern acquisition unit;
    A third preliminary cut pattern is obtained by simulating the behavior of the reinforcing fiber base, which has developed the second preliminary cut pattern in which the cut forming portion has formed the cut, into the shaping mold. 3 preliminary cut pattern acquisition units;
    A cut pattern generation unit that generates a cut pattern for preform by cutting out and developing at least one of the overlapping regions in the third preliminary cut pattern acquired by the third preliminary cut pattern acquisition unit;
    A simulation apparatus comprising:
16. A preform substrate manufactured by the preform substrate manufacturing method according to claim 12.
17. A preform manufactured by the preform manufacturing method according to claim 13 or 14.
18. The preform according to claim 17, wherein a plurality of the preform base materials are laminated so that adjacent positions do not overlap with the notch edge.
19. A preform according to claim 17 or 18,
    A resin impregnated in the preform;
    A fiber-reinforced plastic molded article comprising:
20. To the computer that generates the cut pattern before shaping of the reinforcing fiber base constituting the preform of the fiber reinforced plastic molding by simulation,
    A first preliminary cut pattern is obtained by reading out the shaping characteristics of the reinforcing fiber base from the storage unit and simulating the behavior when shaping the reinforcing fiber base into a shaping mold based on the shaping characteristics. A first preliminary cut pattern acquisition step to be acquired;
    A trim step for trimming unnecessary portions outside the product from the first preliminary cut pattern acquired in the first preliminary cut pattern acquisition step;
    The second preliminary cut for obtaining the second preliminary cut pattern by simulating the behavior when the reinforcing fiber base material developed from the first preliminary cut pattern trimmed in the trim step is shaped into the shaping mold A pattern acquisition step;
    An incision forming step of forming an incision according to the shaping characteristic with respect to the second preliminary cut pattern acquired in the second preliminary cut pattern acquisition step;
    A third preliminary cut pattern is obtained by simulating the behavior when forming the reinforcing fiber base, which has developed the second preliminary cut pattern in which the cut is formed in the cut forming step, into the shaping mold. 3 preliminary cut pattern acquisition steps;
    A cut pattern generation step of generating a cut pattern for preform by cutting and developing at least one of the overlapping regions in the third preliminary cut pattern acquired in the third preliminary cut pattern acquisition step;
    A simulation program characterized by executing

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