JP2008161897A - Welding condition setting method, apparatus and computer program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To optimize press formation conditions and collision analysis conditions and also to determine welding conditions of spot welding. <P>SOLUTION: Plate thickness distribution and distortion distribution of a press formed article are calculated by press formation analysis based on a shape of the press formed article, punch transfer quantity, blank holding load, frictional coefficient and tensile strength, yield strength, a stress-distortion relationship and plate thickness of material, and collision energy absorption and deformation mode are calculated by collision analysis based on, in addition to the plate thickness distribution and distortion distribution of the press formed article, a member shape to be manufactured by spot welding of the press formed article, impact load, the number of spot welding and nugget diameter. The above press formation analysis and collision analysis are repeatedly performed while changing at least one of the press formation conditions and the collision conditions to calculate the press formation condition and collision condition giving the maximum value of the collision energy absorption. Thereafter, on the basis of the plate thickness distribution of the press formed article, the number of spot welding, and the nugget diameter which have been calculated in the repeated calculation, spot weld zone analysis is performed to calculate the welding conditions of the spot welding. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is a member such as a front side member of an automobile, and is used for manufacturing a member for absorbing impact energy generated at the time of an automobile collision. The present invention relates to a method, an apparatus, and a computer program.

  In order to absorb the impact energy generated at the time of automobile collision, members such as front side members generate regular buckling in the major axis direction of the member at the time of collision, and the impact energy is absorbed by plastic deformation due to this buckling. It aims to protect passengers.

  In the design of a conventional impact energy absorbing member, after determining an initial shape, a collision analysis is performed by a method such as a finite element method, and the shape of the member is changed so that the absorbed amount of impact energy becomes a target value. After the evaluation by analysis achieves the target value, final confirmation is made by trial manufacture and experiment, and the design is confirmed.

  These members are manufactured by plastic processing of thin plates, tubes or rods of steel or other materials and joining them as necessary. For the plastic working, a forming method such as pressing, hydroforming or extrusion is used. For joining, methods such as spot welding, arc welding, laser welding or rivet joining are used.

  Conventionally, a technique called coupled analysis from press forming to collision analysis shown in FIG. 10 is known. In FIG. 10, 1001 is a material before processing, 1002 is a result of molding analysis, 1003 is a result of molding analysis converted into input data for collision analysis, and 1004 is a result of collision analysis. In Patent Document 1, after forming the added shape data based on the final part shape data of the pressed part, forming analysis is performed, and characteristic analysis such as impact resistance performance is coupled based on the obtained analysis result. A simulation method is disclosed.

  However, Patent Document 1 does not describe a method for presenting an optimal part shape and molding conditions. Further, it does not describe a method for actually joining and welding the members.

JP 2004-50253 A

  When a metal such as steel is used as a material, changes in the plate thickness due to plastic deformation at the time of manufacturing the member and work hardening due to plastic strain occur, and the member receives an impact compared to when there is no plate thickness change or work hardening. It is known that the buckling deformation mode and the amount of absorption of impact energy change.

  Currently, plate thickness changes and work hardening are not taken into account during analysis using the finite element method, etc., so even if the design is based on the evaluation value of the analysis, the desired buckling deformation mode and impact energy absorption can be obtained in the prototype / experiment. I can't.

  In addition, due to variations in plastic working conditions at the time of member manufacture, variations in plate thickness change and work hardening also occur, and eventually the buckling deformation mode and the amount of shock energy absorbed vary.

  In addition, when spot-welding a reinforcing back plate after press molding, the amount of buckling deformation and impact energy absorption depends on the number of spot welds and the size of the nugget diameter, which is the range that is actually welded by spot welding. It is also known that changes. When the evaluation values of spot spot pitch and nugget diameter in finite element analysis are actually applied to spot welding as they are, it is difficult to surely obtain the necessary nugget diameter unless the thickness change after pressing is taken into consideration.

  The present invention optimizes the press forming conditions and the collision analysis conditions in order to obtain the desired collision performance while taking into account the influence of the plate thickness change and work hardening caused by plastic working during the production of the member, and the welding conditions for spot welding. The purpose is to be able to decide.

The welding condition setting method of the present invention is a welding condition setting method for setting welding conditions for spot welding when spot-welding a press-formed product, and as the press-forming conditions, the shape of the press-formed product, the amount of punch movement, the wrinkle holding Based on the load, friction coefficient, material tensile strength, yield strength, stress-strain relationship, and plate thickness, press molding analysis to calculate the thickness distribution and strain distribution of the press molded product, and the collision analysis conditions, In addition to the thickness distribution and strain distribution of the press-formed product calculated in the press-forming analysis, the impact is based on the shape of the member produced by spot welding the press-formed product, the impact load, the number of spot welds, and the nugget diameter. The collision analysis for calculating the energy absorption amount and the deformation mode is repeatedly performed by changing at least one of the press molding conditions and the collision analysis conditions. The iterative calculation procedure for calculating the press forming condition and the collision condition that gives the maximum value or stable region of the impact energy absorption amount, the plate thickness distribution, the number of spot welds, and the nugget diameter of the press formed product calculated by the repetitive calculation procedure And a spot welded part analysis procedure for performing spot welded part analysis based on the above and calculating spot welding welding conditions.
The welding condition setting device of the present invention is a welding condition setting device for setting welding conditions for spot welding when spot-welding a press-formed product, and as the press-forming conditions, the shape of the press-formed product, the amount of punch movement, and the wrinkle holding Press molding condition input means for inputting load, friction coefficient, material tensile strength, yield strength, stress-strain relationship, and plate thickness, press molded product shape input to the press molding condition input means, punch movement Press that performs press forming analysis based on the amount, wrinkle holding load, coefficient of friction, material tensile strength, yield strength, stress-strain relationship, and plate thickness, and calculates the plate thickness distribution and strain distribution of the press molded product In addition to the plate thickness distribution and strain distribution of the press-formed product calculated by the press-forming analysis means as the forming analysis means and the collision analysis condition, Collision analysis condition input means for inputting the shape of the member to be produced, impact load, number of spot welds, and nugget diameter, and a plate of the press molded product calculated by the press molding analysis means input to the collision analysis condition input means Collision analysis based on thickness distribution and strain distribution, shape of member manufactured by spot welding of press-formed product, impact load, number of spot welds, and nugget diameter, and impact energy absorption and deformation mode are calculated. And at least one of the press molding condition and the collision analysis condition is changed and the process from the press molding condition input unit to the collision analysis unit is repeated, and the maximum value or stable region of the impact energy absorption amount Repetitive calculation control means for providing the thickness of the press-formed product calculated by repetitive calculation by the repetitive calculation control means Cloth, spot welding speed, and performs the spot weld analysis based on nugget diameter, characterized in that a spot weld analyzing means for calculating a welding condition of spot welding.
The computer program of the present invention is a computer program for setting welding conditions for spot welding when spot-welding a press-formed product, and the press-molding conditions include the shape of the press-formed product, the amount of punch movement, the wrinkle holding load, and the friction coefficient. , Press forming analysis based on the tensile strength, yield strength, stress-strain relationship, and plate thickness of the material, and calculating the plate thickness distribution and strain distribution of the press molded product, and the collision analysis conditions In addition to the thickness distribution and strain distribution of the press-formed product calculated by the press-forming analysis, the collision is based on the shape of the member manufactured by spot welding the press-formed product, the impact load, the number of spot welds, and the nugget diameter. A collision analysis for performing an analysis and calculating an impact energy absorption amount and a deformation mode, the press molding condition and the collision analysis condition It is repeatedly performed by changing at least one of them, and a repeated calculation process for calculating a press molding condition and a collision condition that gives a maximum value or a stable region of the impact energy absorption amount, and a press molded product calculated by the repeated calculation process. A spot welded portion analysis is performed based on the plate thickness distribution, the number of spot welds, and the nugget diameter, and a spot welded portion analyzing process for calculating a welding condition for spot welding is executed by a computer.

  According to the present invention, the welding conditions for spot welding for obtaining, for example, a buckling deformation mode and an impact energy absorption amount at the time of an automobile collision are considered while taking into account the influence of plate thickness change and work hardening during member production. In addition, set the welding conditions necessary to maintain the design points (press molding conditions, etc.) that do not greatly change the collision performance even when spot welding is actually performed, even if there are variations in the processing conditions at the time of component production. It becomes possible.

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a flowchart for explaining a welding condition setting method for spot welding in the case of spot welding a press-formed product. First, press-molded product shape, punch travel, wrinkle holding load, friction coefficient, material tensile strength, yield strength, stress-strain relationship, and plate thickness are set as press-molding condition 1, and this is used as input data. The computer performs press forming analysis by the forming analysis program (step S101). In this press molding analysis, the plate thickness distribution and strain distribution 2 of the press molded product are calculated and output. The press molding conditions may be set by further applying pad pressure. By inputting the pad pressure, it is possible to expect the effects of avoiding defects such as cracks and wrinkles during molding and imparting appropriate work hardening (strain).

  Next, the output data (plate thickness distribution and strain distribution of the press-formed product) 2 in step S101 is converted by the computer into input data for collision analysis using a conversion program (step S102). Note that the output data 2 of the press molding analysis may further include the stress distribution of the press molded product. By calculating and outputting the stress distribution of a press-formed product in press forming analysis, and performing the following collision analysis based on this, the deformation and fracture phenomena at the time of the collision are reproduced faithfully to the actual phenomenon, and high-precision analysis Can be expected to be effective.

  Next, in addition to the plate thickness distribution and strain distribution 2 (which may include the stress distribution of the press-formed product) converted in step S102, the member manufactured by spot welding the press-formed product. The shape, impact load, number of spot welds, and nugget diameter are set as the collision analysis condition 3, and this is used as input data, and the computer performs a collision analysis using the collision analysis program (step S103). In this collision analysis, the impact energy absorption amount and the buckling deformation mode 4 are calculated and output.

  Next, output data (impact energy absorption amount and buckling deformation mode) 4 of the collision analysis in step S103 is evaluated (step S104). In the present invention, the collision analysis condition includes the number of spot welds and the nugget diameter when spot-pressing a press-formed product, thereby setting the buckling deformation mode at the time of collision to a desired form and maximizing the amount of collision energy absorption. The effect of doing can be expected. In the collision analysis, a collision energy absorption amount and a deformation mode are calculated. The deformation mode refers to a deformation mode when a member is deformed by receiving an impact. Specifically, a deformation mode that is folded in a lantern shape or a deformation mode that is bent in the middle of the member occurs.

  When the collision performance is not a desired value in step S104, or when the repeated calculation in steps S101 to S103 is less than the set number of times, at least one of the press molding condition 1 and the collision analysis condition 3 is changed. The computer repeats steps S101 to S103. The calculation is repeated in this way, and the process is terminated when the collision performance reaches a desired value. It should be noted that the set number of times is preferably executed ten times or more in order to search for the maximum point of the absorbed amount of impact energy. On the other hand, in order to save a series of analysis time, it is preferable to set it to 100 times or less.

  Thereby, as the optimum design result that gives the maximum value or stable region of the collision energy absorption amount, the press molding condition and the collision condition (including the thickness distribution of the press molded product, the number of spot welds, and the nugget diameter) are calculated ( Step S105).

  Subsequently, among the optimum design results calculated by the above repeated calculation, spot weld analysis is performed based on the plate thickness distribution, the number of spot welds, and the nugget diameter of the press-formed product, and the welding conditions for spot welding are calculated. . That is, based on the optimum design result obtained in step S105, the spot welding position (spotting point) can be determined from the number of spot welds. Thickness data 6) is obtained, and simultaneously the nugget diameter actually necessary for spot welding (hereinafter referred to as “optimum nugget diameter”) is obtained.

  First, welding conditions 5 including electrode shape, applied pressure, welding current value, energizing time, welded part thickness data 6, and steel sheet, such as yield strength, specific resistance value, thermal conductivity, etc. The physical property values are given, and the computer performs spot weld analysis by the spot weld analysis program (step S106). In this spot weld analysis, the nugget diameter is calculated and output.

  Next, the output data (nugget diameter) 7 of the spot weld analysis in step S106 is evaluated (step S107). That is, it is determined whether or not the output data (nugget diameter) 7 of the spot weld analysis satisfies the optimum nugget diameter.

  If the nugget diameter 7 does not satisfy the optimum nugget diameter in step S107, or if the repetitive calculation in step S106 is less than the set number of times, at least one of the welding conditions 5 for spot welding is changed, and the computer executes step S106 is repeated. Since the electrode shape is determined in accordance with the optimum nugget diameter, the welding current value is changed here. Thus, the calculation is repeated, and the process is terminated when the nugget diameter 7 satisfies the optimum nugget diameter. In this case, the set number of times is preferably 10 times or more, but is preferably 50 times or less in order to save a series of analysis times.

  In addition to the welding current value, the applied pressure may be changed and the calculation may be repeated. In general, it is known that the upper limit of the nugget diameter that can be realized by welding with the same pressurizing force becomes smaller as the steel sheet has a higher base metal tensile strength. Therefore, if the tensile strength of the steel plate is increased, it is necessary to secure an upper limit of the nugget diameter that can be realized by increasing the pressure. With regard to the lower limit of the nugget diameter, it is unthinkable that a small nugget diameter is output as the optimum collision condition that gives the maximum value of the impact energy absorption amount or the stable region as in the present invention.

  Thereby, the welding conditions (including the welding current value) of spot welding are calculated as the optimum result that satisfies the optimum nugget diameter (step S108).

  As described above, the welding conditions for spot welding to obtain, for example, the buckling deformation mode and impact energy absorption amount at the time of automobile collision are considered while taking into account the effects of plate thickness change and work hardening during member production. In addition, set the welding conditions necessary to maintain the design points (press molding conditions, etc.) that do not greatly change the collision performance even when spot welding is actually performed, even if there are variations in the processing conditions at the time of component production. It becomes possible.

  The forming analysis, the collision analysis, and the spot weld analysis are performed using an analysis program such as a finite element method. In addition, data conversion from molding analysis to collision analysis, collision performance evaluation, and shape / machining condition change are also performed by a commercially available program or a self-made program. Then, after obtaining the optimal press forming condition and the collision condition after the forming analysis to the collision analysis, data extraction and data conversion for spot welded portion analysis are also performed by a commercially available or self-made program.

  FIG. 2 is a diagram showing a configuration example of a computer system that functions as the welding condition setting device of the present invention. In the figure, reference numeral 200 denotes a computer PC. The PC 200 includes a CPU 201, executes device control software recorded in a ROM 202 or a hard disk (HD) 211, or supplied from a flexible disk drive (FD) 212, and collectively manages each device connected to the system bus 204. To control. Each functional unit of the present invention is realized by a program recorded in the CPU 201, the ROM 202, or the hard disk (HD) 211 of the PC 200.

  Reference numeral 203 denotes a RAM that functions as a main memory, work area, and the like of the CPU 201. A keyboard controller (KBC) 205 controls to input a signal input from the keyboard (KB) 209 into the system main body. A display controller (CRTC) 206 performs display control on the display device (CRT) 210. A disk controller (DKC) 207 is a hard disk that records a boot program (startup program: a program for starting execution (operation) of hardware and software of a personal computer), a plurality of applications, editing files, user files, a network management program, and the like. Controls access to the (HD) 211 and the flexible disk (FD) 212. A network interface card (NIC) 208 performs bidirectional data exchange with a network printer, another network device, or another PC via the LAN 220.

  Note that the welding condition setting device of the present invention may be applied to a system composed of a plurality of devices or an apparatus composed of a single device.

  Another object of the present invention is to supply a recording medium in which a program code of software realizing the functions of the above-described embodiments is recorded to a system or apparatus, and the computer (CPU or MPU) of the system or apparatus stores the recording medium in the recording medium. Needless to say, this can also be achieved by reading and executing the programmed program code. In this case, the program code itself read from the recording medium realizes the functions of the above-described embodiments, and the recording medium on which the program code is recorded constitutes the present invention. As a recording medium for supplying the program code, for example, a flexible disk, hard disk, optical disk, magneto-optical disk, CD-ROM, CD-R, magnetic tape, nonvolatile memory card, ROM, or the like can be used.

  As mentioned above, although this invention was demonstrated with various embodiment, this invention is not limited only to these embodiment, A change etc. are possible within the scope of the present invention.

(Example)
As an embodiment of the present invention, an example of designing a member in which a contact plate is spot welded to a hat-shaped cross-sectional member as shown in FIG. In FIG. 6, 61 indicates a spot welding position. The hat-shaped cross-sectional member is a press-formed product. The member receives an impact load in the major axis direction and is crushed axially, and the welding conditions of the member are optimized so that the amount of impact energy absorption at this time is maximized. Specifically, the number of spot welds and the nugget diameter are optimized for spot welding of the flange of the hat-shaped cross-sectional member and the contact plate. Thereafter, the welding current value that realizes the nugget diameter is optimized at each of the welding locations. Specifically, when the electrode shape, applied pressure, and energization time used for spot welding are known, the welding current value is optimized so as to obtain a desired nugget diameter in accordance with the plate thickness at the spot welding position.

  The dimensions of the hat-shaped cross-section member are 300 mm in length, 50 mm in cross-sectional width, 50 mm in cross-sectional height, 20 mm in flange width, and 1.4 mm in plate thickness. In addition, the length of the contact plate is 300 mm in length, 90 mm in width, and 1.4 mm in thickness. The materials are all 590 MPa class high-tensile steel plates.

  As other press molding conditions, the amount of punch movement was 50 mm, the wrinkle holding load (BHF) was 34 kN, and the friction coefficient was 0.15.

  The press forming conditions were input, press forming analysis was performed using a commercially available finite element analysis program Hyperform, and the thickness distribution (see FIG. 3) and strain distribution (see FIG. 4) of the press-formed product were calculated. .

  Conversion of input data from analysis results of plate thickness distribution and strain distribution of press-molded products to impact analysis by press-molding analysis is made and specified by FORTRAN program, and plate thickness distribution and strain of press-molded products as collision analysis conditions. Distribution and member shape were input.

  As a collision analysis condition, input a shock load equivalent to the case where a rigid body having a mass of 553.6 kg is further collided at a speed of 6.26 m / s, and perform a collision analysis using a commercially available finite element analysis program PAM-CRASH. went.

  The results similar to those shown in FIGS. 5A and 5B were obtained including the case of changing the number of spot welds and the nugget diameter described later. When the number of spot welds is 7 at regular intervals and the nugget diameter is 7 mm, it shows a good buckling deformation mode that can be folded into a lantern. It shows a bad buckling deformation mode that bends. In FIG. 5, the arrow indicates the direction of impact load, 51 indicates regular buckling deformation, and 52 indicates irregular buckling deformation.

  A commercially available optimization tool i-SIGHT was used to perform the procedures of collision performance evaluation, machining condition change, and collision performance re-evaluation. Step S101 in FIG. 1 is performed by changing the number of spot welds in the range of 3-10 pieces on one side and changing the nugget diameter in the range of 3-10 mm so that the collision energy absorption amount is maximum and stable. The computer repeatedly performed the process of S103 16 times, and searched for the optimum press molding condition or the optimum collision condition (including the thickness distribution of the press molded product, the number of spot welds, and the nugget diameter) that gives the maximum collision energy absorption amount. .

  The results are shown in FIG. In the graph, the horizontal axis 1601 is the number of spot welds, the horizontal axis 1602 is the nugget diameter, and the vertical axis 1603 is the impact energy maximum value. From this result, the point 1604 where the impact energy absorption amount is maximum is the impact energy absorption amount 7237J when the number of spot welds is 9 and the nugget diameter is 10 mm. Further, when the number of spot welds is 7 and the nugget diameter is 7 mm, there is a maximum point 1605 of the impact energy absorption amount 7125J, and this can be cited as a candidate for the optimum design point in consideration of the cost of spot welding.

  Further, as shown in FIG. 8, when the optimum welding conditions are given, the wrinkle holding load BHF = 200 kN to 250 kN when the above calculation is performed 13 times while changing the wrinkle holding load as the press forming condition. In this range, it was found that the impact energy absorption amount is highly stable, and this intermediate point should be adopted as the optimum design point. In FIG. 8, 81 is the point where the amount of collision energy absorption is maximum, and 82 is the range where the amount of collision energy absorption is highly stable.

  In order to realize the nugget diameter at the spot welding spot under the optimum welding conditions, it is necessary to search for the welding current value according to the steel plate thickness at each welding spot in the member with the thickness distribution finished by these optimum press forming conditions. It becomes. In order to perform the procedure of nugget diameter prediction-welding current value change-nugget diameter re-prediction, a commercially available optimization tool i-SIGN was used. For calculation of the nugget diameter, commercially available spot weld analysis software Quickspot was used.

  FIG. 9 is a diagram illustrating an example of nugget diameter calculation by spot weld analysis. In FIG. 9, 91 is an electrode and 92 is a nugget. When a nugget with a thickness of 1.4 mm is made of a 590 MPa grade steel plate with a thickness of 1.4 mm, a welding current value is obtained with an electrode of JIS-DR type tip diameter of 8 mm, an electrode pressure of 4.81 kN, and a current application time of 0.32 s Was 8.5 kA. Further, when a nugget having a nugget diameter of 7 mm was formed at a location having a plate thickness of 1.49 mm, a welding current value of 8.75 kA was required. Furthermore, when a nugget having a nugget diameter of 7 mm was formed at a location having a plate thickness of 1.31 mm, a welding current value of 8.3 kA was required.

  As a result, the number of spot welds, 7 mm, which maximizes the impact energy absorption amount considering the economics of the members pressed with the wrinkle holding load BHF = 200 kN to 250 kN, which has been clarified through optimization of the forming to collision analysis, is 7 mm. The current value required to create the nugget diameter was 8.3 kA to 8.75 kA due to fluctuations in the plate thickness distribution, and a desired 7 mm nugget could be created.

It is a flowchart for demonstrating the welding condition setting method of spot welding in the case of carrying out spot welding of a press-formed product. It is a figure which shows the structural example of the computer system which functions as a welding condition setting apparatus of this invention. It is a figure which shows the plate | board thickness distribution of the press molded product by the press molding analysis in an Example. It is a figure which shows the distortion distribution of the press-molded product by the press-molding analysis in an Example. The example of a collision analysis in an Example is shown, (A) is a figure which shows a good buckling deformation mode, (B) is a figure which shows a bad buckling deformation mode. It is a figure which shows the spot welding position of the hat-shaped cross-section member in an Example. It is a characteristic view which shows the relationship between the welding conditions and collision energy absorption amount in an Example. It is a characteristic view which shows the relationship between the wrinkle pressing load and impact energy absorption amount in an Example. It is a figure which shows the nugget diameter calculation example by the spot weld part analysis in an Example. It is a figure for demonstrating the example of the conventional combined analysis of shaping | molding and a collision.

Explanation of symbols

1 Input data for press forming analysis (press forming conditions)
2 Output data for press forming analysis 3 Input data for impact analysis (impact analysis conditions)
4 Collision analysis output data 5 Welding conditions 6 Weld thickness data 7 Spot weld analysis output data 201 CPU
202 ROM
203 RAM
204 System Bus 205 Keyboard Controller 206 Display Controller 207 Disk Controller 208 Network Interface Card 209 Keyboard 210 Display Device 211 Hard Disk 212 Flexible Disk Drive

Claims (4)

A welding condition setting method for setting welding conditions for spot welding when spot-welding a press-formed product,
Thickness distribution of press-molded product based on press-molded product shape, punch travel, wrinkle holding load, friction coefficient, material tensile strength, yield strength, stress-strain relationship, and plate thickness In addition to the press forming analysis for calculating the strain distribution and the collision analysis conditions, the shape of the member manufactured by spot welding the press formed product in addition to the plate thickness distribution and strain distribution of the press formed product calculated by the press forming analysis. The collision analysis for calculating the impact energy absorption amount and the deformation mode based on the impact load, the number of spot welds, and the nugget diameter is repeatedly performed by changing at least one of the press molding conditions and the collision analysis conditions. An iterative calculation procedure for calculating a press molding condition and a collision condition that give a maximum value or a stable region of the impact energy absorption amount;
A spot welded portion analysis procedure for performing spot welded portion analysis based on the thickness distribution, the number of spot welds, and the nugget diameter of the press-formed product calculated by the repeated calculation procedure, and calculating spot welding welding conditions. The welding condition setting method characterized by this.   In the spot welded part analysis procedure, the nugget diameter calculated in the iterative calculation procedure is realized based on the spot weld position obtained from the plate thickness distribution and the number of spot welds calculated in the iterative calculation procedure. The welding condition setting method according to claim 1, wherein a welding current value to be calculated is calculated. A welding condition setting device for setting welding conditions for spot welding in the case of spot welding a press-formed product,
Press molding condition input means for inputting a press molded product shape, punch movement amount, wrinkle holding load, friction coefficient, material tensile strength, yield strength, stress-strain relationship, and plate thickness as press molding conditions;
Press molding analysis based on press molded product shape, punch travel, wrinkle holding load, friction coefficient, material tensile strength, yield strength, stress-strain relationship, and plate thickness input to the press molding condition input means Press molding analysis means for calculating the thickness distribution and strain distribution of the press molded product,
As collision analysis conditions, in addition to the thickness distribution and strain distribution of the press-formed product calculated by the press-forming analysis means, the shape of the member manufactured by spot welding the press-formed product, impact load, number of spot welds, and nugget A collision analysis condition input means for inputting a diameter;
Plate thickness distribution and strain distribution of the press-formed product calculated by the press-forming analysis means input to the collision analysis condition input means, the shape of the member manufactured by spot welding the press-formed product, impact load, number of spot welds And a collision analysis means for performing a collision analysis based on the nugget diameter and calculating a shock energy absorption amount and a deformation mode;
Repeating the process from the press molding condition input means to the collision analysis means by changing at least one of the press molding conditions and the collision analysis conditions, and giving the maximum value or stable region of the impact energy absorption amount Calculation control means;
Spot weld analysis means for performing spot weld analysis based on the thickness distribution, the number of spot welds, and the nugget diameter of the press-formed product calculated by repeated calculation by the repeat calculation control means, and calculating the welding conditions for spot welding. And a welding condition setting device. A computer program for setting spot welding welding conditions when spot-welding a press-formed product,
Thickness distribution of press-molded product based on press-molded product shape, punch travel, wrinkle holding load, friction coefficient, material tensile strength, yield strength, stress-strain relationship, and plate thickness In addition to the press forming analysis for calculating the strain distribution and the collision analysis conditions, the shape of the member manufactured by spot welding the press formed product in addition to the plate thickness distribution and strain distribution of the press formed product calculated by the press forming analysis. The collision analysis for calculating the impact energy absorption amount and the deformation mode based on the impact load, the number of spot welds, and the nugget diameter is repeatedly performed by changing at least one of the press molding conditions and the collision analysis conditions. Repetitive calculation processing for calculating a press molding condition and a collision condition that give a maximum value or a stable region of the impact energy absorption amount;
Performs spot weld analysis based on the thickness distribution, the number of spot welds, and the nugget diameter of the press-formed product calculated in the repeated calculation process, and performs spot weld analysis processing for calculating the welding conditions for spot welding on a computer. A computer program that is executed.

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