A method for accurately predicting the thickness of parts formed by hot drawing and gas bulging

Abstract

The present invention is a method for accurately predicting the thickness of hot deep drawing and gas bulging forming parts. The present invention relates to the technical field of deep drawing / gas bulging forming. The present invention establishes a thermal / mechanical coupling model for the hot deep drawing forming of the target part, conducts hot deep drawing simulation calculations, and after the deep drawing calculation is completed, uses grid repositioning to output a model containing the thickness of the elements after deep drawing; on the basis of the model containing the element thickness, modifies the die and working conditions, and establishes a thermal / mechanical coupling model for the gas bulging forming of the target part; uses the thickness of the elements after deep drawing as the initial thickness for gas bulging forming simulation to predict the thickness of the target part in hot deep drawing / gas bulging forming, and draws a contour map of the formed thickness distribution. The present invention analyzes the accurate thickness distribution of the formed parts during hot deep drawing / gas bulging forming, and controls problems such as wall thickness thinning and local cracking.

Description

Technical Field

[0001] The present invention relates to the technical field of deep drawing / hydro-pneumatic forming, and is a method for accurately predicting the thickness of parts formed by hot deep drawing and hydro-pneumatic forming. Background Art

[0002] The superplastic forming technology originated in the late 1970s. Due to its low forming force, simple process, no need for specific molds, and good forming quality, it has been widely used in the aerospace field. At present, China has successfully manufactured parts such as aircraft pneumatic pump cabin doors, cab partitions, aircraft wing surfaces, side wings, air ducts, missile wing surfaces, engine casings, and missile barrels using superplastic forming or superplastic forming / diffusion bonding combined technology. Although the superplastic forming and diffusion bonding process has many advantages in the aerospace field, its efficiency is low, the formed structure is coarse, and it has extremely high requirements for the manufacturing process level and operation details. When the process parameters are not properly controlled, defects such as surface wrinkling, local cracking, wall thickness reduction, shape differences, internal rib distortion, and triangular area cavities may occur. In response to the problem of wall thickness reduction in superplastic forming technology, scholars at home and abroad have continuously innovated in materials, molds, and the process itself. Nevertheless, the wall thickness uniformity during the superplastic forming process remains the main concern.

[0003] The integral superplastic forming of thin-walled components is a new method for manufacturing lightweight thin-walled structures. However, for components with a large diameter ratio, the process difficulty lies in controlling the forming accuracy and wall thickness uniformity. As the complexity of the formed parts continues to change, sometimes a single process cannot meet the production requirements. At this time, a method of combined forming of multiple processes emerges. This method needs to be carried out step by step during simulation. In traditional simulation technology, generally, an average value of the results of the previous step is taken to replace the whole. However, in the actual process, the stress, strain, thickness, etc. of each part are not uniform. Therefore, using the average value to replace the whole results in inaccurate final results. Summary of the Invention

[0004] In view of the problems existing in the method for predicting the thickness of parts formed by hot deep drawing / hydro-pneumatic forming in the prior art, the present invention provides a method for accurately predicting the thickness of hot deep drawing / hydro-pneumatic forming, analyzes the accurate thickness distribution of the formed parts during hot deep drawing / hydro-pneumatic forming, and controls problems such as wall thickness reduction and local cracking.

[0005] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device.

[0006] The present invention provides a method for accurately predicting the thickness of a thermo-drawing and gas-bulging forming part, and the following technical solutions are provided by the present invention:

[0007] A method for accurately predicting the thickness of a thermo-drawing and gas-bulging forming part, the method comprising the following steps:

[0008] Step 1: Establish a thermal / mechanical coupling model for the thermo-drawing forming of the target part, perform thermo-drawing simulation calculations, and after the drawing calculation is completed, use grid repositioning to output a model containing the thickness of the elements after drawing;

[0009] Step 2: Modify the die and working conditions on the basis of the model containing the element thickness, and establish a thermal / mechanical coupling model for the gas-bulging forming of the target part;

[0010] Step 3: Use the thickness of the elements after drawing as the initial thickness for gas-bulging forming simulation, predict the thickness of the target part in thermo-drawing / gas-bulging forming, and draw a contour map of the formed thickness distribution.

[0011] Preferably, the specific content of Step 1 is as follows:

[0012] Construct a thermal / mechanical coupling model for the thermo-drawing of a thin-walled double-cone according to the actual part size. The thermo-drawing punch, die, blank holder and sheet are all drawn in Solidworks software. Among them, the die and blank holder are regarded as rigid bodies during the finite element simulation, and their stress and strain are ignored, so they can be exported as solids. The sheet is imported into Hypermesh as a deformable body for mesh generation, and the mesh size is 3 mm, and then uniformly imported into MSC.Marc;

[0013] During the simulation, the position of the sheet is taken as the actual neutral plane position of the sheet, and the actual thickness of the sheet is 2 mm. Therefore, the distances between the blank holder and the sheet, and between the sheet and the die are both 1 mm. During the overall forming process, both the die and the blank holder are fixed, and no constraints need to be applied. The drawing punch moves downward during the hot drawing process until it contacts the blank holder, with an actual moving distance of 58 mm. The material for the drawing process is a multi-physics field elastoplastic constitutive model, and the true stress-strain curve is input. After the drawing process ends, the drawing punch remains fixed until the gas bulging process ends. The thickness distribution contour map of the sheet after drawing is the result of the drawing process and also the initial thickness for the gas bulging forming.

[0014] Preferably, using the mesh repositioning function in MSC.Marc software, a model containing the thickness of the elements after drawing is output.

[0015] Preferably, step 2 is specifically as follows:

[0016] After the drawing process ends, open the result file of the analysis task in the thermal / mechanical coupling model of the double-cone hot drawing forming. Select the required increment step under the result file, and then select mesh repositioning under the tool column. At this time, MSC.Marc starts to calculate, and finally obtains the geometric characteristics of the three-dimensional shell structure, obtains the thickness of each element, and saves the calculated file as 2-1-1.mud. This model contains the thickness of the elements after drawing.

[0017] Preferably, the process of establishing the thermal / mechanical coupling model for the gas bulging forming of the part is as follows:

[0018] Retain the sheet thickness parameter in the model output in step 1. According to the Solidworks drawing, use the finite element software MSC.Marc to import the gas bulging die and establish a finite element geometric model, and then set the boundary conditions and load conditions; finally, establish the thermal / mechanical coupling model for the gas bulging forming of the part.

[0019] Preferably, step 3 is specifically as follows:

[0020] According to the saved 2-1-1.mud file, construct a thermal / mechanical coupling model for the gas bulging forming of the thin-walled double-cone, re-import the die for the gas bulging process and re-set the boundary conditions and load conditions. In the gas bulging process, first apply a non-uniform temperature field, adjust the temperature parameters according to the thickness of the sheet after drawing. The material for the gas bulging process is a rigid-plastic constitutive model. Apply a distributed force on the unit surface in the suspended area of the sheet during the gas bulging process, and set fixed constraints in other areas until the forming ends. The thickness distribution contour map of the sheet after gas bulging.

[0021] Preferably, a thermal / mechanical coupling model of the part's hydro-pneumatic forming is established based on the MSC.Marc platform to simulate and analyze the deformation behavior of the sheet metal during the deformation process; then, the required data is extracted through MSC.Marc, the wall thickness at each position is analyzed, and finally, the wall thickness distribution nephogram of the part is obtained.

[0022] A system for accurately predicting the thickness of a hot deep-drawing and hydro-pneumatic forming part, the system comprising:

[0023] A model establishment module, which establishes a thermal / mechanical coupling model for the hot deep-drawing forming of the target part, conducts hot deep-drawing simulation calculations, and after the deep-drawing calculation is completed, uses grid repositioning to output a model containing the thickness of the elements after deep-drawing;

[0024] Based on the model containing the element thickness, the die and working conditions are modified to establish a thermal / mechanical coupling model for the hydro-pneumatic forming of the target part;

[0025] A thickness prediction module, which uses the thickness of the elements after deep-drawing as the initial thickness for hydro-pneumatic forming simulation to predict the thickness of the target part during hot deep-drawing / hydro-pneumatic forming and draw a forming thickness distribution nephogram.

[0026] A computer-readable storage medium, on which a computer program is stored, and the program is executed by a processor to implement a method for accurately predicting the thickness of a hot deep-drawing and hydro-pneumatic forming part.

[0027] A computer device, comprising a memory and a processor, the memory stores a computer program, and when the processor executes the computer program, a method for accurately predicting the thickness of a hot deep-drawing and hydro-pneumatic forming part is implemented.

[0028] The present invention has the following beneficial effects:

[0029] The present invention optimizes the actual hot deep-drawing / hydro-pneumatic process by predicting the wall thickness distribution of the target part during the hot deep-drawing / hydro-pneumatic forming process. Through the final wall thickness distribution nephogram, problems such as wall thickness thinning and non-uniformity can be seen, as well as whether the deep-drawing and hydro-pneumatic parameters are reasonably designed, avoiding the risk of local cracking, which is of great significance for guiding the actual on-site production.

[0030] The present invention uses the grid repositioning function in MSC.Marc as an intermediate link to accurately transfer the data generated in the previous step to the next link, reducing data loss during the intermediate process and avoiding the inaccurate simulation results caused by the traditional use of average values. Its results are more accurate and more instructive for actual production.

[0031] The method for predicting the thickness of parts in hot drawing / pneumatic bulging forming of the present invention is applicable to various materials, various components, and multiple processes. It can predict the wall thickness distribution of various sheet materials during the composite forming of multiple processes, and the results are more accurate and intuitive. It can also extract the results generated in a certain intermediate step, which is more flexible.

[0032] The thermal / mechanical coupling model for parts in hot drawing / pneumatic bulging forming established by the present invention, compared with the traditional method of using the calculated average value to replace the whole, directly defines the deformed body by using the mesh repositioning function, greatly saving the modeling time. It can establish models under different wall thickness distributions, analyze the influence of multiple working conditions on the wall thickness distribution of the formed parts, and can accurately simulate the entire forming process, which is not possessed by the traditional model. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0034] Figure 1 It is the formed part drawing;

[0035] Figure 2 It is the schematic diagram of the placement relationship of the geometric model;

[0036] Figure 3 It is the wall thickness distribution nephogram after the drawing process;

[0037] Figure 4 It is the process diagram of using the mesh repositioning in the tool;

[0038] Figure 5 It is the unit thickness diagram calculated by the mesh repositioning;

[0039] Figure 6 It is the process diagram of saving the model separately after the mesh repositioning;

[0040] Figure 7 It is the boundary condition diagram of the pneumatic bulging process;

[0041] Figure 8 It is the wall thickness distribution nephogram after the pneumatic bulging process. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0042] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0043] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0044] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations. Specific Embodiment 1:

[0046] According to Figures 1 to 8 As shown, the specific optimized technical solution adopted by the present invention to solve the above technical problems is: The present invention relates to a method for accurately predicting the thickness of a hot deep drawing and gas bulging forming part.

[0047] The method includes the following steps:

[0048] Step 1: Establish a thermal / mechanical coupling model for the hot deep drawing forming of the target part, perform hot deep drawing simulation calculations, and after the drawing calculation is completed, use grid repositioning to output a model including the thickness of the cells after drawing;

[0049] Step 2: Modify the die and working conditions on the basis of the model including the cell thickness, and establish a thermal / mechanical coupling model for the gas bulging forming of the target part;

[0050] Step 3: Use the thickness of the cells after drawing as the initial thickness for gas bulging forming simulation, predict the thickness of the target part in hot deep drawing / gas bulging forming, and draw a contour map of the forming thickness distribution.

[0051] The specific content of Step 1 is as follows:

[0052] Construct a thermal / mechanical coupling model of a thin-walled double-cone hot drawing according to the actual part dimensions. The hot drawing punch, die, blank holder, and sheet metal are all drawn in Solidworks software. Among them, the die and the blank holder are regarded as rigid bodies during the finite element simulation, and their stress and strain are ignored. Therefore, they can be exported as solids. The sheet metal is imported into Hypermesh as a deformable body for mesh generation. The mesh size is 3 mm, and then it is uniformly imported into MSC.Marc;

[0053] During the simulation, the position of the sheet metal is taken as the actual neutral plane position of the sheet metal. The actual thickness of the sheet metal is 2 mm. Therefore, the distances between the blank holder and the sheet metal, and between the sheet metal and the die are both 1 mm. During the overall forming process, both the die and the blank holder are fixed and no constraints need to be applied. The drawing punch moves downward during the hot drawing process until it contacts the blank holder. The actual moving distance is 58 mm. The material for the drawing process is a multi-physics elasto-plastic constitutive model, and the true stress-strain curve is input. After the drawing process is completed, the drawing punch remains fixed until the gas bulging process is completed. The thickness distribution cloud map of the sheet metal after drawing is the result of the drawing process and also the initial thickness for the gas bulging forming.

[0054] Use the mesh repositioning function in MSC.Marc software to output a model containing the thickness of the elements after drawing.

[0055] The specific content of step 2 is as follows:

[0056] After the drawing process is completed, open the result file of the analysis task in the thermal / mechanical coupling model of the double-cone hot drawing. Select the required increment step under the result file, and then select mesh repositioning under the tool column. At this time, MSC.Marc starts to calculate, and finally obtains the geometric characteristics of the three-dimensional shell structure, obtains the thickness of each element, and saves the calculated file as 2-1-1.mud. This model contains the thickness of the elements after drawing.

[0057] The process of establishing the thermal / mechanical coupling model for the gas bulging forming of the part is as follows:

[0058] Retain the sheet metal thickness parameter in the model output in step 1. According to the Solidworks drawing, use the finite element software MSC.Marc to import the gas bulging die, establish a finite element geometric model, and then set the boundary conditions and load conditions; finally, establish the thermal / mechanical coupling model for the gas bulging forming of the part.

[0059] The specific content of step 3 is as follows:

[0060] According to the saved 2-1-1.mud file, a thermal / mechanical coupling model for the hydroforming of a thin-walled double-cone is constructed. The die for the hydroforming process is re-imported, and the boundary conditions and load conditions are reset. In the hydroforming process, a non-uniform temperature field is first applied, and the temperature parameters are adjusted according to the thickness of the sheet after drawing. The material for the hydroforming process is a rigid-plastic constitutive model. A distributed force on the unit surface is applied to the suspended area of the sheet in the hydroforming process, and fixed constraints are set in other areas until the forming is completed. The contour map of the sheet thickness distribution after hydroforming is obtained.

[0061] Through the thermal / mechanical coupling model of the part hydroforming established on the MSC.Marc platform, the deformation behavior of the sheet during the deformation process is simulated and analyzed; then the required data is extracted through MSC.Marc, and the wall thickness at each position is analyzed, and finally the contour map of the part wall thickness distribution is obtained. Specific Embodiment 2:

[0063] The difference between Embodiment 2 and Embodiment 1 of this application is only that:

[0064] The present invention provides a system for accurately predicting the thickness of a hot drawing and hydroforming part, and the system includes:

[0065] A model establishment module, which establishes a thermal / mechanical coupling model for the hot drawing forming of a target part, conducts hot drawing simulation calculations, and after the drawing calculation is completed, uses grid repositioning to output a model including the unit thickness after drawing;

[0066] On the basis of the model including the unit thickness, the die and working conditions are modified to establish a thermal / mechanical coupling model for the hydroforming of the target part;

[0067] A thickness prediction module, which uses the unit thickness after drawing as the initial thickness for hydroforming simulation to predict the thickness of the target part in hot drawing / hydroforming, and draws a contour map of the forming thickness distribution. Specific Embodiment 3:

[0069] The difference between Embodiment 3 and Embodiment 2 of this application is only that:

[0070] A method for accurately predicting the thickness of a hot drawing / hydroforming part of the present invention includes the following steps:

[0071] Step 1: Establish a thermal / mechanical coupling model for the hot drawing forming of a certain target part, conduct hot drawing simulation calculations, and after the drawing calculation is completed, use grid repositioning to output a model including the unit thickness after drawing;

[0072] Step 2: On the basis of the model including the unit thickness, modify the die, working conditions, etc. to establish a thermal / mechanical coupling model for the hydroforming of the target part;

[0073] Step 3: Use the thickness of the drawn unit as the initial thickness for the hydroforming simulation, predict the thickness of the target part in hot drawing / hydroforming, and draw the contour map of the forming thickness distribution.

[0074] In Step 1 described above, the finite element software for the part drawing process is MSC.Marc.

[0075] In Step 1 described above, the finite element mesh division of the part in the finite element software can be carried out using Hypermesh.

[0076] In Step 1 described above, the geometries of the die and the formed part required for hot drawing are determined according to the actual parameters.

[0077] In Step 1 described above, the process of establishing the thermal / mechanical coupling model for the part hot drawing is as follows: First, according to the Solidworks drawing, use the finite element software MSC.Marc to import the hot drawing punch, die, blank holder, sheet metal, etc., use Hypermesh for mesh division, establish the finite element geometric model, and then set the boundary conditions and load conditions; finally, establish the thermal / mechanical coupling model for the part hot drawing.

[0078] In Step 1 described above, in the process of establishing the thermal / mechanical coupling model for the part hot drawing, the main content of the analysis is the distribution of the unit thickness of the thin wall during the hot drawing process;

[0079] In Step 1 described above, use the mesh repositioning function in the MSC.Marc software to output a model containing the thickness of the drawn unit.

[0080] In Step 2 described above, the thermal / mechanical coupling model for the part hydroforming is established based on the model output in Step 1.

[0081] In Step 2 described above, the finite element software for the part hydroforming process is MSC.Marc.

[0082] In Step 2 described above, the geometries of the die and the formed part required for hydroforming are determined according to the actual parameters.

[0083] In Step 2 described above, the process of establishing the thermal / mechanical coupling model for the part hydroforming is as follows: First, retain parameters such as the sheet thickness in the model output in Step 1, then according to the Solidworks drawing, use the finite element software MSC.Marc to import the hydroforming die, establish the finite element geometric model, and then set the boundary conditions and load conditions; finally, establish the thermal / mechanical coupling model for the part hydroforming.

[0084] In the aforesaid Step 3, the method for predicting the hot deep drawing / pneumatic bulging forming of parts is as follows: By establishing a thermal / mechanical coupling model for the pneumatic bulging forming of parts with MSC.Marc as the platform, the deformation behavior of the sheet metal during the deformation process is simulated and analyzed; then the required data is extracted through MSC.Marc, and the wall thickness at each position is analyzed. Finally, a contour map of the wall thickness distribution of the part is obtained.

[0085] The application of a method for predicting the thickness of hot deep drawing / pneumatic bulging forming of parts optimizes the actual hot deep drawing / pneumatic bulging process by predicting the wall thickness distribution of the target part during the hot deep drawing / pneumatic bulging forming process. Through the final contour map of the wall thickness distribution, problems such as wall thickness thinning and non-uniformity can be seen, as well as whether the deep drawing and pneumatic bulging parameters are designed reasonably, avoiding the risk of local rupture, which is of great significance for guiding the actual on-site production. Specific Embodiment 4:

[0087] The difference between Embodiment 4 and Embodiment 3 of this application is only that:

[0088] Taking the production of a Figure 1 thin-walled hyperbolic cone as shown as an example, the original sheet metal is a Ti60 sheet with a thickness of 2 mm. The original sheet metal forms a thin-walled hyperbolic cone after hot deep drawing and pneumatic bulging respectively, and the contour map of the wall thickness distribution after forming is analyzed. A method for predicting the thickness of hot deep drawing / pneumatic bulging forming of a thin-walled double cone in this example includes the following steps:

[0089] Step 1: Construct a thermal / mechanical coupling model for the hot deep drawing of a thin-walled double cone according to the actual part size. The hot deep drawing punch, die, blank holder, and sheet metal are all drawn in Solidworks software. Among them, the die and blank holder are regarded as rigid bodies during the finite element simulation, and their stress and strain are ignored, so they can be exported as entities. The sheet metal is imported into Hypemesh as a deformable body for mesh generation, and the mesh size is 3 mm, and then uniformly imported into Marc. The positional relationship of the model is as Figure 2 shown. During the simulation, the position where the sheet metal is located is regarded as the neutral plane position of the actual sheet metal, and the actual thickness of the sheet metal is 2 mm. Therefore, the distances between the blank holder and the sheet metal, and between the sheet metal and the die are both 1 mm. During the overall forming process, both the die and the blank holder are fixed and no constraints need to be applied. The hot deep drawing punch moves downward during the hot deep drawing process until it contacts the blank holder, and the actual moving distance is 58 mm. The material for the deep drawing process is a multi-physical field elastoplastic constitutive model, and the true stress-strain curve of Ti60 high-temperature titanium alloy at 850 °C is input. After the deep drawing process, the hot deep drawing punch remains fixed until the pneumatic bulging process ends. The contour map of the sheet metal thickness distribution after deep drawing is as Figure 3 shown. This thickness distribution is the result of the deep drawing process and is also the initial thickness for the pneumatic bulging forming.

[0090] Step 2: After the deep drawing process is completed, open the result file of the analysis task in the thermal / mechanical coupling model of the double-cone hot deep drawing forming. Select the required increment step under the result file, and then select Mesh Repositioning under the Tools column. As shown in Figure 4 shown, MSC.Marc then starts to calculate, and finally obtains the geometric characteristics of the three-dimensional shell structure. The thickness of each element can be seen. As shown in Figure 5 shown, save the calculated file as 2-1-1.mud. As shown in Figure 6 shown, this model then contains the element thickness after deep drawing.

[0091] Step 3: Open the saved 2-1-1.mud file, construct the thermal / mechanical coupling model of the thin-walled double-cone hydroforming, re-import the die of the hydroforming process and re-set the boundary conditions and load conditions. As shown in Figure 7 shown, in the hydroforming process, a non-uniform temperature field is first applied, and the temperature parameters are adjusted according to the thickness of the sheet after deep drawing. The material in the hydroforming process is a rigid-plastic constitutive model. A distributed force on the element surface is applied to the suspended area of the sheet in the hydroforming process, and fixed constraints are set in other areas until the forming is completed. The cloud diagram of the sheet thickness distribution after hydroforming is as shown in Figure 8 shown.

[0092] Through the finite element simulation of the integrated hot deep drawing / hydroforming of the Ti60 hyperbolic cone structural part, it can be seen from the cloud diagram of the sheet thickness distribution that the thinning situation is considerable, the wall thickness uniformity is greatly improved, and there are no defects such as wrinkling and cracking during forming. Specific Embodiment Five:

[0094] The difference between Embodiment Five and Embodiment Four of this application is only that:

[0095] The present invention provides a computer-readable storage medium, on which a computer program is stored, and the program is executed by a processor to implement a method for accurately predicting the thickness of a hot deep drawing hydroforming part. Specific Embodiment Six:

[0097] The difference between Embodiment Six and Embodiment Five of this application is only that:

[0098] The present invention provides a computer device, including a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, it implements a method for accurately predicting the thickness of a hot deep drawing hydroforming part.

[0099] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or N embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples. Further, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" can explicitly or implicitly include at least one of such features. In the description of the present invention, the meaning of "N" is at least two, such as two, three, etc., unless otherwise specifically and clearly defined. Any process or method description represented in the flowchart or described in other ways herein can be understood to represent a module, segment, or part of code including one or more N executable instructions for implementing a customized logical function or process, and the scope of the preferred embodiments of the present invention includes additional implementations, where the functions can be executed in a manner that is not in the order shown or discussed, including in a substantially simultaneous manner according to the functions involved or in the reverse order, which should be understood by those skilled in the art of the embodiments of the present invention. The logic and / or steps represented in the flowchart or described in other ways herein, for example, can be considered as a sequenced list of executable instructions for implementing a logical function, and can be specifically implemented in any computer-readable medium for use by an instruction execution system, apparatus, or device (such as a computer-based system, a system including a processor, or other systems that can fetch and execute instructions from the instruction execution system, apparatus, or device), or in combination with these instruction execution systems, apparatuses, or devices. For the purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transmit a program for use by or in combination with an instruction execution system, apparatus, or device. More specific examples (non-exhaustive list) of computer-readable media include the following: an electrical connection part (electronic device) having one or N wirings, a portable computer diskette case (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM).In addition, the computer-readable medium can even be paper or other suitable media on which the program can be printed, because the program can be obtained electronically, for example, by optically scanning the paper or other media, followed by editing, interpretation or other appropriate processing if necessary, and then stored in a computer memory. It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above embodiments, the N steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, any one or a combination of the following techniques well known in the art can be used: discrete logic circuits having logic gate circuits for implementing logical functions on data signals, application specific integrated circuits having appropriate combinational logic gate circuits, programmable gate arrays (PGAs), field programmable gate arrays (FPGAs), etc.

[0100] The above description is only a preferred embodiment of a method for accurately predicting the thickness of a hot deep drawing and gas bulging forming part. The protection scope of a method for accurately predicting the thickness of a hot deep drawing and gas bulging forming part is not limited to the above embodiments. Any technical solutions falling within this concept belong to the protection scope of the present invention. It should be noted that for those skilled in the art, several improvements and variations made without departing from the principle of the present invention should also be regarded as within the protection scope of the present invention.

Claims

1. A method for accurately predicting the thickness of a hot drawing and gas bulging forming part, characterized in that: The method includes the following steps: Step 1: Establish a thermal / mechanical coupling model for the hot deep drawing forming of the target part, conduct hot deep drawing simulation calculations, and after the drawing calculation is completed, use mesh repositioning to output a model containing the thickness of the elements after drawing; Specifically, Step 1 is as follows: Construct a thermal / mechanical coupling model for the hot deep drawing of a thin-walled double-cone according to the actual part dimensions. The hot deep drawing punch, die, blank holder, and sheet are all drawn in Solidworks software. Among them, the die and the blank holder are regarded as rigid bodies during the finite element simulation, and their stress and strain are ignored, so they can be exported as solids. The sheet is imported into Hypermesh for mesh division with a mesh size of 3 mm, and then uniformly imported into MSC.Marc; During the simulation, the position of the sheet is taken as the actual neutral plane position of the sheet, and the actual thickness of the sheet is 2 mm. Therefore, the distances between the blank holder and the sheet, and between the sheet and the die are both 1 mm. During the overall forming process, both the die and the blank holder are fixed and no constraints need to be applied. The drawing punch moves downward during the hot deep drawing process until it contacts the blank holder, with an actual moving distance of 58 mm. The material for the drawing process is a multi-physics elastoplastic constitutive model, and the true stress-strain curve is input. After the drawing process is completed, the drawing punch remains fixed until the gas bulging process is completed. The thickness distribution cloud map of the sheet after drawing is the result of the drawing process and also the initial thickness for the gas bulging forming; Use the mesh repositioning function in MSC.Marc software to output a model containing the thickness of the elements after drawing; Step 2: Modify the die and working conditions on the basis of the model containing the element thickness, and establish a thermal / mechanical coupling model for the gas bulging forming of the target part; Specifically, Step 2 is as follows: After the drawing process is completed, open the result file of the analysis task in the thermal / mechanical coupling model for the hot deep drawing forming of the double-cone. Select the required increment step under the result file, and then select mesh repositioning under the tool column. At this time, MSC.Marc starts to calculate, and finally obtains the geometric characteristics of the three-dimensional shell structure and the thickness of each element. Save the calculated file as 2-1-1.mud, and this model contains the thickness of the elements after drawing; Step 3: Use the thickness of the elements after drawing as the initial thickness for the gas bulging forming to conduct gas bulging forming simulation, predict the thickness of the target part during hot deep drawing / gas bulging forming, and draw the forming thickness distribution cloud map.

2. The method according to claim 1, wherein: The process of establishing the thermal / mechanical coupling model for the gas bulging forming of the part is as follows: Retain the sheet thickness parameter in the model output in Step 1. According to the Solidworks drawing, use the finite element software MSC.Marc to import the gas bulging die, establish a finite element geometric model, and then set the boundary conditions and load conditions; finally, establish the thermal / mechanical coupling model for the gas bulging forming of the part.

3. The method according to claim 2, wherein: Specifically, Step 3 is as follows: Based on the saved 2-1-1.mud file, a thermo-mechanical coupling model for the gas-assisted forming of a thin-walled double-cone is constructed. The die for the gas-assisted forming process is re-imported, and the boundary conditions and load conditions are reset. In the gas-assisted forming process, a non-uniform temperature field is first applied, and the temperature parameters are adjusted according to the thickness of the sheet after drawing. The material for the gas-assisted forming process is a rigid-plastic constitutive model. A distributed force on the unit surface is applied to the suspended area of the sheet in the gas-assisted forming process, and fixed constraints are set in other areas until the forming is completed. The thickness distribution nephogram of the sheet after the gas-assisted forming is obtained.

4. The method according to claim 3, characterized in that: Through the thermo-mechanical coupling model for the gas-assisted forming of parts established on the MSC.Marc platform, the deformation behavior of the sheet during the deformation process is simulated and analyzed. Then, the required data is extracted through MSC.Marc, the wall thickness at each position is analyzed, and finally the wall thickness distribution nephogram of the part is obtained.

5. A system for accurately predicting the thickness of parts formed by hot drawing and gas bulging, characterized in that: The system includes: A model establishment module, which establishes a thermo-mechanical coupling model for the hot drawing forming of the target part, conducts hot drawing simulation calculations, and after the drawing calculation is completed, uses grid repositioning to output a model containing the thickness of the elements after drawing. A thermo-mechanical coupling model for the hot drawing of a thin-walled double-cone is constructed according to the actual part dimensions. The hot drawing punch, die, blank holder, and sheet are all drawn in Solidworks software. Among them, the die and the blank holder are regarded as rigid bodies during the finite element simulation, and their stress and strain are ignored, so they can be exported as solids. The sheet is imported into Hypermesh as a deformable body for mesh generation, and the mesh size is 3mm, and then they are uniformly imported into MSC.Marc. During the simulation, the position of the sheet is taken as the neutral plane position of the actual sheet, and the actual thickness of the sheet is 2mm. Therefore, the distances between the blank holder and the sheet, and between the sheet and the die are both 1mm. During the overall forming process, the die and the blank holder are both fixed, and no constraints need to be applied. The hot drawing punch moves downward during the hot drawing process until it contacts the blank holder, and the actual moving distance is 58mm. The material for the hot drawing process is a multi-physics elastoplastic constitutive model, and the true stress-strain curve is input. After the hot drawing process is completed, the hot drawing punch remains fixed until the gas-assisted forming process is completed. The thickness distribution nephogram of the sheet after the hot drawing is the result of the hot drawing process and also the initial thickness of the gas-assisted forming. Using the grid repositioning function in the MSC.Marc software, a model containing the thickness of the elements after drawing is output. Based on the model containing the element thickness, the die and the working conditions are modified to establish a thermo-mechanical coupling model for the gas-assisted forming of the target part. After the hot drawing process is completed, in the thermo-mechanical coupling model for the hot drawing forming of the double-cone, the result file of the analysis task is opened, the required increment step is selected under the result file, and then the grid repositioning under the tool bar is selected. At this time, MSC.Marc starts to calculate, and finally the geometric characteristics of the three-dimensional shell structure are obtained, and the thickness of each element is obtained. The calculated file is saved as 2-1-1.mud, and this model contains the thickness of the elements after drawing. A thickness prediction module, which uses the thickness of the elements after drawing as the initial thickness for the gas-assisted forming simulation, predicts the thickness of the target part during hot drawing / gas-assisted forming, and draws the thickness distribution nephogram of the forming.

6. A computer-readable storage medium having a computer program stored thereon, characterized in that, The program is executed by a processor to implement the method as recited in claims 1-4.

7. A computer device, comprising a memory and a processor, the memory storing a computer program, characterized in that: When the processor executes the computer program, the method as recited in claims 1-4 is implemented.

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