CN115935515A - Rigidity evaluation method for formed automobile outer covering part - Google Patents
Rigidity evaluation method for formed automobile outer covering part Download PDFInfo
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Abstract
The invention relates to a rigidity evaluation method after forming an automobile outer cover, which comprises the following steps: s1, establishing an outer cover part digital model and a modeling CAS surface, and simulating an outer cover part stamping forming simulation process; s2, simulating a drawing process; s3, deriving the drawn part with thickness and strain information after stress release from finite element simulation software; s4, simulating the process of placing the drawing piece on the ground; and the drawing piece which contains the information of the thickness and the strain result and reaches the equilibrium state is led out; s5, simulating the process of pressing the drawing piece by an object; analyzing deformation information of a stress area of the drawing piece reaching the equilibrium state, and exporting an analysis result; s6, evaluating the rigidity of the comparative outer cover drawing piece according to the analysis result in the S5 and the material parameter of the outer cover. The method can theoretically and quantitatively evaluate the rigidity of the automobile outer covering part drawing piece in the early stages of modeling design, product design and process design.
Description
Technical Field
The invention relates to the technical field of manufacturing processes of automobile outer covering parts, in particular to a rigidity evaluation method of an automobile outer covering part after forming.
Background
The existing automobile outer covering part concavity resistance test standard and CAE finite element simulation evaluation method only aim at an automobile outer covering part assembly, the automobile covering part belongs to a large-scale thin plate stamping part, the curved surface of the automobile covering part is gentle, and during molding, due to the inadequacy and nonuniformity of plastic deformation of the automobile outer covering part, the rigidity of certain parts is poor. When the cover member having poor rigidity is vibrated, a cavity sound is generated, and the cover member is likely to vibrate at a high speed, thereby causing early damage to the cover member. It is therefore necessary to ensure a certain rigidity.
The traditional method for evaluating the rigidity of the automobile outer covering part drawing part is to beat the part to distinguish the difference of the sounds of different parts of the part or to press the part by hands to see whether the part is loosened or swelled, so the evaluation result is subjective and difficult to quantify; some automobile manufacturers adopt an object pressing method, as shown in fig. 1, the specific method is as follows: taking a central point of a workpiece, and placing an article with a certain weight in the center of the workpiece; placing a designated weight on the object, and pressing the workpiece by using the self weight of the designated weight; after the pressing, the area size after the deformation is measured is compared with the rigidity and the strength of the part, although the rigidity and the strength can be quantized, the evaluation can be only carried out after the part is manufactured, and if the rigidity of the part is poor, the product or process adjustment is carried out, so that the development period and the cost are increased. There is a lack of a method that enables a theoretical quantitative assessment of the rigidity of an automotive outer cover draw during the styling phase, product design, or process design early stages.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides a method for evaluating the rigidity of an automobile outer cover after forming, which can theoretically and quantitatively evaluate the rigidity of an automobile outer cover drawing part in the early stages of modeling design, product design and process design.
In order to achieve the purpose, the specific technical scheme of the invention is as follows: a rigidity evaluation method after forming an automobile outer cover, the rigidity evaluation method comprising the steps of:
s1, establishing an outer cover part digital model and a modeling CAS surface, and simulating an outer cover part stamping forming simulation process;
s2, simulating a drawing process;
constructing an outer cover drawing process surface, and carrying out outer cover drawing formability simulation analysis; carrying out rebound analysis on the external covering part drawing piece by using finite element simulation software to obtain a stress-released drawing piece;
s3, deriving the drawn part with thickness and strain information after stress release from finite element simulation software;
s4, simulating the process of placing the drawing piece on the ground;
after the drawing piece with the released stress is placed on the ground, applying load to the drawing piece with the released stress at a preset acceleration until the drawing piece with the released stress is balanced, and exporting the drawing piece with the thickness and strain result information and in a balanced state;
s5, simulating the process that an object applies pressure to the drawing piece;
applying load to the drawing part reaching the equilibrium state, analyzing deformation information of a stress area of the drawing part reaching the equilibrium state, and exporting an analysis result;
s6, evaluating the rigidity of the comparative outer cover drawing according to the analysis result in S5 and the material parameter of the outer cover.
Further, in step S5, the drawing member reaching the equilibrium state is constrained according to an object pressure method, then a load is applied to the gravity center position of the drawing member reaching the equilibrium state, then a solver is used to analyze and solve the deformation, the stress value and the plastic strain of the stress area of the drawing member reaching the equilibrium state, and the analysis result is derived.
Further, in step S6, evaluating the comparison means: the maximum stress applied to the stressed area of the drawing member reaching the equilibrium state is compared with the yield strength of the outer cover material, and the magnitude of the deformation amount and the magnitude of the deformation range of the stressed area of the drawing member reaching the equilibrium state are evaluated.
Further, in step S4, firstly, a finite element tool body of the ground is established, and the attribute of the ground is set as a rigid body; secondly, setting a contact relation between the drawing piece after stress release and the ground; applying a load to the drawn piece after the stress is released at a preset acceleration; and finally, submitting the preset acceleration to a solver to perform simulation calculation on the process of placing the drawing piece on the ground, forming the drawing piece reaching the equilibrium state, and performing object pressure application and stress analysis on the drawing piece.
Further, carrying out an object pressure application stress analysis process on the drawing piece reaching the equilibrium state: the method comprises the steps of introducing a drawing piece which contains thickness and strain result information and reaches an equilibrium state and a ground finite element tool body into finite element simulation software together, setting the contact relation between the ground and the drawing piece which reaches the equilibrium state, applying a preset load F to the gravity center position of the drawing piece which reaches the equilibrium state, and submitting the load F to a solver to calculate the deformation, the deformation range and the stress of a stress area of the drawing piece which reaches the equilibrium state.
Further, in step S2, an outer cover drawing formability simulation process: introducing the outer covering part drawing process surface established in the step S1 into finite element simulation software, meshing the outer covering part drawing process surface, establishing a tool body, wherein the tool body sequentially comprises a female die, a flattening ring and a male die from top to bottom, a blank is arranged between the female die and the flattening ring, the size of the blank is set according to the size of the outer covering part drawing process surface, and meshing the blank; setting material properties and material performance parameters of the blank, stamping process parameters and simulation analysis parameters, submitting to a solver, and simulating the blank drawing process to obtain a drawing piece of the outer covering piece.
Further, in step S2, performing free springback simulation analysis on the outer cover drawing piece by using finite element simulation software, submitting a free springback setting file of the outer cover drawing piece to a solver, performing internal stress release calculation on the outer cover drawing piece with internal stress information by using the solver, and after the stress is released, deforming the outer cover drawing piece to form the stress-released drawing piece.
Further, the stamping process parameters comprise the movement stroke of the tool body, the size of the blank holder force and the friction coefficient; the simulation analysis parameters include mesh refinement level, minimum mesh size and result output.
Further, in step S2, a CAS surface or a product model of the outer cover is established, and a stamping direction, a nip surface, and a process supplementary connection portion of the outer cover are determined in conjunction with a stamping process experience of the outer cover, and the CAS surface or the product model is placed on the nip surface through the process supplementary connection portion to construct an outer cover drawing process surface.
Further, in step S1, an outer cover press forming simulation is simulated by three-dimensional modeling software or professional press forming simulation software.
The invention has the beneficial effects that:
the theoretical quantitative evaluation method for rigidity of the automobile outer covering part drawing piece provided by the invention can carry out theoretical quantitative evaluation on the rigidity of the automobile outer covering part drawing piece in the early stages of modeling design, product design and process design, and reduces development cycle and development cost increase caused by changes of modeling, products, processes and molds due to insufficient rigidity of the outer covering part.
The method simultaneously considers the stress release of the automobile outer cover blank after being drawn and the factors influencing the rigidity of the drawn part, such as the thickness change, the plastic strain and the like of the drawn part of the outer cover after being drawn, is consistent with the actual manufacturing process of the outer cover, so that the evaluation result is closer to the reality.
The method is not only suitable for the automobile outer covering piece, but also suitable for the rigidity evaluation of parts formed by stamping parts of aviation, spaceflight, ships, household appliances and the like.
Drawings
FIG. 1 is a schematic representation of a prior art rigidity evaluation of an automotive outer cover draw using object pressing;
FIG. 2 is a flowchart illustrating a method for evaluating rigidity of an automobile outer cover after forming according to the present invention;
FIG. 3 is a drawing part change diagram of the present invention in a theoretical quantitative process of rigidity evaluation by taking a drawing part of an engine hood outer panel as an example;
FIG. 4 is a schematic representation of a CAS surface or product digifax of the hood outer panel of the present invention;
FIG. 5 is a schematic drawing process view of the outer panel of the hood according to the present invention;
FIG. 6 is a schematic drawing of a finite element blank drawing model according to the present invention;
FIG. 7 is a schematic view of a drawn part of an outer panel of a hood after forming a blank according to the present invention;
FIG. 8 is a graph comparing stress values before (graph a) and after (graph b) stress release according to the present invention;
FIG. 9 is a comparison graph of the profile before and after stress release and a cloud of profile variation values according to the present invention;
FIG. 10 is a schematic drawing of a drawn part with die thickness information according to the present invention;
FIG. 11 is a schematic drawing of a part of the present invention with stamping strain information;
FIG. 12 is a schematic view of a finite element model of the invention with a drawn part placed on the ground;
FIG. 13 is a schematic view of the present invention with the drawing member placed on the ground to an equilibrium state;
FIG. 14 is a graph showing a comparison of the front and rear stresses of a drawn part of the present invention placed on the ground;
FIG. 15 is a schematic view of an object pressure analysis finite element model of a drawn part according to the present invention;
FIG. 16 is a comparison of the profile of the drawing member before and after being stressed by pressure;
FIG. 17 is a schematic view of the range of deformation of the drawn member of the present invention;
FIG. 18 is a schematic view showing the Z-direction deformation of the drawing member of the present invention;
FIG. 19 is a stress cloud of the inventive draw.
Wherein: 1-CAS surface or product digifax, 2-pressing surface, 3-process complementary connecting part, 4-female die, 5-flattening ring, 6-male die, 7-blank, 8-engine hood outer plate drawing piece, 9-drawing piece after stress release, 10-ground, 11-drawing piece reaching balance state, and 12-drawing piece deformed by stress.
Detailed Description
In order to make those skilled in the art better understand the technical solutions of the present application, the present invention will be further described in detail below with reference to the accompanying drawings and examples.
The terms of orientation such as up, down, left, right, front, and rear in the present document are established based on the positional relationship shown in the drawings. The corresponding positional relationship may also vary depending on the drawings, and therefore, should not be construed as limiting the scope of protection.
In the present invention, the terms "mounted," "connected," "fixed," and the like are to be understood in a broad sense, and for example, may be fixedly connected, detachably connected, integrally connected, mechanically connected, electrically connected or capable of communicating with each other, directly connected, indirectly connected through an intermediate medium, or communicated between two components, or interacting between two components. The specific meanings of the above terms in the present invention can be understood according to specific situations by those of ordinary skill in the art.
This example describes a method for evaluating rigidity of an automobile outer cover after forming, which is used for theoretical quantitative evaluation of rigidity of an automobile outer cover drawn part in the early stages of design of a figure, design of a product, and design of a process.
In order to reflect the actual force and deformation of the outer cover during the pressing of the object from the product figure to the drawing member more truly, as shown in fig. 2 and 3, the evaluation method comprises the following steps:
1. establishing an outer cover part digital model and a modeling CAS surface, and simulating the stamping forming simulation process of the outer cover part;
2. simulating a drawing process;
firstly, constructing an outer cover drawing technical face through outer cover stamping forming simulation, and then carrying out outer cover drawing formability simulation analysis; carrying out springback analysis, namely internal stress release analysis on the external covering part drawing piece by using finite element simulation software to obtain a stress-released drawing piece with thickness and strain information so as to more truly evaluate the rigidity of the drawing piece in the following process;
3. deriving the stress-released drawing piece with the thickness and strain information obtained in the step 2 from finite element simulation software for a subsequent simulation process;
4. simulating the process of placing the drawing piece on the ground;
and (3) placing the drawing piece with the stress released in the previous step on the ground, applying a load to the drawing piece with the stress released at a preset acceleration to ensure that the drawing piece with the stress released is balanced under the ground support to form the drawing piece reaching the balanced state, and leading out the drawing piece reaching the balanced state and containing the information of the thickness and the strain result for analyzing the pressure and stress of a subsequent object.
5. Simulating the process of pressing the drawing piece by an object;
firstly, constraining a drawing piece reaching an equilibrium state according to an object pressure method, then applying a load to the gravity center position of the drawing piece reaching the equilibrium state, analyzing and solving the deformation, stress value, plastic strain and the like of a stress area of the drawing piece reaching the equilibrium state by using a solver, and exporting the analysis result;
in this embodiment, the solver adopts a dynamic display algorithm to perform analysis and solution, and its equilibrium equation:
M D ＝diagM
the solving method comprises the following steps:
wherein, F: external force, P: internal force, t: time, x: current coordinate, u: displacement, K: stiffness matrix, M: quality matrix, M D Represents a diagonal matrix, i.e. a diagonal matrix of the quality matrix M,
speed,. Or>
Acceleration, k: this time step, k-1: last time step, n: this time step, n-1: last time step, Δ t: the time increment between the last time step and the current time step.
6. The rigidity of the comparative draw was evaluated based on the analysis results derived in step 5 and the material parameters of the outer cover.
Specifically, the evaluation comparison means: the maximum stress applied to the stressed area of the drawing member reaching the equilibrium state is compared with the yield strength of the outer cover material, and the magnitude of the deformation amount and the magnitude of the deformation range of the stressed area of the drawing member reaching the equilibrium state are evaluated.
When the same type of parts are subjected to the same load, the larger the deformation amount and the larger the deformation range, the poorer the rigidity is, and on the contrary, the better the rigidity is; when the maximum stress value of the drawing member reaching the equilibrium state is smaller than the yield strength of the material of the outer cover, the part does not generate plastic deformation and has good rigidity, and conversely, the part generates plastic deformation and has poor rigidity.
In the present embodiment, the evaluation method is described by taking the hood outer panel as an example, and the rigidity theoretical quantitative evaluation is performed on the blank drawn part before the hood outer panel is formed, and the method comprises the following implementation steps:
1) Creating a stamping technical face of a drawn part
In the embodiment, three-dimensional modeling software or professional stamping simulation software is adopted to simulate blank stamping simulation, so that the establishment of the drawing process surface of the outer plate of the engine hood is completed.
Specifically, a CAS surface or a product digifax 1 of the outer panel of the engine hood is established first (see fig. 4), a stamping direction, a swage surface 2 and a process supplement connecting part 3 of the outer panel of the engine hood are determined by combining stamping process experience of the outer panel of the engine hood, the CAS surface or the product digifax 1 is placed on the swage surface 2 through the process supplement connecting part 3 as shown in fig. 5, and then three-dimensional modeling software or professional stamping forming simulation software is adopted to construct a drawing process surface of the outer panel of the engine hood.
2) Simulation analysis of drawing process
Introducing the drawing process surface of the outer plate of the engine hood established in the step 1) into finite element simulation software, and meshing the drawing process surface. The method comprises the steps of establishing a tool body, as shown in fig. 6, sequentially arranging a female die 4, a flattening ring 5 and a male die 6 from top to bottom, arranging a blank 7 between the female die 4 and the flattening ring 5, arranging the size of the blank 7 according to the size of a drawing process surface of an outer plate of the engine hood, and meshing the blank 7.
Setting the material attribute and material performance parameters of the blank 7 in finite element simulation software, wherein if the blank 7 is made of a galvanized steel plate with the material brand of HC180BD + Z, the thickness of the blank is 0.65mm; setting stamping technological parameters such as the motion stroke of the tool body, the size of blank holder force, friction coefficient and the like; and setting simulation analysis parameters such as grid refinement level, minimum grid size, result output and the like.
The parameter information of the blank 7 and the set stamping and simulation parameters are respectively submitted to a solver to simulate the drawing process of the blank 7, and the blank 7 is formed into an engine hood outer plate drawing piece 8 (see figure 7) according to the drawing technical surface of the engine hood outer plate.
3) Stress relief of drawn parts
The actually produced drawn part has internal stress, the internal stress is automatically released after the drawn part is taken out of the die, and in order to reflect the real state of the drawn part more really, the finite element simulation software is utilized to carry out rebound analysis, namely internal stress release analysis, on the drawn part, so that more accurate shape of the drawn part can be obtained, and the rigidity of the drawn part can be evaluated more really in the following process.
And (3) setting a free springback (stress release) simulation analysis step for the engine hood outer plate drawing part 8 after the blank 7 is drawn and formed in the drawing process simulation analysis in the step 2), submitting a free springback setting file of the engine hood outer plate drawing part 8 to a solver, and performing internal stress release calculation on the engine hood outer plate drawing part 8 with internal stress information through the solver.
The solver of this embodiment performs internal stress release calculation by using a static implicit algorithm, and the equilibrium equation is as follows:
R(u,x,t)＝F(x,t)-P(u,x)＝0
the solving method comprises the following steps:
Δu k ＝-[ t+Δt K k ] -1t+Δt R k
t+Δt u k+1 ＝ t+Δt u k +Δu k
wherein R: residual force, F: external force, P: internal force, x: current coordinate, u: displacement, K: a stiffness matrix.
After the stress is released, the drawing piece 8 of the outer plate of the engine cover reaches the stress balance and deforms to form the drawing piece 9 after the stress is released, and the shape of the drawing piece 9 after the stress is released is the accurate shape of the drawing piece. Fig. 8 shows the state before and after the release of the internal stress of the hood outer panel drawing 8, wherein fig. a shows the state of the internal stress of the hood outer panel drawing 8 before the release of the stress, fig. b shows the state of the stress of the drawing 9 after the release of the stress, and the change in the shape of the drawing before and after the release of the stress is compared with fig. 9, wherein it can be seen from fig. 9 a) that the shape of the hood outer panel drawing 8 is significantly changed after the release of the stress, and fig. 9 b) shows a cloud graph comparing the amount of deformation of the shape of the hood outer panel drawing 8.
4) Drawing part 9 with thickness and strain information after stress release is derived
Because the blank 7 is subjected to the drawing process and the stress release process, the thickness of the blank is changed, and corresponding plastic strain is generated, and the information of the results directly influences the rigidity of the drawn part. As shown in fig. 10 and 11, the result file of the stress-relieved drawing member 9 with the stamped thickness and strain information is derived from the finite element simulation software for simulation of the subsequent process of placing the drawing member on the ground.
5) Simulation of the process of placing a drawn part on the ground 10
Guiding the drawn part 9 which is guided out in the last step and has thickness and strain information and is subjected to stress release into finite element simulation software; as shown in fig. 12, firstly, a finite element tool body of the ground 10 is established, and the attribute of the ground 10 is set as a rigid body; secondly, setting the contact relation between the drawing piece 9 after stress release and the ground 10; then, a load is applied to the drawing piece 9 after the stress is released according to the acceleration (such as the gravity acceleration g) in the preset finite element file; finally, submitting a preset finite element setting file A (containing related information of the drawing piece with the preset acceleration load, the ground and the like) to a solver to perform simulation calculation of the placing process of the drawing piece on the ground 10, so that the drawing piece 9 after stress release is supported by the ground 10 to be balanced, and the drawing piece 11 which is shown in fig. 13 and reaches a balanced state is formed.
The solver in this step is the same as the solver in step 3 in calculation process, and a dynamic display algorithm is also used for analysis and solution, and the equilibrium equation is as follows:
the solving method comprises the following steps:
wherein, F: external force, P: internal force, x: current coordinate, u: displacement, K: stiffness matrix, M: a matrix of the quality of the image is determined,
speed,. Or>
Acceleration of the vehicle.
A comparison of the stresses of the stress-relieved drawing part 9 placed in front of and behind the ground 10 is shown in FIG. 14. And finally, exporting a result file of the drawing part 11 which contains the thickness and strain result information and reaches the equilibrium state, and using the result file for analyzing the pressure application and stress of the subsequent object.
6) Object pressure force analysis of drawn parts
The drawing piece 11 which contains thickness and strain result information and reaches the equilibrium state is led into finite element simulation software, the ground 10 finite element tool body in the step 5) is also led in, as shown in fig. 15, the contact relation between the ground 10 and the drawing piece 11 which reaches the equilibrium state is set, a certain load F is applied to the gravity center position of the drawing piece 11 which reaches the equilibrium state, the load F is determined according to the rigidity evaluation requirement, a preset finite element setting file B (including the drawing piece applying the load F, the ground and other related information) is submitted to a solver for calculation, and the deformation amount, the deformation range and the stress magnitude of the stress area of the drawing piece 11 which reaches the equilibrium state are calculated.
7) Quantitative index evaluation of stiffness
After the calculation is finished, the rigidity of the drawing piece is evaluated through analysis results such as the deformation amount, the deformation range, the stress magnitude and the like of the stress area of the drawing piece 11 reaching the equilibrium state. When the same type of parts are subjected to the same load, the larger the deformation amount and the larger the deformation range are, the poorer the rigidity is; conversely, the better the rigidity.
Fig. 16 is a comparison of the profiles (i.e., the shape deformation) of the balanced drawing piece 11 before and after being pressed and stressed, and the balanced drawing piece 11 is pressed and deformed to form the stressed and deformed drawing piece 12. It is obvious from the figure that the drawing part is obviously deformed in the stressed area. FIG. 17 is a schematic view of the deformation range of the drawing member 12 deformed by force, and the deformation range of the middle part of the drawing member 12 deformed by force is the circle part in the figure, and the diameter is
FIG. 18 is a cloud chart of Z-direction deformation of the drawn part 12 deformed by force, and it can be seen from the cloud chart that the value of the middle dent is the largest and the dent is 6.147mm. Fig. 19 is a stress cloud graph of the drawn part 12 deformed by force, and it can be seen from the graph that the stress applied to the middle part of the drawn part 12 deformed by force is large, the maximum stress is 132.789MPa, the yield strength of the material HC180BD + Z of the blank 7 is greater than 180MPa, and the maximum stress applied to the drawn part 12 deformed by force is 132.789MPa, and the yield strength of the material is not exceeded, that is, plastic deformation is not generated. If the stress on the drawn part 12 subjected to the forced deformation exceeds the yield strength of the material, unrecoverable plastic deformation will occur, and the rigidity of the part is poor.
While the principles of the invention have been described in detail in connection with the preferred embodiments thereof, it will be understood by those skilled in the art that the foregoing embodiments are merely illustrative of exemplary implementations of the invention and are not limiting of the scope of the invention. The details in the examples are not to be construed as limitations on the scope of the invention, and any obvious modifications, equivalent alterations, simple substitutions, etc. based on the technical solution of the present invention are intended to fall within the scope of the present invention without departing from the spirit and scope of the present invention.
Claims (10)
1. A rigidity evaluation method after forming an automobile outer cover, characterized by comprising the steps of:
s1, establishing an outer cover part digital model and a modeling CAS surface, and simulating an outer cover part stamping forming simulation process;
s2, simulating a drawing process;
constructing an outer covering part drawing technical surface, and carrying out outer covering part drawing formability simulation analysis; carrying out rebound analysis on the external covering part drawing piece by using finite element simulation software to obtain a stress-released drawing piece;
s3, deriving the drawn part with thickness and strain information after stress release from finite element simulation software;
s4, simulating the process of placing the drawing piece on the ground;
after the drawing piece with the released stress is placed on the ground, applying load to the drawing piece with the released stress at a preset acceleration until the drawing piece with the released stress is balanced, and exporting the drawing piece with the thickness and strain result information and in a balanced state;
s5, simulating the process of pressing the drawing piece by an object;
applying load to the drawing part reaching the equilibrium state, analyzing deformation information of a stress area of the drawing part reaching the equilibrium state, and exporting an analysis result;
s6, evaluating the rigidity of the comparative outer cover drawing according to the analysis result in S5 and the material parameter of the outer cover.
2. The method for evaluating rigidity of an automobile outer cover after forming, according to claim 1, wherein in step S5, the drawing member that has reached the equilibrium state is first constrained according to an object pressing method, then a load is applied to a position of a center of gravity of the drawing member that has reached the equilibrium state, and then a deformation amount, a stress value, and a plastic strain of a force-receiving region of the drawing member that has reached the equilibrium state are solved by analysis using a solver, and a result of the analysis is derived.
3. The method for evaluating rigidity of an automobile outer cover after forming, according to claim 2, wherein in step S6, the evaluation comparison is: the maximum stress applied to the stressed area of the drawing member reaching the equilibrium state is compared with the yield strength of the outer cover material, and the magnitude of the deformation amount and the magnitude of the deformation range of the stressed area of the drawing member reaching the equilibrium state are evaluated.
4. The method for evaluating rigidity of an automobile outer cover after forming, according to claim 1, wherein in step S4, a finite element tool body of the ground (10) is first established, and the attribute of the ground (10) is set as a rigid body; secondly, setting a contact relation between the drawing piece (9) after stress release and the ground (10); applying a load to the drawing piece (9) after the stress is released at a preset acceleration; and finally, submitting the preset acceleration to a solver to perform simulation calculation on the placing process of the drawing piece on the ground (10), forming the drawing piece (11) reaching the equilibrium state, and performing object pressure application and stress analysis on the drawing piece.
5. The method for evaluating rigidity of an automobile outer cover after forming according to claim 4, wherein the drawn member (11) which has reached the equilibrium state is subjected to an object pressing force analysis process of: the drawing piece (11) which contains thickness and strain result information and reaches the equilibrium state and the ground (10) finite element tool body are led into finite element simulation software together, the contact relation between the ground (10) and the drawing piece (11) which reaches the equilibrium state is set, a preset load F is applied to the gravity center position of the drawing piece (11) which reaches the equilibrium state, and the load F is submitted to a solver to calculate the deformation, the deformation range and the stress of the stress area of the drawing piece (11) which reaches the equilibrium state.
6. The method for evaluating rigidity of an automobile outer cover after forming, according to claim 1, wherein in step S2, the outer cover draw formability simulation process: introducing the outer covering part drawing process surface established in the step S1 into finite element simulation software, and carrying out grid division on the outer covering part drawing process surface to establish a tool body, wherein the tool body sequentially comprises a female die (4), a flattening ring (5) and a male die (6) from top to bottom, a blank (7) is arranged between the female die (4) and the flattening ring (5), the size of the blank (7) is set according to the size of the outer covering part drawing process surface, and the blank (7) is divided into grids; setting the material attribute and material performance parameter of the blank (7), the stamping process parameter and the simulation analysis parameter, submitting a solver, and simulating the drawing process of the blank (7) to obtain the drawing piece of the outer covering piece.
7. The method of claim 6, wherein in step S2, the outer cover drawing is subjected to a free springback simulation analysis using finite element simulation software, a free springback profile of the outer cover drawing is submitted to a solver, an internal stress release calculation is performed on the outer cover drawing with internal stress information by the solver, and after the stress release, the outer cover drawing is deformed to form the stress-released drawing.
8. The method for evaluating rigidity of an automobile outer cover after forming according to claim 6, wherein the press process parameters include a tool body movement stroke, a blank holder force level, and a friction coefficient; the simulation analysis parameters include mesh refinement level, minimum mesh size and result output.
9. The method for evaluating rigidity of an automobile outer cover after forming according to claim 1, wherein in step S2, a CAS surface or product model (1) of the outer cover is established, a stamping direction, a nip (2) and a process supplement connection portion (3) of the outer cover are determined in combination with a stamping process experience of the outer cover, and the CAS surface or product model (1) is placed on the nip (2) through the process supplement connection portion (3) to construct an outer cover drawing process surface.
10. The method for evaluating rigidity of an automobile outer cover after forming according to claim 1, wherein in step S1, an outer cover press forming simulation is simulated by a three-dimensional modeling software or a professional press forming simulation software.
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| CN116933447A (en) * | 2023-09-17 | 2023-10-24 | 浙江大学高端装备研究院 | Method for evaluating reliability of damping structure of coated turbine blade |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116933447A (en) * | 2023-09-17 | 2023-10-24 | 浙江大学高端装备研究院 | Method for evaluating reliability of damping structure of coated turbine blade |
| CN116933447B (en) * | 2023-09-17 | 2024-01-09 | 浙江大学高端装备研究院 | Method for evaluating reliability of damping structure of coated turbine blade |
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