Finite element simulation method for laser shock forming of ribbed wallboard

Abstract

The invention provides a finite element simulation method for a ribbed wallboard formed through laser shock. The finite element simulation method comprises the steps that initial laser shock pressure time-space distribution corresponding to laser process parameters is determined; applying the impact pit as a load to a laser multi-point continuous dynamic impact finite element model to obtain a simulated impact pit size; judging whether the size of the simulation and experiment impact pit is within an allowable error range or not; a strain field and a residual stress field after laser shock are obtained, and average inherent strain distribution in the depth direction is output; and introducing the average inherent strain distribution into the layered shell unit model of the ribbed wallboard and solving to obtain a deformation result of the ribbed wallboard impacted by the laser process parameters. Dynamic simulation of laser multi-point continuous impact is realized through display analysis, and deformation simulation of the ribbed wallboard formed through laser impact is realized through thermoelastic analysis, so that effective forming simulation can be performed on the complex ribbed wallboard, and the effects of low cost, high efficiency and accurate prediction result are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of laser shock forming, and in particular to a finite element simulation method for laser shock forming ribbed wall panels. Background Art

[0002] Laser shock forming technology is a new type of surface strengthening and forming technology. While forming the target shape of the part, it can also introduce a certain depth of residual compressive stress and microstructure changes on the surface of the part, thereby improving the mechanical properties of the formed part. Since the existing laser shock forming technology belongs to moldless forming, in order to obtain the required shape of the part, it is necessary to select and optimize the laser shock process parameters. However, due to the complexity of the laser shock forming mechanism and the influence of many variable factors in the forming process, it is extremely difficult to optimize the process parameters only through experiments and operating experience. Therefore, combining finite element simulation to optimize the laser shock forming process parameters is a simpler, more effective and low-cost method.

[0003] The Chinese patent with publication number CN107633115 discloses a "finite element simulation method for multi-point laser shock forming", which selects characteristic units for multi-point laser shock simulation, obtains residual stress distribution, and uses it as the initial stress field to simulate the forming results. This patent uses the direct stress method to simulate the laser shock forming of flat parts, but does not consider the problem of errors between the simulation results and the experimental results, and this patent is only applicable to flat parts and does not involve the forming simulation of ribbed wall panels. In addition, the existing technology mainly performs forming simulation on simple structures of non-ribbed wall panels, and the existing forming simulation methods all start from known stress distribution or inherent strain, and fail to map the laser process parameters and deformation simulation one by one.

[0004] Therefore, there is an urgent need for a complete method that can simulate the laser shock forming of ribbed sidings based on laser process parameters, so that the inherent strain method can be applied to the laser shock forming simulation of ribbed sidings. Summary of the invention

[0005] The present invention provides a finite element simulation method for laser shock formed ribbed wall panels, which is mainly used to solve the problem that the existing laser shock forming technology combined with finite element simulation cannot effectively simulate the forming of ribbed wall panels, thereby achieving the effect of being able to effectively simulate the forming of complex ribbed wall panels with low cost, high efficiency and accurate prediction results.

[0006] The present invention achieves the above-mentioned purpose through the following technical solutions:

[0007] A finite element simulation method for laser shock forming ribbed wall panels, comprising:

[0008] Step 1: Determine the preliminary laser shock pressure time-space distribution corresponding to the laser process parameters.

[0009] Step 2: Establish a laser multi-point continuous dynamic impact finite element model, and apply the preliminary laser shock pressure time-space distribution as a load to the laser multi-point continuous dynamic impact finite element model to obtain the simulated impact crater size of the laser process parameters.

[0010] Step 3: Correct the time-space distribution of laser shock pressure, and determine whether the error value between the simulated shock crater size and the experimental shock crater size under the same laser process parameters is within the allowable error range. If so, output the time-space distribution of laser shock pressure corresponding to the laser process parameters and execute the next step. If not, adjust the laser absorption coefficient and return to step 1.

[0011] Step 4: Apply the time-space distribution of the laser shock pressure to the laser multi-point continuous dynamic shock finite element model and solve it to obtain the strain field and residual stress field after the laser process parameters are impacted, and extract the inherent strain distribution along the depth direction, so as to output the average inherent strain distribution along the depth direction corresponding to the laser process parameters.

[0012] Step 5: Introduce the average inherent strain distribution along the depth direction into the layered shell element model of the ribbed wall panel and solve it to obtain the deformation result of the ribbed wall panel impacted by the laser process parameters.

[0013] A further solution is that the temporal and spatial distribution of the preliminary laser shock pressure in step 1 is:

[0014]

[0015] Where, τ is the laser pulse width; α p is the laser absorption coefficient; α is the coefficient of internal energy conversion into thermal energy; γ is the specific heat capacity of air; R is the laser spot radius; I is the laser power density; Z is the total impact impedance.

[0016] A further solution is that the laser multi-point continuous dynamic impact finite element model uses a three-dimensional deformable entity type, the finite element area of ​​which is located in the middle of the three-dimensional model and includes a 4×4 arrangement of light spot impacts.

[0017] The boundary of the finite element region is 1 mm larger than the boundary of the light spot impact region.

[0018] Wherein, the edge of the three-dimensional model is an infinite element region, and the width of the infinite element region is greater than 2 mm.

[0019] A further solution is that the material of the laser multi-point continuous dynamic impact finite element model is set to an isotropic Johnson-Cook material constitutive model.

[0020] A further solution is that step 2 also includes:

[0021] Step 21: Load application setting: The application of laser shock multi-spot position and shock pressure time-space distribution is realized through the Vdload subroutine, and its application position is the top surface of the finite element area.

[0022] Step 22: Analysis step time setting: Three analysis steps need to be set for a single spot application, and the analysis step time is divided into the pressure rise stage analysis step time, the pressure drop stage analysis step time and the stable stage analysis step time.

[0023] Step 23: Boundary condition setting: setting the bottom surface of the finite element region of the three-dimensional model as a completely fixed constraint.

[0024] Step 24: Write the preliminary laser shock pressure time-space distribution into the Vdload subroutine using Fortran language.

[0025] A further solution is that step 3 further includes:

[0026] Step 31: Extract the deformation contour of the impact crater from the simulation results of the laser multi-point continuous dynamic impact finite element.

[0027] Step 32: Calculate the depth and width error values ​​of the simulated impact crater and the experimental impact crater respectively, and determine whether they are within the allowable error range.

[0028] Wherein, the allowable error range is less than 5%.

[0029] A further solution is that step 4 further includes:

[0030] Step 41: Divide the average inherent strain into several layers along the depth direction, and perform linear interpolation processing with each layer having a thickness of 0.1 to 0.3 mm.

[0031] A further solution is that step 5 further includes:

[0032] Step 51: Use three-dimensional shell elements to establish the layered shell element model of the ribbed wall panel and divide it into wall panel strips.

[0033] Wherein, the material of the layered shell element model of the ribbed wall panel is set to a composite material shell element.

[0034] A further solution is that step 5 further includes:

[0035] Step 52: Divide the panel shell elements in the layered shell element model of the ribbed panel into several layers in the thickness direction, and set the average inherent strain distribution along the depth direction as the thermal expansion coefficient in the panel material properties in layers.

[0036] Step 53: Obtaining inherent strain through the thermal expansion coefficient and the temperature rise value, and applying the inherent strain to the laser shock region.

[0037] A further solution is that step 5 further includes:

[0038] Step 54: Analysis step setting: setting strips on the wall panels of the layered shell unit model with ribbed wall panels, and calculating the width and number of the strips. The number of analysis steps is consistent with the number of the strips.

[0039] Step 55: Boundary condition setting: Perform a completely fixed constraint on the center point of the bottom surface of the ribbed slab layered shell unit model.

[0040] It can be seen that the present invention has the following beneficial effects:

[0041] 1. The present invention realizes dynamic simulation of laser multi-point continuous impact through display analysis, and realizes deformation simulation of laser impact forming ribbed wall panels through thermoelastic analysis, so that effective forming simulation of complex ribbed wall panels can be performed, providing a basis for parameter control of deformation, and has the advantages of low cost, high efficiency, and accurate prediction results, and has good prospects for engineering application.

[0042] 2. The time-space distribution of laser shock pressure proposed in the present invention has only a single unknown parameter. Through the single-spot impact experiment, a database with one-to-one correspondence between laser process parameters and the time-space distribution of laser shock pressure is established, and an inherent strain database corresponding to the process parameters is established. The laser shock pressure distribution correction is simple, which can effectively control the error between the simulation results and the experimental results.

[0043] 3. The present invention proposes a simulation method for the dynamic response process of laser multi-point continuous impact. The method is different from the explicit and implicit alternating analysis simulation method. The steps are simpler and the continuous dynamic process of multi-point laser impact can be calculated at one time, thereby obtaining the complete strain distribution, residual stress distribution and deformation distribution of the laser impact process. The implementation method is simpler and more effective.

[0044] 4. The layered shell unit model of the ribbed wall panel proposed in the present invention transforms the complex dynamic process of the laser shock formed ribbed wall panel into a thermoelastic deformation process, and improves the prediction accuracy and calculation efficiency of the laser shock formed ribbed wall panel by optimizing the number of analysis steps.

[0045] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a flow chart of the finite element simulation method of the laser shock formed ribbed wall panel in the embodiment of the present invention.

[0047] Figure 2 It is a schematic diagram of the structural dimensions of the ribbed wall panel in an embodiment of the present invention.

[0048] Figure 3 3 is a diagram of laser impact time distribution in an embodiment of the present invention.

[0049] Figure 4 3 is a spatial distribution diagram of laser shock in an embodiment of the present invention.

[0050] Figure 5 It is a schematic diagram of the establishment and meshing of the laser multi-point continuous dynamic impact finite element model in an embodiment of the present invention.

[0051] Figure 6 It is a deformation result diagram of the laser multi-point continuous dynamic impact model in an embodiment of the present invention.

[0052] Figure 7 Schematic diagram of the deformation size of the impact crater in the embodiment of the present invention.

[0053] Figure 8 3 is a graph showing the average inherent strain depth distribution in an embodiment of the present invention.

[0054] Fig. 9 This is a diagram showing the simulated deformation results of the laser shock formed ribbed wall panel in an embodiment of the present invention.

[0055] Fig.10 It is a comparison diagram of the simulated and experimental deformation of the laser shock formed ribbed wall panel in an embodiment of the present invention. DETAILED DESCRIPTION

[0056] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0057] Embodiment of a finite element simulation method for laser shock forming ribbed wall panels

[0058] See also Figure 1 The present invention relates to a finite element simulation method for laser shock forming ribbed wall panels, comprising:

[0059] Step 1: Determine the preliminary laser shock pressure time-space distribution corresponding to the laser process parameters.

[0060] Step 2: Establish a laser multi-point continuous dynamic impact finite element model, and apply the preliminary laser shock pressure time-space distribution as a load to the laser multi-point continuous dynamic impact finite element model to obtain the simulated impact crater size of the laser process parameters.

[0061] Step 3: Correct the time-space distribution of laser shock pressure, and determine whether the error value between the simulated shock crater size and the experimental shock crater size under the same laser process parameters is within the allowable error range. If so, output the time-space distribution of laser shock pressure corresponding to the laser process parameters and execute the next step. If not, adjust the laser absorption coefficient and return to step 1.

[0062] Step 4: Apply the time-space distribution of the laser shock pressure to the laser multi-point continuous dynamic shock finite element model and solve it to obtain the strain field and residual stress field after the laser process parameters are impacted, and extract the inherent strain distribution along the depth direction, so as to output the average inherent strain distribution along the depth direction corresponding to the laser process parameters.

[0063] Step 5: Introduce the average inherent strain distribution along the depth direction into the layered shell element model of the ribbed wall panel and solve it to obtain the deformation result of the ribbed wall panel impacted by the laser process parameters.

[0064] Specifically, in step 1 of this embodiment, the corresponding laser shock pressure time-space distribution P(t, x, y) is calculated according to the laser process parameters by formula (1):

[0065]

[0066] Where τ is the laser pulse width, unit: ns; α p is the laser absorption coefficient; α is the coefficient of internal energy conversion into thermal energy; γ is the specific heat capacity of air; R is the laser spot radius, unit: mm; I is the laser power density, unit: GW / cm2; Z is the total impact impedance, unit: g / cm^2s.

[0067] Specifically, the laser power density I in this embodiment is calculated by formula (2):

[0068]

[0069] Where E is the laser energy, unit: J.

[0070] Specifically, the total impact impedance Z in this embodiment is obtained by formula (3):

[0071]

[0072] Among them, Z1 and Z2 are the impact impedances of the target material and the constrained layer material respectively.

[0073] Specifically, in this embodiment, laser is used to perform full-area laser shock treatment on the upper surface of the ribbed wall panel, and the laser shock process parameters are:

[0074] The laser energy is E = 9 J; the laser pulse width τ = 20 ns; the laser spot radius is a circular spot, its value is R = 1 mm, and the spot overlap rate in the X direction and the Y direction is 0%. Substituting it into formula (2) yields:

[0075]

[0076] In this embodiment, the target is aluminum alloy 7075-T651 and the constraining layer is water flow, so Z1=0.165×10 6 g / cm 2 s; Z2=1.71×10 6 g / cm 2 s, and substitute it into formula (3) to obtain the total impact impedance Z.

[0077] In this embodiment, α is the coefficient of internal energy conversion into thermal energy, α=0.2; γ is the specific heat capacity of air, γ=1.4. Substituting the above parameter values ​​into formula (1) yields:

[0078]

[0079] Among them, α p is the laser absorption coefficient, which ranges from 0.8 to 1. p =0.9, and the laser shock time-space distribution is used as the applied load of a single spot of the laser multi-point continuous dynamic shock model.

[0080] See also Figure 3 and Figure 4 , the time distribution and spatial distribution of laser shock pressure can be obtained from the above formula P(t,x,y).

[0081] Specifically, in step 2 of this embodiment, the finite element simulation of laser multi-point continuous dynamic impact includes:

[0082] See also Figure 5 , Model establishment and mesh division: The laser multi-point continuous dynamic impact finite element model uses a three-dimensional deformable entity type, and its finite element area is located in the middle of the three-dimensional model and contains a 4×4 arrangement of light spot impact. Among them, the boundary of the finite element area is 1mm larger than the boundary of the light spot impact area. Among them, the edge of the three-dimensional model is an infinite element area, and the width of the infinite element area is greater than 2mm.

[0083] See also Figure 2Specifically, the ribbed wall panel described in this embodiment is a ribbed wall panel with a M-shaped grid rib distribution, with a flat upper surface and ribs on the lower surface. The ribbed wall panel is made of 7075-T651 aluminum alloy, with an overall size of 100mm×100mm×6mm, a sheet thickness of 3mm, and a rib height and width of 3mm.

[0084] Specifically, in this embodiment, according to the above-mentioned ribbed wall panel structure, the size of the three-dimensional model is 12mm×12mm×4mm; the size of the finite element area is 10mm×10mm×4mm, and is located in the middle of the three-dimensional model, and the finite element area contains a 4×4 arrangement of spot impacts; the unit type in the finite element area is C3D8R, and the infinite element type CIN3D8 is selected in the infinite element area; the grid size in the X and Y directions is 0.05mm, and the grid size in the Z direction is 0.025mm.

[0085] In this embodiment, the material of the laser multi-point continuous dynamic impact finite element model is set to a Johnson-Cook material constitutive model of the Homogeneous type.

[0086] In this embodiment, step 2 also includes:

[0087] Step 21: Load application setting: The application of laser shock multi-spot position and shock pressure time-space distribution is realized through the Vdload subroutine, and its application position is the top surface of the finite element area.

[0088] Specifically, this embodiment selects a user-defined load distribution type and sets the amplitude value to 1.

[0089] Step 22: Analysis step time setting: Three analysis steps need to be set for a single spot application, and the analysis step time is divided into the pressure rise stage analysis step time, the pressure drop stage analysis step time and the stable stage analysis step time.

[0090] Specifically, the total analysis step time applied by a single light spot in this embodiment is 1.02×10-5s, and the analysis step time of the pressure rise stage, the analysis step time of the pressure drop stage, and the analysis step time of the stable stage are 2.6×10-8s, 1.74×10-7s, and 1×10-5s, respectively.

[0091] Step 23: Boundary condition setting: setting the bottom surface of the finite element region of the three-dimensional model as a completely fixed constraint.

[0092] Step 24: Write the preliminary laser shock pressure time-space distribution into the Vdload subroutine using Fortran language.

[0093] Specifically, this embodiment creates an Abaqus job, adds the path of the Vdload subroutine in the job creation window, completes the load application, and then submits the job for calculation to obtain the deformation results and residual stress field of the laser process parameter impact, thereby completing the finite element simulation of laser multi-point continuous dynamic impact.

[0094] When submitting the job, add the path of the Vdload subroutine in the User subroutine file column in the General options, then submit the Abaqus job and perform the calculation.

[0095] See also Figure 6 It can be seen that this embodiment obtains the continuous laser shock plastic deformation result of 4×4 spots in the Z-shaped scanning path.

[0096] In this embodiment, step 3 also includes:

[0097] Step 31: Extract the deformation contour of the impact crater from the simulation results of the laser multi-point continuous dynamic impact finite element.

[0098] Specifically, the method for extracting the deformation contour of the impact crater described in this embodiment is: using a Python script to extract the deformation of the impact crater along the Z direction at the last moment along the X and Y directions of the center of the light spot.

[0099] Step 32: Calculate the depth and width error values ​​of the simulated impact crater and the experimental impact crater respectively, and determine whether they are within the allowable error range.

[0100] Wherein, the allowable error range is less than 5%.

[0101] See also Figure 7 Specifically, the depth of the impact crater described in this embodiment is the difference between the Y values ​​of the highest point and the lowest point, and its width is the difference between the X values ​​of the two highest points.

[0102] Specifically, this embodiment compares the impact crater deformation size measured by the experimental plate under the same parameters. The specific method is to calculate the impact crater depth and impact crater width respectively until the impact crater size error values ​​between the simulation and the experiment are both less than 5%; otherwise, the laser absorption coefficient α is adjusted to optimize the impact crater deformation size. p The value of α returns to execute step 1 and step 2; when α p =0.93, the depth and width differences of the impact crater sizes between the simulation and the experiment are both less than 5%, so proceed to the next step 4.

[0103] In this embodiment, step 4 also includes:

[0104] See also Figure 8, step 41: dividing the average inherent strain into several layers along the depth direction, and performing linear interpolation processing with each layer of 0.1 to 0.3 mm.

[0105] Specifically, the method for extracting the average inherent strain in this embodiment is: extracting the average inherent strain along the depth direction of the finite element region at the last moment through a Python script.

[0106] Specifically, in step 5 of this embodiment, the following steps are included:

[0107] Step 51: Model establishment and mesh division: Use three-dimensional shell elements to establish the layered shell element model of the ribbed wall panel, and divide it into wall panel strips.

[0108] Specifically, this embodiment selects the S4R four-node reduced integral shell element, and the global element size is 500um.

[0109] The material of the layered shell element model of the reinforced wall panel is set as a composite material shell element, which is a Composite type of the Shell category.

[0110] In this embodiment, step 5 further includes:

[0111] Step 52: Step 52: Divide the wall panel shell elements in the layered shell element model of the reinforced wall panel into several layers in the thickness direction, and set the average inherent strain distribution along the depth direction as the thermal expansion coefficient in the wall panel material properties in layers.

[0112] Specifically, the material properties of the rib structure in the layered shell unit model of the ribbed wall panel described in this embodiment do not set the thermal expansion coefficient.

[0113] Step 53: Obtain an intrinsic strain using the thermal expansion coefficient and the value of , and apply the intrinsic strain to the laser shock region.

[0114] The inherent strain is obtained by formula (4):

[0115] ε e =Α*ΔT, ΔT=1 (4)

[0116] Where A is the coefficient of thermal expansion and ΔT is the temperature rise.

[0117] In this embodiment, step 5 further includes:

[0118] Step 54: Analysis step setting: setting strips on the wall panels of the layered shell unit model with ribbed wall panels, and calculating the width and number of the strips. The number of analysis steps is consistent with the number of the strips.

[0119] Specifically, the number of strips in this embodiment corresponds to the number of laser impact paths in the Y direction.

[0120] Specifically, in this embodiment, the strip width is obtained by formula (5):

[0121] Δd=2R(1-η y )=2×1×(1-0)=2mm (5)

[0122] The number of stripes is obtained by formula (5):

[0123]

[0124] Among them, η y is the spot overlap rate in the Y direction; L y is the length of the impact area in the Y direction.

[0125] Step 55: Boundary condition setting: Perform a completely fixed constraint on the center point of the bottom surface of the ribbed slab layered shell unit model.

[0126] Specifically, this embodiment uses Abaqus / Standard to solve, so as to obtain the deformation result of the laser process parameters impact forming of the ribbed wall panel, and complete the finite element simulation of the laser impact forming of the ribbed wall panel.

[0127] See also Fig. 9 In this embodiment, the complete deformation process and final deformation result of the ribbed wall panel under the laser process parameters are obtained. Since the laser shock processing process is difficult to observe, the simulation is beneficial to the research of laser shock forming process.

[0128] See also Fig.10 In this embodiment, the simulated deformation results are compared with the experimental forming results. The error between the simulated results of the deformation contours in the X and Y directions and the experimental results is less than 3%, which is a good way to predict the forming of this example.

[0129] The above-mentioned embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.

Claims

1. A finite element simulation method for laser shock forming ribbed wall panels, characterized in that: include: Step 1: Determine the preliminary time-space distribution of laser shock pressure corresponding to the laser process parameters; Step 2: Establishing a laser multi-point continuous dynamic impact finite element model, applying the preliminary laser impact pressure time-space distribution as a load to the laser multi-point continuous dynamic impact finite element model to obtain the simulated impact crater size of the laser process parameters; Step 3: Correct the time-space distribution of laser shock pressure, and determine whether the error value between the simulated shock crater size and the experimental shock crater size under the same laser process parameters is within the allowable error range. If so, output the time-space distribution of laser shock pressure corresponding to the laser process parameters and execute the next step; if not, adjust the laser absorption coefficient and return to step 1; Step 4: applying the laser shock pressure time-space distribution to the laser multi-point continuous dynamic shock finite element model and solving it to obtain the strain field and residual stress field after the laser process parameter shock, and extracting the inherent strain distribution along the depth direction, so as to output the average inherent strain distribution along the depth direction corresponding to the laser process parameter; Step 5: Introduce the average inherent strain distribution along the depth direction into the layered shell element model of the ribbed wall panel and solve it to obtain the deformation result of the ribbed wall panel impacted by the laser process parameters.

2. The finite element simulation method of laser shock forming ribbed wall panels according to claim 1 is characterized in that: The temporal and spatial distribution of the preliminary laser shock pressure in step 1 is: Where, τ is the laser pulse width; α p is the laser absorption coefficient; α is the coefficient of internal energy conversion into thermal energy; γ is the specific heat capacity of air; R is the laser spot radius; I is the laser power density; Z is the total impact impedance.

3. The finite element simulation method of laser shock forming ribbed wall panel according to claim 1 is characterized in that: The laser multi-point continuous dynamic impact finite element model uses a three-dimensional deformable entity type, and its finite element area is located in the middle of the three-dimensional model and contains at least 4×4 arranged light spot impacts; Wherein, the boundary of the finite element region is at least 1 mm larger than the boundary of the light spot impact region; The edge of the three-dimensional model is an infinite element region, and the width of the infinite element region is greater than 2 mm.

4. The finite element simulation method of laser shock forming ribbed wall panels according to claim 3 is characterized in that: The material of the laser multi-point continuous dynamic impact finite element model is set as an isotropic Johnson-Cook material constitutive model.

5. The finite element simulation method of laser shock forming ribbed wall panels according to claim 3 is characterized in that: Step 2 also includes: Step 21: Load application setting: Implement the application of laser shock multi-spot position and shock pressure time-space distribution through the Vdload subroutine, and its application position is the top surface of the finite element area; Step 22: Analysis step time setting: Three analysis steps need to be set for a single spot application, and the analysis step time is divided into the pressure rise stage analysis step time, the pressure drop stage analysis step time and the stable stage analysis step time; Step 23: Boundary condition setting: setting the bottom surface of the finite element region of the three-dimensional model as a completely fixed constraint; Step 24: Write the preliminary laser shock pressure time-space distribution into the Vdload subroutine using Fortran language.

6. The finite element simulation method of laser shock forming ribbed wall panels according to claim 1, characterized in that: Step 3 also includes: Step 31: extracting the deformation contour of the impact crater from the simulation results of the laser multi-point continuous dynamic impact finite element; Step 32: Calculate the depth and width error values ​​of the simulated impact crater and the experimental impact crater, and determine whether they are within the allowable error range; Wherein, the allowable error range is less than 5%.

7. The finite element simulation method of laser shock forming ribbed wall panels according to claim 1, characterized in that: Step 4 also includes: Step 41: Divide the average inherent strain into several layers along the depth direction, and perform linear interpolation processing with each layer having a thickness of 0.1 to 0.3 mm.

8. The finite element simulation method of laser shock forming ribbed wall panels according to claim 1, characterized in that: Step 5 also includes: Step 51: using three-dimensional shell elements to establish a layered shell element model of the ribbed wall panel, and dividing the wall panel into strips; Wherein, the material of the layered shell element model of the ribbed wall panel is set to a composite material shell element.

9. The finite element simulation method of laser shock forming ribbed wall panels according to claim 8, characterized in that: Step 5 also includes: Step 52: dividing the wall panel shell element in the ribbed wall panel layered shell element model into a plurality of layers in the thickness direction, and setting the average inherent strain distribution along the depth direction as the thermal expansion coefficient in the wall panel material properties in a layered manner; Step 53: Obtaining inherent strain through the thermal expansion coefficient and the temperature rise value, and applying the inherent strain to the laser shock region.

10. The finite element simulation method of laser shock forming ribbed wall panels according to claim 9, characterized in that: Step 5 also includes: Step 54: setting analysis steps: setting strips on the wall panels of the layered shell element model of the ribbed wall panels, and calculating the width and number of the strips, wherein the number of analysis steps is consistent with the number of the strips; Step 55: Boundary condition setting: Perform a completely fixed constraint on the center point of the bottom surface of the ribbed slab layered shell unit model.

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