Structural part lightweight method based on variable configuration lattice filling

Abstract

The invention discloses a structural part lightweight method based on variable configuration lattice filling, which comprises the following steps of: calculating stress distribution and displacement distribution of a part model by using a finite element method, and dividing an area capable of being filled by adopting a lattice structure; removing an internal entity in the fillable dot matrix area to enable the part to be of a thin-wall cavity structure; according to the stress condition of the part, the inner cavity of the part is filled with a multi-configuration lattice structure; the manufacturability of part manufacturing is considered, a part model is optimized, finite element analysis is carried out to verify the reliability of a final result, stress and deformation distribution are analyzed based on finite elements, an area capable of being subjected to dot matrix filling is judged, parameter iteration is carried out through a theoretical formula, and a quadruple rotational symmetry variable configuration type dot matrix structure is subjected to distribution design in a targeted mode. The rationality of dot matrix filling is improved, the weight of the part is effectively reduced, no transition problem exists at the unit connecting position of the dot matrix, and the manufacturability problem is solved while the working conditions are met.

Description

Technical Field

[0001] The invention belongs to the technical field of structural lightweight design, and in particular to a structural component lightweight method based on variable configuration lattice filling. Background Art

[0002] The lattice structure is a porous structure, usually composed of spatial connecting rods, and a regular truss structure is formed in a periodic array in three-dimensional space. It has the characteristics of light weight, high specific strength and high specific stiffness. With the increasing maturity of metal additive manufacturing technology, the lattice structure can achieve the envisioned force and thermal performance through active design, and it is a multifunctional structural form. A large number of studies on the use of lattice structures for multifunctionality and lightweight have been reported, and it is very likely to become the preferred structural material system for building efficient load-bearing structures.

[0003] At present, the aerospace field has an increasingly urgent demand for structural lightweighting, and the application of lattice structures in its components is becoming more and more extensive. At present, the use of lattice structures to replace solid structures is considered to be an effective lightweight method. The working environment of future spacecraft will be more complex and harsh. For some load-bearing structural parts, the force forms are varied, and a single lattice structure is difficult to meet the load requirements of its working conditions. At present, gradient lattice structures have been developed, which can achieve the effect of changing relative density by changing the diameter of the support rods, the size of the unit, etc., and complex structural parts filled with lattices can be manufactured through additive manufacturing technology. However, due to the difference in size between adjacent units, the above method of filling the lattice will cause problems such as lack of effective transition at the connection of unit nodes, inability to closely arrange the lattice, and the existence of limit sizes, resulting in poor processability of the product for additive manufacturing and inability to be used in aerospace products. Summary of the invention

[0004] Purpose of the invention: To provide a method for lightweighting a structural part based on variable configuration lattice filling, so as to solve the problems in the prior art of filling lattices, such as lack of effective transition at the connection of unit nodes, inability to closely pack the lattices, and existence of limit sizes, due to the difference in sizes between adjacent units, resulting in poor processability of the product for additive manufacturing and inability to be applied in aerospace products.

[0005] Technical solution:

[0006] A method for lightweighting a structural component based on variable configuration lattice filling, the method comprising the following steps:

[0007] Step 1: Establish a geometric finite element model of the part, and use the finite element method to analyze and calculate the established model, obtain the distribution results of the stress distribution and displacement distribution of the model by simulation, divide the model into regions according to the distribution results, and obtain a plurality of first entity feature regions and a plurality of second entity feature regions;

[0008] Step 2: removing the solid parts of a plurality of the second solid feature regions, so that the second solid feature regions of the model become thin-walled cavity structures, and retaining the solid structure of the first solid feature regions;

[0009] Step 3: According to the actual stress condition of the model, select at least three multilayer lattice structures formed by different configurations to test fill each of the second entity feature regions forming the thin-walled cavity structure, so that each of the second entity feature regions is filled;

[0010] Step 4: Based on the characteristics of the connections between the layers of the multi-layer lattice structure formed by the at least three different configurations and the manufacturing process of the part, a finite element analysis is performed on the thin-walled cavity structure of the second solid feature area after filling to determine whether the reliability of the analysis verification result meets the preset value. If the reliability of the verification result does not meet the preset value, return to step 3 to replace the parameters of each layer of the lattice structure in the multi-layer lattice structure, and continue to verify the reliability of the result through finite element analysis until the reliability of the selected lattice structure meets the preset value.

[0011] In a further embodiment, the step 1 specifically comprises the following steps:

[0012] Step 1-1: setting boundary conditions and loads for the established model, analyzing and calculating to obtain the simulated distribution results, wherein the boundary conditions and loads set for the model include preset force and deformation data of the model;

[0013] Step 1-2: Observe the distribution results to obtain stress distribution and displacement distribution data of each area in the model, wherein the stress distribution and displacement distribution data include actual force and deformation data, and divide the area where the actual force and deformation data are less than the preset force and deformation data into a second entity feature area, and divide the area where the actual force and deformation data are greater than the preset force and deformation data into a first entity feature area.

[0014] In a further embodiment, in step 1-2, dividing the area where the actual force and deformation data are less than the preset force and deformation data into the second entity feature area further comprises:

[0015] The actual force and deformation data are less than or equal to 70% of the preset force and deformation data.

[0016] In a further embodiment, step 3 specifically includes the following steps:

[0017] Step 3-1: Select 3 to 4 lattice structures with different stiffness to test fill the thin-walled cavity structure of the selected second solid feature area to obtain the optimal lattice structure and the optimal lattice unit cell size;

[0018] Step 3-2: Fill several corresponding thin-walled cavity structures with lattice structures of corresponding quadruple rotation self-supporting configurations according to different stress distributions and displacement distributions of several second entity feature regions, and select a suitable lattice unit cell size until the thin-walled cavity structure of the second entity feature region is filled.

[0019] In a further embodiment, the lattice structure of the quadruple rotation self-supporting configuration in step 3-2 determines the number of filling layers according to the actual situation of the thin-walled cavity structure in the second entity feature region, and performs multi-layer arrangement in the thin-walled cavity structure, and different types of lattice arrangement structures exist in the equivalent length direction and width direction in the thin-walled cavity structure of the second entity feature region, and the arrangement mode of each layer of lattice arrangement structure in the thickness direction of the thin-walled cavity structure is consistent;

[0020] The equivalent strength formula of the lattice structure of the quadruple rotation self-supporting configuration is as follows:

[0021]

[0022] In the formula, is the equivalent yield strength, σ ys is the yield strength of the matrix material, ρ * is the relative density of the lattice structure unit, θ is the inclination angle of the support rod, η is a constant, and the inclination angle and relative density of the support rod of the lattice structure are selected according to the above formula by presetting the single-layer equivalent solid strength of the lattice structure.

[0023] In a further embodiment, based on geometric relationships, the relative density of the lattice structure of the four-fold rotation self-supporting configuration is expressed as follows:

[0024]

[0025] L4-B, L4-V, L4-S and L4-F are basic type, reinforced type, oblique rod type and double oblique rod type lattice structures respectively, H is the height of the lattice unit, θ is the inclination angle of the lattice support rod, and d is the diameter of the lattice support rod;

[0026] For the multilayer lattice structure, its mechanical behavior is expressed as follows:

[0027]

[0028] In the formula, is the calculated value of the compressive strength of the multilayer lattice structure, is the corresponding equivalent calculated value of the single-layer lattice structure in formula (1), M is the number of layers of the lattice structure, and L and W are the numbers of lattice unit cells arranged in the length and width directions, respectively.

[0029] In a further embodiment, according to the geometric relationship, M, W and L are expressed as follows:

[0030]

[0031]

[0032] Wherein, G, J, and K are the equivalent thickness, length, and width of the thin-walled cavity structure filled with the second solid feature area by the structural member, respectively.

[0033] Combining the above, the expanded expression of formula (6) is as follows:

[0034]

[0035] According to equations (10) to (13) and the actual distribution of stress, the equivalent stress of multilayer lattice structures with different configurations is calculated and filled in the thin-walled cavity structure corresponding to the second solid feature area.

[0036] In a further embodiment, step 4 specifically includes the following steps:

[0037] Step 4-1: Determine whether there is an overhang surface in the second physical feature region, and whether the overhang surface angle is less than a preset angle. If there is an overhang surface in the second physical feature region and the overhang surface angle is less than the preset angle, optimize the overhang surface;

[0038] Step 4-2: Determine whether there is a horizontal circular hole in the second entity feature region, and whether the diameter of the horizontal circular hole is greater than the preset diameter data; if there is a horizontal circular hole in the second entity feature region and the diameter of the horizontal circular hole is greater than the preset diameter data, modify and optimize the diameter of the horizontal circular hole;

[0039] Determine whether there is a cross section smaller than the preset cross section data in the second entity feature region, and if there is a cross section smaller than the preset cross section data, modify and optimize the cross section;

[0040] Determine whether there is a thin wall smaller than the preset thin wall data in the second entity feature region, and if there is a thin wall smaller than the preset thin wall data, modify and optimize the thin wall;

[0041] Determine whether there is a closed cavity in the second entity feature region, and if there is a closed cavity, modify and optimize the closed cavity;

[0042] Step 4-3: Combine the dot matrix and parts into a complete model, import it into the finite element software for calculation, and determine whether the result meets the specifications.

[0043] In a further embodiment, in step 4-1, the preset angle of the overhanging surface is 45°.

[0044] In a further embodiment, in step 4-2, the preset diameter data is 8 mm, and the preset cross-section data is 0.25 mm. 2 The preset thin-wall data is 1.5 mm, and the modification and optimization of the closed cavity includes filling or adding powder discharge holes.

[0045] The beneficial effects of the present invention are as follows: based on the finite element analysis of stress and deformation distribution, the area that can be filled with lattice is determined, and parameter iteration is performed through theoretical formulas, and the four-fold rotationally symmetric variable configuration lattice structure is targetedly distributed and designed, thereby increasing the rationality of lattice filling, effectively reducing the weight of the parts, and there is no transition problem at the unit connection of the lattice, thus solving the process problem while meeting the working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 (a) is the appearance of the structural part, and (b) is a schematic diagram of the cross-section of the structural part along the thickness direction.

[0047] Figure 2 (a) is the stress distribution cloud diagram of the initial model under the working environment, and (b) is the displacement distribution cloud diagram of the initial model under the working environment.

[0048] Figure 3 Schematic diagram of the lattice structure filling strategy.

[0049] Figure 4 Schematic diagram of the optimized design model after dot filling.

[0050] Figure 5 (a) is the stress distribution cloud diagram of the optimized model under the working environment, and (b) is the displacement distribution cloud diagram of the optimized model under the working environment. DETAILED DESCRIPTION

[0051] In the following description, a large number of specific details are provided to provide a more thorough understanding of the present invention. However, it is apparent to those skilled in the art that the present invention can be implemented without one or more of these details. In other examples, in order to avoid confusion with the present invention, some technical features well known in the art are not described.

[0052] The present invention is further described in detail below in conjunction with the accompanying drawings.

[0053] Reference Figure 1-5 , is a structural component lightweighting method based on variable configuration lattice filling disclosed by the present invention, the method comprising the following steps:

[0054] Step 1: Establish a geometric finite element model of the part, and use the finite element method to analyze and calculate the established model, obtain the distribution results of the stress distribution and displacement distribution of the model by simulation, divide the model into regions according to the distribution results, and obtain a number of first entity feature regions and a number of second entity feature regions. For example, the lift structure of a certain aircraft Figure 1 As shown, the interior is filled with some mesh ribs, which has a large solid area with a weight of 48.02Kg. The entire surface is subjected to aerodynamic loads. The material is titanium alloy TA15. It is required that the maximum stress of the part under load does not exceed the material yield strength of 885MPa, the maximum deformation does not exceed 2mm, and the safety factor is 2.0. Therefore, according to the following steps, the structure is lightweight designed by lattice filling (maximum strength ≤ 442.5MPa), and the stress condition of the structure is calculated by finite element. Through the stress distribution and displacement distribution, it can be seen that the stress and deformation in the middle area are relatively small. The simulation distribution results are as follows, as shown in the figure. Figure 2 As shown, observing the simulation distribution results, the stress of the solid area in the middle red box of the structural part is 65% of the maximum stress, and the maximum displacement is 66% of the maximum displacement, which is within the yield range of the titanium alloy and meets the judgment conditions. Therefore, the middle solid area is the second solid feature area and can be filled with a lattice structure, and the other areas are the first solid feature areas.

[0055] The step 1 specifically includes the following steps:

[0056] Step 1-1: setting boundary conditions and loads for the established model, analyzing and calculating to obtain the simulated distribution results, wherein the boundary conditions and loads set for the model include preset force and deformation data of the model;

[0057] Step 1-2: Observe the distribution results to obtain stress distribution and displacement distribution data of each area in the model, wherein the stress distribution and displacement distribution data include actual force and deformation data, and divide the area where the actual force and deformation data are less than the preset force and deformation data into a second entity feature area, and divide the area where the actual force and deformation data are greater than the preset force and deformation data into a first entity feature area.

[0058] In step 1-2, dividing the area where the actual force and deformation data are smaller than the preset force and deformation data into the second entity feature area further includes:

[0059] If the actual force and deformation data are less than or equal to 70% of the preset force and deformation data, it can be considered that the reduction in stiffness caused by lattice filling is allowed, otherwise filling should be considered according to actual working conditions.

[0060] Step 2: removing the solid parts of several of the second solid feature regions, so that the second solid feature regions of the model become thin-walled cavity structures, retaining the solid structure of the first solid feature regions, selecting the middle solid region in the design software, performing a shelling operation to make the solid become a thin-walled cavity structure, and obtaining a hollowed-out model;

[0061] Step 3: According to the actual stress condition of the model, select at least three multilayer lattice structures formed by different configurations to try to fill each of the second entity feature regions forming the thin-walled cavity structure, so that each of the second entity feature regions is filled, import the model into the lattice design software, and select the middle thin-walled cavity structure region; Figure 3 As shown in Figure 1, based on the rigidity performance and equivalent strength formula, a four-fold rotationally symmetric self-supporting lattice structure is used as the filling unit. Figure 3 As shown in the figure, according to the previous stress and displacement distribution, the filling is carried out from the middle to the surrounding in a ring manner, and the stiffness of the lattice unit changes from small to large. The stiffness gradient needs to be changed to meet the actual working conditions. Four lattice structures with stiffness from small to large are used for filling: basic type (L4-B), reinforced type (L4-V), inclined rod type (L4-S), and double inclined rod type (L4-F); the initial state sets the lattice unit's support rod inclination angle of 45°, the diameter of 1mm, and the unit height of 30mm. After entering the formula for calculation, the equivalent strength of L4-S and L4-F is 491.25MPa and 584.77MPa, which exceeds the safety factor index; after 3 rounds of iterations, it is determined to increase the lattice unit diameter to 1.6mm. At this time, the maximum equivalent strength is 389.72MPa, which meets the safety factor requirements. Therefore, the final lattice unit parameters are a support rod inclination angle of 45°, a diameter of 1.6mm, and a unit height of 30mm.

[0062] The step 3 specifically includes the following steps:

[0063] Step 3-1: Import the modified three-dimensional model into the lattice design software, select the cavity area to be filled with the lattice, select 3 to 4 lattice structures with different stiffness to test fill the thin-walled cavity structure of the selected second solid feature area, and obtain the optimal lattice structure and the optimal lattice unit cell size;

[0064] Step 3-2: Fill several corresponding thin-walled cavity structures with lattice structures of corresponding quadruple rotation self-supporting configurations according to different stress distributions and displacement distributions of several second entity feature regions, and select a suitable lattice unit cell size until the thin-walled cavity structure of the second entity feature region is filled.

[0065] The lattice structure of the quadruple rotation self-supporting configuration in step 3-2 determines the number of filling layers according to the actual situation of the thin-walled cavity structure in the second entity feature region, and performs multi-layer arrangement in the thin-walled cavity structure, and different types of lattice arrangement structures exist in the equivalent length direction and width direction in the thin-walled cavity structure of the second entity feature region, and the arrangement mode of each layer of lattice arrangement structure in the thickness direction of the thin-walled cavity structure is consistent;

[0066] The equivalent strength formula of the lattice structure of the quadruple rotation self-supporting configuration is as follows:

[0067]

[0068] In the formula, is the equivalent yield strength, σ ys is the yield strength of the matrix material, ρ * is the relative density of the lattice structure unit, θ is the inclination angle of the support rod, η is a constant, and the inclination angle and relative density of the support rod of the lattice structure are selected according to the above formula by presetting the single-layer equivalent solid strength of the lattice structure.

[0069] According to the geometric relationship, the relative density of the lattice structure of the four-fold rotation self-supporting configuration is expressed as follows:

[0070]

[0071]

[0072] L4-B, L4-V, L4-S and L4-F are basic type, reinforced type, oblique rod type and double oblique rod type lattice structures respectively, H is the height of the lattice unit, θ is the inclination angle of the lattice support rod, and d is the diameter of the lattice support rod;

[0073] For the multilayer lattice structure, its mechanical behavior is expressed as follows:

[0074]

[0075] In the formula, is the calculated value of the compressive strength of the multilayer lattice structure, is the corresponding equivalent calculated value of the single-layer lattice structure in formula (1), M is the number of layers of the lattice structure, L and W are the number of lattice unit cells arranged in the length and width directions, respectively. According to the above formula, the unit size and number of layers of the lattice can be selected by presetting the equivalent solid strength of the multi-layer lattice structure.

[0076] According to the geometric relationship, M, W and L are expressed as follows:

[0077]

[0078] Wherein, G, J, and K are the equivalent thickness, length, and width of the thin-walled cavity structure filled with the second solid feature area by the structural member, respectively.

[0079] Combining the above, the expanded expression of formula (6) is as follows:

[0080]

[0081]

[0082] According to equations (10) to (13) and the actual distribution of stress, the equivalent stress of multilayer lattice structures with different configurations is calculated and filled in the thin-walled cavity structure corresponding to the second solid feature area.

[0083] It can be seen from the formula that if equivalent strength is to be obtained, the values ​​of H, θ and d need to be obtained. The initial state can consider the optimality of the 3D printing process, set the initial value of θ to 45° to ensure that there is no overhang angle, the initial value of d to 1mm, and the initial value of H to be able to cover more than 3 layers in the thickness direction and ensure that d / H is more than 1 / 8. Substitute the data into the formula for the first round of calculations. If each lattice structure meets the strength requirements of the designated area, this solution can be adopted. If not, increase d first, then consider reducing H, and finally consider increasing θ to obtain the second set of data and perform the second round of calculations. Repeat this cycle until the final required values ​​of H, θ and d are obtained. The appropriate lattice structure is selected by calculation according to the above formula, which reduces the time for selection and trial, speeds up the efficiency of lattice filling, and makes the connection transition between lattice structures better, effectively improving the overall stability of the part.

[0084] Step 4: According to the characteristics of the connection between the layers of the multi-layer lattice structure formed by the at least three different configurations and the manufacturing process of the part, a finite element analysis is performed on the thin-walled cavity structure of the second solid feature area after filling to determine whether the reliability of the analysis verification result meets the preset value. If the reliability of the verification result does not meet the preset value, return to step 3 to replace the parameters of each layer of the lattice structure in the multi-layer lattice structure, and continue to verify the reliability of the result through finite element analysis until the reliability of the selected lattice structure meets the preset value. According to the process constraints of additive manufacturing, the reliability of the lattice structure is determined as follows: Figure 4 In the placement scheme shown, there are overhanging surfaces at the top of the inner cavity and the lower end of the assembly interface. The dot matrix of this part is deleted and replaced with a rib solid support to ensure the printing success rate. The overall part does not have a very small circular hole or an extreme cross section. The wall thickness of the thin-walled area of ​​the overall part is 2mm and does not need to be modified. The overall filling area is a closed cavity, so powder discharge holes are added on the partition surface to ensure that there is no residual powder inside the part after printing. The dot matrix and the part shell are combined in the dot matrix design software and imported into the finite element software for calculation to obtain the following Figure 5 The results show that stress and deformation are within the allowable range. The final weight of the structural component is 33.70Kg, a weight reduction of 29.82%. The maximum stress is 432.5MPa, which meets the safety factor requirements. The maximum displacement is 0.517mm, which meets the working conditions.

[0085] The step 4 specifically includes the following steps:

[0086] Step 4-1: Determine whether there is an overhang surface in the second physical feature region, and whether the overhang surface angle is less than a preset angle. If there is an overhang surface in the second physical feature region and the overhang surface angle is less than the preset angle, optimize the overhang surface, and the preset angle of the overhang surface angle is 45°;

[0087] Step 4-2: Determine whether there is a horizontal circular hole in the second entity feature area, and whether the diameter of the horizontal circular hole is greater than a preset diameter data, the preset diameter data is 8 mm. If there is a horizontal circular hole in the second entity feature area and the diameter of the horizontal circular hole is greater than the preset diameter data, modify and optimize the diameter of the horizontal circular hole;

[0088] Determine whether the second entity feature area has a cross section smaller than the preset cross section data, the preset cross section data is 0.25mm 2 If there is a cross section smaller than the preset cross section data, modify and optimize the cross section;

[0089] Determine whether there is a thin wall smaller than a preset thin wall data in the second entity feature region, the preset thin wall data is 1.5 mm, and if there is a thin wall smaller than the preset thin wall data, modify and optimize the thin wall;

[0090] Determine whether there is a closed cavity in the second entity feature area. If there is a closed cavity, modify and optimize the closed cavity. Modifying and optimizing the closed cavity includes filling or adding a powder discharge hole.

[0091] Step 4-3: Combine the dot matrix and parts into a complete model, import it into the finite element software for calculation, and determine whether the result meets the specifications.

[0092] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

[0093] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings; however, the present invention is not limited to the specific details in the above embodiments; within the technical concept of the present invention, various equivalent transformations can be made to the technical scheme of the present invention, and these equivalent transformations all belong to the protection scope of the present invention.

Claims

1. A method for lightweighting a structural part based on variable configuration lattice filling, characterized in that: The method comprises the following steps: Step 1: Establish a geometric finite element model of the part, and use the finite element method to analyze and calculate the established model, obtain the distribution results of the stress distribution and displacement distribution of the model by simulation, divide the model into regions according to the distribution results, and obtain a plurality of first entity feature regions and a plurality of second entity feature regions; Step 2: removing the solid parts of a plurality of the second solid feature regions, so that the second solid feature regions of the model become thin-walled cavity structures, and retaining the solid structure of the first solid feature regions; Step 3: According to the actual stress condition of the model, select at least three multilayer lattice structures formed by different configurations to test fill each of the second entity feature regions forming the thin-walled cavity structure, so that each of the second entity feature regions is filled; Step 4: Based on the characteristics of the connections between the layers of the multi-layer lattice structure formed by the at least three different configurations and the manufacturing process of the part, a finite element analysis is performed on the thin-walled cavity structure of the second solid feature area after filling to determine whether the reliability of the analysis verification result meets the preset value. If the reliability of the verification result does not meet the preset value, return to step 3 to replace the parameters of each layer of the lattice structure in the multi-layer lattice structure, and continue to verify the reliability of the result through finite element analysis until the reliability of the selected lattice structure meets the preset value.

2. A method for lightweighting a structural component based on variable configuration lattice filling according to claim 1, characterized in that: The step 1 specifically includes the following steps: Step 1-1: setting boundary conditions and loads for the established model, analyzing and calculating to obtain the simulated distribution results, wherein the boundary conditions and loads set for the model include preset force and deformation data of the model; Step 1-2: Observe the distribution results to obtain stress distribution and displacement distribution data of each area in the model, wherein the stress distribution and displacement distribution data include actual force and deformation data, and divide the area where the actual force and deformation data are less than the preset force and deformation data into a second entity feature area, and divide the area where the actual force and deformation data are greater than the preset force and deformation data into a first entity feature area.

3. A method for lightweighting a structural component based on variable configuration lattice filling according to claim 2, characterized in that: In step 1-2, dividing the area where the actual force and deformation data are smaller than the preset force and deformation data into the second entity feature area further includes: The actual force and deformation data are less than or equal to 70% of the preset force and deformation data.

4. A method for lightweighting a structural component based on variable configuration lattice filling according to claim 1, characterized in that: The step 3 specifically includes the following steps: Step 3-1: Select 3 to 4 lattice structures with different stiffness to test fill the thin-walled cavity structure of the selected second solid feature area to obtain the optimal lattice structure and the optimal lattice unit cell size; Step 3-2: Fill several corresponding thin-walled cavity structures with lattice structures of corresponding quadruple rotation self-supporting configurations according to different stress distributions and displacement distributions of several second entity feature regions, and select a suitable lattice unit cell size until the thin-walled cavity structure of the second entity feature region is filled.

5. A method for lightweighting a structural component based on variable configuration lattice filling according to claim 4, characterized in that: The lattice structure of the quadruple rotation self-supporting configuration in step 3-2 determines the number of filling layers according to the actual situation of the thin-walled cavity structure in the second entity feature region, and performs multi-layer arrangement in the thin-walled cavity structure, and different types of lattice arrangement structures exist in the equivalent length direction and width direction in the thin-walled cavity structure of the second entity feature region, and the arrangement mode of each layer of lattice arrangement structure in the thickness direction of the thin-walled cavity structure is consistent; The equivalent strength formula of the lattice structure of the quadruple rotation self-supporting configuration is as follows: In the formula, is the equivalent yield strength, σ ys is the yield strength of the matrix material, ρ * is the relative density of the lattice structure unit, θ is the inclination angle of the support rod, η is a constant, and the inclination angle and relative density of the support rod of the lattice structure are selected according to the above formula by presetting the single-layer equivalent solid strength of the lattice structure.

6. A method for lightweighting a structural component based on variable configuration lattice filling according to claim 5, characterized in that: According to the geometric relationship, the relative density of the lattice structure of the four-fold rotation self-supporting configuration is expressed as follows: L4-B, L4-V, L4-S and L4-F are basic type, reinforced type, oblique rod type and double oblique rod type lattice structures respectively, H is the height of the lattice unit, θ is the inclination angle of the lattice support rod, and d is the diameter of the lattice support rod; For the multilayer lattice structure, its mechanical behavior is expressed as follows: In the formula, is the calculated value of the compressive strength of the multilayer lattice structure, is the corresponding equivalent calculated value of the single-layer lattice structure in formula (1), M is the number of layers of the lattice structure, and L and W are the numbers of lattice unit cells arranged in the length and width directions, respectively.

7. A method for lightweighting a structural component based on variable configuration lattice filling according to claim 6, characterized in that: According to the geometric relationship, M, W and L are expressed as follows: Wherein, G, J, and K are the equivalent thickness, length, and width of the thin-walled cavity structure filled with the second solid feature area by the structural member, respectively; Combining the above, the expanded expression of formula (6) is as follows: According to equations (10) to (13) and the actual distribution of stress, the equivalent stress of multilayer lattice structures with different configurations is calculated and filled in the thin-walled cavity structure corresponding to the second solid feature area.

8. The method for lightweighting a structural component based on variable configuration lattice filling according to claim 1, characterized in that: The step 4 specifically includes the following steps: Step 4-1: Determine whether there is an overhang surface in the second physical feature region, and whether the overhang surface angle is less than a preset angle. If there is an overhang surface in the second physical feature region and the overhang surface angle is less than the preset angle, optimize the overhang surface; Step 4-2: Determine whether there is a horizontal circular hole in the second entity feature region, and whether the diameter of the horizontal circular hole is greater than the preset diameter data; if there is a horizontal circular hole in the second entity feature region and the diameter of the horizontal circular hole is greater than the preset diameter data, modify and optimize the diameter of the horizontal circular hole; Determine whether there is a cross section smaller than the preset cross section data in the second entity feature region, and if there is a cross section smaller than the preset cross section data, modify and optimize the cross section; Determine whether there is a thin wall smaller than the preset thin wall data in the second entity feature region, and if there is a thin wall smaller than the preset thin wall data, modify and optimize the thin wall; Determine whether there is a closed cavity in the second entity feature region, and if there is a closed cavity, modify and optimize the closed cavity; Step 4-3: Combine the dot matrix and parts into a complete model, import it into the finite element software for calculation, and determine whether the result meets the specifications.

9. A method for lightweighting a structural component based on variable configuration lattice filling according to claim 8, characterized in that: In step 4-1, the preset angle of the overhanging surface is 45°.

10. The method for lightweighting a structural component based on variable configuration lattice filling according to claim 8, characterized in that: In step 4-2, the preset diameter data is 8 mm, and the preset cross-section data is 0.25 mm. 2 The preset thin-wall data is 1.5 mm, and the modification and optimization of the closed cavity includes filling or adding powder discharge holes.

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