Flexible structure 3D printing support control method combined with resistor

Abstract

The invention discloses a flexible structure 3D printing support control method combined with a resistor, and relates to the technical field of 3D printing, and the flexible structure 3D printing support control method comprises the following steps: generating a continuous density field and a dynamic damping parameter field of a support structure based on multi-target topological optimization of dynamic stiffness constraint and material distribution; quantifying the contact probability of the support structure and the target model through a membership function, and constructing a nonlinear gradient field of a contact interface; the stress coupling relation between the supporting structure and the model interface is defined based on the mixed constitutive tensor, the interface stress transfer coefficient is adaptively updated based on the material shrinkage rate difference, multi-physics field collaborative optimization is achieved in combination with regularization constraint, the key part of the supporting structure is recognized, and the resistor is integrated to the key part of the supporting structure. Through multi-target topological optimization, membership construction and adaptive stress transfer coefficient updating, the material consumption is reduced, the printing efficiency is improved, stress concentration at an interface is inhibited, the forming defect risk is reduced, and the structural reliability is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of 3D printing, and specifically to a flexible structure 3D printing support control method combined with a damper. Background Art

[0002] 3D printing technology is increasingly widely used in fields such as aerospace, medical devices, and precision manufacturing. However, due to the existence of geometric features such as cantilevers and overhangs, it is often necessary to construct support structures during the printing process to ensure forming accuracy and structural integrity. Traditional support structures usually adopt simple regular arrays or uniform topology designs, which are difficult to meet the dynamic response requirements while ensuring static stiffness, and are prone to waste of excess materials and interfacial stress concentration, resulting in deformation or warping of the printed products.

[0003] In the prior art, topology optimization methods have been widely applied to the design of support structures. By optimizing the material distribution, lightweight and static stiffness improvement are achieved, but most of them ignore the dynamic inertia and damping characteristics during the printing process, and it is difficult to effectively suppress the vibration and resonance phenomena during forming. In addition, due to material discontinuity or shrinkage rate differences at the support-model interface, high stress concentration areas will be formed, leading to cracks, peeling, and forming defects. Existing improvement schemes mostly rely on post-processing or adding redundant supports, increasing the manufacturing cost and process complexity.

[0004] Therefore, there is an urgent need for an additive manufacturing support solution that can introduce a dynamic damping mechanism inside the support structure and combine multi-objective topology optimization with contact surface gradient control to reduce the material usage and suppress interfacial stress concentration while ensuring static and dynamic performance. Summary of the Invention

[0005] Based on the above-mentioned disadvantages of the prior art, the purpose of the present invention is to provide a flexible structure 3D printing support control method combined with a damper to solve the above technical problems.

[0006] To achieve the above purpose, the present invention provides the following technical solution: A flexible structure 3D printing support control method combined with a damper, including: S1: Generate the continuous density field and dynamic damping parameter field of the support structure based on multi-objective topology optimization of dynamic stiffness constraints and material distribution; S2: Quantify the contact probability between the support structure and the target model through a membership function, and construct a non-linear gradient field of the contact interface to suppress interfacial stress concentration; S3: Define the stress coupling relationship between the support structure and the model interface based on the mixed constitutive tensor, and adaptively update the interfacial stress transfer coefficient based on the material shrinkage rate difference; S4: Through the current continuous density field, dynamic damping parameter field and membership function, combined with regularization constraints, realize the collaborative optimization of multiple physical fields, identify the key parts of the support structure, and integrate the damper into the key parts of the support structure.

[0007] The present invention is further configured such that step S1 includes: Discretize the design domain of the support structure and define the initial density and initial damping parameters of each finite element; Construct a global dynamic stiffness matrix according to the initial density and initial damping parameters of each finite element, apply a dynamic load to the global dynamic stiffness matrix, and solve for the response displacement; Construct a multi-objective optimization function based on the initial density, initial damping parameters, and response displacement, and perform multi-objective optimization iteration to solve for the continuous density field and dynamic damping parameter field.

[0008] The present invention is further configured such that the design domain of the support structure is discretized into finite elements , the element numbers are , define the initial density field , is the initial density value of element , is the initial uniform density value, map the initial damping field according to the density field , is the initial dynamic damping parameter of element , and are the minimum and maximum values of the damping parameter, is the exponential factor of the damping distribution, obtain the volume of element and the strain-displacement matrix ; The construction logic of the global dynamic stiffness matrix is: , is the global dynamic stiffness matrix, is the transpose of the strain-displacement matrix , is the elastic material constitutive matrix, is the viscoelastic damping material matrix; Apply a dynamic load to the global dynamic stiffness matrix , solve for the response displacement , satisfying ; The multi-objective optimization includes: , , ; The density optimization function is: ; The damping parameter optimization function is as follows: , is the density after the and are weight coefficients, is the initial damping parameter after the Update and using the optimality criterion or sequential quadratic programming to minimize the density optimization function and the damping parameter optimization function until convergence, and satisfying , .

[0009] The present invention is further configured such that step S2 includes: Calculate the density gradient of each unit according to the continuous density field, and calculate the membership degree of each unit according to the density gradient; Normalize the membership degrees of all units by weighting according to the unit volume to obtain the initial membership degree distribution, and perform neighborhood weighted filtering on the initial membership degree distribution; Iterate the filtered membership degree field according to the preset discretized time step until convergence to obtain the non-linear gradient field of the contact interface.

[0010] The present invention is further configured such that the calculation logic of the membership degree is: , is the membership degree of unit , is the gradient sensitivity parameter, is the density gradient of unit , is the steepness coefficient of the transition zone, is the continuous density field, is the density threshold; The calculation logic of the neighborhood weighted filtering is: , is the membership degree of the neighborhood weighted filtering, is the number of units, is the neighborhood weighted weight, is the weighted normalized membership degree, , is the filtering radius, is the unit center distance; The iteration logic is: , and are the membership degrees of the and the iterations, is the discretized time step size, is unit and the adjacent unit At the moment membership difference gradient of , as a variable is the diffusion suppression parameter.

[0011] The present invention is further configured such that step S3 includes: Obtain the constitutive tensor of the support material and the constitutive tensor of the model material for each unit of the support structure and the model interface; For each interface unit, weight and combine the constitutive tensor of the support material and the constitutive tensor of the model material according to the initialized interface stress transfer coefficient to obtain a mixed constitutive tensor; Based on the mixed constitutive tensor, obtain the stress distribution in the interface region, calculate the predicted shrinkage rates of the support material and the model material for each interface unit, and calculate the local shrinkage rate difference; Iterate the interface stress transfer coefficient according to the local shrinkage rate difference until convergence, and output the final interface stress transfer coefficient and the stress distribution in the interface region.

[0012] The present invention is further configured such that the weighted logic of the mixed constitutive tensor is: , is the mixed constitutive tensor, is the constitutive tensor of the support material, is the constitutive tensor of the model material, is the interface stress transfer coefficient; The calculation logic of the stress in the interface region is: , is the stress in the interface region, is the strain displacement matrix, is the response displacement; The iteration logic of the interface stress transfer coefficient is: , and is the and the interface stress transfer coefficients of the iteration, is the update step size, is the stability parameter,

[0013] The present invention is further configured such that step S4 includes: Update the multi-objective optimization based on the current continuous density field, dynamic damping parameter field and membership function , and ; Based on the updated multi-objective optimization and the regularization term combination, form an overall objective function; Define the continuous density field, dynamic damping parameter field, and membership function as design variables. According to the comprehensive sensitivity, use the optimality criterion or sequential quadratic programming method to update the design variables while satisfying the constraints of the design variables. Calculate the comprehensive score of the key parts of the element according to the updated design variables, and select the preset number of elements in descending order to be set as the key parts.

[0014] The present invention is further configured such that the calculation logic of the overall objective function is: , is the overall objective function, is the weight coefficient, is the multi-objective optimization function, is the regularization coefficient, is the density field gradient, is the damping parameter gradient, is the mixed constitutive tensor gradient; The calculation logic of the comprehensive score of the key parts of the element is: , is the comprehensive score of the key parts of the element, is the weight coefficient, is the element density, is the element damping parameter, is the element membership.

[0015] The present invention provides a flexible structure 3D printing support control method combined with a damper. Through multi-objective topology optimization based on dynamic stiffness constraints and material distribution, a continuous density field and a dynamic damping parameter field of the support structure are generated; the contact probability between the support structure and the target model is quantified through a membership function, and a non-linear gradient field of the contact interface is constructed to suppress the stress concentration at the interface; based on the mixed constitutive tensor, the stress coupling relationship between the support structure and the model interface is defined, and the interface stress transfer coefficient is adaptively updated based on the material shrinkage rate difference; through the current continuous density field, dynamic damping parameter field, and membership function, combined with regularization constraints, multi-physical field collaborative optimization is realized, the key parts of the support structure are identified, and the damper is integrated into the key parts of the support structure. The beneficial effects include: 1. Lightweight and efficiency improvement: Through multi-objective topology optimization coupling dynamic stiffness and material distribution, the beneficial effect is to significantly reduce the material usage and improve the printing efficiency; 2. Interface stress suppression: By constructing a non-linear gradient field through a fuzzy membership function, the beneficial effect is to effectively suppress the stress concentration at the support-model interface and reduce the risk of forming defects; 3. Interface stress balance: The stress transfer coefficient is adaptively updated by mixing the constitutive tensor and the shrinkage rate difference, and the beneficial effect is to automatically balance the interface stress of multiple materials and improve the structural reliability.

[0016] The above description is only an overview of the technical solution of the present application. In order to be able to understand the technical means of the present application more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features and advantages of the present application more obvious and understandable, the following specifically gives the specific implementation manners of the present application. Brief Description of the Drawings

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings. In the drawings: Figure 1 It is a flowchart of a flexible structure 3D printing support control method combined with a damper shown in an exemplary embodiment of the present invention. Detailed Description of the Preferred Embodiments

[0018] The following will describe the embodiments of the present invention with reference to the drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for explaining the present invention, rather than for limiting the protection scope of the present invention.

[0019] It should be noted that the drawings provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner. Therefore, only the components related to the present invention are shown in the drawings, rather than being drawn according to the number, shape and size of the components in actual implementation. The type, quantity and proportion of each component in actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0020] In the following description, a large number of details are discussed to provide a more thorough explanation of the embodiments of the present invention. However, it is obvious to those skilled in the art that the embodiments of the present invention can be implemented without these specific details. In other embodiments, well-known structures and devices are shown in the form of block diagrams rather than in detail to avoid making the embodiments of the present invention difficult to understand.

[0021] A flexible structure 3D printing support control method combined with a damper, as Figure 1 shown, includes: S1: Generate the continuous density field and dynamic damping parameter field of the support structure based on multi-objective topology optimization with dynamic stiffness constraints and material distribution. S2: Quantify the contact probability between the support structure and the target model through the membership function, construct the non-linear gradient field of the contact interface, and suppress the interface stress concentration. S3: Define the stress coupling relationship between the support structure and the model interface based on the mixed constitutive tensor, and adaptively update the interface stress transfer coefficient based on the material shrinkage rate difference. S4: Through the current continuous density field, dynamic damping parameter field and membership function, combined with regularization constraints, realize the collaborative optimization of multiple physical fields, identify the key parts of the support structure, and integrate the damper into the key parts of the support structure.

[0022] The present invention is further configured such that step S1 includes: Discretize the design domain of the support structure and define the initial density and initial damping parameters of each finite element; the present invention is further configured such that the design domain of the support structure is discretized into finite elements with element numbers , define the initial density field , as the initial density value of element , is the initial uniform density value, map the initial damping field according to the density field , as the initial dynamic damping parameter of element , and are the minimum and maximum values of the damping parameter, is the exponential factor of the damping distribution, obtain the volume of element and the strain-displacement matrix ; specifically, divide the design domain of the model to be printed and its support structure into small-volume and regular-shaped elements , , assign the initial topology density value and damping parameter to each element for gradual adjustment in subsequent topology optimization iterations; further, the design domain refers to the three-dimensional space region jointly occupied by the model and the support structure during the additive manufacturing process, and the finite element is the small-volume element obtained by dividing the design domain, which is used for numerical integration and sensitivity analysis; the initial density field The material occupancy ratio at the initial optimization moment for each unit, with a value range of (0, 1), is used to characterize the "filling" degree of the material in the unit; the initial damping parameter The damping coefficient at the initial optimization moment for each unit, which is used to describe the energy dissipation ability of the unit during the dynamic response process; the strain-displacement matrix In the finite element method, it is the matrix that maps the nodal displacements of the unit to the material strain, and is used to construct the local stiffness and damping matrices; the initial uniform density value It is the density benchmark, with a value in the open interval (0, 1). Usually, it is initially set to 0.5 - 0.8 to ensure that there is enough material participating in the response while avoiding the non-physical stiffness peak caused by excessive initial filling; the exponential factor of the damping distribution The damping mapping exponent, with a value range of (1, 3); the minimum and maximum values of the damping parameter and are determined according to the materials used and the printing process Generally, 0 is taken and the material limiting damping value is taken; Construct the global dynamic stiffness matrix according to the initial density and initial damping parameter of each finite element unit, apply the dynamic load to the global dynamic stiffness matrix, and solve for the response displacement; the construction logic of the global dynamic stiffness matrix is: , is the global dynamic stiffness matrix is the strain-displacement matrix is the transpose of is the elastic material constitutive matrix is the viscous damping material matrix; apply the dynamic load to the global dynamic stiffness matrix , and solve for the response displacement , satisfying ; Specifically, for each finite element unit in the discretized support structure design domain , according to its initial density and the initial damping parameter , construct the element-level dynamic stiffness and damping stiffness, and summarize them into the global dynamic stiffness matrix ; Apply the dynamic load during the printing process to this matrix, and solve for the system displacement response to evaluate the contribution of the current design variables to the static-dynamic performance of the structure; the strain-displacement matrix is the matrix that maps the nodal displacements of the unit to the internal strain of the material. The dimension depends on the element type (6×12 for tetrahedral elements), and is used for the construction of the local stiffness matrix; the elastic material constitutive matrix Describe the stress-strain relationship of materials within the elastic range, which depends on Young's modulus E and Poisson's ratio ν. At room temperature, for metallic materials, E≈70–210 GPa and ν≈0.25–0.35; for polymeric materials, E≈0.5–5 GPa and ν≈0.3–0.45; for viscoelastic damping material matrices Characterize the viscoelastic energy dissipation characteristics of materials, which depend on the viscous coefficient c and the structural geometry; the above parameters are determined by the material type and geometry, which are prior arts and will not be elaborated here; Construct a multi-objective optimization function based on the initial density, initial damping parameters, and response displacement, and perform multi-objective optimization iterations to solve for the continuous density field and dynamic damping parameter field; the multi-objective optimization includes: , , ; the density optimization function is: ; the damping parameter optimization function is: , is the density after the th iteration, and are weight coefficients, is the initial damping parameter after the th iteration; specifically, after completing the initial field calculation and obtaining the structural response, the three indicators of lightweight, dynamic stiffness, and topological smoothing are used as sub-goals respectively, and through sensitivity analysis and weighted aggregation, the iterative updates of the density field and damping field are driven until a convergent continuous density field and dynamic damping parameter field are obtained; Update and to convergence using the optimality criterion or sequential quadratic programming to minimize the density optimization function and damping parameter optimization function, and satisfy ; specifically, determine the increasing and decreasing trends on each element according to so that material peeling or filling is most beneficial to reducing the comprehensive goal; adjust the damping parameters of each element according to to improve the dynamic response; perform projection or filtering after update to maintain ; repeat sensitivity analysis - weighted aggregation - update projection until convergence.

[0023] The present invention is further configured such that step S2 includes: Calculate the density gradient of each element according to the continuous density field, and calculate the membership degree of each element according to the density gradient; the present invention is further configured such that the calculation logic of the membership degree is: , is the membership degree of element , is the gradient sensitivity parameter, is element The density gradient, is the steepness coefficient of the transition zone, is the continuous density field, is the density threshold; specifically, at the center of each finite element of the optimized continuous density field, the density gradient is calculated using finite differences or interpolation within the element , and the magnitude of the density gradient is substituted into the membership function expression to obtain the contact probability membership of each element . The membership characterizes the weak and transition zone positions of the support-model interface region, providing a basis for subsequent gradient field evolution and stress suppression; the gradient sensitivity parameter controls the attenuation rate of the gradient term and can be set to 1% - 5% of the printing model scale according to the expected interface smoothness; the steepness coefficient of the transition zone adjusts the jump steepness of the membership near the density threshold , with a value range of [1, 3]; the density threshold is used to distinguish the "substantial material area" from the "void or model area", with a value range of (0, 1); it is usually set to 0.4 - 0.6 to balance support strength and removability; The memberships of all elements are weighted and normalized according to the element volume to obtain the initial membership distribution, and the initial membership distribution is subjected to neighborhood weighted filtering; the calculation logic of the neighborhood weighted filtering is: , , is the membership of the neighborhood weighted filtering, is the number of elements, is the neighborhood weighted weight, is the weighted and normalized membership, , is the filtering radius, is the distance between element centers; specifically, first multiply the membership of each element by the corresponding element volume , and divide by the sum of the total volumes to eliminate the influence of element size differences, obtaining the volume weighted and normalized membership; for each element , consider all elements within its neighborhood, and construct a linear weight based on the distance between the element centroids and the preset filtering radius , reflecting the influence intensity of neighboring elements on . Sum up all the normalized memberships within the neighborhood according to the weight , and divide by the sum of the weights to calculate the filtered membership, in order to obtain a smooth and continuous initial gradient field distribution; Iterate the filtered membership field according to the preset discrete time steps until convergence to obtain the non - linear gradient field of the contact interface; the iteration logic is as follows: , and are the membership degrees of the th and th iterations, is the discrete time step size, is the membership degree difference gradient between element and its adjacent element at time , is a variable, is the diffusion suppression parameter; specifically, apply non - linear diffusion iteration to the filtered membership field to smooth the local membership degree and retain significant edges, realizing the construction of the non - linear gradient field of the contact interface. In each iteration, determine the diffusion intensity between adjacent elements according to the current membership degree difference gradient, and use the normalized weight to ensure local conservation until the change amount of the whole field is lower than the convergence threshold; the diffusion suppression parameter controls the gradient sensitivity, and is usually set to 1 - 2 times the average value of the membership degree difference gradient to balance smoothing and edge retention; The present invention is further set such that step S3 includes: Obtain the constitutive tensors of the support material and the model material for each element of the support structure and the model interface; specifically, for each interface element respectively extract the support material parameters corresponding to the position of the support structure of this element (including Young's modulus , Poisson's ratio , density ) from the material database or the predefined material list, and the model material parameters corresponding to the position of the main body of the model (including , , ), and use the extracted material parameters to convert them into fourth - order elastic (constitutive) tensors through isotropic elastic theory or anisotropic constitutive relations; for isotropic elastic materials, , , , is the Kronecker , for anisotropic or laminated materials, according to the material symmetry classification (orthotropic, hexagonal, etc.), call the corresponding constitutive matrix construction rules; For each interface element, weight - combine the constitutive tensors of the support material and the model material according to the initialized interface stress transfer coefficient to obtain the mixed constitutive tensor; the present invention is further set such that the weighting logic of the mixed constitutive tensor is: , is the mixed constitutive tensor, is the constitutive tensor of the support material, is the constitutive tensor of the model material, is the interface stress transfer coefficient; specifically, for the interface element , the constitutive tensor of the support material and the constitutive tensor of the model material are respectively read. For each interface element , the corresponding initialized interface stress transfer coefficient is used to reflect the distribution ratio of the stress of the element between the two materials. The mixed constitutive tensor of the interface element is calculated according to the weighted logic of the mixed constitutive tensor and used as the material constitutive relationship of the element in subsequent stress balance and response calculations; the value range of the interface stress transfer coefficient is [0, 1], which is a dimensionless scalar. When it is 1, it means that the element completely follows the mechanical response of the support material. When it is 0, it means that it completely follows the response of the model material; the intermediate value means a mixture of the two. The initial interface stress transfer coefficient can be set to 0.5 according to the initial interface quality or experience, or selected in the range of 0.2 - 0.8 according to the local material ratio, support density or experimental calibration results; in subsequent iterations, it can be dynamically adjusted to the range of [0, 1] according to the shrinkage rate difference or stress deviation; Based on the mixed constitutive tensor, the stress distribution in the interface region is obtained. For each interface element, the predicted shrinkage rates of the support material and the model material are calculated, and the local shrinkage rate difference is calculated; the calculation logic of the interface region stress is: , is the interface region stress, is the strain displacement matrix, is the response displacement; specifically, data is obtained from the three of the mixed constitutive tensor, the element strain displacement matrix and the response displacement vector, and the stress tensor of the element is calculated using the tensor - matrix product form; in the prediction of the material shrinkage rate, for the support material and the model material of the element , the shrinkage rates are predicted respectively according to the curing or thermal cooling model, , ; is the material process parameter, is the current temperature, is the printing time; the predicted shrinkage rate is determined by the material process parameter, the current temperature and the printing time, and can be predicted through historical statistical data, which will not be elaborated here; the shrinkage rate difference of each interface element is calculated ; The interface stress transfer coefficient is iterated until convergence according to the local shrinkage rate difference, and the final interface stress transfer coefficient and the interface region stress distribution are output; the iteration logic of the interface stress transfer coefficient is: , and are the interface stress transfer coefficients for the -th and -th iterations, is the update step size, is the stability parameter, is the local shrinkage rate difference; specifically, for each element update the interface stress transfer coefficient according to the above calculation logic, where the update step size determines the response strength to the shrinkage difference in each iteration, and its value range is [0.1, 2], and the stability parameter prevents excessive drift of the numerical value when there is no shrinkage difference, and its value range is [10 -4 , 10 -3 .

[0024] The present invention is further configured such that step S4 includes: Update the multi-objective optimization , and based on the current continuous density field, dynamic damping parameter field, and membership function; specifically, the multi-objective optimization , and refer to the above calculation logic; Form an overall objective function based on the updated multi-objective optimization and regularization term combination; the present invention is further configured such that the calculation logic of the overall objective function is: , is the overall objective function, is the weight coefficient, is the multi-objective optimization function, is the regularization coefficient, is the density field gradient, is the damping parameter gradient, is the mixed constitutive tensor gradient; specifically, the regularization coefficient balances the trade-off between the sub-objective and field smoothness, and its value range is [10 -4 , 10 -1 ; Define the continuous density field, dynamic damping parameter field, and membership function as design variables, and update the design variables according to the comprehensive sensitivity using the optimality criterion or sequential quadratic programming method while satisfying the constraints of the design variables; Calculate the comprehensive score of the key parts of the element according to the updated design variables, and select a preset number of elements in descending order and set them as key parts; the calculation logic of the comprehensive score of the key parts of the element is: , is the comprehensive score of the key parts of the element, is the weight coefficient, is the density of the unit ; is the damping parameter of the unit ; is the membership degree of the unit ; Specifically, after the multi-objective collaborative optimization iteration is completed, obtain the latest design variables of each unit: density , damping parameter and membership degree , as well as their gradients in space , and ; According to the linear weighting of the above six indicators, calculate the comprehensive score of each unit ; Arrange all units in descending order according to , and select the top N units as "key parts" for subsequent damper layout or local densification design; the weight coefficient is flexibly configured according to the design focus, and no restrictions are imposed here; through the multi-objective topology optimization of dynamic stiffness and material distribution coupling, the beneficial effect is to significantly reduce the material usage and improve the printing efficiency; through the construction of a non-linear gradient field by the fuzzy membership function, the beneficial effect is to effectively suppress the stress concentration at the support-model interface and reduce the risk of forming defects; through the adaptive update of the stress transfer coefficient by the mixed constitutive tensor and shrinkage rate difference, the beneficial effect is to achieve automatic stress balance at the multi-material interface and improve the structural reliability.

[0025] The above embodiments can be implemented in whole or in part by software, hardware, firmware or any other combination. When implemented using software, the above embodiments can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer programs are loaded or executed on the computer, the processes or functions described in the embodiments of the present application are generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website, computer, server or data center to another website, computer, server or data center by wire (such as infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that the computer can access or a data storage device such as a server or data center that includes one or more collections of available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium. The semiconductor medium can be a solid-state drive.

[0026] It should be understood that the term "and / or" in this text is merely a description of the association relationship between associated objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. Here, A and B can be singular or plural. Additionally, the character " / " in this text generally represents an "or" relationship between the preceding and following associated objects, but it may also represent an "and / or" relationship, and specific understanding can be made by referring to the context before and after.

[0027] In this application, "at least one" means one or more, and "a plurality" means two or more. "At least one of the following items" or its similar expressions refer to any combination of these items, including any combination of single items or plural items. For example, at least one of a, b, or c can represent: a, b, c, a - b, a - c, b - c, or a - b - c, where a, b, and c can be single or multiple.

[0028] It should be understood that in various embodiments of this application, the magnitude of the sequence numbers of the above processes does not mean the order of execution. The order of execution of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of this application.

[0029] Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed in this text can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods for each specific application to implement the described functions, but this implementation should not be considered to exceed the scope of this application.

[0030] Those skilled in the art can clearly understand that for the convenience and brevity of description, the specific working processes of the systems, devices, and units described above can refer to the corresponding processes in the foregoing method embodiments, and will not be elaborated here.

[0031] In several embodiments provided in this application, it should be understood that the disclosed system can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units is only a logical function division, and there can be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed coupling or direct coupling or communication connection between each other can be through some interfaces, and the indirect coupling or communication connection of the devices or units can be in an electrical, mechanical, or other forms.

[0032] The unit described as a separation component may or may not be physically separated. The component displayed as a unit may or may not be a physical unit, that is, it may be located in one place or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0033] In addition, in each embodiment of the present application, each functional unit can be integrated in a processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit.

[0034] If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, in essence, or the part that contributes to the prior art, or a part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in each embodiment of the present application. The aforementioned storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memories (ROM), random access memories (RAM), magnetic disks, or optical discs that can store program codes.

[0035] The above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of changes or substitutions, which should all be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claimed rights.

Claims

1. A flexible structure 3D printing support control method combined with a damper, characterized in that Including: S1: Based on multi-objective topology optimization with dynamic stiffness constraints and material distribution, generate the continuous density field and dynamic damping parameter field of the support structure; S2: Quantify the contact probability between the support structure and the target model through the membership function, construct the non-linear gradient field of the contact interface, and suppress the interface stress concentration; S3: Define the stress coupling relationship between the support structure and the model interface based on the mixed constitutive tensor, and adaptively update the interface stress transfer coefficient based on the material shrinkage rate difference; S4: Through the current continuous density field, dynamic damping parameter field and membership function, combine the regularization constraint to realize the collaborative optimization of multiple physical fields, identify the key parts of the support structure, and integrate the damper into the key parts of the support structure.

2. The flexible structure 3D printing support control method combined with a damper according to claim 1, characterized in that Step S1 includes: Discretize the design domain of the support structure and define the initial density and initial damping parameters of each finite element; Construct the global dynamic stiffness matrix according to the initial density and initial damping parameters of each finite element, apply dynamic loads to the global dynamic stiffness matrix, and solve for the response displacement; Construct a multi-objective optimization function based on the initial density, initial damping parameters and response displacement, and perform multi-objective optimization iteration to solve for the continuous density field and dynamic damping parameter field.

3. A flexible structure 3D printing support control method combined with a damper according to claim 2, characterized in that, Discretize the design domain of the support structure into finite elements with element numbers and define the initial density field , where is the initial density value of element and is the initial uniform density value. Map the initial damping field according to the density field where is the initial dynamic damping parameter of element and are the minimum and maximum values of the damping parameter, is the exponential factor of the damping distribution. Obtain the volume of element and the strain-displacement matrix . The construction logic of the global dynamic stiffness matrix is as follows: , is the global dynamic stiffness matrix, is the transpose of the strain-displacement matrix , is the elastic material constitutive matrix, is the visco-damping material matrix; For the global dynamic stiffness matrix Apply dynamic loads , and solve for the response displacement , satisfying ; Multi-objective optimization includes: , , ; The density optimization function is: ; The damping parameter optimization function is: , is the density after the -th iteration, and is the initial damping parameter after the Update by minimizing the density optimization function and the damping parameter optimization function using the optimality criterion or sequential quadratic programming and until convergence, and satisfying , .

4. A flexible structure 3D printing support control method combined with a damper according to claim 1, characterized in that, Step S2 includes: Calculate the density gradient of each element according to the continuous density field, and calculate the membership of each element according to the density gradient; Normalize the memberships of all elements by volume weighting to obtain the initial membership distribution, and perform neighborhood weighted filtering on the initial membership distribution; Iterate the filtered membership field at preset discrete time steps until convergence to obtain the non-linear gradient field of the contact interface.

5. A flexible structure 3D printing support control method combined with a damper according to claim 4, characterized in that, The calculation logic of membership degree is as follows: , is the membership degree of unit , is the gradient sensitivity parameter, is the density gradient of unit , is the steepness coefficient of the transition zone, is the continuous density field, is the density threshold; The calculation logic of neighborhood weighted filtering is as follows: , is the membership degree of neighborhood weighted filtering, is the number of cells, is the neighborhood weighted weight, is the membership degree of weighted normalization, , is the filtering radius, is the distance from the cell center; The iterative logic is as follows: , and are the membership degrees of the and th iterations, is the discretized time step, is for the cell and the adjacent cell at the moment of the membership degree difference gradient, , is a variable, is the diffusion suppression parameter.

6. A flexible structure 3D printing support control method combined with a damper according to claim 1, characterized in that, Step S3 includes: Obtain the constitutive tensor of the support material and the constitutive tensor of the model material for each element at the interface between the support structure and the model; For each interface element, weight and combine the constitutive tensor of the support material and the constitutive tensor of the model material according to the initialized interface stress transfer coefficient to obtain the mixed constitutive tensor; Obtain the stress distribution in the interface region based on the mixed constitutive tensor, calculate the predicted shrinkage rates of the support material and the model material for each interface element, and calculate the local shrinkage rate difference; Iterate the interface stress transfer coefficient according to the local shrinkage rate difference until convergence, and output the final interface stress transfer coefficient and the stress distribution in the interface region.

7. A flexible structure 3D printing support control method combined with a damper according to claim 6, characterized in that, The weighted logic of the mixed constitutive tensor is as follows: , is the mixed constitutive tensor, is the constitutive tensor of the support material, is the constitutive tensor of the model material, is the interfacial stress transfer coefficient; The calculation logic of the interface area stress is as follows: , is the interface area stress, is the strain-displacement matrix, is the response displacement; The iterative logic of the interface stress transfer coefficient is as follows: , and are the interface stress transfer coefficients for the -th and -th iterations, is the update step size, is the stability parameter, is the local shrinkage rate difference.

8. A flexible structure 3D printing support control method combined with a damper according to claim 3, characterized in that, Step S4 includes: Updating multi-objective optimization based on the current continuous density field, dynamic damping parameter field, and membership function , and ; Based on the updated combination of multi-objective optimization and regularization terms, form the overall objective function; Define the continuous density field, dynamic damping parameter field and membership function as design variables, and use the optimality criterion or sequential quadratic programming method according to the comprehensive sensitivity, while satisfying the constraints of the design variables, to update the design variables; Calculate the comprehensive score of the key parts of each element according to the updated design variables, and select the preset number of elements in descending order and set them as the key parts.

9. A flexible structure 3D printing support control method combined with a damper according to claim 8, characterized in that, The calculation logic of the overall objective function is as follows: , is the overall objective function, is the weight coefficient, is the multi-objective optimization function, is the regularization coefficient, is the density field gradient, is the damping parameter gradient, is the mixed constitutive tensor gradient; The calculation logic for the comprehensive score of the key parts of the unit is as follows: , is the comprehensive score of the key parts of the unit, is the weight coefficient, is the unit density, is the unit damping parameter, is the unit membership degree.

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