WO2018082642A1 - 产品结构设计方法 - Google Patents

产品结构设计方法 Download PDF

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Publication number
WO2018082642A1
WO2018082642A1 PCT/CN2017/109255 CN2017109255W WO2018082642A1 WO 2018082642 A1 WO2018082642 A1 WO 2018082642A1 CN 2017109255 W CN2017109255 W CN 2017109255W WO 2018082642 A1 WO2018082642 A1 WO 2018082642A1
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Prior art keywords
product
design
ball unit
design method
analysis
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PCT/CN2017/109255
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English (en)
French (fr)
Inventor
韩品连
张坤
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南方科技大学
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Priority claimed from CN201610962100.1A external-priority patent/CN106599348A/zh
Priority claimed from CN201610964724.7A external-priority patent/CN106599349A/zh
Priority claimed from CN201610964738.9A external-priority patent/CN106649975A/zh
Priority claimed from CN201610965886.2A external-priority patent/CN106649976A/zh
Priority claimed from CN201610962099.2A external-priority patent/CN106641066A/zh
Application filed by 南方科技大学 filed Critical 南方科技大学
Priority to US16/071,005 priority Critical patent/US11238194B2/en
Publication of WO2018082642A1 publication Critical patent/WO2018082642A1/zh

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B33—ADDITIVE MANUFACTURING TECHNOLOGY
    • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
    • B33Y50/00—Data acquisition or data processing for additive manufacturing
    • B33Y50/02—Data acquisition or data processing for additive manufacturing for controlling or regulating additive manufacturing processes
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00—Computer-aided design [CAD]
    • G06F30/10—Geometric CAD
    • G06F30/17—Mechanical parametric or variational design
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00—Computer-aided design [CAD]
    • G06F30/20—Design optimisation, verification or simulation
    • G06F30/23—Design optimisation, verification or simulation using finite element methods [FEM] or finite difference methods [FDM]
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B33—ADDITIVE MANUFACTURING TECHNOLOGY
    • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
    • B33Y10/00—Processes of additive manufacturing
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2111/00—Details relating to CAD techniques
    • G06F2111/06—Multi-objective optimisation, e.g. Pareto optimisation using simulated annealing [SA], ant colony algorithms or genetic algorithms [GA]
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2111/00—Details relating to CAD techniques
    • G06F2111/10—Numerical modelling
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2113/00—Details relating to the application field
    • G06F2113/10—Additive manufacturing, e.g. 3D printing
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2119/00—Details relating to the type or aim of the analysis or the optimisation
    • G06F2119/08—Thermal analysis or thermal optimisation
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2119/00—Details relating to the type or aim of the analysis or the optimisation
    • G06F2119/10—Noise analysis or noise optimisation

Definitions

  • the present disclosure relates to the field of structural design techniques, for example, to a product structure design method.
  • the porous mesh structure is lightweight, versatile and designable, with excellent mechanical properties such as high specific strength, high specific stiffness, high strength and high energy absorption, as well as shock absorption, heat dissipation, sound absorption, electromagnetic shielding and permeability. It has special properties and thus has broad application prospects.
  • the closed-cell porous structure has a low heat transfer coefficient for thermal insulation, the open-cell porous structure has a flow channel for heat dissipation, and the designability facilitates optimization of the design of the mechanics and heat dissipation structure.
  • the topology optimization thermal conduction channel design method is based on the geometric average temperature-based thermal performance description index, and the heat dissipation structure design optimization model is established as the objective function, and the sensitivity analysis of the objective function is performed to obtain the thermal conduction channel characterized by the superior thermal conductivity material distribution.
  • the conceptual design while maintaining the structural characteristics unchanged, through the simple regularization and smooth boundary of the high thermal conductivity material distribution, the high thermal conductivity channel design for engineering use is obtained.
  • 3D (3Dimensions, 3D) printing also known as rapid prototyping technology, additive manufacturing technology
  • the principle is to discretize the three-dimensional physical digital model (CAD file) into a slice model, and then convert the slice model into the walking path of the print head, through The printhead continuously adds material to the print, so that the material is continuously added according to the print path and printed layer by layer to form the final physical print.
  • CAD file three-dimensional physical digital model
  • 3D printing Unlike traditional manufacturing “material reduction manufacturing technology”, 3D printing complies with the principle of addition, which can directly convert the design in the computer into a model, directly manufacturing parts or products, eliminating the need for traditional tools, fixtures and machine tools; Directly transforming the virtual digital solid model into a product greatly simplifies the production process, reduces the production cost of the material, shortens the design and development cycle of the product, makes it possible to produce arbitrarily complex structural parts, and realizes the material microstructure.
  • An important technical means of design and performance. 3D printing consumables include: plastic, rubber, metal, powder, nylon, film, resin, paraffin, gypsum, nylon, titanium alloy and ceramics. 3D printing technology will make the production of goods enter a new stage, the organization of production will be more flat, and its potential liberation of production can greatly improve the efficiency of our society.
  • a product structure design method solves the problem that the manufacturing technology in the related art is difficult to meet the design requirements to form a component with light weight and high strength.
  • a product structure design method which obtains a subsurface mesh structure through ball unit filling and functional optimization design, thereby forming a product through an additive manufacturing process.
  • the design method specifically includes the following steps:
  • Step S1 completing a preliminary design of the subsurface mesh structure by performing finite element analysis optimization after filling the ball unit at the specified position;
  • Step S2 completing the filling optimization of the ball unit by the heat insulation design method, the reinforced damping structure design method, the controllable failure structure design method, the sound absorption and noise reduction design method, and the stress relief design method;
  • Step S3 further designing the subsurface mesh structure by topology optimization, mechanical analysis, vibration analysis and optimization, and gradient material application and variable thickness design.
  • the heat dissipation heat dissipation design method is: designing a superior heat conduction channel by using a topology optimization method; filling a topography of a ball unit or a ball unit by specifying a position at a product; , thereby constructing a better heat conduction channel.
  • controllable failure structure design method comprises the following steps:
  • Step B1 designing the original model
  • Step B2 performing finite element and photoelastic experiment analysis steps under actual working conditions on the original model to obtain analysis data
  • Step B3 combining the analysis data to fill the spherical unit at a specified position, designing a porous material having a spherical unit, and obtaining an initial model of the product;
  • step B4 the initial model is subjected to mechanical analysis, and a gradient material is used for the ball unit at the critical deformation position according to the demand of the product.
  • the sound absorption and noise reduction design method comprises the following steps:
  • Step C1 defining a design domain, a load, and a boundary condition
  • Step C2 Divide the finite element mesh into the product area, and initialize each variable at the same time
  • Step C3 Using the optimization model based on the homogenization calculation theory combined with the structural configuration design and the material configuration design, and the acoustic radiation power as the target, the finite element analysis is performed on each unit of the product, and the model is used to construct a superior sound absorption and noise reduction.
  • Porous structure Using the optimization model based on the homogenization calculation theory combined with the structural configuration design and the material configuration design, and the acoustic radiation power as the target, the finite element analysis is performed on each unit of the product, and the model is used to construct a superior sound absorption and noise reduction.
  • Step C4 filling the topography of the ball unit or the ball unit at a specified position of the product, thereby constructing a superior porous structure for sound absorption and noise reduction;
  • Step C5 Perform finite element analysis on the product with the designed internal structure under the design requirements, and obtain the parameters related to the stress distribution and mechanical properties of the product;
  • Step C6 performing data analysis and summarization on the mechanical parameters obtained in the step C5, obtaining systematic and comprehensive mechanical problems and optimization orientation, and realizing the required strength requirements of the product by changing the material and structure of the ball unit;
  • Step C7 Perform computer simulation analysis and related test verification on the structure designed in the step C6.
  • the stress relief design method comprises the following steps:
  • Step D1 acquiring a solid model and a working condition, and obtaining a stress concentration problem by analyzing, obtaining a physical parameter of a scope, a stress concentration factor, and a degree of damage to the material;
  • Step D2 According to the working condition and the stress concentration problem obtained in the step D1, the stress concentration is close to or exceeds the material bearing criticality, and the sub-surface mesh based on the ball unit is distributed in the surrounding area by the law obtained by calculation and experiment.
  • the structure distributes the stress out of the concentrated position; for the stress concentration but lower than the criticality of the material, the subsurface design is performed in the area and the periphery to avoid the stress concentration point.
  • the reinforced damping structure is designed to: provide a porous unit between the two substrates; the porous unit is a ball, a spherical shell derived from a ball, and a surface containing a hole At least one of a spherical shell and a topological structure of the sphere; the base is in the form of a plate.
  • controllable failure structure design method further includes the following steps:
  • Step B5 rationally arranging and transforming the ball unit in the adjacent area of the modified material for the change made to form a later model of the product;
  • Step B6 The model established after replacing the material is analyzed by using finite element and photoelastic experiments to analyze whether there is a problem of significant decrease in strength after replacing the material. If the strength performance index does not meet the design requirements, repeat step B4 and step B5 until The model in step B5 satisfies the design requirements and obtains the final model of the product.
  • the heat insulation design method specifically includes the following steps:
  • Step A1 defining a design domain, a load, and a boundary condition
  • Step A2 dividing a finite element mesh into the heat conduction region, and simultaneously initializing each variable
  • Step A3 using a topology optimization method based on the SIMP material model, performing finite element analysis on each unit of the product, solving the temperature field, and designing a superior heat conduction channel;
  • Step A4 filling the topography of the ball unit or the ball unit at a specified position of the product, thereby constructing a superior heat conduction channel, so that the product has good heat dissipation performance;
  • Step A5 Perform finite element analysis on the product with the designed internal structure under the design requirements, and obtain the parameters related to the stress distribution and mechanical properties of the product;
  • Step A6 performing data analysis and summarization on the mechanical parameters obtained in the step A5, obtaining systematic and comprehensive mechanical problems and optimization orientation, and realizing the required strength requirements of the product by changing the material and structure of the ball unit;
  • Step A7 Perform computer simulation analysis and related test verification on the structure designed in the step A6.
  • the obtained subsurface network structure establishes a corresponding matrix of the three-dimensional position of the spherical center and the radius of the spherical core, and a corresponding structural algorithm is designed, and the 3D printing technology is used for quantitative production.
  • a product structure design method including:
  • the preliminary design of the subsurface mesh structure is completed by filling the ball unit at a preset position of the product body model and optimizing by finite element analysis;
  • the optimization of the filling characteristics of the ball unit is completed through simulation analysis, so that the product structure satisfies the preset index.
  • the method further includes:
  • the functional optimization design method comprises at least one of an insulation heat dissipation design method, a reinforced damping structure design method, a controllable failure structure design method, an acoustic noise reduction design method, and a stress relief design method.
  • the filling feature of the ball unit includes at least one of the following: a shape, a size, and an arrangement of the ball unit.
  • the heat insulation design method comprises: designing a characteristic parameter of the heat conduction channel by using a topology optimization method; filling the ball unit at a preset position of the product body model according to the characteristic parameter of the heat conduction channel, thereby constructing a Said heat conduction channel.
  • controllable failure structure design method comprises:
  • the initial model is subjected to mechanical analysis, and a gradient material is used for the ball unit at the critical deformation position according to the demand of the product.
  • the sound absorption and noise reduction design method comprises:
  • the finite element analysis is carried out on multiple elements of the product main model, and the porous structure of sound absorption and noise reduction is constructed by using the model. ;
  • the finite element analysis is carried out on the product body model with the above porous structure under the design requirements, and the parameters related to the stress distribution and mechanical properties of the product are obtained;
  • a computer simulation analysis and related test verification are performed on the material structure to verify whether the material structure meets the predetermined strength requirement.
  • the stress concentration concentration design method comprises the following steps:
  • the surrounding region of the first region is distributed based on the rule obtained by calculation and experiment based on the spherical unit a subsurface network that disperses the stress out of the concentrated position; for a second region where the stress is concentrated but below the material's criticality, a subsurface design is performed in the surrounding region of the second region, To avoid stress concentration points.
  • the reinforced damping structure design method comprises: arranging a ball unit (2) between two bases (1) of the product; the ball unit (2) is a ball, a spherical shell derived from the ball, and the surface includes At least one of a spherical shell of the hole and a topology of the ball; wherein the base (1) is plate-shaped.
  • the method further includes:
  • the improved model is analyzed by finite element and photoelastic experiments. It is analyzed whether there is a problem that the strength reduction value is greater than the preset intensity value after the material is replaced. If the strength performance index does not meet the preset design requirements, the mechanical analysis of the initial model is repeated. The improved model was analyzed using finite element and photoelastic experiments until the improved model met the preset design requirements and the final model of the product was obtained.
  • the thermal insulation design method includes the following steps:
  • the finite element analysis is carried out on the products with the designed internal structure under the design requirements, and the stress distribution and mechanical performance parameters of the product are obtained.
  • the method further comprises: establishing a structural matrix of the corresponding three-dimensional position of the spherical center and the radius of the spherical core according to the obtained subsurface network structure, and performing production by using 3D printing technology.
  • the product structure design method of the present disclosure is an active design method, that is, a subsurface mesh structure is obtained by ball unit filling and functional optimization design before manufacturing, and a product with light weight and high strength is formed by additive manufacturing technology, Improve the quality of the product, the product has the functions of heat insulation and sound absorption and noise reduction. At the same time, the stress concentration and failure problems are largely avoided, the product strength is higher, and the failure rate is lower when used, especially for the aero engine. For components, performance is better.
  • FIG. 2 is a second block diagram of a product structure design method provided by this embodiment
  • FIG. 3 is a flow chart of a heat insulation design method provided by the embodiment.
  • FIG. 6 is a flow chart of a stress concentration concentration design method provided by the embodiment.
  • FIG. 7 is a schematic structural view of a reinforced damping structure provided by the embodiment.
  • FIG. 8 is a schematic structural diagram of a ball unit according to the embodiment.
  • FIG. 9 is a schematic structural diagram of another ball unit provided by this embodiment.
  • the embodiment provides a product structure design method, which can be applied to large-scale mechanical products with high requirements for strength and lightness in aerospace and other fields, and can also be applied to precision parts in the fields of precision machining and the like.
  • the precision parts may be including aero-engine components such as blades.
  • the product structure design method includes the following steps S10-S30.
  • the preliminary design of the subsurface mesh structure is completed by finite element analysis optimization by filling the ball unit with the preset of the product body model.
  • the subsurface refers to the internal space of the product with fixed geometric shape.
  • the mechanical properties and physical properties of the product including stress distribution, stiffness, strength and heat transfer characteristics, are optimized by changing the internal structure of the product.
  • the ball unit includes a sphere 11 (see FIG. 8), a spherical shell derived from a sphere, a spherical shell 12 having a surface containing a hole (see FIG. 9), and a topology of the sphere. At least one of them.
  • the design of the ball unit may include designing a cell type and a distribution feature of the ball unit, the unit type includes a solid ball and a surface-perforated spherical shell, and the distribution features include a three-dimensional coordinate mathematical parameter of the ball unit.
  • the attributes of the ball unit include at least one of the following: a shape, a size, and an arrangement of the ball unit.
  • the method further comprises manufacturing the product by the additive manufacturing technology, which greatly improves the quality of the product, and the product adopts a subsurface network structure filling the ball unit, because the subsurface network
  • the structure is a porous structure, which makes the product have the characteristics of light weight and high strength, and has the functions of heat insulation, heat absorption and noise reduction.
  • the stress concentration and failure problems are largely avoided, and the product strength is higher.
  • the failure rate is lower when used, for example, for aero engine parts.
  • the corresponding spherical center of the spherical unit in the subsurface network structure is established by analyzing and optimizing the product structure.
  • the structural matrix of the three-dimensional position and the radius of the core is produced using 3D printing technology.
  • the product failure may refer to a product failure, a functional failure, and the like.
  • the heat insulation design method includes the following steps:
  • Step A1 defines a design domain of the product body model, a load type, and a boundary condition of the preset load bearing.
  • the design domain refers to a physical area in the product main body model that needs to complete the heat insulation design.
  • Step A2 Divide the finite element mesh into the design domain, and initialize multiple variables at the same time.
  • the variable may refer to a general variable of a finite element mesh, such as a mesh shape and a size.
  • Step A3 Using a topology optimization method based on SIMP (Solid Isotropic Material with Penalization), finite element analysis is performed on the design domain of the finite element mesh, and the temperature field is solved to obtain better heat conduction. The positional parameters of the channel.
  • SIMP Solid Isotropic Material with Penalization
  • Step A4 filling the ball unit in the product body model according to the position parameter, thereby constructing a better heat conduction channel, so that the product has good heat dissipation performance.
  • Step A5 Perform finite element analysis on the product with the designed internal structure under the design requirements, and obtain the product and stress distribution and mechanical performance parameters.
  • Step A6 According to the mechanical parameters obtained in step A5, the material and structure of the ball unit are changed to achieve the required strength requirements of the product.
  • Step A7 Perform computer simulation analysis and test verification on the structure designed in step A6.
  • Step A7 may include the following steps:
  • Step A71 experimentally testing 3D to print the basic physical and mechanical properties of the product, wherein the basic physical and mechanical properties include: tensile strength, elastic modulus, Brinell hardness, Poisson's ratio, yield strength, and cut Line modulus and density.
  • Step A72 According to the working condition of the product in actual work, build a miniature test platform, gradually increase the load from zero, load test the product on the test platform, and test the deformation distribution and deformation of the product under different load conditions by using the resistance strain gauge method. The amount changes.
  • the micro-test platform refers to reducing the full-scale test bench required for actual working conditions to a test bench operable in the laboratory.
  • step A73 the basic physical and mechanical properties of the product measured in step A71 and the basic physical and mechanical properties and the different load conditions in step A72 are used as basic input values, and the force simulation analysis of the product is performed by using finite element analysis software. Compare the simulated variable analysis result with the measured result in step A72. If the degree of compliance is greater than 90%, proceed to step A74. Otherwise, return to step A73 to adjust the basic physical and mechanical performance type and load condition, and perform simulation analysis again until the theory and test meet the requirements. The degree meets the preset requirements.
  • step A74 the load condition adjusted in step A73, the basic physical and mechanical performance type, and the basic physical and mechanical properties of the material in step A71 are taken as input parameters, and the finite element analysis software is used to simulate the force of the product, and the load force is increased from zero.
  • the size of the product, simulating the strength of the product can be used to push the corresponding product under the actual working conditions without deformation and failure, and can withstand the load.
  • the load conditions in the above steps A71, A72, A73, and A74 refer to the magnitude, direction, action point, and distribution of the applied load force.
  • the superior heat transfer channel is designed by using the topology optimization method to improve the heat dissipation performance of the product, or the thermal insulation performance of the product is improved by changing the pore size of the porous structure, and then the subsurface porous network structure is designed.
  • the structural strength, compressive and anti-wear properties of the product and realizing the mass distribution, stiffness distribution, load path, damping distribution, failure distribution and modal distribution of the structure according to the structural requirements without changing the structural shape.
  • Mechanical properties such as heat transfer distribution and life distribution, and construct a porous mesh structure with excellent heat insulation or heat dissipation properties to meet the external stress requirements of the product.
  • the thermal insulation design method is a superior thermal conduction channel constructed by the topology optimization method.
  • the thermal conduction channel is constructed by filling the ball unit and the topological structure in the product, and the structural properties of the spherical unit are changed under the premise of satisfying the superior thermal conductivity. It can meet the external stress requirements of the product, and increase the strength of the internal structure in the place where the stress is concentrated. For example, use a solid sphere or a solid hemisphere to reduce the strength of the internal structure in the place where the stress is dispersed, for example, using a hollow spherical shell.
  • the porous structure can effectively reduce the three basic heat transfer modes of conduction, convection and radiation by a very low bulk density and a large number of internal nanopores, and the density of the internal structure can greatly reduce the solid state thermal conductivity. rate. While maintaining the porous structure, minimize the size of the cavity. When the diameter is smaller than the normal temperature, the average free path of air is 70 nm. In the case of m), the thermal motion of the gas molecules is limited, so that the convective heat conduction of the gas can be ignored. The thermal insulation properties of the product can be enhanced by a well-designed structure.
  • the normal temperature may mean 25-35 degrees Celsius.
  • controllable failure structure design method comprises the following steps:
  • Step B1 provides a product body model.
  • Step B2 Perform finite element and photoelastic experiment analysis steps under actual working conditions on the product main body model to obtain analytical data.
  • Step B3 Combining the analysis data, filling the ball unit at a preset position of the product body model, designing a porous material having a ball unit structure, and obtaining an initial model of the product.
  • Step B4 Perform mechanical analysis on the initial model, and use a gradient material for the ball unit at the key deformation position according to the demand of the product, wherein the key deformation position refers to a key area that restricts the deformation of the product, including the connection point between the ball units and the center spherical shape. Unit, etc.
  • the gradient material includes a material of a spherical unit in the direction of the load, a gradient material of a common material or a high-strength material which has a high rigidity at both ends and a low strength transition to the middle.
  • the gradient material includes material properties from the ball joint point of the ball unit to the spherical pores, such as a gradient material having a large rigidity, a low strength, and a normal or high strength.
  • Different gradient materials are selected for different product design requirements and actual working conditions, and materials are replaced in key deformation zones.
  • the products are only partially subjected to overload and large loads.
  • the structure first destroys the absorbed energy and the whole is intact or the whole is broken according to the predetermined direction, thereby solving the safety problem when the product working under complicated and severe working conditions fails.
  • Step B5 changing the filling characteristics of the ball unit in the adjacent region using the gradient material to avoid the problem of stress concentration caused by the replacement of the material, and forming a later model of the product.
  • Step B6 analyzing the late model using finite element and photoelastic experiments to analyze whether there is a problem of significant decrease in strength after using the gradient material, and repeating step B4 and step B5 if the performance index such as strength does not meet the design requirements.
  • the model in step B5 satisfies the design requirements of the failed structure and obtains the final model of the product.
  • step B7 of manufacturing the final model in the step B6 by using the 3D printing technique, which has a highly safe product with a directional failure function.
  • the above controllable failure structure design method solves the safety problem of the product failure under the stress condition of the super design range by reasonably designing the material types in different places, so that the designed product can be controlled to fail under the stress condition of the super design range. It can guarantee the failure of mechanical products working in complex situations to become safe and controllable, and improve the overall safety performance of the products.
  • step S20 the sound absorption and noise reduction design method comprises the following steps:
  • Step C1 defines a design domain of the product body model, a load type, and a boundary condition of the preset load bearing.
  • the design domain refers to a physical area in the product that needs to complete the heat insulation design.
  • the load may be including temperature as well as pressure and the like.
  • Step C2 Divide the finite element mesh into the design domain, and initialize multiple variables at the same time.
  • the variable may refer to a general variable of a finite element mesh, such as a mesh shape and a size.
  • Step C3 using the optimization model based on the homogenization calculation theory combined with the structural configuration design and the material configuration design, and aiming at the acoustic radiation power, performing finite element analysis on the design domain, and constructing a superior image by using the optimization model Sound absorption and noise reduction of the porous structure.
  • a porous structure that absorbs sound and noise is constructed by the JCA model.
  • the JCA model refers to an acoustic model, the Johnson-Champoux-Allard model, which is used to simulate the sound absorption process in porous media.
  • Step C4 filling the topography of the ball unit or the ball unit at a specified position of the product body model, thereby constructing a superior porous structure for sound absorption and noise reduction, so that the product has good sound absorption and noise reduction performance.
  • Step C5 Perform finite element analysis on the product body model having the above porous structure under the design requirements, and obtain parameters related to the stress distribution and mechanical properties of the product.
  • Step C6 According to the mechanical parameters obtained in step C5, the material and structure of the ball unit are changed to achieve the required strength requirements of the product.
  • Step C7 Perform computer simulation analysis and test on the structure designed in step C6 to verify whether the product meets the preset strength design requirement.
  • step C7 the following steps are further included:
  • Step C71 experimentally testing the basic physical and mechanical properties of the product by 3D printing, wherein the basic physical and mechanical properties include: tensile strength, elastic modulus, Brinell hardness, Poisson's ratio, yield strength, tangent modulus, and density.
  • Step C72 According to the working condition of the product in actual working conditions, build a miniature test platform, gradually increase the load from zero, load test the product on the test platform, and test the deformation distribution and deformation of the product under different load conditions by using the resistance strain gauge method. The amount of change.
  • step C73 the basic physical and mechanical properties of the product measured in step C71 and the basic physical and mechanical properties and the different load conditions in step C72 are taken as basic input values, and the force simulation analysis of the product is performed by using finite element analysis software. Compare the simulated variable analysis results with the measured results in step C72. If the compliance is greater than 90%, proceed to the next step, otherwise return to C73 to adjust the basic physical and mechanical performance types and Under the conditions of the load, the simulation analysis is performed again until the theoretical and test conformity meets the requirements, for example, the compliance is greater than or equal to 90%.
  • Step C74 taking the load condition adjusted in step C73, the basic physical and mechanical performance type, and the basic physical and mechanical properties of the material in C71 as input parameters, using finite element analysis software to simulate the force of the product, increasing the load force from zero. Size, simulation analysis of the strength of the product, you can push the corresponding product under the actual working conditions will not deform too large and fail, can withstand the corresponding load.
  • the load conditions in steps C72, C73, and C74 refer to the magnitude of the applied load force, the direction of the force, the point of application of the force, and the distribution of the force.
  • the above-mentioned uniformity calculation theory is combined with structural configuration design and material configuration design to establish a porous structure with excellent sound absorption and noise reduction performance, and then through the porous subsurface network structure design, thereby improving the structural strength, compression and wear resistance of the product.
  • Mechanical properties such as performance and physical properties such as super-damping that are not available in conventional structures, which can change the mass distribution, stiffness distribution, load path, damping distribution, failure distribution, and mode of the structure according to structural requirements without changing the structural shape.
  • Mechanical properties such as distribution, heat transfer distribution, life distribution, etc., construct a porous mesh structure with excellent sound absorption and noise reduction performance to meet the external stress requirements of the product, and achieve the purpose of improving the sound absorption and noise reduction performance, mechanical properties and physical properties of the product. .
  • step S20 the stress concentration design method includes the following steps:
  • Step D1 Obtaining the product main body model and working conditions, obtaining the finite element analysis result, and obtaining the stress concentration problem through analysis, which may be a physical parameter that obtains the scope, the stress concentration factor, and the degree of damage to the material.
  • Step D2 According to the working condition and stress concentration problem obtained in step D1, the stress concentration has approached or exceeded the criticality of the material, or the stress concentration factor is extremely high, which will quickly damage the product, and should avoid the strong action area in the surrounding area.
  • the distribution of the subsurface mesh structure based on the ball unit by the regularity obtained by calculation and experiment disperses the stress out of the concentrated position. Stress concentration but below the material's criticality will damage the product during long-term accumulation, and subsurface design in the area and surrounding to avoid stress concentration.
  • Step D3 Perform stress distribution test on the product, and the test method includes computer numerical analysis or photoelastic entity test.
  • Step D4 repeating step D2 and step D3, in order to continuously optimize the design scheme, after accumulating certain design examples, the subsurface mesh structure design library for stress concentration problem is established by summarizing and summarizing to guide the design of related fields.
  • the above method can solve the stress concentration problem occurring in a large-sized mechanical product whose shape is basically fixed, and also realizes the design at the sub-surface level.
  • step S20 includes: providing a porous spherical unit 2 in a cavity formed by the base 1 of the product, optionally, the spherical unit 2 is closely arranged in the cavity linearly or nonlinearly. Inside.
  • the base body 1 has a plate shape, and the base body 1 may be a metal material having a thickness of 1 mm to 5 mm.
  • a ball unit 2 is filled between the two plate-shaped base bodies 1, and the ball unit 2 is formed of a metal material having a height of 1 mm to 5 mm.
  • the above ball unit changes the damping distribution to attenuate the vibration energy transmitted by the structure.
  • the disclosure provides a product structure design method to obtain a subsurface mesh structure by ball unit filling and functional optimization design before manufacturing, and a product with light weight and high strength is formed by the additive manufacturing technology, thereby greatly improving the quality of the product, and the product is advanced in advance. It has the functions of heat insulation, heat absorption and noise reduction. At the same time, stress concentration and failure problems are avoided to a large extent. The product strength is higher and the failure rate is lower when used, especially for aero-engine parts. Better.

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Abstract

一种产品结构设计方法，包括：通过在产品主体模型的预设位置填充球单元，并通过有限元分析优化完成亚表面网状结构的初步设计；以及根据功能性优化设计方法通过仿真分析完成球单元的填充特征的优化，使所述产品结构满足预设指标。

Description

产品结构设计方法 技术领域
本公开涉及结构设计技术领域，例如涉及一种产品结构设计方法。
背景技术
多孔网状结构具备轻质、多功能和可设计等特点，具有高比强度、高比刚度、高强韧以及高能量吸收等优良机械性能，以及减震、散热、吸声、电磁屏蔽以及渗透性等特殊性质，从而具有广泛的应用前景。闭孔多孔结构具有较低的传热系数可用于隔热，开孔多孔结构具有流动通道可用于散热，而可设计性便于对力学和散热结构的设计优化。
拓扑优化的导热通道设计方法通过基于几何平均温度的散热性能描述指标，以此为目标函数建立散热结构设计优化模型，并对目标函数进行敏度分析，得到用较优导热材料分布表征的导热通道的概念设计，同时在保持结构特征不变的前提下，通过对高导热材料分布进行简单的规则化和边界光滑，得到便于工程使用的高导热通道设计。
3D(3Dimensions，三维)打印，也叫快速成形技术、增材制造技术，原理是将三维的实体的数字模型(CAD文件)离散化成切片模型，再将切片模型转化为打印头的行走轨迹，通过打印头将材料不断添加到打印件上去，这样材料就按照打印轨迹不断的被添加，逐层打印起来，就形成了最终的实体打印件。与传统制造业的“减材制造技术”不同，3D打印遵从的是加法原则，可以直接将计算机中的设计转化为模型，直接制造零件或产品，不再需要传统的刀具、夹具和机床；同时直接将虚拟的数字化实体模型转变为产品，极大地简化了生产的流程，降低了材料的生产成本，缩短了产品的设计与开发周期，使得生产任意复杂结构零部件成为可能，也是实现材料微观组织结构和性能的可设计的重要技术手段。3D打印耗材包括：塑料、橡胶、金属、粉末、尼龙、薄膜、树脂、石蜡、石膏、尼龙丝、钛合金以及陶瓷等不同材料。3D打印技术将使得商品的生产制造进入全新的阶段，生产的组织方式也会更加扁平化，而它潜在的对生产的巨大解放，能够极大提高我们社会生产效率。
相关技术中，针对一些产品结构，例如航空发动机的零部件，难以应用增材制造技术成型出重量轻强度大的零部件。
发明内容
一种产品结构设计方法，解决了相关技术中的制造技术难以满足设计要求从而成型出重量轻强度大的零部件的问题。
本公开采用以下技术方案：
一种产品结构设计方法，所述设计方法为通过球单元填充和功能性优化设计获得亚表面网状结构，从而能经增材制造工艺成型出产品。
作为本公开的一个优选方案，所述设计方法具体包括下述步骤：
步骤S1、通过在指定位置填充球单元后进行有限元分析优化完成亚表面网状结构初步设计；
步骤S2、通过隔热散热设计方法、强化阻尼结构设计方法、可控的失效结构设计方法、吸声降噪设计方法以及消除应力集中设计方法完成球单元的填充优化；
步骤S3、通过拓扑优化、力学分析、振动分析与优化以及梯度材料应用与变厚度设计完成亚表面网状结构进一步设计。
作为本公开的一个优选方案，所述步骤S2中，所述隔热散热设计方法为：利用拓扑优化的方法设计较优的导热通道；通过在产品指定的位置填充球单元或球单元的拓扑结构，从而构造出较优的导热通道。
作为本公开的一个优选方案，所述步骤S2中，所述可控的失效结构设计方法包括下述步骤：
步骤B1、设计原始模型；
步骤B2、对原始模型进行实际工况下的有限元和光弹实验分析步骤，得到分析数据；
步骤B3、结合分析数据在指定的位置填充球单元，设计出具有球单元的多孔材料，获得产品的初期模型；
步骤B4、对初期模型进行力学分析，根据产品的需求对在关键形变位置的球单元采用梯度材料。
作为本公开的一个优选方案，所述步骤S2中，所述吸声降噪设计方法包括下述步骤：
步骤C1、定义设计域、载荷和边界条件；
步骤C2、对产品区域划分有限元网格，同时初始化各变量；
步骤C3、利用基于均匀化计算理论结合结构构型设计和材料构型设计、以声辐射功率为目标的优化模型，对产品各单元进行有限元分析，利用模型构造出较优的吸声降噪的多孔结构；
步骤C4、在产品的指定位置填充球单元或球单元的拓扑结构，从而构造出较优的吸声降噪的多孔结构；
步骤C5、对设计好内部结构的产品在设计要求的工况下进行有限元分析，得出产品的应力分布与力学性能相关的参数；
步骤C6、对所述步骤C5中获得的力学参数进行数据分析、归纳整理，得到系统性、综合性的力学问题和优化导向，通过改变球单元的材料、结构实现产品所需的强度要求；
步骤C7、对所述步骤C6中设计出的结构，进行计算机仿真分析和相关测试验证。
作为本公开的一个优选方案，所述步骤S2中，所述消除应力集中设计方法包括下述步骤：
步骤D1、获取实体模型和工况，通过分析获取应力集中问题，得到作用域、应力集中系数以及对于材料的损伤程度的物理性参数；
步骤D2、根据所述步骤D1中获取的工况和应力集中问题，对于应力集中已接近或超过材料承受临界的，在周围区域以由计算和实验获得的规律分布基于球单元的亚表面网状结构，使应力分散出集中位置；对于应力集中但低于材料承受临界的问题，在该区域及周边进行亚表面设计，以避免出现应力集中点。
作为本公开的一个优选方案，所述步骤S2中，所述强化阻尼结构设计方法为：在两基体之间设置多孔单元；所述多孔单元为球、由球衍生出的球壳、表面含孔洞的球壳以及球的拓扑结构中的至少一种；所述基体呈板状。
作为本公开的一个优选方案，所述可控的失效结构设计方法还包括下述步骤：
步骤B5、针对做出的改动在更改材料的相邻区域合理调配、变换球单元，形成产品的后期模型；
步骤B6、对替换材料后建立的模型使用有限元、光弹实验分析，分析在更换材料后是否出现有强度明显降低问题，若强度性能指标不符合设计要求则重复所述步骤B4、步骤B5直到步骤B5中的模型满足设计需求，得到产品的最终模型。
作为本公开的一个优选方案，所述步骤S2中，所述隔热散热设计方法具体包括下述步骤：
步骤A1、定义设计域、载荷和边界条件；
步骤A2、对导热区域划分有限元网格，同时初始化各变量；
步骤A3、利用基于SIMP材料模型的拓扑优化方法，对产品各单元进行有限元分析，求解温度场，同时设计出较优的导热通道；
步骤A4、在产品的指定位置填充球单元或球单元的拓扑结构，从而构造出较优的导热通道，使产品具有良好的散热性能；
步骤A5、对设计好内部结构的产品在设计要求的工况下进行有限元分析，得出产品的应力分布与力学性能相关的参数；
步骤A6、对所述步骤A5中获得的力学参数进行数据分析、归纳整理，得到系统性、综合性的力学问题和优化导向，通过改变球单元的材料、结构实现产品所需的强度要求；
步骤A7、对所述步骤A6中设计出的结构，进行计算机仿真分析和相关测试验证。
作为本公开的一个优选方案，将获得的亚表面网状结构建立相应的球心的三维位置、球心半径的结构矩阵，设计出相应的结构算法，利用3D打印技术进行量化生产。
一种产品结构设计方法，包括：
通过在产品主体模型的预设位置填充球单元，并通过有限元分析优化完成亚表面网状结构的初步设计；以及
根据功能性优化设计方法通过仿真分析完成球单元的填充特征的优化，使所述产品结构满足预设指标。
可选的，在所述通过仿真分析完成球单元的填充特征的优化之后，还包括：
根据拓扑优化、力学分析、振动分析与优化，改变所述球单元的材料以及填充特性完成亚表面网状结构的设计。
可选的，功能性优化设计方法包括隔热散热设计方法、强化阻尼结构设计方法、可控的失效结构设计方法、吸声降噪设计方法以及消除应力集中设计方法中的至少一种。
可选的，所述球单元的填充特征包括下述至少一项：球单元的形状、尺寸以及排布。
可选的，所述隔热散热设计方法包括：利用拓扑优化的方法设计导热通道的特征参数；根据所述导热通道的特征参数，在产品主体模型的预设位置填充球单元，从而构造出所述导热通道。
可选的，所述可控的失效结构设计方法包括：
对产品主体模型进行实际工况下的有限元和光弹实验分析步骤，得到分析数据；
结合分析数据在产品主体模型的预设位置填充球单元，设计出具有球单元结构的，获得产品的初步模型；
对初期模型进行力学分析，根据产品的需求对在关键形变位置的球单元采用梯度材料。
可选的，所述吸声降噪设计方法包括：
定义产品主体模型的设计域、载荷种类和预设承受载荷的边界条件；对设计所述设计域划分有限元网格，同时初始化多个变量；
利用基于均匀化计算理论结合结构构型设计和材料构型设计、以声辐射功率为目标的优化模型，对产品主体模型多个单元进行有限元分析，利用模型构造出吸声降噪的多孔结构；
在产品主体模型的指定位置填充球单元，从而构造出吸声降噪的多孔结构；
对具有上述多孔结构的产品主体模型在设计要求的工况下进行有限元分析，得出产品的应力分布与力学性能相关的参数；
对所述与力学性能相关的参数进行数据分析以及归纳整理，得到系统性且综合性的力学问题和优化导向，并根据所述力学问题和优化导向改变球单元的材料结构，以使所述材料结构达到预设强度要求；
对所述材料结构，进行计算机仿真分析和相关测试验证，以验证所述材料结构是否达到所述预设强度要求。
可选的，所述消除应力集中设计方法包括下述步骤：
获取产品主体模型和工况，通过分析获取应力集中问题，得到作用域、应力集中系数以及对于材料的损伤程度的物理性参数；
根据所述获取的工况和应力集中问题，对于应力集中已接近或超过材料承受临界值的第一区域，在所述第一区域的周围区域以由计算和实验获得的规律分布基于球单元的亚表面网状结构，使应力分散出集中位置；对于应力集中但低于材料承受临界的第二区域，在所述第二区域的周围区域进行亚表面设计， 以避免出现应力集中点。
可选的，所述强化阻尼结构设计方法包括：在产品的两基体(1)之间设置球单元(2)；所述球单元(2)为球、由球衍生出的球壳、表面含孔洞的球壳以及球的拓扑结构中的至少一种；其中，所述基体(1)呈板状。
可选的，在根据产品的需求对在关键形变位置的球单元采用梯度材料之后，还包括：
针对做出的改动在更改材料的相邻区域合理调配和变换球单元，形成产品的后期模型；
对改进模型使用有限元和光弹实验分析，分析在更换材料后是否出现有强度降低值大于预设强度值的问题，若强度性能指标不符合预设设计要求则重复执行对初期模型进行力学分析至对改进模型使用有限元和光弹实验分析直到改进模型满足预设设计要求，得到产品的最终模型。
可选的，所述隔热散热设计方法包括下述步骤：
定义产品主体模型的设计域、载荷种类和预设承受载荷的边界条件
对设计所述设计域划分有限元网格，同时初始化多个变量；利用基于SIMP材料模型的拓扑优化方法，对产品各单元进行有限元分析，求解温度场，同时设计出预设导热通道的位置参数；
根据位置参数在产品主体模型中填充球单元或球单元的拓扑结构，从而构造出预设导热通道，使产品具有预设程度的散热性能；
对设计好内部结构的产品在设计要求的工况下进行有限元分析，得出产品的应力分布与力学性能参数；
根据所述与力学性能相关的参数，改变球单元的材料结构，以使所述材料结构达到预设强度要求；
对所述材料结构，进行计算机仿真分析和相关测试验证。
可选的，还包括根据获得的亚表面网状结构建立相应的球心的三维位置和球心半径的结构矩阵，利用3D打印技术进行生产。
本公开的产品结构设计方法是一种主动设计方法，即，在制造之前通过球单元填充和功能性优化设计获得亚表面网状结构，通过增材制造技术成型出重量轻强度大的产品，大大提高了产品的品质，该产品具有隔热散热以及吸声降噪等功能，同时，较大程度地避免了应力集中和失效问题，产品强度更高，使用时故障率较低，尤其针对航空发动机零部件而言，性能更优良。
附图概述
图1是本实施例提供的产品结构设计方法的流程框图之一；
图2是本实施例提供的产品结构设计方法的流程框图之二；
图3是本实施例提供的隔热散热设计方法的流程框图；
图4是本实施例提供的可控的失效结构设计方法的流程框图；
图5是本实施例提供的吸声降噪设计方法的流程框图；
图6是本实施例提供的消除应力集中设计方法的流程框图；
图7是本实施例提供的强化阻尼结构的结构示意图；
图8是本实施例提供的一种球单元的结构示意图；
图9是本实施例提供的另一种球单元的结构示意图。
具体实施方式
本实施例提供了一种产品结构设计方法，该方法既可以应用于航空航天等领域的对强度、轻量等有极高要求的大型机械产品当中，也可以应用于精密加工等领域的精密零件结构设计中，所述精密零件可以是包括航空发动机零部件，如叶片。如图1和图2所示，产品结构设计方法包括下述步骤S10-S30。
在S10中，通过产品主体模型的预设填充球单元后进行有限元分析优化完成亚表面网状结构的初步设计。
其中，亚表面是指在几何外形固定的产品的内部空间，通过改变产品内部的结构优化产品的力学性能和物理特性，包括应力分布、刚度、强度和传热特性等。
本实施例以及其他实施例中，球单元包括球体11(参见图8)、由球衍生出的球壳、表面含孔洞的球壳12(参见图9)以及球的拓扑结构等多种几何体中的至少一种。球单元的设计可以是包括对球单元的单元种类和分布特征进行设计，单元种类包括实体球和表面打孔的球壳等，分布特征包括球单元三维坐标数学参数等。
在S20中，通过隔热散热设计方法、强化阻尼结构设计方法、可控的失效结构设计方法、吸声降噪设计方法以及消除应力集中设计方法完成球单元的填充特征的优化。
可选的，所述球单元的属性包括下述至少一项：球单元的形状、尺寸以及排布。
在S30中，根据拓扑优化、力学分析、振动分析与优化，改变所述球单元的材料以及填充特性完成亚表面网状结构的设计。
可选的，在上述步骤的基础上，还包括通过增材制造技术制造出产品，大大提高了产品的品质，该产品由于采用了填充球单元的亚表面网状结构，由于所述亚表面网状结构是一种多孔结构，使得产品具有质量轻强度大的特点，且具有隔热散热以及吸声降噪等功能，同时，较大程度地避免了应力集中和失效问题，产品强度更高，使用时故障率较低，例如针对航空发动机零部件而言，性能更优良。
为了实现隔热散热以及吸声降噪等功能，避免应力集中以及产品失效等问题，本实施例中，通过对产品结构进行分析和优化，建立亚表面网状结构中球单元的相应的球心的三维位置和球心半径的结构矩阵，利用3D打印技术进行生产。所述产品失效可以是指产品发生故障，功能失效等。
可选的，步骤S20中，如图3所示，隔热散热设计方法包括下述步骤：
步骤A1、定义产品主体模型的设计域、载荷种类和预设承受载荷的边界条件。
其中，所述设计域是指产品主体模型中需完成隔热散热设计的物理区域。
步骤A2、对设计所述设计域划分有限元网格，同时初始化多个变量。
所述变量可以是指有限元网格的一般变量，例如网格形状以及尺寸等参数。
步骤A3、利用基于SIMP(Solid Isotropic Material with Penalization，固体各向同性材料惩罚模型)的拓扑优化方法，对划分有限元网格的设计域进行有限元分析，求解温度场，以得到较优的导热通道的位置参数。
步骤A4、根据位置参数在产品主体模型中填充球单元，从而构造出较优的导热通道，使产品具有良好的散热性能。
步骤A5、对设计好内部结构的产品在设计要求的工况下进行有限元分析，得出产品与应力分布与力学性能参数。
步骤A6、根据步骤A5中获得的力学参数，改变球单元的材料及结构以实现产品所需的强度要求。
步骤A7、对步骤A6中设计出的结构，进行计算机仿真分析和测试验证。步骤A7可以是包括下述步骤：
步骤A71、通过实验测试3D打印出产品的基本物理机械性能，其中，基本物理机械性能包括：抗拉强度、弹性模量、布氏硬度、泊松比、屈服强度、切 线模量和密度。
步骤A72、按照产品在实际工作中的工况搭建微缩的试验平台，从零逐渐增加载荷，在试验平台上对产品进行加载试验，采用电阻应变片法测试不同载荷条件下产品的变形分布以及变形量变化。所述微缩的试验平台是指将实际工况所需全尺度的试验台缩小到实验室内可操作的试验台。
步骤A73、将步骤A71中测量的产品的基本物理机械性能以及基本物理机械性能种类与步骤A72中的不同载荷条件作为基本输入值，采用有限元分析软件进行产品的受力模拟分析。将模拟的变量分析结果与步骤A72中实测结果进行对照，符合度大于90％则进行步骤A74，否则返回到步骤A73调整基本物理机械性能种类及载荷条件，再次进行模拟分析，直到理论和试验符合度达到预设要求。
步骤A74、将步骤A73中调整好的载荷条件、基本物理机械性能种类和步骤A71中的材料基本物理机械性能作为输入参数，采用有限元分析软件进行产品受力模拟分析，从零开始增加载荷力的大小，模拟分析出产品的强度，即可推演出相应产品在实际工况下不会变形过大而失效，能够承受得住的载荷。
上述步骤A71、A72、A73、A74中的载荷条件指的是施加载荷力的大小、方向、作用点和分布。
上述方法中，通过利用拓扑优化方法设计出较优的传热通道来提升产品的散热性能，或通过改变多孔结构的孔径大小来提升产品的隔热性能，之后通过设计亚表面多孔网状结构，从而提升产品的结构强度、抗压抗磨损性能等力学性能，实现在不改变结构外形条件下能根据结构使用要求改变结构的质量分布、刚度分布、载荷路径、阻尼分布、失效分布、模态分布、传热分布以及寿命分布等机械性能，构建出具有优良隔热或散热性能、满足产品外部应力需求的多孔网状结构，
隔热散热设计方法通过拓扑优化方法构造出的较优的导热通道，通过在产品内通过填充球单元及拓扑结构来构造导热通道，在满足较优导热性能的前提下通过改变球单元的结构属性可以满足产品的外部应力需求，在应力集中的地方增大内部结构的强度，例如使用实心球体或实心半球等，在应力分散的地方减小内部结构的强度，例如使用空心球壳等。同时多孔结构通过以极低的体积密度和内部大量的纳米孔洞对传导、对流和辐射这3种基本的传热方式形成有效的抑制，且内部结构较低的密度，能大幅度降低固态热导率。在维持多孔结构的同时，尽量减小空洞的尺寸，当直径小于常温下空气的平均自由程70nm(纳 米)时，气体分子的热运动受到限制，因而可忽略气体对流热传导。通过设计合理的结构可以增强产品的隔热性能。所述常温可以是指25-35摄氏度。
可选的，步骤S20中，如图4所示，可控的失效结构设计方法包括下述步骤：
步骤B1、提供产品主体模型。
步骤B2、对产品主体模型进行实际工况下的有限元和光弹实验分析步骤，得到分析数据。
步骤B3、结合分析数据，在所述产品主体模型的预设位置填充球单元，设计出具有球单元结构的多孔材料，获得产品的初期模型。
步骤B4、对初期模型进行力学分析，根据产品的需求对在关键形变位置的球单元采用梯度材料，其中，关键形变位置是指限制产品形变的关键区域，包括球单元间的连接点以及中心球状单元等。梯度材料包括球单元沿载荷方向的材料特性由两端刚度大、强度低过渡到中间的普通材料或高强度材料的梯度材料。梯度材料包括从球单元的球连接点到球状孔隙的材料特性由刚度大、强度低到普通或高强度的梯度材料等。
针对不同的产品设计要求和实际工况选择不同的梯度材料，对关键形变区域进行材料的更换，通过非均匀材料的特性，在满足力学性能的情况下，使得产品遭遇超负荷大载荷时仅部分结构率先破坏吸收能量而整体完整或整体按照预定方向破裂，进而解决了复杂恶劣工况下工作的产品失效时的安全性问题。
步骤B5、改变在采用梯度材料的相邻区域的球单元的填充特征，以避免产生应更换材料而导致的应力集中等问题，形成产品的后期模型。
步骤B6、对所述后期模型使用有限元以及光弹实验等分析，分析在采用梯度材料后是否出现有强度明显降低等问题，若强度等性能指标不符合设计要求则重复步骤B4、步骤B5直到步骤B5中的模型满足失效结构的设计需求，得到产品的最终模型。
还可以是包括步骤B7、利用3D打印技术对步骤B6中的最终模型进行制造，既得具有定向失效功能的安全性较高的产品。
上述可控的失效结构设计方法，通过合理设计不同地方的材料种类从而使设计的产品在超设计范围应力条件下可控的失效，解决了产品在超设计范围应力条件下失效时的安全问题，可以保障复杂情况下工作的机械产品失效变得安全、可控，提高产品的整体安全性能。
可选的，步骤S20中，如图5所示，吸声降噪设计方法包括下述步骤：
步骤C1、定义产品主体模型的设计域、载荷种类和预设承受载荷的边界条件。
其中，所述设计域是指产品中需完成隔热散热设计的物理区域。所述载荷可以是包括温度以及压力等。
步骤C2、对所述设计域划分有限元网格，同时初始化多个变量。
所述变量可以是指有限元网格的一般变量，例如网格形状以及尺寸等参数。
步骤C3、利用基于均匀化计算理论结合结构构型设计和材料构型设计、以声辐射功率为目标的优化模型，对所述设计域进行有限元分析，利用所述优化模型构造出较优的吸声降噪的多孔结构。可选的，通过JCA模型构造出较优的吸声降噪的多孔结构。
其中，所述JCA模型是指一种声学模型，即Johnson-Champoux-Allard模型，用来模拟多孔介质中的吸声过程。
步骤C4、在产品主体模型的指定的位置填充球单元或球单元的拓扑结构，从而构造出较优的吸声降噪的多孔结构，使产品具有良好的吸声降噪性能。
步骤C5、对具有上述多孔结构的产品主体模型在设计要求的工况下进行有限元分析，得出产品的应力分布与力学性能相关的参数。
步骤C6、根据步骤C5获得的力学参数，改变球单元的材料、结构实现产品所需的强度要求。
步骤C7、对步骤C6中设计出的结构，进行计算机仿真分析和测试验证产品是否满足预设强度设计需求。
在步骤C7中，还包括如下步骤：
步骤C71、通过实验测试3D打印出产品的基本物理机械性能，其中，基本物理机械性能包括：抗拉强度、弹性模量、布氏硬度、泊松比、屈服强度、切线模量和密度。
步骤C72、按照产品在实际工作中的工况搭建微缩的试验平台，从零逐渐增加载荷，在试验平台上对产品进行加载试验，采用电阻应变片法测试不同载荷条件下产品的变形分布以及变形量变化情况。
步骤C73、将步骤C71中测量的产品的基本物理机械性能以及基本物理机械性能种类与步骤C72中的不同载荷条件作为基本输入值，采用有限元分析软件进行产品的受力模拟分析。将模拟的变量分析结果与步骤C72中实测结果进行对照，符合度大于90％则进行下一步，否则返回到C73调整基本物理机械性能种类及载 荷条件，再次进行模拟分析，直到理论和试验符合度达到要求，例如符合度大于等于90％。
步骤C74、将步骤C73中调整好的载荷条件、基本物理机械性能种类和C71中的材料基本物理机械性能作为输入参数，采用有限元分析软件进行产品受力模拟分析，从零开始增加载荷力的大小，模拟分析出产品的强度，即可推演出相应产品在实际工况下不会变形过大而失效，能够承受得住相应的载荷。
步骤C72、C73、C74中的载荷条件指的是施加载荷力的大小、力的方向、力的作用点和力的分布情况。
上述基于均匀化计算理论结合结构构型设计和材料构型设计建立具有优良吸声降噪性能的多孔结构，之后通过多孔的亚表面网状结构设计，从而提升产品的结构强度、抗压抗磨损性能等力学性能和增加传统结构所没有的超阻尼等物理特性，实现在不改变结构外形条件下能根据结构使用要求改变结构的质量分布、刚度分布、载荷路径、阻尼分布、失效分布、模态分布、传热分布、寿命分布等机械性能，构建出具有优良吸声降噪性能，满足产品外部应力需求的多孔网状结构，达到提升产品的吸声降噪性能、力学性能和物理特性的目的。
可选的，步骤S20中，如图6所示，消除应力集中设计方法包括下述步骤：
步骤D1、获取产品主体模型和工况，得到有限元分析结果，通过分析获取应力集中问题，可以是得到作用域、应力集中系数、以及对于材料的损伤程度的物理性参数。
步骤D2、根据步骤D1获取的工况和应力集中问题，应力集中已接近或超过材料承受临界的，或应力集中系数极高的情况，会快速损伤产品，应避开强作用区域，在周围区域以由计算和实验获得的规律分布基于球单元的亚表面网状结构，使应力分散出集中位置。应力集中但低于材料承受临界的情况，会在长期积累中损伤产品，在该区域及周边进行亚表面设计，以避免出现应力集中点。
步骤D3、对产品进行应力分布测试，测试方法包括计算机数值分析或光弹性实体测试。
步骤D4、重复步骤D2与步骤D3，以不断优化设计方案，在积累一定设计实例之后，通过归纳总结建立关于应力集中问题的亚表面网状结构设计库，以对相关领域的设计进行指导。
上述方法可以解决外形基本定型的大型机械产品中出现的应力集中问题，同时也实现了在亚表面层面的设计。
可选的，如图7所示，步骤S20包括：在产品的基体1形成的空腔内设置多孔的球单元2，可选为，球单元2呈线性或非线性紧密排列在所述空腔内。
可选的，基体1呈板状，基体1可以为厚度1mm～5mm的金属材料。所述两个板状的基体1之间填充有球单元2，所述球单元2形成的结构为高度1mm～5mm的金属材料。
上述球单元改变阻尼分布可以使结构传递的振动能量衰减。
工业实用性
本公开提供产品结构设计方法在制造之前通过球单元填充和功能性优化设计获得亚表面网状结构，通过增材制造技术成型出重量轻强度大的产品，大大提高了产品的品质，该产品预先即具有了隔热散热以及吸声降噪等功能，同时，较大程度地避免了应力集中和失效问题，产品强度更高，使用时故障率较低，尤其针对航空发动机零部件而言，性能更优良。

Claims (12)

  1. 一种产品结构设计方法，包括：
    通过在产品主体模型的预设位置填充球单元，并通过有限元分析优化完成亚表面网状结构的初步设计；以及
    根据功能性优化设计方法通过仿真分析完成球单元的填充特征的优化，使所述产品结构满足预设指标。
  2. 根据权利要求1所述的产品结构设计方法，其中，在所述通过仿真分析完成球单元的填充特征的优化之后，还包括：
    根据拓扑优化、力学分析、振动分析与优化，改变所述球单元的材料以及填充特性完成亚表面网状结构的设计。
  3. 根据权利要求1或2所述的产品结构设计方法，其中，功能性优化设计方法包括隔热散热设计方法、强化阻尼结构设计方法、可控的失效结构设计方法、吸声降噪设计方法以及消除应力集中设计方法中的至少一种。
  4. 根据权利要求3任一所述的产品结构设计方法，其中，所述球单元的填充特征包括下述至少一项：球单元的形状、尺寸以及排布。
  5. 根据权利要求4所述的产品结构设计方法，其中，所述隔热散热设计方法包括：利用拓扑优化的方法设计导热通道的特征参数；根据所述导热通道的特征参数，在产品主体模型的预设位置填充球单元，从而构造出所述导热通道。
  6. 根据权利要求4所述的产品结构设计方法，其中，所述可控的失效结构设计方法包括：
    对产品主体模型进行实际工况下的有限元和光弹实验分析步骤，得到分析数据；
    结合分析数据在产品主体模型的预设位置填充球单元，设计出具有球单元结构的多孔材料，获得产品的初步模型；
    对初期模型进行力学分析，根据产品的需求对在关键形变位置的球单元采用梯度材料。
  7. 根据权利要求4所述的产品结构设计方法，其中，所述吸声降噪设计方法包括：
    定义产品主体模型的设计域、载荷种类和预设承受载荷的边界条件；对设计所述设计域划分有限元网格，同时初始化多个变量；
    利用基于均匀化计算理论结合结构构型设计和材料构型设计、以声辐射功率为目标的优化模型，对所述设计域进行有限元分析，利用模型构造出吸声降 噪的多孔结构；
    在产品主体模型的指定位置填充球单元，从而构造出吸声降噪的多孔结构；
    对具有上述多孔结构的产品主体模型在设计要求的工况下进行有限元分析，得出产品的应力分布与力学性能相关的参数；
    根据所述与力学性能参数改变球单元的材料结构，以使所述材料结构达到预设强度要求；
    对所述材料结构，进行计算机仿真分析和相关测试验证，以验证所述材料结构是否达到所述预设强度要求。
  8. 根据权利要求4所述的产品结构设计方法，其中，所述消除应力集中设计方法包括下述步骤：
    获取产品主体模型和工况，通过分析获取应力集中问题，得到作用域、应力集中系数以及对于材料的损伤程度的物理性参数；
    根据所述获取的工况和应力集中问题，对于应力集中已接近或超过材料承受临界值的第一区域，在所述第一区域的周围区域以由计算和实验获得的规律分布基于球单元的亚表面网状结构，使应力分散出集中位置；对于应力集中但低于材料承受临界的第二区域，在所述第二区域的周围区域进行亚表面设计，以避免出现应力集中点。
  9. 根据权利要求4所述的产品结构设计方法，其中，所述强化阻尼结构设计方法包括：在产品的两基体(1)之间设置球单元(2)；所述球单元(2)为球、球壳、表面含孔洞的球壳以及球的拓扑结构中的至少一种；其中，所述基体(1)呈板状。
  10. 根据权利要求6所述的产品结构设计方法，其中，在根据产品的需求对在关键形变位置的球单元采用梯度材料之后，还包括：
    改变在采用梯度材料的相邻区域的球单元的填充特征，形成产品的后期模型；
    对所述后期模型使用有限元和光弹实验分析，分析在采用梯度材料后是否出现有强度降低值大于预设强度值的问题，若强度性能指标不符合预设设计要求则重复对初期模型进行力学分析，根据产品的需求对在关键形变位置的球单元采用梯度材料，并改变在采用梯度材料的相邻区域的球单元的填充特征，直到改进模型满足预设设计要求，得到产品的最终模型。
  11. 根据权利要求5所述的产品结构设计方法，其中，所述隔热散热设计 方法包括下述步骤：
    定义产品主体模型的设计域、载荷种类和预设承受载荷的边界条件
    对设计所述设计域划分有限元网格，同时初始化多个变量；利用基于固体各向同性材料惩罚模型SIMP的拓扑优化方法，对划分有限元网格的设计域进行有限元分析，求解温度场，以得到预设导热通道的位置参数；
    根据位置参数在产品主体模型中填充球单元或球单元的拓扑结构，从而构造出预设导热通道，使产品具有预设程度的散热性能；
    对设计好内部结构的产品在设计要求的工况下进行有限元分析，得出产品的应力分布与力学性能参数；
    根据所述与力学性能相关的参数，改变球单元的材料结构，以使所述材料结构达到预设强度要求；
    对所述材料结构，进行计算机仿真分析和相关测试验证。
  12. 根据权利要求1-11任一项所述的产品结构设计方法，还包括根据获得的亚表面网状结构建立相应的球心的三维位置和球心半径的结构矩阵，利用3D打印技术进行生产。
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