CN103399991A - Intelligent low-carbon lightweight oriented equipment rotating table design method - Google Patents

Abstract

The invention discloses an intelligent low-carbon lightweight oriented equipment rotating table design method. The method includes according to different bearing functions, dividing a rotating table into an applying portion of main loading, namely a table top supporting portion, a portion playing a main role in supporting, namely a lateral supporting portion, and constructing two-dimensional feature section models of the two portions respectively; acquiring two-dimensional optimal rib plate conformations of the table top supporting portion and the lateral supporting portion respectively; designing three-dimensional conformations of the table top supporting portion and the lateral supporting portion respectively according to the acquired two-dimensional optimal rib plate conformations, and combining the three-dimensional conformations of the table top supporting portion and the lateral supporting portion properly to acquire a complete equipment rotating table structural design scheme. The intelligent creation principles of bearing the conformations are applied to different function portions after the rotating table is reasonably divided, so that optimal structural design of the rotating table is realized, and the method is applicable to structural optimization design of rotating tables of heavy and extra-heavy equipment.

Description

Low-carbon lightweight equipment rotary worktable intelligent design method

Technical Field

The invention relates to an optimized design method for the structure of a heavy and ultra-heavy manufacturing equipment bearing piece, in particular to an intelligent design method for a low-carbon and light-weight equipment rotary worktable.

Background

Heavy and ultra-heavy manufacturing equipment is key equipment in equipment manufacturing industry, integrates advanced technologies of various disciplines and represents the level of national manufacturing industry. Meanwhile, under the current development trend of low carbon and environmental protection, people continuously explore how to realize the light weight of heavy and ultra-heavy manufacturing equipment design and the low carbon of the manufacturing process.

The rotary worktable is an important component of heavy and ultra-heavy manufacturing equipment, and the structural characteristics of the rotary worktable greatly influence the overall performance of the manufacturing equipment. The traditional rotary worktable structure design mainly depends on experience, analogy, simple finite element analysis and the like, the reliability of the structure is guaranteed by adopting a larger safety factor, so that the rotary worktable structure is heavy, the potential of materials cannot be well exerted, the performance of the rotary worktable is difficult to improve, the manufacturing cost is increased, and the design requirements of low carbon and light weight of the current heavy and ultra-heavy manufacturing equipment cannot be met.

Disclosure of Invention

The invention aims to provide an intelligent design method for a low-carbon and light-weight equipment rotary worktable.

In order to achieve the purpose, the invention adopts the following technical scheme.

An intelligent design method for a low-carbon light-weight equipment rotary worktable comprises the following steps: the method comprises the steps of dividing a rotary worktable into different functional parts according to different bearing effects, abstracting a two-dimensional characteristic section model of each functional part, applying an intelligent creation criterion on each two-dimensional characteristic section model respectively, converting a structural design problem of the rotary worktable into an intelligent creation problem of the optimal bearing configuration of each functional part, and combining the functional parts with the optimal bearing configuration to obtain the complete optimal structure of the rotary worktable.

The intelligent design method specifically comprises the following steps:

1) construction of two-dimensional characteristic section model

According to different bearing functions, the rotary table is divided into a table top supporting part and a side supporting part, the table top supporting part is a part for applying main load, the side supporting part is a part for playing a main supporting role, abstracting the table top supporting part into a two-dimensional regular hexadecimal stress model formed by shell units according to the boundary condition of the table top supporting part, setting the two-dimensional regular hexadecimal stress model as a two-dimensional characteristic of a rib plate configuration of the table top supporting part to create a space, abstracting the side supporting part into a two-dimensional rectangular stress model consisting of shell units according to the boundary condition of the side supporting part, setting the two-dimensional rectangular stress model as a two-dimensional characteristic of a rib plate configuration of the side supporting part to create a space, and adding beam units mutually coupled with the shell units between adjacent shell unit nodes of the two stress models respectively;

2) intelligent creation of rib plate configuration in two-dimensional characteristic section model

Taking the section height h of the upper beam unit of the two-dimensional characteristic section as a design variable, and implementing bifurcation and degradation operation in the growth process of the beam unit by optimizing and changing the value of the section height h of the upper beam unit of the two-dimensional characteristic section, thereby realizing the optimal creation of the structure of the rib plate on the two-dimensional characteristic section; since the cross-sectional height h is the only geometrical dimension that determines the beam element weight W, the essence of the intelligent creation process is the optimal distribution of material, and the mathematical model of the whole optimization process is as follows:

designing variables: w = [ W =₁,W₂,…,W_N]

An objective function: minimum Total Strain energy Min f (W)

Constraint conditions are as follows: w_sum≤W₀

W_i ^U>W_i>W_i ^L,i=1,2,…,N

Wherein f (W) is the total strain energy of the structural model, W_sumIs the total mass of the structure, W₀Is a predetermined upper limit of the structural mass, W_iIs the ith design variable, W_i ^URepresents W_iUpper limit value of, W_i ^LRepresents W_iN is the number of design variables;

3) post-processing of rotary table structural design

Designing a three-dimensional optimal configuration of the table top supporting part according to the rib plate configuration of the table top supporting part in the two-dimensional characteristic section model, designing a three-dimensional optimal configuration of the rib plate of the side supporting part according to the rib plate configuration of the side supporting part in the two-dimensional characteristic section model, performing circumferential array processing on the three-dimensional optimal configuration of the rib plate of the side supporting part around a rotating center of the workbench to obtain a final three-dimensional optimal configuration of the side supporting part, and combining the final three-dimensional optimal configuration of the side supporting part and the three-dimensional optimal configuration of the table top supporting part to obtain the complete rotating workbench.

The intelligent creation of the rib plate configuration in the two-dimensional characteristic section model comprises the following specific steps:

1) according to the actual installation constraint and the loading condition of the functional part, applying boundary constraint and load to the constructed two-dimensional characteristic section model;

2) defining a solving type as structural statics analysis, solving an initialization model, setting a display result of analysis as equivalent stress, and calculating the total strain energy of structural deformation;

3) storing the values of the design variable parameter h and the total strain energy of structural deformation;

4) constraint parameter W for setting intelligent optimization of structure₀Setting material increment delta W given by each cycle iteration in the structure optimization process, and setting bifurcation threshold h of competing beam unit_bAnd a degradation threshold h_d；

5) Selecting a plurality of points with relatively high initial strain energy on the two-dimensional characteristic cross section as creation starting points, wherein the selected points are contained in a creation point set { B }, and beam units which can grow around the creation points are contained in a beam unit set { C } to be competitively grown;

6) in each cycle iteration, the weight of each beam unit participating in competition in the set { C } is distributed with a material increment delta W in a proportional way according to the corresponding generalized sensitivity D value, so that the optimal distribution of the material is realized, and the weight iteration calculation criterion after the growth of each competition beam unit is as follows:

${W_i}^{(k+1)}=\mathrm{\α}\·{(D_i\·\frac{\mathrm{\ΔW}}{D_{\mathrm{sum}}})}^{\left(k\right)}+(1-\mathrm{\α})\·{W_i}^{\left(k\right)},(i=1,...,N)$

wherein,

e is the total strain energy of the current structure,

for sensitivity of total strain energy to competing beam element weights, α represents an iteration step size factor, k represents the number of steps of the iteration,

7) because the beam unit section width b is a fixed value, the section height h is a geometrical dimension which uniquely determines the weight of the beam unit, the distribution of materials in each cycle is reflected by the updated change of the section height h of each competing beam unit, and if the section height of the competing beam unit after updating is smaller than the degradation threshold h_dConsidering the competitive beam unit to meet the degradation condition, removing the competitive beam unit from the set { C } of the competitive beam units, removing nodes at two ends of the competitive beam unit from the set { B } of the creation points, and assigning the height of the section of the competitive beam unit as h_d(ii) a If the updated section height is greater than or equal to the bifurcation threshold h_bIf the competing beam unit is deemed to have the branching capability, the competing beam unit is assigned as h_bMeanwhile, the nodes at the two ends are used as new creation points to be added into the creation point set { B }, and all beam units connected around the new creation points are added into the set { C }, so that the competing materials can be distributed in the next cycle;

8) storing the updated design variable parameter h, and updating the wholeA two-dimensional characteristic section model, calculating the total weight of the material of the updated structure model, and judging whether the total weight reaches the upper limit W of the total mass₀If yes, the loop iteration is terminated, otherwise, the iteration step is repeated;

9) after the whole intelligent optimization iteration is finished, in [ h ]_d,h_b]Upper selection value h_vAs a standard for further screening beam units, filtering out the beam units with a cross-sectional height less than h_vThe reserved beam units and the two-dimensional characteristic section form a thin plate reinforced structure which is clear in layout and optimal and reasonable, and therefore the optimal creation of the structure of the functional part rib plate is obtained.

The invention has the beneficial effects that: the invention divides the rotary worktable into a plurality of functional parts according to the difference of the bearing effect of different parts of the rotary worktable, then transforms the structural design problem of the rotary worktable into the intelligent creation problem of the rib plate structure of each functional part based on the construction of the two-dimensional characteristic section model of each functional part, obtains the corresponding optimal bearing structure by intelligently creating the bearing structure of each functional part, and finally combines each functional part with the optimal bearing structure to obtain the optimal structure of the rotary worktable, compared with the traditional rotary worktable structural design method based on engineering experience, the method of the invention realizes low carbon and material saving, obviously improves the structural rigidity and other properties of the optimal design scheme, realizes the high specific rigidity and low carbon design of the rotary worktable, and can be used for the structural optimization design of the rotary worktable of heavy and ultra-heavy equipment, and simultaneously, the design efficiency is improved.

Drawings

FIG. 1 is a two-dimensional characteristic cross-sectional model diagram of a rotary table, wherein (a) is a two-dimensional characteristic cross-sectional model diagram of a table top supporting part, and (b) is a two-dimensional characteristic cross-sectional model diagram of a side supporting part;

fig. 2 is an intelligent creation diagram of the configuration of the rib plate of the table top supporting part of the rotary worktable, wherein (a) is a boundary condition diagram of a two-dimensional characteristic cross section of the table top supporting part, (b) is a layout diagram of a starting point created by the configuration of the rib plate of the table top supporting part, and a dot is a creation starting point, (c) is a configuration diagram created by the rib plate of the table top supporting part;

fig. 3 is an intelligent creation diagram of the configuration of the rib plate of the side supporting part of the rotary table, wherein (a) is a boundary condition diagram of a two-dimensional characteristic cross section of the side supporting part, (b) is a layout diagram of a creation starting point of the configuration of the rib plate of the side supporting part, a dot is the creation starting point, and (c) is a creation configuration diagram of the rib plate of the side supporting part;

fig. 4 is a structural diagram of an optimized rotary table, wherein (a) is a three-dimensional optimal layout diagram of rib plates of a table top supporting part, (b) is a three-dimensional optimal layout diagram of rib plates of a side supporting part, and (c) is a structural diagram of an optimized rotary table.

Detailed Description

The invention aims to provide a low-carbon lightweight design scheme of an equipment rotary table structure based on intelligent creation criteria of a bearing configuration, the design result of the low-carbon lightweight design scheme is clearer than that of the traditional topological optimization result, and scheme support can be directly provided for actual engineering design. The design scheme of the invention firstly divides the rotary worktable of the equipment into a table top supporting part and a side supporting part according to different bearing functions. The two parts are respectively applied with an intelligent creation criterion of a bearing configuration, and the structural design problem of the rotary worktable is converted into an intelligent creation problem of rib plate configurations of a table top supporting part and a side supporting part:

1. pretreatment: according to the difference of the bearing function, the rotary table is divided into a main load applying part, namely a table top supporting part and a part playing a main supporting role, namely a side supporting part. Respectively constructing two-dimensional characteristic section models of the two parts; 2. the intelligent generation is as follows: respectively obtaining a two-dimensional optimal layout of rib plates of the table top supporting part and a two-dimensional optimal layout of rib plates of the side supporting part; 3. and (3) post-treatment: and respectively designing the three-dimensional configurations of the table surface bearing part and the side surface bearing part according to the obtained optimal layout of the two-dimensional rib plate, and finally obtaining a complete structural design scheme of the equipment rotary worktable after combining the two parts.

The specific implementation process comprises the following steps:

1) construction of two-dimensional characteristic section model of creation space

According to the difference of bearing functions, a rotary worktable is divided into a table top supporting part and a side supporting part, the table top supporting part is a part for applying main load, the side supporting part is a part for playing a main supporting role, in order to improve the numerical adaptability of the model, the table top supporting part is abstracted into a two-dimensional regular hexadecimal stress model formed by a shell unit according to the boundary conditions (actual installation constraint and loading condition) of the table top supporting part, the two-dimensional regular hexadecimal stress model is set into a two-dimensional characteristic creating space of the rib plate configuration of the table top supporting part, the side supporting part is abstracted into a two-dimensional rectangular stress model formed by the shell unit according to the boundary conditions (actual installation constraint and loading condition) of the side supporting part, the two-dimensional rectangular stress model is set into a two-dimensional characteristic creating space of the rib plate configuration of the side supporting, the beam unit mutually coupled with the shell unit is added between the adjacent shell unit nodes of two stress models (two-dimensional regular hexadecimal stress model and two-dimensional rectangular stress model), and the cross section of the beam unit is assumed to be a rectangular cross section, and the cross section width is as follows: b, cross-sectional height: h;

2) intelligent creation of rib plate configuration in two-dimensional characteristic section model

Based on the construction of a two-dimensional characteristic section model for equipping a table top supporting part and a side supporting part of a rotary worktable, the structural design problem of the rotary worktable is converted into an intelligent creation problem of rib plate configurations of the table top supporting part and the side supporting part, the intelligent creation problem is specifically reflected as an optimization process taking the section height h of a beam unit on a two-dimensional characteristic section as a design variable, and the optimal creation of the rib plate configuration on the two-dimensional characteristic section is realized by optimizing and changing the value of the section height h of the beam unit on the two-dimensional characteristic section and implementing branching and degradation operations in the growth process of the beam unit; since the cross-sectional height h is the only geometrical dimension that determines the beam element weight W, the essence of the intelligent creation process is the optimal distribution of material (weight), the mathematical model of which is as follows for the whole optimization process:

designing variables: w = [ W =₁,W₂,…,W_N]

An objective function: minimum Total Strain energy Min f (W)

Constraint conditions are as follows: w_sum≤W₀

W_i ^U>W_i>W_i ^L,i=1,2,…,N

Wherein f (W) is the total strain energy of the structural model, W_sumIs the total mass of the structure, W₀Is a predetermined upper limit of the structural mass, W_iIs the ith design variable, W_i ^URepresents W_iUpper limit value of, W_i ^LRepresents W_iN is the number of design variables;

setting various parameters (including the upper limit W of the total weight of the whole structural material) required by intelligent creation₀Given material increment Δ W per iteration of the loop, and the bifurcation threshold h of competing beam elements_bAnd a degradation threshold h_d) And then, applying a creation rule of the bearing configuration to the two-dimensional characteristic section models of the table top supporting part and the side supporting part respectively to realize the optimal creation of the bearing configurations of the two parts.

The intelligent creation of the rib plate configuration in the two-dimensional characteristic section model comprises the following specific steps:

1) according to the actual installation constraint and the loading condition of the functional part, applying boundary constraint and load to the constructed two-dimensional characteristic section model;

2) defining a solving type as structural statics analysis, solving an initialization model, setting a display result of analysis as equivalent stress, and calculating the total strain energy of structural deformation;

3) storing the values of the design variable parameter h and the total strain energy of structural deformation;

4) constraint parameter W for setting intelligent optimization of structure₀Setting the material increment delta W given by each cycle iteration in the structure optimization process, and setting the bifurcation threshold h of the competitive beam unit_bAnd a degradation threshold h_d；

5) Selecting a plurality of points with relatively high initial strain energy on the two-dimensional characteristic cross section as creation starting points, wherein the selected points are contained in a creation point set { B }, and beam units which can grow around the creation points are contained in a beam unit set { C } to be competitively grown;

6) in each cycle iteration, the weight of each beam unit participating in competition in the set { C } is distributed with a material increment delta W in a proportional way according to the corresponding generalized sensitivity D value, so that the optimal distribution of the material is realized, and the weight iteration calculation criterion after the growth of each competition beam unit is as follows:

${W_i}^{(k+1)}=\mathrm{\α}\·{(D_i\·\frac{\mathrm{\ΔW}}{D_{\mathrm{sum}}})}^{\left(k\right)}+(1-\mathrm{\α})\·{W_i}^{\left(k\right)},(i=1,...,N)$

wherein,

e is the total strain energy of the current structure,for sensitivity of total strain energy to competing beam element weights, α represents an iteration step size factor, k represents the number of steps of the iteration,

7) because the beam unit section width b is a fixed value, the section height h is a geometrical dimension which uniquely determines the weight of the beam unit, the distribution of materials in each cycle can be reflected as the updated change of the section height h of each competition beam unit, and if the section height of each competition beam unit after updating is smaller than the degradation threshold h_dConsidering the competitive beam unit to meet the degradation condition, removing the competitive beam unit from the set { C } of the competitive beam units, removing nodes at two ends of the competitive beam unit from the set { B } of the creation points, and assigning the height of the section of the competitive beam unit as h_d(ii) a If the updated section height is greater than or equal to the bifurcation threshold h_bIf the competing beam unit is deemed to have the branching capability, the competing beam unit is assigned as h_bMeanwhile, the nodes at the two ends are used as new creation points to be added into the creation point set { B }, and all beam units connected around the new creation points are added into the set { C }, so that the competing materials can be distributed in the next cycle;

8) storing the updated design variable parameter h, and updatingCalculating the total weight of the materials of the updated structural model by the two-dimensional characteristic section model, and judging whether the total weight reaches the upper limit W of the total mass₀If yes, the loop iteration is terminated, otherwise, the iteration step is repeated;

9) after the whole intelligent optimization iteration is finished, in [ h ]_d,h_b]Upper selection value h_vAs a standard for further screening beam units, filtering out the beam units with a cross-sectional height less than h_vThe reserved beam units and the two-dimensional characteristic section form a thin plate reinforced structure which is clear in layout and optimal and reasonable, and therefore the optimal creation of the structure of the functional part rib plate is obtained.

3) Post-processing of rotary table structural design

The method comprises the steps of designing a three-dimensional optimal configuration of a table top supporting part according to the intelligent formation configuration of a rib plate of the table top supporting part in a two-dimensional characteristic section model, designing a three-dimensional optimal layout of the rib plate of the side supporting part according to the intelligent formation configuration of the rib plate of the side supporting part in the two-dimensional characteristic section model, performing circumferential array processing on the three-dimensional optimal layout around a rotation center of a workbench to obtain the final three-dimensional optimal configuration of the side supporting part, and combining the three-dimensional optimal configuration of the side supporting part and the three-dimensional optimal configuration of the table top supporting part to obtain the complete rotary workbench. And finally, further correcting the structure of the rotary worktable under the comprehensive consideration of the processing technology of the rotary worktable and the requirements of manufacturing and assembling to obtain the optimal structural design scheme of the rotary worktable.

The design method provided by the invention can be used for structural design of rotary working tables of various manufacturing equipment, and a specific implementation process is described below by taking a cylindrical gear grinding machine of a certain model as an example.

Construction of created space two-dimensional characteristic section model

Firstly, according to the different bearing functions of different parts of the rotary worktable, the upper half part of the rotary worktable is taken as a table top supporting part, and the lower half part is taken as a side supporting part. According to the actual boundary conditions of different functional parts, abstracting the table top supporting part into a two-dimensional regular hexadecagon stress model formed by shell units, and setting the two-dimensional regular hexadecagon stress model as a two-dimensional characteristic of a rib plate configuration of the table top supporting part to create a space, as shown in fig. 1 (a); the side supporting part is abstracted into a two-dimensional rectangular stress model composed of shell units, and the two-dimensional rectangular stress model is set as a two-dimensional characteristic creating space of the rib plate configuration of the side supporting part, as shown in fig. 1 (b). And respectively establishing beam units coupled with the adjacent shell unit nodes on the two stress models. The shell cells were simulated with shell63 and the beam cells were simulated with beam188 and the cross-sectional width b was set to 1e-2mm and the cross-sectional height h was 1e-4 mm.

Intelligent creation of bearing configuration of different functional parts of (II) rotary worktable

Based on the established two-dimensional characteristic section model, the structural design problem of the rotary worktable is converted into the intelligent creation problem of the rib plate configurations of the table top supporting part and the side supporting part.

1. The intelligent formation of the rib plate configuration of the rotary worktable table surface supporting part is as follows:

the method is characterized in that the minimum total strain energy of a table top supporting part of the rotary worktable is taken as an objective function, the total weight of a two-dimensional characteristic section upper beam unit of the table top supporting part is taken as a constraint condition, the section height h of the section upper beam unit is taken as a design variable, and the design variable h is updated by optimizing distribution materials.

According to the actual working condition of the rotary working table of the cylindrical gear grinding machine, uniformly distributed pressure loads are applied to the two-dimensional characteristic section of the table top supporting part, and all degrees of freedom of eight nodes in the center of the section are fixedly restrained, as shown in fig. 2 (a); selecting 4 nodes with relatively high initial strain energy of the two-dimensional characteristic section of the table top supporting part as a creation starting point, as shown in fig. 2 (b); a series of relevant parameters required for intelligently creating the rib plate configuration of the supporting part of the table top are set, including W₀、ΔW、h_b、h_d. Here, W₀The upper limit of the total weight of the cross-section upper beam unit is taken as the table top supporting partThe weight of the two-dimensional characteristic cross section is 1.1 times, Δ W is adaptively adjusted according to the number of competing beam units in the optimization process, taking the k-th iteration as an example, assuming that n beam units participate in competition in the k-th iteration, Δ W is equal to the total weight of the n competing beam units at this time (the k-1-th iteration is completed, the k-th iteration just starts, and the weight of the n competing beam units is not changed in the k-th iteration), so the material increment Δ W is adaptively adjusted according to the number of competing beam units. h is_bFor competing beam element bifurcation threshold, its value is 1mm, h_dFor the competitive beam cell degradation threshold, the value is 1e-4 mm.

And applying a bearing configuration intelligent creation criterion to the two-dimensional characteristic section of the table top supporting part, and obtaining a model optimization result of beam units with different section heights distributed on the two-dimensional characteristic section of the table top supporting part after optimization cycle iteration. And filtering out the beam units with the cross-sectional height of less than 0.7mm to obtain a clear rib plate configuration, as shown in fig. 2 (c).

2. The intelligent formation of the rib plate configuration of the side supporting part of the rotary worktable is as follows:

the method comprises the steps of taking the minimum total strain energy of a side surface supporting part of the rotary worktable as an objective function, taking the total weight of a two-dimensional characteristic section upper beam unit of the side surface supporting part as a constraint condition, taking the section height h of the section upper beam unit as a design variable, and updating the design variable h by optimizing distribution materials.

According to the actual working condition of the rotary working table of the cylindrical gear grinding machine, uniformly distributed pressure loads are applied to the upper boundary of the two-dimensional characteristic section of the side supporting part, and the total freedom degrees of 6 nodes on the lower boundary are fixedly restrained, as shown in fig. 3 (a); selecting 3 nodes with relatively high initial strain energy of the two-dimensional characteristic section of the side supporting part as creation starting points, as shown in fig. 3 (b); a series of relevant parameters required by intelligent generation of rib plate configuration of side supporting part are set, including W₀、ΔW、h_b、h_d. Here, W₀The upper limit of the total weight of the beam unit on the section is 0.9 times of the weight of the two-dimensional characteristic section of the side supporting part, and the value is delta WIn the process of formation, the number of competing beam units is adaptively adjusted, taking the k-th iteration as an example, assuming that n beam units participate in competition in the k-th iteration, Δ W is equal to the total weight of the n competing beam units at this time (the k-1-th iteration is completed, the k-th iteration just starts, and the weight of the n competing beam units has not changed in the k-th iteration), so the material increment Δ W is adaptively adjusted according to the number of competing beam units. h is_bFor competing beam element bifurcation threshold, its value is 1mm, h_dFor the competitive beam cell degradation threshold, the value is 1e-2 mm.

And applying a bearing configuration intelligent creation criterion to the two-dimensional characteristic section of the side supporting part, and obtaining a model optimization result of beam units with different section heights distributed on the two-dimensional characteristic section of the side supporting part after optimization cycle iteration. And filtering out the beam units with the cross-sectional height of less than 0.9mm to obtain a clear rib plate configuration, as shown in fig. 3 (c).

(III) post-treatment of rotary worktable structural design

The layout is intelligently created according to the rib plates of the two-dimensional characteristic section of the table top supporting part, and the three-dimensional optimal configuration of the table top supporting part is designed, as shown in fig. 4 (a). And (3) designing a three-dimensional optimal layout of the rib plates of the side supporting part according to the intelligent layout of the rib plates of the two-dimensional characteristic section of the side supporting part, as shown in fig. 4 (b), and performing circumferential array processing on the rib plates around the rotation center of the workbench to obtain a final three-dimensional optimal configuration of the side supporting part. And combining the three-dimensional optimal configuration of the side supporting part with the three-dimensional optimal configuration of the table top supporting part to obtain the complete machine tool rotary worktable. Finally, under the comprehensive consideration of the machining process and the manufacturing and assembling requirements of the machine tool rotary table, the structure of the machine tool rotary table is further modified to obtain an optimal design scheme of the structure of the machine tool rotary table, as shown in fig. 4 (c).

In order to prove the reasonability of the design result, finite element analysis is respectively carried out on the structures of the rotary working table before and after optimization, and the weight, the maximum deformation, the maximum equivalent stress and the natural frequency of the model before and after optimization are compared, wherein the comparison result is shown in table 1.

TABLE 1 comparison of Performance parameters of Rotary tables before and after structural optimization

	Weight kg	Maximum stress MPa	Maximum deformation mm	Natural frequency Hz
					Original rotary worktable	1296.0	4.737	3.52E-6	13955
Optimized rotary worktable	1238.4	3.549	2.94E-6	13893
					Relative increase	-6.2%	-25.1%	-16.4%	-0.44%

As can be seen from Table 1, the weight of the optimized model is reduced by 6.2% relative to the original structure, the maximum stress is reduced by 25.1%, and the maximum deformation is reduced by 16.4%. Although the natural frequency of the structure is lowered, the natural frequency is still within the allowable range.

In conclusion, the rotary worktable structure optimally designed by the design method of the invention can obviously improve the structural performance of the rotary worktable and obtain the structural efficiency with high specific stiffness on the premise of light weight, low carbon and material saving.

Claims (3)

1. The intelligent design method for the low-carbon light-weight equipment rotary worktable is characterized by comprising the following steps of: the intelligent design method comprises the following steps: the method comprises the steps of dividing the rotary worktable into different functional parts according to different bearing effects, abstracting a two-dimensional characteristic section model of each functional part, applying an intelligent creation criterion of a bearing configuration on each two-dimensional characteristic section model respectively, converting a structural design problem of the rotary worktable into an intelligent creation problem of the optimal bearing configuration of each functional part, and combining the functional parts with the optimal bearing configuration to obtain the complete optimal structure of the rotary worktable.

2. The intelligent design method for the low-carbon and light-weight equipment rotary worktable as claimed in claim 1, is characterized in that: the intelligent design method specifically comprises the following steps:

1) construction of two-dimensional characteristic section model

According to different bearing functions, the rotary table is divided into a table top supporting part and a side supporting part, the table top supporting part is a part for applying main load, the side supporting part is a part for playing a main supporting role, abstracting the table top supporting part into a two-dimensional regular hexadecimal stress model formed by shell units according to the boundary condition of the table top supporting part, setting the two-dimensional regular hexadecimal stress model as a two-dimensional characteristic of a rib plate configuration of the table top supporting part to create a space, abstracting the side supporting part into a two-dimensional rectangular stress model consisting of shell units according to the boundary condition of the side supporting part, setting the two-dimensional rectangular stress model as a two-dimensional characteristic of a rib plate configuration of the side supporting part to create a space, and adding beam units mutually coupled with the shell units between adjacent shell unit nodes of the two stress models respectively;

2) intelligent creation of rib plate configuration in two-dimensional characteristic section model

Taking the section height h of the upper beam unit of the two-dimensional characteristic section as a design variable, and implementing bifurcation and degradation operation in the growth process of the beam unit by optimizing and changing the value of the section height h of the upper beam unit of the two-dimensional characteristic section, thereby realizing the optimal creation of the structure of the rib plate on the two-dimensional characteristic section; since the cross-sectional height h is the only geometrical dimension that determines the beam element weight W, the essence of the intelligent creation process is the optimal distribution of material, and the mathematical model of the whole optimization process is as follows:

designing variables: w = [ W =₁,W₂,…,W_N]

An objective function: minimum Total Strain energy Min f (W)

Constraint conditions are as follows: w_sum≤W₀

W_i ^U>W_i>W_i ^L,i=1,2,…,N

Wherein f (W) is the total strain energy of the structural model, W_sumIs the total mass of the structure, W₀Is a predetermined upper limit of the structural mass, W_iIs the ith design variable, W_i ^URepresents W_iUpper limit value of, W_i ^LRepresents W_iN is the number of design variables;

3) post-processing of rotary table structural design

Designing a three-dimensional optimal configuration of the table top supporting part according to the rib plate configuration of the table top supporting part in the two-dimensional characteristic section model, designing a three-dimensional optimal configuration of the rib plate of the side supporting part according to the rib plate configuration of the side supporting part in the two-dimensional characteristic section model, performing circumferential array processing on the three-dimensional optimal configuration of the rib plate of the side supporting part around a rotating center of the workbench to obtain a final three-dimensional optimal configuration of the side supporting part, and combining the final three-dimensional optimal configuration of the side supporting part and the three-dimensional optimal configuration of the table top supporting part to obtain the complete rotating workbench.

3. The intelligent design method for the low-carbon and light-weight equipment rotary worktable as claimed in claim 2, wherein the method comprises the following steps: the intelligent creation of the rib plate configuration in the two-dimensional characteristic section model comprises the following specific steps:

1) according to the actual installation constraint and the loading condition of the functional part, applying boundary constraint and load to the constructed two-dimensional characteristic section model;

2) defining a solving type as structural statics analysis, solving an initialization model, setting a display result of analysis as equivalent stress, and calculating the total strain energy of structural deformation;

3) storing the values of the design variable parameter h and the total strain energy of structural deformation;

4) constraint parameter W for setting intelligent optimization of structure₀Setting material increment delta W given by each cycle iteration in the structure optimization process, and setting bifurcation threshold h of competing beam unit_bAnd a degradation threshold h_d；

5) Selecting a plurality of points with relatively high initial strain energy on the two-dimensional characteristic cross section as creation starting points, wherein the selected points are contained in a creation point set { B }, and beam units which can grow around the creation points are contained in a beam unit set { C } to be competitively grown;

6) in each cycle iteration, the weight of each beam unit participating in competition in the set { C } is distributed with a material increment delta W in a proportional way according to the corresponding generalized sensitivity D value, so that the optimal distribution of the material is realized, and the weight iteration calculation criterion after the growth of each competition beam unit is as follows:

${W_i}^{(k+1)}=\mathrm{\α}\·{(D_i\·\frac{\mathrm{\ΔW}}{D_{\mathrm{sum}}})}^{\left(k\right)}+(1-\mathrm{\α})\·{W_i}^{\left(k\right)},(i=1,...,N)$

wherein,

e is the total strain energy of the current structure,

for sensitivity of total strain energy to competing beam element weights, α represents an iteration step size factor, k represents the number of steps of the iteration,

7) because the beam unit section width b is a fixed value, the section height h is a geometrical dimension which uniquely determines the weight of the beam unit, the distribution of materials in each cycle is reflected by the updated change of the section height h of each competing beam unit, and if the section height of the competing beam unit after updating is smaller than the degradation threshold h_dConsidering the competitive beam unit to meet the degradation condition, removing the competitive beam unit from the set { C } of the competitive beam units, removing nodes at two ends of the competitive beam unit from the set { B } of the creation points, and assigning the height of the section of the competitive beam unit as h_d(ii) a If the updated section height is greater than or equal to the bifurcation threshold h_bIf the competing beam unit is deemed to have the branching capability, the competing beam unit is assigned as h_bMeanwhile, the nodes at the two ends are used as new creation points to be added into the creation point set { B }, and all beam units connected around the new creation points are added into the set { C }, so that the competing materials can be distributed in the next cycle;

8) storing the updated design variable parameter h, updating the whole two-dimensional characteristic section model, calculating the total weight of the material of the updated structural model, and judging whether the total weight reaches the upper limit W of the total mass₀If yes, the loop iteration is terminated, otherwise, the iteration step is repeated;

9) after the whole intelligent optimization iteration is finished, in [ h ]_d,h_b]Upper selection value h_vAs a standard for further screening beam units, filtering out the beam units with a cross-sectional height less than h_vThe reserved beam units and the two-dimensional characteristic section form a thin plate reinforced structure which is clear in layout and optimal and reasonable, and therefore the optimal creation of the structure of the functional part rib plate is obtained.

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