CN112989515B - Prediction method for space envelope metal flow and high-rib growth of thin-wall multilayer high-rib component - Google Patents

Abstract

The invention relates to a prediction method for space envelope metal flow and high-rib growth of a thin-wall multilayer high-rib component, which comprises the following steps of: s1, decomposing the thin-wall multilayer high-rib component into a plurality of areas; s2, mixing II_BThe region abstraction is a corner extrusion model, and a deformation power method is adopted to derive II_BHorizontal pressing force q on the interface of zone and zone III_nDeriving the horizontal extrusion force q on the interface of IV and III regions by deformation_w(ii) a S3, determination of III_AZone radial stress σ_{r_n}Distribution equation and III_BZone radial stress σ_{r_w}A distribution equation; s4, establishing a relation equation of a diversion surface and a confluence surface; s5, solving the flow surface position r when the thickness of the thin bottom plate is H in the space envelope forming process of the thin-wall multilayer high-rib component_g(H) (ii) a And S6, obtaining the height of the outer layer high rib of the envelope-formed thin-wall multi-layer high rib component. The method can accurately predict the metal flowing process of the space enveloping forming of the thin-wall multilayer high-rib component and the synergistic growth process of the multilayer high-rib, and provides a basis for the optimization design of the space enveloping forming process condition of the thin-wall multilayer high-rib component and the optimization design of the mold structure.

Description

Spatial enveloping metal flow and high-rib growth prediction method for thin-walled and multi-layer high-rib members

technical field

The invention relates to the field of forming and manufacturing of thin-walled and multi-layered high-rib components, in particular to a method for predicting the spatial enveloping metal flow and high-rib growth of thin-walled and multi-layered high-rib components.

Background technique

Thin-walled and multi-layered high-rib components are typical structural parts with thin bottom plates and multi-layer high-rib structures. They are widely used in aerospace, weaponry, precision machine tools and other fields. Due to the complex geometry of thin-walled and multi-layered high-rib components, the traditional manufacturing method is cutting. However, the manufacturing efficiency of cutting processing is low, the material utilization rate is low, and continuous metal streamlines cannot be formed. Therefore, it is difficult to achieve high-efficiency and high-quality manufacturing of thin-walled, multi-layered and high-rib components by cutting processing. In order to achieve high-efficiency and high-quality manufacturing of thin-walled, multi-layered and high-rib components, in recent years, some scholars have proposed the use of spatial enveloping forming technology instead of cutting. However, in the process of spatial envelope forming of thin-walled, multi-layered high-rib components, the complex geometry of the component and the multi-degree-of-freedom mold space envelope motion lead to very complex metal flow, and the growth process between the multi-layered high-ribs is obviously asynchronous. It is very easy to produce forming defects such as high rib filling, rib threading, and streamline disorder. In order to avoid the above-mentioned forming defects, it is necessary to accurately predict the metal flow and high-rib growth in the space enveloping forming of thin-walled multi-layer high-rib members, so as to optimize the design and mold structure for the spatial enveloping forming process conditions of thin-walled, multi-layer high-rib members. Provide the basis for optimal design.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a method for predicting the spatial enveloping metal flow and high rib growth of thin-walled, multi-layer high-rib components, which can accurately predict the metal flow process and multi-dimensional enveloping forming of thin-walled, multi-layer high-rib components. The synergistic growth process of the layers and high ribs provides a basis for the optimal design of the spatial envelope forming process conditions and the optimal design of the mold structure for thin-walled and multi-layered high-rib components, thereby effectively avoiding forming defects such as unsatisfactory high-rib filling, rib penetration, and streamline disorder.

The technical scheme adopted by the present invention to solve the technical problem is: constructing a thin-walled multi-layer high-rib component space-envelope metal flow and high-rib growth prediction method, which includes the following steps:

S1. Decompose the thin-walled and multi-layered high-rib components into multiple zones. Zone I is the thin floor area within the inner high-rib, zone II is the inner high-rib zone, and zone III is the inner-layer high-rib and outer-layer high-rib zone. The thin floor area in between, and the area IV is the outer high-rib area; with the confluence surface as the boundary, the Ⅱ area is divided into the Ⅱ _A inner layer area and the Ⅱ _B outer layer area _. Inner ring area and III _B outer ring area;

S2. Abstract area II _B as a corner extrusion model, use the deformation work method to deduce the horizontal extrusion force q _n on the interface between area II _B and area III, and obtain q _n to solve equation (1); similarly, abstract area IV For the corner extrusion model, the horizontal extrusion force q _w on the interface between zone IV and zone III is deduced by the deformation work method, and q _w is obtained to solve equation (2);

where H is the thickness of the thin bottom plate at any instant of enveloping forming, r ₂ is the outer surface radius of the inner high rib, b _w is the thickness of the outer high rib, r _p is the flow surface radius of the II zone at any instant of enveloping forming, and K is the material yield strength, m is the shear friction coefficient;

S3. Abstract the zone III as a ring upsetting model where the inner cylindrical surface and the outer cylindrical surface bear the radial constraint load, the radial constraint load on the inner cylindrical surface is q _n obtained in step S2, and the radial constraint load on the outer cylindrical surface is q _w obtained in step S2; radial stress analysis is carried out on the inner ring zone III _A and the outer ring zone III _B by using the principal stress method, and the radial stress σ _{r_n} distribution equation (3) of the III _A zone and the diameter of the III _B zone are obtained. The distribution equation (4) of the stress σ _{r_w} ;

where x is the radial distance from any position of zone III to the axis of the component, r ₃ is the radius of the inner surface of the outer high rib, and r _g is the radius of the flow surface of zone III at any instant of envelope forming;

S4. According to the condition that the metal in areas II _A and II _B on both sides of the inner high-rib confluence surface must maintain the same height at any instant of envelope forming, establish the relationship equation (5) between the split surface and the confluence surface;

where r ₁ is the radius of the inner surface of the inner high rib;

同时满足步骤S4所建立的分流面和汇流面关系方程(5)，求解薄壁多层高筋构件空间包络成形过程中薄底板厚度为H时分流面位置r_g(H)；S5. According to the stress balance condition that the radial forces on the left and right sides of the shunt surface r _g are equal in magnitude, that is,

At the same time, the relationship equation (5) of the split surface and the confluence surface established in step S4 is satisfied, and the position of the split surface r _g (H) when the thickness of the thin bottom plate is H during the spatial envelope forming process of the thin-walled multi-layer high-rib member is solved;

S6. Bring r _g (H) obtained in step S5 into equation (6), and obtain the height of the inner layer of the enveloping thin-walled multi-layer high-rib member; bring r _g obtained in step S6 into equation (7) , to obtain the height of the outer layer of the enveloping forming thin-walled multi-layer high-rib member;

where H ₀ is the initial thickness of the blank and H _t is the final thickness of the thin base plate.

In the above scheme, the thin-walled multi-layer high-rib member is manufactured by the space enveloping forming process, and the mold is composed of an enveloping punch and a concave mold; The concave mold is formed, and the rest of the profile is formed by the enveloping punch, and the concave die must be located below, and the enveloping punch is located above; the envelope punch is a cone-shaped mold body, and the enveloping punch rotates around its own axis while wrapping around the blank. The axis rotates to realize the space enveloping motion; the cavity of the concave model is determined by the bottom surface of the thin bottom plate of the thin-walled multi-layer high-rib member and the outer surface of the outer layer of high-ribs, and the die pushes the blank to move up in the axial direction; Under the action of the space enveloping motion of the enveloping punch, the blank undergoes plastic deformation and gradually forms thin-walled, multi-layered and high-rib components.

In the above scheme, the blank used for the spatial enveloping forming of thin-walled and multi-layered high-rib components is a thick plate with uniform thickness, and the axial cross-sectional shape of the thick plate is the same as the axial cross-sectional shape of the thin bottom plate. The profile surface must be in contact with the side wall of the die, and the bottom surface of the blank and the bottom surface of the die.

In the above scheme, during the space enveloping forming process of the thin-walled multi-layer high-rib member, the contact area between the enveloping punch and the blank shall not be less than 75% of the upper surface area of the blank.

In the above solution, the cone angle α of the enveloping punch is not less than 178°.

The implementation of the thin-walled multi-layer high-rib component space-envelope metal flow and high-rib growth prediction method of the present invention has the following beneficial effects:

(1) The rib height prediction method for the spatial envelope forming of thin-walled, multi-layered high-rib components proposed by the present invention can accurately predict the metal flow law and the growth process of the multi-layered high-ribs in the spatial envelope forming of thin-walled, multi-layered high-rib components. Thereby, forming defects such as high-rib filling dissatisfaction, rib-piercing, and streamline disorder are effectively avoided.

(2) The method for predicting the rib height of the space enveloping forming of the thin-walled, multi-layered high-rib member proposed by the present invention can provide a basis for the optimal design of the spatial enveloping forming process conditions and the optimal design of the mold structure for the thin-walled, multi-layered and high-rib member. Significantly improve the product quality and manufacturing efficiency of thin-walled, multi-layer high-rib components.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings and embodiments, in which:

Figure 1 is a schematic diagram of the geometric shape of a thin-walled multi-layer high-rib member;

Fig. 2 is a schematic diagram of space envelope forming of thin-walled multi-layer high-rib members;

Figure 3 is a schematic diagram of the partition of a thin-walled multi-layer high-rib member;

Figure 4 is a schematic diagram of a corner extrusion model of thin-walled multi-layer high-rib member space envelope forming;

Figure 5 is a schematic diagram of the radially constrained annular upsetting model in zone III of the space envelope forming of thin-walled, multi-layered high-rib members

Fig. 6 is a curve diagram of the height change of the thin-walled multi-layer high-rib member in the space enveloping forming.

Detailed ways

In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

The target thin-walled multi-layer high-rib member in this example consists of a thin bottom plate 1, an inner layer of high ribs 2, and an inner layer of high ribs 3. Its geometric shape is shown in Figure 1, and its main geometric dimensions are shown in Table 1.

S1 adopts the space enveloping forming process to manufacture thin-walled, multi-layered high-rib members. Figure 2 is a schematic diagram of the spatial enveloping forming of thin-walled, multi-layered and high-ribbed members. The outer surface is formed by the die 4, and the rest of the profile is formed by the enveloping punch 5, and the die 4 must be located below, and the enveloping punch 5 must be located above; blanks for space envelope forming of thin-walled, multi-layered high-rib components 63 is a thick plate with uniform thickness, the axial cross-sectional shape of the thick plate is the same as that of the thin bottom plate 1, the blank 6 is placed in the die 4, and the circumferential profile of the blank 6 must be in contact with the side wall of the die 4, and the blank 6 The bottom surface is in contact with the bottom surface of the concave mold 4; the enveloping convex mold 5 is a cone-shaped mold body, and its cone angle α=179°. The enveloping punch 5 acts on the upper surface of the blank 6, and takes the axis of the blank 6 as the rotation axis for multi-cycle rolling on the upper surface of the blank 6, and the female die 4 pushes the blank 6 upward in the axial direction, and its feed speed is 2mm/s , so as to ensure that the contact area between the enveloping punch 5 and the blank 6 shall not be less than 75% of the upper surface area of the blank 6 .

Table 1: Main dimensions of thin-walled and multi-layered high-rib members

S2. Decompose the thin-walled multi-layer high-rib component into 6 areas, as shown in Figure 3. Area I is the thin floor area 1 within the inner high rib 2, area II is the inner high rib area 2, area III is the thin floor area 1 between the inner high rib 2 and the outer diameter, and area IV is the inner high rib area 1. Rib 3 zone. Taking the confluence surface 8 as the boundary, the II area is divided into the _IIA inner layer area and the _IIB outer layer area, and the branch surface 7 is the boundary, the III area is divided into the _IIIA inner ring area and the _IIIB outer ring area.

S3. Abstract the II _B area as a corner extrusion model, use the deformation work method to deduce the horizontal extrusion force q _n on the interface between II _B area and III area, and obtain q _n to solve equation (1). Similarly, the area IV is abstracted as a corner extrusion model, and the horizontal extrusion force q _w on the interface between area IV and area III is deduced by the deformation work method, and q _w is obtained to solve equation (2).

where H is the thickness of the thin bottom plate 1 at any instant of enveloping forming, r ₂ is the outer surface radius of the inner high rib 2, b _w is the thickness of the inner high rib 3, and r _p is the radius of the flow surface 7 of the II section at any instant of the enveloping forming , K is the material yield strength, the value is 55MPa, m is the shear friction coefficient, the value is 0.4.

S4. Abstract zone III as a ring upsetting model with the inner cylindrical surface and the outer cylindrical surface bearing radial restraint loads, as shown in Figure 5. The radial constraint load on the inner cylindrical surface is q _n obtained in step S3 , and the radial constraint load on the outer cylindrical surface is q _w obtained in step S3 . The radial stress analysis of the inner ring zone Ⅲ _A and the outer ring zone Ⅲ _B is carried out by the principal stress method, and the radial stress σ _{r_n distribution equation (3) of the Ⅲ A zone and the radial stress σ r_w distribution equation} (4) of the Ⅲ _B zone are obtained. ).

where x is the radial distance from any position in zone III to the axis of the component, r ₃ is the radius of the inner surface of the inner high rib 3 , and r _g is the radius of the flow surface 7 in zone III at any instant of envelope forming.

S5. According to the condition that the metal in the areas II _A and II _B on both sides of the confluence surface 8 of the inner layer high rib 2 must maintain the same height at any instant of envelope forming, establish the relationship equation (5) of the split surface 7 and the confluence surface 8.

where r ₁ is the radius of the inner surface of the inner high rib 2 .

同时满足步骤S5所建立的分流面7和汇流面8关系方程(5)，求解薄壁多层高筋构件空间包络成形过程中薄底板1厚度为H时分流面7位置r_g(H)。S6. According to the stress balance condition that the radial forces on the left and right sides of the shunt surface 7r _g are equal in magnitude, that is,

At the same time, the relationship equation (5) of the split surface 7 and the confluence surface 8 established in step S5 is satisfied, and the position r _g (H) of the split surface 7 when the thickness of the thin bottom plate 1 is H during the spatial envelope forming process of the thin-walled multi-layer high-rib member is solved. .

S7. Bring r _g (H) obtained in step S6 into equation (6) to obtain the height of the inner layer high rib 2 of the enveloping forming thin-walled multi-layer high rib member. Bring r _g obtained in step S6 into equation (7), and obtain the height of the inner layer high rib 3 of the enveloping forming thin-walled multi-layer high rib member. FIG. 6 is the change curve of the height of the inner layer high rib 2 and the inner layer high rib 3 obtained by the above method.

Wherein H ₀ is the initial thickness of the blank 6 H ₀ =6 mm, and H _t is the final thickness of the thin bottom plate 1 H _t =3 mm.

The embodiments of the present invention have been described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific embodiments, which are merely illustrative rather than restrictive. Under the inspiration of the present invention, without departing from the scope of protection of the present invention and the claims, many forms can be made, which all belong to the protection of the present invention.

Claims (5)

1. A prediction method for space envelope metal flow and high-rib growth of a thin-wall multilayer high-rib component is characterized by comprising the following steps:

s1, decomposing the thin-wall multilayer high-rib component into a plurality of areas, wherein the area I is a thin baseplate area within the inner-layer high ribs, the area II is an inner-layer high rib area, the area III is a thin baseplate area between the inner-layer high ribs and the outer-layer high ribs, and the area IV is an outer-layer high rib area; dividing II into II areas by using the convergence plane as a boundary_AInner zone and II_BThe outer zone is divided into III zones by using the flow dividing surface as a boundary_AInner ring zone and III_BAn outer annular zone;

s2, mixing II_BThe region abstraction is a corner extrusion model, and a deformation power method is adopted to derive II_BHorizontal pressing force q on the interface of zone and zone III_nObtaining q_nSolving equation (1); abstracting the IV area into a corner extrusion model, and deducing the horizontal extrusion force q on the interface of the IV area and the III area by adopting a deformation power method_wObtaining q_wSolving equation (2);

wherein H is the thickness of the thin bottom plate at any instant of envelope forming, r₂Is the outer surface radius of the inner high rib, b_wIs the thickness of the outer layer high rib, r_pDividing the radius of the flow surface for enveloping any instant II, wherein K is the yield strength of the material, and m is the shear friction coefficient;

s3, abstracting the III area into a ring upsetting model with an inner cylindrical surface and an outer cylindrical surface bearing radial constraint loads, wherein the inner cylindrical surface radial constraint loads are q obtained in the step S2_nThe outer cylindrical surface radial restraining load is q obtained in step S2_w(ii) a Inner ring zone III by main stress method_AAnd the outer annular region III_BRadial stress analysis is carried out to obtain III_AZone radial stress σ_{r_n}Distribution equations (3) and III_BZone radial stress σ_{r_w}Distribution equation (4);

wherein x is the radial distance from any position in zone III to the axis of the member, r₃Is the radius of the inner surface of the outer high rib, r_gFlow surface radius is distinguished for envelope forming at any instant III;

s4, according to two sides II of the inner-layer high-rib converging surface_AZone and II_BIn the zone, the condition that the heights of the metals are required to be kept equal at any time of envelope forming is adopted, and a relation equation (5) of a flow dividing surface and a flow converging surface is established;

wherein r is₁Is an inner layerThe radius of the inner surface of the high rib;

s5 according to the flow distribution surface r_gIn a stress balance condition where the radial forces on the left and right sides are equal in magnitude, i.e.

Simultaneously satisfies the relation equation (5) of the flow dividing surface and the flow converging surface established in the step S4, and solves the position r of the flow dividing surface when the thickness of the thin bottom plate is H in the space envelope forming process of the thin-wall multilayer high-rib component_g(H)；

S6, the step S5 is executed to obtain r_g(H) Substituting equation (6) to obtain the height of the inner layer high rib of the envelope-formed thin-wall multilayer high rib component; step S6 is performed to obtain r_gSubstituting equation (7) to obtain the height of the outer layer high rib of the envelope-formed thin-wall multilayer high rib component;

wherein H₀Is the initial thickness of the blank, H_tIs the final thickness of the thin bottom plate.

2. The prediction method for the space envelope metal flow and the high-rib growth of the thin-wall multilayer high-rib component according to claim 1 is characterized in that the thin-wall multilayer high-rib component is manufactured by adopting a space envelope forming process, and a mold of the thin-wall multilayer high-rib component consists of an envelope convex mold and a concave mold; the bottom surface of the thin bottom plate and the outer surface of the outer layer high rib of the thin-wall multilayer high rib component are formed by a female die, the other molded surfaces are formed by an enveloping male die, the female die is required to be positioned below, and the enveloping male die is positioned above; the enveloping convex die is a conical die body, and rotates around the axis of the blank while rotating around the axis of the enveloping convex die, so that space enveloping motion is realized; the female die cavity is determined by the bottom surface of the thin bottom plate of the thin-wall multilayer high-rib component and the outer surface of the outer layer high-rib component, and the female die pushes the blank to move upwards along the axial direction; under the action of the axial motion of the female die and the space enveloping motion of the enveloping male die, the blank is subjected to plastic deformation, and the thin-wall multilayer high-rib component is gradually formed.

3. The prediction method for space-enveloped metal flow and high-tendon growth of the thin-wall multilayer high-tendon component according to claim 2, wherein the blank for space-enveloped formation of the thin-wall multilayer high-tendon component is a thick plate with uniform thickness, the axial cross-section shape of the thick plate is the same as that of the thin bottom plate, the blank is placed in the female die, the circumferential profile of the blank must be in contact with the side wall of the female die, and the bottom surface of the blank is in contact with the bottom surface of the female die.

4. The prediction method for the space-enveloped metal flow and the high-rib growth of the thin-wall multilayer high-rib component according to claim 3, characterized in that in the space-enveloped forming process of the thin-wall multilayer high-rib component, the contact area of an enveloping male die and a blank is not less than 75% of the upper surface area of the blank.

5. The prediction method for space-enveloped metal flow and high-rib growth of the thin-wall multi-layer high-rib component according to claim 1, characterized in that the cone angle alpha of the enveloping convex die is not less than 178 degrees.

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