CN114669669A - Curved surface stretching forming method based on cooperative motion of discrete die and clamping mechanism - Google Patents

Curved surface stretching forming method based on cooperative motion of discrete die and clamping mechanism Download PDF

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CN114669669A
CN114669669A CN202210444718.4A CN202210444718A CN114669669A CN 114669669 A CN114669669 A CN 114669669A CN 202210444718 A CN202210444718 A CN 202210444718A CN 114669669 A CN114669669 A CN 114669669A
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discrete
unit body
curved surface
discrete die
stretching
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CN114669669B (en
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杨振
郑林
丰学宇
钱程
刘跃洲
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Dalian Polytechnic University
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Dalian Polytechnic University
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D37/00—Tools as parts of machines covered by this subclass
    • B21D37/10—Die sets; Pillar guides
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D22/00—Shaping without cutting, by stamping, spinning, or deep-drawing
    • B21D22/20—Deep-drawing
    • B21D22/22—Deep-drawing with devices for holding the edge of the blanks
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D22/00—Shaping without cutting, by stamping, spinning, or deep-drawing
    • B21D22/20—Deep-drawing
    • B21D22/26—Deep-drawing for making peculiarly, e.g. irregularly, shaped articles

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  • Mechanical Engineering (AREA)
  • Shaping Metal By Deep-Drawing, Or The Like (AREA)
  • Moulds For Moulding Plastics Or The Like (AREA)

Abstract

The application provides a curved surface stretch forming method based on cooperative motion of a discrete die and a clamping mechanism, which comprises the following steps: constructing a stretching model comprising discrete dies, a plurality of clamping mechanisms and a plate; simulating a stretched forming process of the plate material and calculating stretching data according to the stretching model; according to the stretching data, the height change of the unit body in practice and the length change of the clamping mechanism are controlled to realize the curved surface stretching forming of the plate. Compared with the prior art, the height of each unit body in the discrete mould of this application accessible adjustment forms different enveloping surfaces, realizes the curved surface stretch forming of sheet material according to the needs of difference to and, through adjusting every fixture's length, guarantee that sheet material and discrete mould closely laminate, be convenient for realize under the less transition zone that big curvature curved surface takes shape, reduce inhomogeneities, reduce the resilience volume of the curved surface that takes shape, improved the shaping precision.

Description

Curved surface stretching forming method based on cooperative motion of discrete die and clamping mechanism
Technical Field
The application relates to a plastic forming process of a material, in particular to a curved surface stretching forming method based on the cooperative motion of a discrete die and a clamping mechanism.
Background
The three-dimensional curved surface is widely applied to the fields of aviation manufacturing, high-speed trains, modern buildings and the like, and the main forming mode is stretching forming.
However, with the increase of personalized and diversified demands of the manufacturing industry, the stretch forming specific gravity of the curved surface formed by the large-curvature curved surface is continuously improved, but the traditional stretch forming still adopts a special die and an integral clamp to carry out small-batch production, so that the production cost is higher, manual operation is required to be doped in the stretch forming process of the curved surface formed by the complex curved surface, and a heat treatment process is added if necessary, so that the forming efficiency is reduced. In addition, the plate is clamped by the integral clamp, the plate does not actively deform along with the molded surface of the die, a longer transition area is needed for ensuring the die attaching degree, the material utilization rate is reduced, and the manufacturing cost is invisibly improved.
Although the prior art carries out a large number of optimized designs on the production process, the traditional stretching forming with large curvature still has the problems that defects are easily generated in the stretching process, the forming quality is unstable and the like.
Disclosure of Invention
The application provides a curved surface stretch forming method based on cooperative motion of a discrete die and a clamping mechanism, which can solve the problems that the existing large-curvature traditional stretch forming still has defects easily generated in the stretching process and unstable forming quality.
The technical scheme of the application is that the curved surface stretch forming method based on the cooperative motion of the discrete die and the clamping mechanism is adopted, the discrete die comprises a plurality of unit bodies which are regularly arranged into m rows and n columns and the heights of which can be independently changed, and the method comprises the following steps:
s1: constructing a drawing model which comprises the discrete die, a plurality of clamping mechanisms which are symmetrically arranged on two sides of the discrete die and can be independently changed in length, and a sheet material which is clamped by the clamping mechanisms, is arranged at the top end of the discrete die and can be drawn and formed;
s2: according to the stretching model, calculating stretching data including the height of each unit body at any moment, the profile function of a discrete die at any moment and the length change of a clamping mechanism at any moment in the process of stretching and forming the plate;
s3: and according to the stretching data, realizing the curved surface stretching forming of the plate by controlling the height change of the unit body and the length change of the clamping mechanism in practice.
Optionally, the shape of the top end of the unit body is a spherical crown shape, and the extending direction of the central line of the spherical crown top end of the unit body is parallel to the length change direction of the unit body.
Optionally, the gripping mechanisms disposed on both sides of the discrete mold are disposed at equal intervals.
Optionally, the number of the clamping mechanisms arranged on the two sides of the discrete die is the same;
and, each of the clamping mechanisms comprises:
the clamp clamps extend along the row direction or the row direction of a plurality of unit bodies and are used for clamping the plate materials, and the oil cylinders are used for controlling the movement of the clamp clamps and have variable lengths.
Optionally, a resilient rubber sheet is placed between the discrete dies and the sheet stock.
Optionally, in the stretching model, a plurality of the unit bodies are initially arranged at the same horizontal position and have the same horizontal height, and the plate stock is initially arranged in a flat plate shape extending in the horizontal direction;
and the step S2 includes:
s21: according to the stretching model, a rectangular coordinate system is constructed, the arrangement direction of a plurality of unit bodies in the discrete die is set to be the X direction, the arrangement direction is the Y direction, the height direction of the unit bodies is the Z direction, and the coordinate of the axial lead of each unit body is set to be (X)i，yi) I is 1,2 … … m; y is 1,2 … … n, m and n are respectively the column number and the row number of the unit body, and q pairs of clamps which are sequentially corresponding are uniformly distributed on both sides of the discrete die;
s22: according to a target surface function equation z (x, y) and parameters of the unit bodies, firstly, a coordinate [ x ] corresponding to a tangent point of a surface and each unit body at the T moment when the sheet is stretched and formed is obtained by solving an equation (1)ij(T)，yij(T)]Secondly, the corresponding height z of each unit body at the T moment is obtained by solving the equation (2)ij(T)；
Figure BDA0003616177480000031
Figure BDA0003616177480000032
Wherein, deltaBulletIs the thickness, delta, of the elastic rubber sheetBoardThe thickness of the formed plate is measured;
s23: setting initial heights of a plurality of unit bodies in a discrete mold and adjusting the initial height z coordinate of each unit body to be min [ zij(T)]；
S24: solving an equation (3) to determine a z coordinate corresponding to the height of each unit body at any time T (T is more than or equal to 0 and less than or equal to T) in the process from the beginning to the end of the curved surface stretching forming;
zij(t)＝t[zij(T)-min(zij(T))]/T, (i＝1,2…m；j＝1,2…n；0≤t≤T) (3)
s25: using least squares to measure data points [ x ] of each of said elementsi，yi，zij(t)]Carrying out cubic polynomial fitting to determine the profile function expression z of the discrete die at any moment(t)(x, y), solving equation (5) to determine polynomial coefficients cl,k-l；
Figure BDA0003616177480000033
Figure BDA0003616177480000034
S26: setting one side which can reach the discrete die along the direction parallel to the X-axis extending direction as a first side by taking the discrete die as reference, setting one side which can reach the discrete die against the direction parallel to the X-axis extending direction as a second side, taking a P-th pair of clamps which are positioned on the same extending line with the X-axis extending direction and symmetrically arranged at two sides of the discrete die as reference, and calculating the X-direction displacement u of a clamp control point corresponding to the first side in the P-th pair of clamps at the t moment through equations (6) and (7)1(t) and z-direction displacement w1(t) and the displacement u in the x-direction of the clamp control point on the second side2(t) and z-direction displacement w2(t)；
Figure BDA0003616177480000041
Figure BDA0003616177480000042
Wherein X0And Z0X and z coordinate values corresponding to the right end line of the plate at the initial time t equal to 0 respectively; l is0The initial length of the plate is taken as the initial length of the plate; y is(p)A y coordinate value corresponding to the pth pair of the clamp control points;
Figure BDA0003616177480000043
is y ═ ypX-coordinate, delta, corresponding to the highest point of the cross-sectional profilepIs the elongation of the panel in the section;
s27: and (3) respectively calculating the length change of the clamping mechanism at any moment, namely the stroke of the oil cylinder corresponding to each clamp in the pth pair of clamps through equation (8) and equation (9):
Figure BDA0003616177480000044
Figure BDA0003616177480000045
wherein L isa1p(t) and La2p(t) cylinders a for the first and second sides, respectively1p、a2pStroke of, La1And La2When t is equal to 0, the oil cylinders a on two sides1pAnd a2pEffective length of (a)1And a1When t is 0 respectively1pAnd a2pThe included angle of the axis and the X axis; l is a radical of an alcoholb1p(t) and Lb2p(t) cylinders b on the first and second sides, respectively1p、b2pStroke of, Lb1And Lb2When t is 0, the oil cylinders b on two sides1p、b2pThe effective length of (a); beta is a beta1And beta2When t is 0 respectively1pAnd b2pThe axis forms an included angle with the X axis.
In summary, the present application provides a curved surface stretch forming method based on the cooperative motion of a discrete mold and a clamping mechanism, which realizes the continuous change of the profile of the discrete mold by adjusting the height of each unit body, and controls the motion of each clamping mechanism to adapt to the change of the profile of the mold, therefore, compared with the prior art, the present application has the following advantages:
(1) forming different enveloping surfaces by adjusting the height of each unit body in the discrete die, and realizing curved surface stretch forming of the plate according to different requirements;
(2) through adjusting the length of each clamping mechanism, the plate material is guaranteed to be tightly attached to the discrete die, the large-curvature curved surface forming under a small transition area is facilitated, the unevenness is reduced, the resilience of the formed curved surface is reduced, and the forming precision is improved.
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In order to more clearly describe the technical solution of the present application, the drawings required to be used in the embodiments will be briefly described below, and it is obvious for those skilled in the art to obtain other drawings without inventive labor.
FIG. 1 is a schematic flow chart of a curved surface stretch forming method based on cooperative motion of a discrete mold and a clamping mechanism according to an embodiment of the present disclosure;
FIG. 2 is a schematic structural diagram of a drawing die in an embodiment of the present application;
FIG. 3 is a schematic view showing a contact state of a unit body, a plate material and a rubber plate in the embodiment of the present application;
FIG. 4 is a schematic diagram of the profile of the discrete die and the clamp in the process of stretch forming the sheet in the embodiment of the present application;
wherein, 1-discrete mould; 11-unit body; 2-a clamping mechanism; 21-clamping a clamp; 22-oil cylinder; 3-sheet material; 4-rubber plate.
Detailed Description
Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following examples do not represent all embodiments consistent with the present application. But merely as exemplifications of systems and methods consistent with certain aspects of the application, as recited in the claims.
The embodiment of the application provides a curved surface stretch forming method based on cooperative motion of a discrete die and a clamping mechanism, wherein the discrete die 1 comprises a plurality of unit bodies 11 which are regularly arranged in m rows and n columns and have independently changeable heights, as shown in fig. 1, fig. 1 is a schematic flow diagram of the curved surface stretch forming method based on cooperative motion of the discrete die and the clamping mechanism in the embodiment of the application, and the method comprises the following steps:
s1: the method comprises the steps of constructing a drawing model which comprises a discrete die 1, a plurality of clamping mechanisms 2 which are symmetrically arranged on two sides of the discrete die 1 and can be independently changed in length, and a sheet material 3 which is clamped by the clamping mechanisms 2, is arranged at the top end of the discrete die 1 and can be drawn and formed.
Specifically, as shown in fig. 2 and 3, fig. 2 is a schematic structural diagram of a tensile model in an embodiment of the present application, fig. 3 is a schematic contact state diagram of a unit body, a plate material and a rubber plate in the embodiment of the present application, an arrangement shape of a top end of the unit body 11 is a spherical crown shape, an extending direction of a center line of the spherical crown top end of the unit body 11 is parallel to a length change direction of the unit body 11, and a height of each unit body 11 can be independently controlled.
Different enveloping surfaces are formed by adjusting the height of each unit body 11 in the discrete die 1, and the curved surface stretching forming of the plate is realized according to different requirements.
Set up and be in 1 both sides of discrete mould equal interval sets up between fixture 2, and sets up 1 both sides of discrete mould fixture 2's the quantity that sets up is the same, and every fixture 2 includes: a clamp 21 extending along the row direction or the array direction of the plurality of unit bodies 11 for clamping the plate 3, and an oil cylinder 22 fixedly connected with the clamp 21 for controlling the movement of the clamp 21 and having a variable length. The movement of the clamp 21 is accurately controlled by means of the stroke of the oil cylinder 22.
The stroke of the oil cylinder 22 corresponding to each clamp 21 is adjusted, so that the spatial position of the clamp 21 is controlled, different clamp 21 profiles are formed, and the forming of a large-curvature curved surface in a small transition area is facilitated.
S2: and according to the stretching model, calculating stretching data including the height of each unit body 11 at any moment, the profile function of the discrete die 1 at any moment and the length change of the clamping mechanism 2 at any moment in the process of stretching and forming the sheet material 3.
Specifically, as shown in fig. 4, fig. 4 is a schematic diagram of the profile of the discrete die and the profile state of the clamp in the process of stretch forming a sheet material, the left side in fig. 4 is a schematic diagram of the profile state of the discrete die 1 in the process of stretch forming a sheet material 3, the right side in fig. 4 is a schematic diagram of the profile state of the clamp 21 in the process of stretch forming a sheet material 3, each unit body 11 is lifted at a constant speed in the process of forming a sheet material 3, so that the profile of the discrete die 1 is continuously changed, the stroke of the oil cylinder 22 is controlled to realize the movement of the clamp 21, the profile of the clamp 21 is changed to adapt to the change of the profile of the discrete die 1, the sheet material 3 is ensured to be always tightly attached to the discrete die 1, and the forming of a large-curvature curved surface is realized under the condition of a small transition area.
In some embodiments, to avoid direct contact of the sheet 3 with the unit cells 11 to form the indentations, a resilient rubber sheet 4 is placed between the discrete dies 1 and the sheet 3.
In some embodiments, in the stretching model, the plurality of unit cells 11 are initially disposed at the same horizontal position and have the same horizontal height, the sheet 3 is initially disposed in a flat plate shape extending in the horizontal direction, and the step S2 includes:
s21: a rectangular coordinate system is constructed based on a drawing model, the arrangement direction of a plurality of unit bodies 11 in a discrete die 1 is set to be an X direction, the arrangement direction is a Y direction, the height direction of the unit bodies 11 is a Z direction, and the coordinate of the axial line of each unit body 11 is set to be (X)i，yi) I is 1,2 … … m; y is 1,2 … … n, m and n are respectively the column number and the row number of the unit body, and q pairs of clamps 21 which correspond to each other in sequence are uniformly distributed on two sides of the discrete die 1;
s22: according to a target surface function equation z (x, y) and parameters of the unit bodies 11, firstly, a coordinate [ x ] x corresponding to a tangent point of the surface and each unit body 11 at the T moment when the sheet 3 is stretched and formed is obtained by solving an equation (1)ij(T)，yij(T)]Secondly, the corresponding height z of each unit body at the T moment is obtained by solving the equation (2)ij(T)；
Figure BDA0003616177480000071
Figure BDA0003616177480000072
Specifically, the parameter of the unit body 11 mainly refers to the ball head radius r of the unit body 11.
S23: setting the initial height of a plurality of unit bodies 11 in the discrete mold 1 and adjusting the initial height z coordinate of each unit body 11 to min [ zij(T)]；
S24: solving an equation (3) to determine a z coordinate corresponding to the height of each unit body 11 at any time T (T is more than or equal to 0 and less than or equal to T) in the process from the beginning to the end of the curved surface stretching forming;
zij(t)＝t[zij(T)-min(zij(T))]/T, (i＝1,2…m；j＝1,2…n；0≤t≤T) (3)
s25: for each using the least square methodData point [ x ] of individual unit cell 11i，yi，zij(t)]Carrying out cubic polynomial fitting to determine the surface function expression z of the discrete die 1 at any moment(t)(x, y), solving equation (5) to determine polynomial coefficients cl,k-l；
Figure BDA0003616177480000073
Figure BDA0003616177480000074
In particular, a polynomial coefficient c is determinedl,k-lThen, the profile function of the discrete die 1 at any moment can be obtained, the spatial position of the clamp 21 is determined, and the stroke of the oil cylinder 22 is calculated.
S26: taking the discrete die 1 as a reference, setting one side which can reach the discrete die 1 along the direction parallel to the X-axis extending direction as a first side, setting one side which can reach the discrete die 1 against the direction parallel to the X-axis extending direction as a second side, taking a P-th pair of clamps 21 which are positioned on the same extending line with the X-axis extending direction and symmetrically arranged at two sides of the discrete die 1 as a reference, and calculating the X-direction displacement u of the control point X of the clamp 21 corresponding to the first side in the P-th pair of clamps at the t moment through equations (6) and (7)1(t) and z-direction displacement w1(t) and the control point x-direction displacement u of the second side gripper 212(t) and z-direction displacement w2(t)；
Figure BDA0003616177480000081
Figure BDA0003616177480000082
Wherein, X0And Z0X and z coordinate values corresponding to the right end line of the plate 3 when the initial time t is equal to 0 respectively; l is0The initial length of the plate 3; y is(p)As the p-th pair of tongs 21, controlling the corresponding y coordinate value;
Figure BDA0003616177480000083
is y ═ ypX-coordinate, delta, corresponding to the highest point of the cross-sectional profilepThe elongation of the sheet material 3 in this section.
S27: the length change of the clamping mechanism 2 at any moment, namely the stroke of the oil cylinder 22 corresponding to each clamp in the pth pair of clamps 21 is calculated through equation (8) and equation (9):
Figure BDA0003616177480000084
Figure BDA0003616177480000085
wherein L isa1p(t) and La2p(t) cylinders a for the first and second sides, respectively1p、a2pStroke of, La1And La2When t is equal to 0, the oil cylinders a on two sides1pAnd a2pEffective length of (a)1And a1When t is 0 respectively1pAnd a2pThe included angle of the axis and the X axis; l isb1p(t) and Lb2p(t) cylinders b on the first and second sides, respectively1p、b2pStroke of, Lb1And Lb2When t is 0, the oil cylinders b on two sides1p、b2pThe effective length of (a); beta is a1And beta2When t is 0 respectively1pAnd b2pThe axis forms an included angle with the X axis.
S3: according to the stretching data, the curved surface stretching forming of the plate is realized by controlling the height change of the unit body 11 and the length change of the clamping mechanism 2 in practice.
Specifically, according to the calculation result, the curved surface stretch forming process of the discrete die 1 and the clamping mechanism 2 in the coordinated movement on the sheet 3 is realized by specifically controlling the actual movement of the unit 11 and the stroke of the oil cylinder 22.
In summary, the embodiment of the present application provides a curved surface stretch forming method based on cooperative motion of a discrete mold and a clamping mechanism, where the discrete mold 1 includes a plurality of unit bodies 11 with independently changeable heights, which are regularly arranged in m rows and n columns, and includes: constructing a stretching model comprising a discrete die 1, a clamping mechanism 2 and a plate 3; simulating a stretched forming process of the plate 3 according to the stretching model and calculating stretching data; according to the stretching data, the curved surface stretching forming of the plate 3 is realized by controlling the height change of the unit 11 and the length change of the clamping mechanism in practice.
Wherein, through the height of each unit cell 11 in the adjustment discrete mould forms different enveloping surface, realize the curved surface stretch forming of sheet material 3 according to the needs of difference to and adjust the length variation of every fixture 2, be convenient for realize that big curvature curved surface takes shape under the less transition region, consequently compare in prior art, this application embodiment can reduce the mould cost, improve the utilization ratio of material and make each regional abundant deformation of sheet material 3, reduce the inhomogeneity, reduce the resilience volume of shaping curved surface, improve the shaping precision.
The embodiments of the present application have been described in detail, but the present application is only a preferred embodiment of the present application and should not be construed as limiting the scope of the present application. All equivalent changes and modifications made within the scope of the present application shall fall within the scope of the present application.

Claims (6)

1. A curved surface stretching forming method based on cooperative motion of a discrete die and a clamping mechanism, wherein the discrete die comprises a plurality of unit bodies which are regularly arranged in m rows and n columns and can independently change in height, and the method is characterized by comprising the following steps:
s1: constructing a drawing model which comprises the discrete die, a plurality of clamping mechanisms which are symmetrically arranged at two sides of the discrete die and can be changed in length independently, and a sheet material which is clamped by the clamping mechanisms, is arranged at the top end of the discrete die and can be drawn and formed;
s2: according to the stretching model, the stretching data including the height of each unit body at any time, the profile function of a discrete die at any time and the length change of the clamping mechanism at any time in the sheet material stretching forming process are calculated;
s3: and according to the stretching data, realizing the curved surface stretching forming of the plate by controlling the height change of the unit body and the length change of the clamping mechanism in practice.
2. The method as claimed in claim 1, wherein the unit body has a top end in a shape of a spherical crown and the central line of the top end of the spherical crown of the unit body extends in a direction parallel to the direction of the change in length of the unit body.
3. The method of claim 2, wherein the gripping mechanisms are disposed at equal intervals on both sides of the discrete die.
4. The method for stretch-forming a curved surface based on the cooperative motion of the discrete die and the clamping mechanisms according to claim 3, wherein the clamping mechanisms arranged on both sides of the discrete die are arranged in the same number;
and, each said clamping mechanism comprises:
the clamp clamps extend along the row direction or the row direction of a plurality of unit bodies and are used for clamping the plate materials, and the oil cylinders are used for controlling the movement of the clamp clamps and have variable lengths.
5. The method of claim 4, wherein an elastic rubber sheet is placed between the discrete die and the sheet.
6. A curved surface stretch-forming method based on cooperative motion of discrete dies and clamping mechanisms according to claim 5, characterized in that in the stretching model, a plurality of the unit bodies are initially arranged at the same horizontal position and have the same horizontal height, and the sheet is initially arranged in a flat plate shape extending along the horizontal direction;
and, the step S2 includes:
s21: according to the stretching model, a rectangular coordinate system is constructed, the arrangement direction of a plurality of unit bodies in the discrete die is set to be the X direction, the arrangement direction is the Y direction, the height direction of the unit bodies is the Z direction, and the coordinate of the axial lead of each unit body is set to be (X)i，yi) I is 1,2 … … m; y is 1,2 … … n, m and n are respectively the column number and the row number of the unit body, and q pairs of clamps which are sequentially corresponding are uniformly distributed on both sides of the discrete die;
s22: according to a target surface function equation z (x, y) and parameters of the unit bodies, firstly, a coordinate [ x ] corresponding to a tangent point of a surface and each unit body at the T moment when the sheet is stretched and formed is obtained by solving an equation (1)ij(T)，yij(T)]Secondly, the corresponding height z of each unit body at the T moment is obtained by solving the equation (2)ij(T)；
Figure FDA0003616177470000021
Figure FDA0003616177470000022
Wherein, deltaBulletIs the thickness, delta, of the elastic rubber sheetBoardThe thickness of the formed plate is measured;
s23: setting initial heights of a plurality of unit bodies in a discrete mold and adjusting the initial height z coordinate of each unit body to be min [ zij(T)]；
S24: solving an equation (3) to determine a z coordinate corresponding to the height of each unit body at any time T (T is more than or equal to 0 and less than or equal to T) in the process from the beginning to the end of the curved surface stretching forming;
zij(t)＝t[zij(T)-min(zij(T))]/T,(i＝1,2…m；j＝1,2…n；0≤t≤T) (3)
s25: using least square method to determine data point [ x ] of each unit bodyi，yi，zij(t)]Performing cubic polynomial fitting to determine the surface function expression z of the discrete mold at any time(t)(x, y), solving equation (5) to determine polynomial coefficients cl,k-l；
Figure FDA0003616177470000031
Figure FDA0003616177470000032
S26: setting one side which can reach the discrete die along the direction parallel to the X-axis extending direction as a first side by taking the discrete die as reference, setting one side which can reach the discrete die along the direction parallel to the X-axis extending direction as a second side against the direction parallel to the X-axis extending direction, taking a Pth pair of clamps which are positioned on the same extending line with the X-axis extending direction and symmetrically arranged at two sides of the discrete die as reference, and calculating the X-direction displacement u of a clamp control point X on the first side in the Pth pair of clamps at the time t through equations (6) and (7)1(t) and z-direction displacement w1(t) and the displacement u in the x-direction of the clamp control point on the second side2(t) and z-direction displacement w2(t)；
Figure FDA0003616177470000033
Figure FDA0003616177470000034
Wherein, X0And Z0When the initial time t is equal to 0, x and z coordinate values corresponding to the edge of the second side of the plate are respectively set; l is0The initial length of the plate is taken as the initial length of the plate; y is(p)A y coordinate value corresponding to the pth pair of the clamp control points;
Figure FDA0003616177470000041
is y ═ ypX-coordinate, delta, corresponding to the highest point of the cross-sectional profilepIs the elongation of the panel in the section;
s27: and (3) respectively calculating the length change of the clamping mechanism at any moment, namely the stroke of the oil cylinder corresponding to each clamp in the pth pair of clamps through an equation (8) and an equation (9):
Figure FDA0003616177470000042
Figure FDA0003616177470000043
wherein L isa1p(t) and La2p(t) cylinders a for the first and second sides, respectively1p、a2pStroke of, La1And La2When t is equal to 0, the oil cylinders a on two sides1pAnd a2pEffective length of (a)1And a1When t is 0 respectively1pAnd a2pThe included angle of the axis and the X axis; l is a radical of an alcoholb1p(t) and Lb2p(t) cylinders b on the first and second sides, respectively1p、b2pStroke of, Lb1And Lb2When t is 0, the oil cylinders b on two sides1p、b2pThe effective length of (a); beta is a1And beta2When t is 0 respectively1pAnd b2pThe axis forms an included angle with the X axis.
CN202210444718.4A 2022-04-26 2022-04-26 Curved surface stretch forming method based on cooperative movement of discrete die and clamping mechanism Active CN114669669B (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116460198A (en) * 2023-04-07 2023-07-21 吉林大学 Sheet flexible stretch forming method based on back stretch forming machine

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20130086966A1 (en) * 2010-06-11 2013-04-11 Steel Flower Co., Ltd. Method for manufacturing a sheet molded to form a multi-dimensional curved surface
CN103722070A (en) * 2014-01-22 2014-04-16 吉林大学 Method for forming three-dimensional curve surface by using discrete displacement loading mode
CN104391482A (en) * 2014-11-26 2015-03-04 江西洪都航空工业集团有限责任公司 Longitudinal tensile loading trajectory design method based on mold surface extension
CN104438538A (en) * 2014-10-30 2015-03-25 吉林大学 Three-dimensional curved surface stretch forming method based on surface-changing discrete mould
CN105478539A (en) * 2015-12-29 2016-04-13 哈尔滨工业大学（威海） Plate multipoint progressive forming device
US20160167099A1 (en) * 2014-12-12 2016-06-16 Steel Flower Co., Ltd. Multipoint stretch forming apparatus enabling individual clamping control for manufacturing a curved panel
CN106391813A (en) * 2016-12-09 2017-02-15 吉林大学 Three-dimensional curve stretch forming method based on multi-point force loading mode
CN108280274A (en) * 2018-01-09 2018-07-13 吉林大学 A kind of swollen drawing manufacturing process of curved surface by die face variation driving
CN109175051A (en) * 2018-08-21 2019-01-11 吉林大学 A kind of no mould multiple spot spinning three-dimensional curve generation method

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20130086966A1 (en) * 2010-06-11 2013-04-11 Steel Flower Co., Ltd. Method for manufacturing a sheet molded to form a multi-dimensional curved surface
CN103722070A (en) * 2014-01-22 2014-04-16 吉林大学 Method for forming three-dimensional curve surface by using discrete displacement loading mode
CN104438538A (en) * 2014-10-30 2015-03-25 吉林大学 Three-dimensional curved surface stretch forming method based on surface-changing discrete mould
CN104391482A (en) * 2014-11-26 2015-03-04 江西洪都航空工业集团有限责任公司 Longitudinal tensile loading trajectory design method based on mold surface extension
US20160167099A1 (en) * 2014-12-12 2016-06-16 Steel Flower Co., Ltd. Multipoint stretch forming apparatus enabling individual clamping control for manufacturing a curved panel
CN105478539A (en) * 2015-12-29 2016-04-13 哈尔滨工业大学（威海） Plate multipoint progressive forming device
CN106391813A (en) * 2016-12-09 2017-02-15 吉林大学 Three-dimensional curve stretch forming method based on multi-point force loading mode
CN108280274A (en) * 2018-01-09 2018-07-13 吉林大学 A kind of swollen drawing manufacturing process of curved surface by die face variation driving
CN109175051A (en) * 2018-08-21 2019-01-11 吉林大学 A kind of no mould multiple spot spinning three-dimensional curve generation method

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
陈雪;陈成;李明哲;: "离散夹钳柔性拉形机的研制及实验验证", 机床与液压 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116460198A (en) * 2023-04-07 2023-07-21 吉林大学 Sheet flexible stretch forming method based on back stretch forming machine

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