阅读说明：本技术 一种管材复合柔性弯曲成形方法 (Composite flexible bending forming method for pipe ) 是由 郭训忠 韦桂 王成 于 2019-12-16 设计创作，主要内容包括：本发明公开了一种管材复合柔性弯曲成形方法,将具有复杂形状弯管的三维几何模型进行分段,包括直段、大弯曲半径段、小弯曲半径段；对分段进行弯曲半径评估,将管材弯曲半径分为较小弯曲半径和较大弯曲半径,两种弯曲半径的过渡位置即为不同弯曲参数的结合点；建立直段、大弯曲半径段、小弯曲半径段的几何形状参数与管材轴向送进速度v、运动时间t、偏心距U、弯曲模运动速度u之间的数量关系；采用有限元方法建立三维弯曲模型,通过多次模拟结果对各个工艺参数之间的关系优化分析；采用所述优化后的数量关系作为弯曲工艺参数,使三维自由弯曲和绕弯二者精确复合；将最终的工艺参数以及两种弯曲方式的结合点传送给设备,执行实际弯曲成形。(The invention discloses a pipe composite flexible bending forming method, which comprises the steps of segmenting a three-dimensional geometric model with a bent pipe with a complex shape, wherein the three-dimensional geometric model comprises a straight section, a large bending radius section and a small bending radius section; evaluating the bending radius of the subsection, dividing the bending radius of the pipe into a smaller bending radius and a larger bending radius, wherein the transition position of the two bending radii is a combination point of different bending parameters; establishing the quantitative relation among the geometric shape parameters of the straight section, the large bending radius section and the small bending radius section, the axial feeding speed v of the pipe, the movement time t, the eccentricity U and the movement speed U of the bending die; establishing a three-dimensional bending model by adopting a finite element method, and optimizing and analyzing the relationship among all process parameters through multiple simulation results; the optimized quantity relation is used as a bending process parameter, so that three-dimensional free bending and bending are accurately combined; and (4) transmitting the final process parameters and the combination point of the two bending modes to equipment to perform actual bending forming.)

1. The composite flexible bending and forming method of the pipe is characterized by comprising the following steps:

the method comprises the following steps that firstly, a three-dimensional geometric model with a bent pipe with a complex shape is segmented, wherein the three-dimensional geometric model comprises a straight section, a large bending radius section and a small bending radius section;

secondly, evaluating the bending radius of the subsection in the first step, dividing the bending radius of the pipe into a smaller bending radius and a larger bending radius, wherein the transition position of the two bending radii is a combination point of different bending parameters;

thirdly, establishing the quantitative relation among the geometric parameters of the straight section, the large bending radius section and the small bending radius section, the length L of the straight section, the bending radius R, the bending angle theta, the axial feeding speed v of the pipe, the movement time t, the eccentricity U and the movement speed U of the bending dieWherein, for the tube blank with the same material and size, the change of U can be obtained by the formula according to the difference of R;

fourthly, establishing a three-dimensional bending model by adopting a finite element method, carrying out multiple times of simulation verification on the quantitative relation in the third step, and carrying out optimization analysis on the relation among the process parameters through multiple times of simulation results;

fifthly, the optimized quantitative relation in the fourth step is used as a bending process parameter, so that three-dimensional free bending and bending are accurately combined;

and a sixth step: transmitting the final technological parameters and the joint point of the two bending modes to the equipment, executing actual bending forming, and judging the joint point by R/D₀When the value of R/D is₀Small bending radius at 3 or less, R/D₀Large bending radius > 3.

2. The method of claim 1, wherein: in the first step, a three-dimensional geometric model of the bent pipe with the complex shape is divided according to a straight section, a large bending radius section and a small bending radius section.

3. The method of claim 1, wherein: in the second step, a straight section exists between the large bending radius section and the small bending radius section, and the two bending modes are tightly combined by controlling the length of the straight section.

4. The method of claim 1, wherein: before forming, finite element simulation is needed to optimize technological parameters, and the length of a straight section between bent sections is optimized.

5. The method of claim 2, wherein: in the second step, the size of the bending radius is analyzed and submitted to computer analysis and calculation through a three-dimensional bent pipe optical measurement system, and the bending mode is determined.

6. The method of claim 3, wherein: in the process of bending and forming the composite flexible pipe, the straight section is a combined section of numerical control bending and three-dimensional free bending.

Technical Field

The invention belongs to the technical field of advanced manufacturing of metal complex components, and particularly relates to a composite flexible bending forming method for a pipe.

Background

Various metal components with complex bent shapes have wide application in various fields such as aerospace, nuclear power, automobiles, ships, petrochemicals, buildings and other civil industries, and play an important role in reducing the production cost and weight of products.

At present, the conventional metal member bending technology mainly includes press bending, stretch bending, wrap bending, push bending and bending processes derived from the above basic processes. The traditional pipe forming method can not meet the requirement of high precision of the pipe when the pipe with the complex axial line shape is bent. Meanwhile, according to the difference of relative bending radius, the bending die must be continuously replaced by the pipe bending method, so that the production efficiency is greatly reduced. Therefore, the pipe bending method is only suitable for the bending process of the pipes with large batch and simple shapes. For the space bent pipe with a complex shape or the bent pipe with a complex shape with a continuously changed curvature, the traditional bent pipe method can not be realized.

The composite flexible bending forming of the pipe of the complex component combines three-dimensional free bending and numerical control bending to realize high-precision forming of the pipe, the section and the wire under various bending radius conditions, and forms a huge challenge to the traditional metal bending forming technology, thereby being an important technical innovation recognized in the field of plastic forming.

Disclosure of Invention

The existing pipe composite flexible bending forming system does not have a mature optimization method for the bending forming process of the metal complex component. The invention provides a novel bending forming method for a metal complex component, aiming at the defects of the existing pipe composite flexible bending system. The metal complex member is segmented firstly, the quantitative relation between the geometric shapes of different segments and key process parameters is established according to the different diameters of the bending segments, the bending step is determined according to the quantitative relation, and the advantages that the pipe composite flexible bending forming system can realize the forming of the pipe bending radii of different sizes and the bending of the complex modeling metal member are fully exerted.

A composite flexible bending forming method for a pipe is realized by the following steps:

the method comprises the following steps that firstly, a three-dimensional geometric model with a bent pipe with a complex shape is segmented, wherein the three-dimensional geometric model comprises a straight section, a large bending radius section and a small bending radius section;

secondly, evaluating the bending radius of the subsection in the first step, dividing the bending radius of the pipe into a smaller bending radius and a larger bending radius, wherein the transition position of the two bending radii is a combination point of different bending parameters;

thirdly, establishing the quantitative relation among the geometric parameters of the straight section, the large bending radius section and the small bending radius section, the length L of the straight section, the bending radius R, the bending angle theta, the axial feeding speed v of the pipe, the movement time t, the eccentricity U and the movement speed U of the bending dieWherein, for the tube blank with the same material and size, the change of U can be obtained by the formula according to the difference of R;

fourthly, establishing a three-dimensional bending model by adopting a finite element method, carrying out multiple times of simulation verification on the quantitative relation in the third step, and carrying out optimization analysis on the relation among the process parameters through multiple times of simulation results;

fifthly, the optimized quantitative relation in the fourth step is used as a bending process parameter, so that three-dimensional free bending and bending are accurately combined;

and a sixth step: transmitting the final technological parameters and the joint point of the two bending modes to the equipment, executing actual bending forming, and judging the joint point by R/D₀When the value of R/D is₀Small bending radius at 3 or less, R/D₀Large bending radius > 3.

In the first step, a three-dimensional geometric model of the bent pipe with the complex shape is divided into a straight section, a large bending radius section and a small bending radius section.

In the method, in the second step, a straight section exists between the large bending radius section and the small bending radius section, and the two bending modes are tightly combined by controlling the length of the straight section.

In the method, before forming, finite element simulation is needed to optimize process parameters, and the length of a straight section between bent sections is optimized.

In the second step, the method analyzes the bending radius through a three-dimensional bent pipe optical measurement system, and submits the size of the bending radius to a computer for analysis and calculation so as to determine the bending mode.

According to the method, in the composite flexible bending and forming process of the pipe, the straight section is a combined section of numerical control bending and three-dimensional free bending.

Has the advantages that:

1. the invention provides a new forming device and a process optimization method for the composite flexible bending forming of a metal complex component;

2. the invention is a matched bending process of the composite flexible bending forming device of the pipe, and fully exerts the advantages of the composite flexible bending forming device of the pipe, such as changing the bending radius of the pipe in real time and realizing the bending of a metal component with a complex shape;

3. the method is simple and feasible, has high production efficiency, and has important engineering application value and obvious economic benefit in the engineering fields of aerospace, nuclear power, automobiles and the like.

Drawings

FIG. 1 is a flow chart of a composite flexible bending process of a pipe.

FIG. 2 is a schematic view of the principle of the composite flexible bending forming of the pipe.

1, digitally controlling a bending part; 2 a free bend portion; 3, a propulsion device;

Detailed Description

The present invention will be described in detail with reference to specific examples.

Firstly, segmenting a three-dimensional geometric model of a bent pipe with a complex shape and a length of 2000 mm;

and secondly, evaluating the bending radius of the subsection in the first step, and dividing the bending radius of the pipe into a smaller bending radius and a larger bending radius, wherein 5 straight sections are provided, 3 straight sections are formed, and 2 straight sections are tail end pushing straight sections. The bending section 2 with large variable curvature bending radius is formed by a three-dimensional free bending technology. The total number of the bending sections with small bending radius formed by the numerical control bending technology is 2.

And thirdly, establishing the quantitative relation among the geometric shape parameters of the straight section, the large bending radius section and the small bending radius section, such as the length L of the straight section, the bending radius R, the bending angle theta and the like, the axial feeding speed v of the pipe and the movement time t. When in useThe free bending forming mode can be adopted when the large bending radius is formed, and the free bending forming mode can be adopted when the large bending radius is formed

Wherein s is v t. R/D₀When the bending radius is less than or equal to 3, the bending radius is small, a forming mode of numerical control bending can be adopted, D₀Is the initial outer diameter of the metal pipe;

fourthly, establishing a three-dimensional bending model by adopting a finite element method, and carrying out multiple times of simulation verification on the quantitative relation in the third step, wherein the length of 5 sections of straight sections is 1000mm in total, the length of 4 sections of bent sections is 1000mm in total, the bending radius of the first and second bent sections is 60mm and is a small bending radius, and the bending radius of the third and fourth bent sections is 120mm and is a large bending radius;

fifthly, the optimized quantitative relation in the fourth step is used as a bending process parameter, so that three-dimensional free bending and numerical control bending are accurately combined;

and a sixth step: and (4) transmitting the final process parameters and the combination point of the two bending modes to equipment to perform actual bending forming.

In this example, the selected pipe is a 6061 aluminum alloy pipe, and the original specification of the miniature metal round pipe is D0 × t × L, which is 20mm × 1mm × 2000mm, wherein D0 is the initial outer diameter of the metal pipe, t is the wall thickness of the metal pipe, and L is the pipe length of the metal pipe; the bending radius of the pipe is divided into a small bending radius and a large bending radius, wherein 5 sections of straight sections are provided, 3 sections are forming straight sections, and 2 sections are tail end pushing straight sections. The bending section 2 with large variable curvature bending radius is formed by a three-dimensional free bending technology. The total number of the bending sections with small bending radius formed by the numerical control bending technology is 2; wherein the length of the 5 sections of straight sections is 1000mm in total, the length of the 4 sections of bent sections is 1000mm in total, the bending radius of the first and second bent sections is 60mm, the first and second bent sections are small, and the bending radius of the third and fourth bent sections is 120mm, and the third and fourth bent sections are large.

It will be understood that modifications and variations can be made by persons skilled in the art in light of the above teachings and all such modifications and variations are intended to be included within the scope of the invention as defined in the appended claims.