阅读说明：本技术 一种机翼缘条结构的激光喷丸控形方法 (Laser shot blasting shape control method for flange strip structure ) 是由 张峥 吴瑞煜 张永康 于 2019-10-18 设计创作，主要内容包括：本发明公开了一种机翼缘条结构的激光喷丸控形方法,主要包括已完成铣削加工但尺寸超差的缘条和定位夹具,其中缘条是具有翼缘和腹板结构的大曲率长梁类零件,定位夹具包括旋转支撑台架和棘轮机构。该方法原理是利用高能脉冲激光(激光喷丸/激光冲击强化)在零件表面引入1-2mm深的高幅值残余压应力,由于应力平衡导致处理区域产生宏观变形,通过合理分配处理区域刚度与输入能量的定量对应关系,进行特定顺序和方向的凸起变形用于抵消腹板和翼缘的铣削变形,从而达到尺寸公差要求。本发明提出的方法属于表面改性技术,是冷加工工艺,不会影响零件后续工序和服役性能。(The invention discloses a laser shot blasting shape control method of a flange strip structure of a machine, which mainly comprises a flange strip which is milled and has an out-of-tolerance size and a positioning fixture, wherein the flange strip is a long beam part with large curvature and a web structure, and the positioning fixture comprises a rotary support rack and a ratchet mechanism. The method is characterized in that high-energy pulse laser (laser shot blasting/laser shock peening) is utilized to introduce 1-2mm deep high-amplitude residual compressive stress on the surface of a part, macroscopic deformation is generated in a processing area due to stress balance, and through reasonably distributing the quantitative corresponding relation between the rigidity of the processing area and input energy, the protruding deformation in a specific sequence and direction is carried out to offset the milling deformation of a web plate and a flange, so that the requirement of dimensional tolerance is met. The method provided by the invention belongs to a surface modification technology, is a cold machining process, and cannot influence the subsequent process and service performance of parts.)

1. A laser shot blasting shape control method for a flange strip structure is characterized by comprising the following steps:

step S1: determining milling deformation modes of a web and a flange and determining primary and secondary envelope lines;

step S2: determining a deformation mode of laser shot blasting through a process parameter experiment, and obtaining a parameter-deformation data table/matrix;

step S3: clamping the part in a natural state by using a tool clamp, and controlling a clamping angle by using a ratchet wheel to rotate the part until the curved and deformed concave surface/the distorted and deformed concave center line faces to the laser incidence direction;

step S4: performing inverse deformation processing according to data in the parameter-deformation data table;

step S5: the deformation control strategy is as follows: symmetrically proceeding from the center of the concave surface to two ends; the distortion laser shot blasting path is as follows: from the center of the concave surface to the center symmetry direction of the two ends.

2. The method of claim 1, wherein the step S1 determines that the primary and secondary envelopes of the deformation in the milling deformation mode are two perpendicular axial paths on the geometric central axis of the selected curved surface, wherein the primary envelope is the deformation with a large value and the secondary envelope is the deformation with a small value.

3. The method of claim 1, wherein the step S1 comprises measuring the deformation in situ at the machining center using a relative laser displacement sensor.

4. The method of claim 1, wherein the parameter-deformation data table/matrix in step S2 is expanded from two sets of parameter experiments, the first set is a thickness-isoenergy experiment, and a quantitative relationship between thickness and deformation is obtained at a specific energy; the second group is a variable energy-equal thickness experiment to obtain the quantitative relation between energy and deformation under a specific thickness; and finally, forming a parameter-deformation data table/matrix for determining the inverse deformation parameters through interpolation and expansion of two groups of experimental data.

5. The method of claim 1, wherein the table/matrix of parameters-distortion data in step S2 includes three parameters, respectively: the row vector is the m input parameters laser energy, the column vector is the thickness of the n processing objects, and the value of any cell in the table is the output deformation, which represents the deformation generated by laser peening under any energy and thickness.

6. The method of laser peening shaping of a leading edge strip structure of claim 1, wherein said step S4 further comprises: when the inverse deformation processing is performed according to the data in the parameter-deformation data table/matrix, the deformation pattern, the deformation amount, and the thickness of the object to be processed are obtained in step S1, and the laser energy required for controlling the deformation can be obtained by referring to the parameter-deformation data table/matrix.

Technical Field

The invention relates to the technical field of aeronautical manufacturing, in particular to a laser shot blasting shape control method for milling deformation of a wing edge strip structure.

Background

Due to the design requirements of high efficiency and low consumption, most wings of modern aircrafts are designed into an integral structure, and the flanges are used as main bearing structural members of wing spars and mainly play a role in keeping structural rigidity and appearance. From the structure, the section of the edge strip can be divided into a T shape, a ten shape or a double ten shape, the length direction of the edge strip has large curvature deflection, and the length-width ratio is about 10 times. Because the wing adopts overall structure design, the flange strip is usually formed by directly milling the section bar in a numerical control manner, the material removal rate is high, the machining time is long, and the technical difficulties of high clamping difficulty and easy deformation in machining are also commonly existed. In order to solve the technical problems, an improved process is usually adopted to optimize and control milling deformation at present, but the effect is not obvious under the influence of multiple factors such as the residual stress amplitude of the section bar, the programming of the milling process, the processing path and the like.

Accordingly, further improvements and improvements are needed in the art.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a laser shot blasting shape control method for a wing edge strip structure.

The purpose of the invention is realized by the following technical scheme:

a laser shot blasting shape control method for a flange strip structure mainly comprises the following specific steps:

step S1: determining the milling deformation modes of the web and the flange and determining the primary envelope line and the secondary envelope line, wherein the milling deformation is the existing unfavorable deformation exceeding the dimensional tolerance after the processing and is the object to be eliminated by the invention.

In a preferred embodiment of the present invention, in the milling deformation mode, the step S1 determines that the primary envelope and the secondary envelope of the deformation are two perpendicular axial paths on the geometric central axis of the selected curved surface, where the primary envelope is larger in deformation and the secondary envelope is smaller in deformation.

Preferably, the deformation measurement in step S1 may be performed in situ at the processing center by using a relative laser displacement sensor.

Step S2: and determining the deformation mode of the laser shot blasting through a process parameter experiment, and obtaining a parameter-deformation data table/matrix. The deformation mode of the laser shot blasting is the deformation amount which needs to be artificially introduced in the invention, and the purpose of deformation control is realized through the positive and negative counteraction of the deformation amount. Wherein, the positive deformation is milling deformation, and is the object to be processed as described in step S1, and needs to be eliminated; the reverse deformation is laser shot deformation, which is an artificially introduced deformation amount and needs to be offset by the same amount as the existing positive deformation. The significance of establishing the parameter-deformation data table (matrix) is that aiming at various milling deformations with different thicknesses, appropriate parameters can be obtained through table lookup to perform equivalent inverse deformation offset, and the time for process trial and error and debugging is saved.

As a preferred embodiment of the present invention, the parameter-deformation data table/matrix in step S2 is formed by expanding two sets of parameter experiments, the first set is a variable thickness-equal energy experiment, and a quantitative relationship between the thickness and the deformation under a specific energy is obtained; the second group is a variable energy-equal thickness experiment to obtain the quantitative relation between energy and deformation under a specific thickness; and finally, forming a parameter-deformation data table/matrix for determining the inverse deformation parameters through interpolation and expansion of two groups of experimental data.

Preferably, the parameter-transformation data table/matrix in step S2 includes three parameters, which are: the row vector is the m input parameters laser energy, the column vector is the thickness of the n processing objects, and the value of any cell in the table is the output deformation, which represents the deformation generated by laser peening under any energy and thickness.

Step S3: and (3) clamping the part in a natural state by using a tool clamp, and controlling a clamping angle by using a ratchet wheel to rotate the part until the curved and deformed concave surface/the distorted and deformed concave central line faces to the laser incidence direction.

Step S4: and performing inverse deformation processing according to the data in the parameter-deformation data table.

As a preferable embodiment of the present invention, the step S4 further includes: when the inverse deformation processing is performed according to the data in the parameter-deformation data table/matrix, the deformation pattern, the deformation amount, and the thickness of the object to be processed are obtained in step S1, and the laser energy required for controlling the deformation can be obtained by referring to the parameter-deformation data table/matrix.

Step S5: the deformation control strategy is as follows: symmetrically proceeding from the center of the concave surface to two ends; the distortion laser shot blasting path is as follows: from the center of the concave surface to the center symmetry direction of the two ends.

The working process and principle of the invention are as follows: according to the invention, high-energy pulse laser (laser shot blasting/laser shock peening) is utilized to introduce 1-2mm deep high-amplitude residual compressive stress on the surface of the part, macroscopic deformation is generated in a processing region due to stress balance, and through reasonably distributing the quantitative corresponding relation between the rigidity of the processing region and input energy, the protruding deformation in a specific sequence and direction is carried out to offset the milling deformation of a web plate and a flange, so that the requirement of dimensional tolerance is met.

Compared with the prior art, the invention also has the following advantages:

(1) the laser shot blasting shape control method of the wing edge strip structure provided by the invention belongs to a surface modification technology, and the treatment process does not involve material removal and has no thermal effect, so that the subsequent process and the service performance of parts are not influenced.

(2) The laser shot blasting shape control method for the wing edge strip structure provided by the invention has good accuracy and feasibility of a data matrix determined by a parameter experiment, and ensures the precision and efficiency of deformation control of a large structural member.

Drawings

FIG. 1 is a schematic cross-sectional view of three types of leading edges provided by the present invention.

Fig. 2 is a schematic diagram of the twisting deformation of the T-shaped edge strip provided by the present invention after milling.

Fig. 3 is a schematic diagram of two deformation modes and primary and secondary envelopes provided by the present invention.

FIG. 4 is a schematic diagram of laser shot-peening deformation of a sample at an equal energy of 5J in a first set of thickness-varying and equal-energy experiments provided by the present invention.

FIG. 5 is a schematic diagram of the laser peening deformation of a sample in a second set of constant thickness-variable energy experiments provided by the present invention.

FIG. 6 is a schematic diagram of a laser peening deformation pattern of a sample provided by the present invention.

Fig. 7 is a schematic diagram of the main envelope-variation provided by the present invention.

Fig. 8 is a schematic of deformation-thickness-energy obtained from the first and second sets of experimental data provided by the present invention.

FIG. 9 is a table of parameter data obtained by interpolation and expansion of two sets of experimental data provided by the present invention.

FIG. 10 is a perspective view and a front view of a bead positioning fixture provided by the present invention.

FIG. 11 is a schematic view of a curved anamorphic laser peening path provided by the present invention.

FIG. 12 is a schematic diagram of a distortion laser peening path provided by the present invention.

FIG. 13 is a flow chart of a method for laser peening a leading edge strip structure in accordance with the present invention.

The reference numerals in the above figures illustrate:

1-curvature of the edge in the length direction, 2-web of a double cross edge, 3-flange of a double cross edge, 4-web of a T edge, 5-flange of a T edge, 6-web of a single cross edge and 7-flange of a single cross edge; 8-bending deformation, 9-twisting deformation, 10-primary envelope, 11-secondary envelope, 12-center of deformation; 13-a to-be-processed edge strip, 14-a rotary supporting rack, 15-a cylindrical auxiliary support and 16-a ratchet mechanism; 17-actual profile, 18-theoretical profile; 19-direction and sequence of bend-deformed laser peening paths, 20-deformed profile, 21-distorted convex, 22-distorted concave, 23-distorted laser peening paths and sequence.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer and clearer, the present invention is further described below with reference to the accompanying drawings and examples.