Summary of the invention:
Different with the comprehensive wide cut contour peening of tradition method, the present invention adopts extremely narrow band shot-peening mode by certain shot-peening path and the shot-blast process parameter main tangential profile that is shaped, and the processing of the large-scale wing wallboard chordwise shot-peening forming technique problem of proposition is divided into following 4 key steps:
1) obtains curvature and thickness distribution on each primary structure point of wallboard profile by geometrical analysis;
2) shot-peening path planning: the shot-peening path curve is along the direction of curved surface constant percentage chord line, and the shot-peening path forms banded shot-peening path by less position and the thicker position of wallboard of very shallow curvature radius on the wallboard curved surface;
3) equal strength dividing region and determine: as principal element, dividing the approximate thickness district with the wallboard varied in thickness, is that principal element marks off the iso-curvature district with the radius of curvature in the approximate thickness district, and the iso-curvature district in the approximate thickness district is the equal strength district;
4) determine the shot-peening parameter: with equal strength district on the wallboard and the match of shot-peening path planning, set the shot-peening parameter in each equal strength district respectively, will constitute the shot-peening parameter of integral panel along the shot-peening parameter serial connection in each the equal strength district on the shot-peening path.
■ profile curvature and thickness analysis
The 3D design digital-to-analogue of wing wallboard is made of structural information and appearance curved surface two parts, wherein structural information is to represent with some curved sections on the wallboard perspective view, constitute several regions by different curved sections, each zone has identical varied in thickness rule, and appearance curved surface is with discrete representing by certain regularly arranged series of points.Curvature has been described the local geometric character of curved surface at certain some place, is the important Differential Geometry Characteristics of curved surface, and principal curvatures is the embodiment of this local shape, and Gauss curvature can be determined the character put on the curved surface.Before planning wallboard shot-peening path and Design Fundamentals shot-blast process parameter, must carry out geometrical analysis, to obtain thickness and two critical datas of curvature on the wallboard characteristic point to the wallboard appearance curved surface.
Characteristic point on the wall panel structure designs rib bit line and long purlin axis with wallboard and is made as characteristic point on the wall panel structure at the intersection point of wallboard outer surface projection, and the geometrical Characteristics Analysis of characteristic point is mainly comprised following two aspects:
1, the appearance curved surface analysis on the characteristic point: the appearance curved surface of the theoretical digital-to-analogue of 3D is carried out geometrical analysis with the analysis analysis functional module of CATIA system platform, the curved surface data that can obtain has sectional curvature, principal curvatures, Gauss curvature etc., its inside is normally obtained by analytic expression by the curved surface parameter when calculating, and ratio of precision is higher.Principal curvatures in the geometric buckling is a topmost parameter in the technological design of wallboard contour peening, and principal curvatures generally is divided into Rmax and Rmin, and wherein the very big curvature of the correspondence of Rmin is tangential curvature, and Rmax is called exhibition to radius of curvature;
2) the thickness analysis on the characteristic point: use the measurement Measure functional module of CATIA system platform can directly obtain the section thickness of wallboard everywhere.Also should carry out the thickness analysis to the reinforcement boss on the wallboard, mouthful edge edge and ultra-thin special area such as sink simultaneously.
Also can expand to that add at the adjacent rib interdigit and the some lines rib line parallel and the intersection point of long purlin axis to the selection of the characteristic point of profile complex region in the projection of wallboard outer surface.In a word, it is many more that characteristic point is selected, and is beneficial to the description to the wallboard feature more, but too much characteristic point makes analysis become too complicated again.
■ shot-peening path planning
The shot-peening path is meant when panel surfaces is carried out the selectivity contour peening, the route of nozzle or impeller motion or the track that bullet forms.The shaping law of wallboard appearance curved surface has been reflected in the shot-peening path in fact, and the profile of large-scale complicated double-curvature wallboard is shaped has decisive influence.Tradition ruled surface single-curvature external form wallboard shot-peening path can be set by constant percentage chord line, and large complicated hyperboloid external form wing wallboard, it is to be generated by a plurality of chains of command that its profile constitutes, do not have definite constant percentage chord line, how to plan that therefore the shot-peening path is the biggest problem that solves this type of wallboard contour peening.
The planning difficulty in complicated wing wallboard shot-peening path is very big, consider respectively the wallboard curvature of curved surface distribute, with reference to influence factors such as constant percentage chord line direction, thickness distribution and shot-peening path separations, the principle that generally should abide by of path planning is:
1) direction of shot-peening path curve should be as far as possible along the direction of curved surface constant percentage chord line: because complicated airfoil camber is determined consistent constant percentage chord line, all tangential control curve construction constant percentage chord lines that at first use Airfoil Design to adopt when planning shot-peening path are as the reference constant percentage chord line of this airfoil camber;
2) influenced by curved profile, tangential shot-peening path should with R in the characteristic point on the curved surface
MaxThe direction unanimity, and pass through R as far as possible
MinThe middle less point of numerical value.
3) be subjected to the wallboard thickness effect, the shot-peening path should be as far as possible by the thicker position of wallboard;
4) according to specific lathe band contour peening operational characteristic, rationally adjust the width and the distribute spacing in shot-peening path, satisfy the requirement of the nozzle or the effective shot-peening area of impeller of specific lathe.
Comprehensive above influence factor, the planning process in shot-peening path be at first to the wallboard appearance curved surface by the rib bit line, carry out grid discretization with reference to constant percentage chord line and necessary boost line, the direction of each characteristic point Rmax curvature is carried out match; According to the rule of shot-peening path planning, at first near the reference constant percentage chord line of the tangential center of wallboard, obtain a curve again, and adjust it roughly by the relative thicker position of wallboard by the Rmax radius of curvature direction match of adjacent features point; According to specific lathe band shot-peening fundamental characteristics the width of this matched curve is carried out interactive mode adjustment then, obtain first shot-peening path, referring to Fig. 1.After first paths is determined, calculate other curve according to other successively with reference to constant percentage chord line again, thereby obtain the shot-peening path that tangential curvature is shaped in these both sides, shot-peening path.
■ equal strength dividing region and definite
It is in order to adapt to the variation of wing wallboard profile curvature and thickness that the equal strength zone is divided, curved surface with this gradual change, be divided into a plurality of equal strength districts, again the theoretical shot-peening parameter of selecting this intensity region according to the average thickness and the average curvature in equal strength district with near-sighted thickness range and near-sighted curvature range.The large and super-critical wing wallboard is carried out the equal strength dividing region should follow following principle and step:
(1) with varied in thickness as principal element, divide the approximate thickness district:
According to relevant test data, when wallboard thickness was increased to 8mm by 4mm, the same curvature radius that be shaped, shot peening strength need increase near 4 times, and the thickness difference in this interval approximate thickness district is divided into suitable with 1mm-2mm; When the division of thickness pairing approximation caliper zones during greater than 8mm should reduce thickness difference at interval successively; also to divide separately for zone equally less than 4mm; the intensity level that the aluminium alloy plate of this thickness needs because be shaped is less, also needs to cover protection sometimes, and this zone is generally near wallboard wing position slightly.
(2) in the approximate thickness district be that principal element is divided the iso-curvature district with the radius of curvature:
The curvature analysis data that each characteristic point is done are foundations that the wallboard curved surface is analyzed, in two principal curvatures with tangential radius of curvature R
MinBe changed to the master.The tangential curvature R of large-scale wing wallboard
MinRadius is between 2500mm~10000mm, and it is in the majority with the tangential radius of curvature between 5000mm~8000mm, wherein focus mostly in wallboard wing position slightly less than the radius of curvature of 4000mm, this zone walls plate thickness is thinner, be easy to be shaped, therefore the wallboard radius of curvature can be divided into below the 4000mm 5000mm~6000mm, the above 4 kinds of equivalent curvature of 6000mm~8000mm and 8000mm.
(3) after the zone is divided and is finished, will be to providing equivalent plate thickness and equivalent curvature by defining thickness and radius of curvature along each zone on the shot-peening path, should be analyzed separately differing big zone with equivalent plate thickness and equivalent curvature value in each subregion, be seen whether belong in adjacent area or processing separately.
■ chordwise shot-peening forming initial technological parameter is determined
Each equivalent thickness and equivalent area of curvature with large-scale wallboard is divided into can carry out shot-peening according to identical shot-peening parameter to the same area when carrying out contour peening, so these zones can be described as the equal strength district.The arrangement own because of the zone do not have certain rule, have only this zone is reflected on the shot-peening path, can be by changing the variation that the shot-peening parameter realizes intensity, after shot-peening path and the match of equal strength district, form a kind of varying strength section, the theoretical shot-peening parameter of each intensity section is connected in series integrated chordwise shot-peening forming initial technological parameter along the shot-peening path.
Not strict precedence is divided in shot-peening path planning and wallboard equal strength zone as can be seen, if more help the optimal design of the two alternately.Different equal strength zone is divided still needs profile curvature and the thickness analysis each characteristic point of wallboard carried out in conjunction with early stage, but stresses again the shot-peening path center line planned and each rib bit line or necessary boost line are carried out curvature and thickness analysis at the intersection point of wallboard outer surface projection line.
The theoretical shot-peening parameter in each equal strength district is the infrastest data of carrying out according to same curvature radius and sheet metal thickness.For each the equal strength zone that analyzes on wallboard, what at first need to determine is the theoretical shot-peening parameter in this kind equal thickness and iso-curvature zone.Thisly both considered that mathematics curvature constituted, the practice of considering wallboard thickness again is actually to be handled wing wallboard as the physics curved surface.Because the local characteristics of testpieces there are differences when the overall permanence of wallboard workpiece and infrastest, bigger as basic test spare boundary condition and integral panel difference, theoretical shot-peening data need to adjust when carrying out wallboard integral body shot-peening, and how to be transplanted to the basic test parameter in the integral panel shaping is a key issue.
Propose in the present invention to carry out the basic test parameter to upward transplanting of integral panel shaping by changing coverage rate, can effectively reduce and change other many shot-blast process parameter and the complex nature of the problem that aggravates to be shaped, be beneficial to large-scale wallboard forming technology is designed and optimizes.
After each regional nominal shot peening strength is determined, the unique shot-peening parameter that will determine is exactly a lathe speed, because the contour peening major part is carried out under less than 100% coverage rate, so can directly change by the bullet coverage rate of spray plate surface by changing lathe speed, lathe speed is determined comparatively science of integral panel contour peening initial parameter by 20%-50% coverage rate on the used saturation curve of corresponding basic test during the band shot-peening.
Below in conjunction with the embodiment accompanying drawing this application is further described
Concrete embodiment:
ARJ21 aircraft outer wing is a supercritical airfoil, and squab panel is 1 of size maximum in the ARJ21 aircraft outer wing wallboard on it, and material is 7055T7751, and appearance and size is long 12670mm * wide 2130mm, and the cross section maximum ga(u)ge is δ 11.6mm.The product design digital-to-analogue of last squab panel is the theoretical digital-to-analogue of being set up by the parametrization designing technique with the CATIA system platform of wallboard 3D, and is as follows by the result of the step formation of the present invention to its typical position 1~10 rib:
1) table 1 shows that shot-peening path D22~D46 and rib line 6~10 can be with reference to Fig. 1 in the table to the analysis situation of two principal curvatures on the local part shot-peening of last squab panel 6~10 ribs path and the rib line intersection point and corresponding thickness.As can be seen from the table, this wallboard has complicated hyperboloid profile.
(2) shown in Figure 1 is the shot-peening path of going up the tangential curvature of squab panel, and D22~D46 is the numbering in different shot-peenings path among the figure, 1~10 expression wallboard, 1 to 10 rib bit line.The exhibition that supercritical airfoil had can just can obtain requiring shape by blowing is carried out in the certain zone of wallboard to profile after tangential profile has been shaped, the definite of these zones can obtain in calculating and analysis tangential by wallboard and that open up to deflection.
(3) shown in Figure 2 is the dividing condition that goes up squab panel 1 rib~10 rib equal strength districts behind subregion, forms a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r totally 18 equal strength zones altogether.
(4) Fig. 3 is the match of going up squab panel shot-peening path and intensity subregion.After the match, every shot-peening path is divided into different equal strength sections by the equal strength district of process, be divided into six equal strength area segments I, II, III, IV, V, VI as shot-peening path D34, integrated along this path shot-blast process parameter by the parameter serial connection of each equal strength area segments, I section wherein: air pressure 0.26Mpa, speed 7.1m/min; II section: air pressure 0.24Mpa, speed 6m/min; III section: air pressure 0.25Mpa, speed 6.5m/min; IV section: air pressure 0.25Mpa, speed 5m/min; V section: air pressure 0.27Mpa, speed 5m/min, VI section: air pressure 0.35Mpa, speed 7m/min.Principle herewith, the shot-peening parameter in each shot-peening path is integrated by each equal strength section serial connection.Lathe speed is determined integral panel contour peening initial parameter by 30% coverage rate on the used saturation curve of corresponding basic test in the enforcement.
(5) Fig. 4 is by the qualified last squab panel of this invention contour peening.
Local part typical structure point curvature of squab panel 6~10 ribs and thickness distribution table on the table 1
Illustrate: " tangential ", " exhibition to " be meant projection line on the wallboard appearance curved surface at certain intersection point place along tangential, exhibition to bending radius, unit is mm.String exhibition has shown the bending direction of projection line at this intersection point place to the positive negative value of bending radius: shape is surperficial for just bending towards in; Otherwise, for negative.