A method for shot peening and shaping of a double-convex thin-walled area between the frame and the wall panel

Abstract

This invention discloses a method for rotary blade shot peening and straightening of a double-convex thin-walled region between a panel frame and a wall panel. The method includes: determining the deformation zone; performing chordal shot peening on the deformation zone until the double-convex thin-walled region meets delivery tolerance requirements; marking the critical points of the deformation zone in the developmental direction and connecting the critical points to form a curve; creating several equally spaced straightening lines perpendicular to the curve; measuring the developmental curvature along the straightening lines; extending the line segment between the start and end points of the non-compliant curvature area on each straightening line chordally into a straightening strip; performing developmental pre-bending; performing developmental shot peening on all the straightening strips until the double-convex thin-walled region meets delivery tolerance requirements; and performing localized chordal shot peening on local areas where the chordal curvature does not meet delivery tolerance requirements until the delivery tolerance requirements are met. Using this method for rotary blade shot peening and straightening of the double-convex thin-walled region between a panel frame and a wall panel results in high straightening efficiency and fewer straightening operations.

Description

Technical Field

[0001] This invention patent belongs to the field of aircraft manufacturing, and further to the field of wing panel shot peening forming process, specifically involving a method for shot peening and straightening of a double convex thin-walled area between the panel opening frame. Background Technology

[0002] Modern aircraft wings are becoming increasingly complex in shape, with most wing panels exhibiting both chordal and spanwise curvature. Sheet metal processing is inefficient and lacks the precision to guarantee. Therefore, shot peening is currently the common method to bend the flat sheet metal into the theoretical shape. Some wing panels have multiple continuous frames arranged in a row between the two stringers, with thickened areas at the edges and thin-walled areas between adjacent thickened areas. The thin-walled areas are as thin as 2mm, while the thickness of the thickened areas at the frame edges can be up to three times that of the thin-walled areas. Using high-pressure shot peening on the frame areas causes bulging and deformation in the thin-walled areas, while low-pressure shot peening cannot achieve the required curvature in the thickened areas. Therefore, the current method is to first use high pressure to shot peen the thickened areas, and then use low pressure to shot peen the thin-walled areas.

[0003] If the chordal and spanwise curvatures of a local area in a wall panel are in the same direction, this local area is called a biconvex region. After shot peening the thickened area of ​​the biconvex thin-walled region with high pressure, the formed thickened area exerts a "tensioning" effect on the surrounding thin-walled areas, equivalent to applying prestress to the thin-walled areas, which enhances the forming effect of the thin-walled areas. However, the central area of ​​the thin-walled area is not subjected to this "tensioning" effect, resulting in a relatively poor forming effect. After forming, the local chordal and spanwise curvatures of the central area of ​​the biconvex thin-walled region are insufficient, and shot peening correction is necessary to ensure the shape meets requirements.

[0004] Currently, rotary blade shot peening is commonly used to correct the aforementioned biconvex thin-walled regions. Because there is an interrelationship between chordal and spanwise curvature during shot peening, correcting the chordal curvature of a region will simultaneously change its spanwise curvature, and vice versa. Therefore, shot peening of these biconvex thin-walled regions requires multiple iterations to ensure that both the chordal and spanwise curvatures meet the delivery tolerance requirements. Repeated correction of the thin-walled region is not only inefficient but can also lead to localized waviness deviations and bulging deformation, severely impacting product quality and potentially causing product scrap. Summary of the Invention

[0005] The purpose of this application is to address the problem described in the background art that the local chordal curvature and spanwise curvature of the double convex thin-walled area between the wall panel frame are insufficient after shot peening, and to provide a method for correcting the shape of the double convex thin-walled area between the wall panel frame by rotary blade shot peening.

[0006] Embodiments of this application provide a method for shot peening and straightening a double-convex thin-walled region between a panel frame, comprising:

[0007] The deformation zone is determined by fitting a chordal template along the chordal direction to the outer surface of the already shot-peened biconvex thin-walled region and marking the chordal critical point of the deformation zone. A first curve is drawn along the spanning direction through the chordal critical point. A spanning template is then fitted along the spanning direction to mark the first spanning critical point of the deformation zone. A second curve is drawn along the chordal direction through the first spanning critical point. The intersection of the first curve and the second curve forms the deformation zone, which is then marked.

[0008] The deformed area is chordally shot-peened until the fitting gap between the double-convex thin-walled area and the chordal template meets the delivery tolerance requirements.

[0009] The stretching template is used to fit the deformation zone along the stretching direction, and the second stretching critical point of the deformation zone is marked. The second stretching critical point is then connected to form a third curve.

[0010] Several equal-spaced, perpendicular straightening lines are drawn on the third curve. The span curvature of the straightening lines is measured. The start and end points of the curvature non-compliant areas on each straightening line are marked. The line segment between the start and end points of the curvature non-compliant areas on each straightening line is extended along the chord direction to form a straightening strip.

[0011] After pre-bending the biconvex thin-walled area in the spanwise direction, all the correction strips are shot-peened in the spanwise direction until the fitting gap between the biconvex thin-walled area and the spanwise template meets the delivery tolerance requirements.

[0012] The chordal template is used to measure the biconvex thin-walled region. Local areas where the chordal curvature does not meet the delivery tolerance requirements are locally shot-peened until the fit gap between the biconvex thin-walled region and the chordal template meets the delivery tolerance requirements.

[0013] Preferably, the deformation zone refers to the area where the fitting gap with the template is greater than the delivery tolerance requirement when the chordal template and the spanning template are used to fit the biconvex thin-walled area.

[0014] Preferably, when performing the first chordal shot peening on the deformed area, the rotary blade shot peening machine uses a 9 / 16 inch × 1-1 / 4 inch rotary blade, a rotation speed of 6000-7000 rpm, and a coverage of 20%-30% for shot peening.

[0015] Preferably, after the first chordal shot peening of the deformed area, a chordal template is used to check the shaping effect. If the gap between the chordal template and the double-convex thin-walled area is greater than the part delivery tolerance requirement, the deformed area needs to be determined again, and the coverage size is adjusted according to the previous shaping effect for shaping, until the gap between the chordal template and the double-convex thin-walled area meets the part delivery tolerance requirement.

[0016] Preferably, when drawing a plurality of correction lines perpendicular to the third curve, if the distance between the second spanwise critical points is less than 50 mm, a correction line is drawn in the middle. If the distance between the second spanwise critical points is greater than 50 mm, a correction line is drawn at 50 mm intervals, and the distance between the correction line and the second spanwise critical point must be greater than 25 mm.

[0017] Preferably, when making the correction strip, the strip width is 20mm.

[0018] The beneficial effects of this application are as follows: 1) The deformation zone is determined by the area where the gap between the biconvex thin-walled region and the chordal and spanwise templates is greater than the delivery tolerance requirements. During chordal shot peening, the deformation zone is shot peened, making reasonable use of the mutual influence between the chordal and spanwise curvatures during thin-walled region shaping. Simultaneously with chordal shot peening, part of the spanwise shape is corrected, reducing the number of shaping operations and improving shaping efficiency. 2) During spanwise shot peening, the shaping strips distributed along the chordal direction are shot peened under spanwise pre-bending conditions. This effectively suppresses the mutual influence between the chordal and spanwise curvatures during biconvex thin-walled region shaping. While correcting the spanwise curvature, the change in chordal curvature is suppressed, avoiding large-area non-compliance in the chordal shape after spanwise shaping, thus preventing repeated shaping. 3) When performing tangential shot peening for correction, use a 9 / 16-inch × 1-1 / 4-inch rotary blade at a speed of 6000-7000 rpm and a coverage of 20%-30%. This effectively corrects the curvature of the thin-walled area and reveals the sensitivity of the thin-walled area's curvature changes to rotary blade shot peening. This avoids blindly selecting shot peening parameters, which could lead to bulging deformation in the thin-walled area. 4) Distribute a 20mm wide correction strip evenly every 50mm along the spanwise direction. This reduces the impact of spanwise correction on the spanwise waviness of the thin-walled area, improving its overall shape quality. Using this method for rotary blade shot peening correction of the double-convex thin-walled area between the panel frame and the wall panel results in high correction efficiency and fewer correction cycles. This avoids the increased risk of localized bulging deformation and waviness exceeding tolerances caused by repeated corrections in the double-convex thin-walled area, effectively ensuring product quality.

[0019] The method will be described in further detail below with reference to the embodiments and accompanying drawings. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the inner surface structure of the double-convex thin-walled region between the wall panel frame.

[0021] Figure 2 A schematic diagram of the chordal template fitting the outer surface of the thin-walled region when marking the deformation zone.

[0022] Figure 3 For along Figure 2 A cross-sectional view of line A-A in the middle.

[0023] Figure 4 A schematic diagram of the stretching template fitting the outer surface of the thin-walled region when marking the deformation zone.

[0024] Figure 5 For along Figure 4 A cross-sectional view along line B-B in the middle.

[0025] Figure 6 This is a schematic diagram of the deformation zone on the outer surface of the wall panel.

[0026] Figure 7 This is a schematic diagram of the second deformation zone on the outer surface of the wall panel.

[0027] Figure 8 A schematic diagram of the stretching template adhering to the outer surface of the thin-walled area when marking the alignment strip.

[0028] Figure 9 This is a schematic diagram of the alignment strip markings.

[0029] Figure 10 A schematic diagram of spanwise prestressing.

[0030] The numbering in the diagram is as follows: 1. Wall panel; 2. Frame No. 1; 3. Thin-walled area; 4. Frame No. 2; 5. Thickened area No. 1; 6. Thickened area No. 2; 7. Chord template; 8. Chord critical point No. 1; 9. Chord critical point No. 2; 10. First curve No. 1; 11. First curve No. 2; 12. Span template; 13. First span critical point No. 1; 14. First span critical point No. 2; 15. Second curve No. 1; 16. Second curve No. 2; 17. Deformation area; 18. Deformation area II; 19. Second span critical point No. 1; 20. Second span critical point No. 2; 21. Third curve; 22. Correction line No. 1; 23. Correction line No. 2; 24. Correction strip No. 1; 25. Correction strip No. 2; 26. Three-point pre-bending fixture; 27. Stress point No. 1; 28. Stress point No. 2; 29. ​​Force application point. Detailed Implementation

[0031] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0032] The purpose of this invention is to provide a method for shot peening and straightening a double-convex thin-walled area between the opening and frame of a wall panel, which can solve the problem of insufficient local chordal curvature and spanwise curvature after shot peening of the double-convex thin-walled area between the opening and frame of the wall panel.

[0033] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] Figure 1 The wall panel 1 shown has a first frame 2 and a second frame 4. The edges of the first frame 2 and the second frame 4 have a first thickened area 5 and a second thickened area 6, respectively. A thin-walled area 3 is located between the first thickened area 5 and the second thickened area 6. After shot peening, the local chordal curvature and spanwise curvature of the thin-walled area 3 are insufficient, failing to meet the delivery tolerance requirement that the gap between the wall panel's shape and the template after shot peening be less than or equal to 0.5 mm. Taking the rotary blade shot peening correction of the thin-walled area 3 as an example, the specific implementation of this method is further illustrated.

[0035] Step 1: Determine the deformation zone

[0036] Step 1.1: Fabricate a chordal template 7 based on the chordal shape at the center of the outer surface of the thin-walled region 3. To facilitate determining the template position when measuring the chordal shape, extend the length of the chordal template 7 to cover the entire chordal area. Determine the fitting position during measurement based on the edge line of the wall panel 1 and the corresponding engraved lines on the chordal template 7. Fit the chordal template 7 against the outer surface of the thin-walled region 3, as follows: Figure 2 As shown. Measure the fitting gap between the chordal template 7 and the outer surface of the thin-walled region 3. Mark the first chordal critical point 8 and the second chordal critical point 9, where the fitting gap is greater than 0.5 mm, on the outer surface of the thin-walled region 3 with a marker pen, as shown. Figure 3 As shown. Draw the first curve 10 along the span direction from the first chordal critical point 8, and draw the second curve 11 along the span direction from the second chordal critical point 9, as shown. Figure 6 As shown.

[0037] Step 1.2: Fabricate a spanning template 12 based on the spanning profile at the center of the outer surface of the thin-walled region 3. To facilitate determining the template position when measuring the spanning profile, the spanning template 12 is enlarged to fit the first frame 2 and the second frame 4. The fitting position during measurement is determined based on the edge lines of the frames and the corresponding engraving lines on the spanning template 12. The spanning template 12 is then fitted to the outer surface of the thin-walled region 3, as follows: Figure 4 As shown. The fit gap between the spanwise template 12 and the outer surface of the thin-walled region 3 is measured. The first spanwise critical point 13 and the second spanwise critical point 14, with a fit gap greater than 0.5 mm, are marked on the outer surface of the thin-walled region 3 with a marker pen, as shown. Figure 5 As shown. Draw the first second curve 15 along the chord direction through the first spanwise critical point 13, and draw the second second curve 16 along the chord direction through the second first spanwise critical point 14, as shown. Figure 6 As shown.

[0038] Step 1.3: First curve 10, first curve 11, second curve 15, and second curve 16 intersect on the outer surface of thin-walled region 3 to form deformation region 17. Mark deformation region 17 on the outer surface of thin-walled region 3, as follows: Figure 6 As shown.

[0039] Step 2: Wire-direction shot peening and shaping

[0040] Step 2.1: The rotary blade shot peening machine uses a 9 / 16 inch × 1-1 / 4 inch rotary blade and a rotation speed of 6500 rpm to uniformly shot peen the deformation zone 17 on the outer surface of the thin-walled zone 3 once with a coverage of 20% to 30%.

[0041] Step 2.2: Use the chordal template 7 to check the shaping effect against the outer surface of the thin-walled area 3. The gap between the chordal template 7 and the outer surface of the thin-walled area 3 is still greater than 0.5mm. Determine the deformation zone 2 18 according to the method in Step 1, such as... Figure 7 Because the increase in chordal curvature of deformation zone 17 caused by chordal shot peening in step 2.1 is greater than the expected increase in chordal curvature of deformation zone 18 in this correction, a shot peening operation of 6500 rpm with a coverage of 10%–20% was performed on deformation zone 18. After shot peening, the gap between the chordal template 7 and the outer surface of the thin-walled zone 3 is less than or equal to 0.5 mm. The chordal shot peening correction is now complete.

[0042] Step 3: Mark the alignment strips

[0043] Note: If the gap between a portion of the thin-walled region 3 and the spanning template 12 is greater than 0.5 mm, while the gaps between its two sides and the spanning template are less than or equal to 0.5 mm, it indicates that the spanning curvature of the thin-walled region 3 is insufficient. In this case, a correction strip is marked on the outer surface of the thin-walled region 3. If a portion of the thin-walled region 3 is completely fitted with the spanning template 12, while the gaps between its two sides and the spanning template 12 are greater than 0.5 mm, it indicates that the spanning curvature of the thin-walled region 3 is excessive. In this case, a correction strip is marked on the inner surface of the thin-walled region 3.

[0044] Step 3.1: The spanwise template 12 is fitted against the outer surface of the thin-walled region 3. The gap between the outer surface of the thin-walled region 3 and the spanwise template 12 is greater than 0.5 mm in some areas, while the gaps on both sides are less than or equal to 0.5 mm, indicating insufficient spanwise curvature in the thin-walled region 3. Mark the first second spanwise critical point 19 and the second second spanwise critical point 20 on the outer surface of the thin-walled region 3, where the gap is greater than 0.5 mm. Figure 8Connect the first second spanwise critical point 19 and the second second spanwise critical point 20 to form the third curve 21. The distance between the first second spanwise critical point 19 and the second second second spanwise critical point 20 is 106 mm. Perpendicular to the third curve 21, the first correction line 22 and the second correction line 23 can be drawn, as shown below. Figure 9 .

[0045] Step 3.2: Adjust the curvature meter span to 100mm. Use the curvature meter to move along calibration lines 22 and 23 respectively to measure the spanwise arc height value and observe the change in the spanwise arc height value. The area where the difference between the spanwise arc height value and the theoretical spanwise arc height value is greater than 0.5mm is the area where the spanwise curvature is unqualified. Extend the line segment between the start and end points of the area where the spanwise curvature is unqualified on each calibration line into a strip area with a width of 20mm, to obtain calibration strip 24 and calibration strip 25, as shown. Figure 9 Marked on the outer surface of thin-walled region 3.

[0046] Step 4: Spread shot peening and shaping

[0047] Step 4.1: Apply spanwise prestress to the thin-walled region 3 using the three-point pre-bending fixture 26. The actual spanwise radius of curvature at the application point 29 on the thin-walled region 3 is half of the theoretical radius of curvature at the application point 29. The first application point 27 is located in the first thickened region 5, the second application point 28 is located in the second thickened region 6, and the application point 29 is located between the first shaping strip 24 and the second shaping strip 25. Figure 10 Using a rotary vane shot peening machine, at a speed of 6000 rpm, shot peening strips 24 (No. 1) and 25 (No. 2) with a coverage rate of 20% to 30% was performed once.

[0048] Step 4.2: Use the spanning template 12 to check the shaping effect. The gap between the spanning template 12 and the outer surface of the thin-walled area 3 should be less than or equal to 0.5 mm. The spanning shot peening shaping is complete.

[0049] Step 5: Local shot peening and reshaping

[0050] Step 5.1: Use the chordal template 7 to fit against the outer surface of the thin-walled region 3 and check the fitting gap. The outer surface of the thin-walled region 3 is partially completely fitted with the chordal template 7, but the gaps on both sides are greater than 0.5mm. This indicates that the chordal curvature of the local fitting area between the outer surface of the thin-walled region 3 and the chordal template 7 is too large. Mark the local fitting area between the outer surface of the thin-walled region 3 and the chordal template 7 on the inner surface of the thin-walled region 3 as a local correction area.

[0051] Step 5.2: Using a rotary vane shot peening machine at a speed of 6000 rpm, gradually expand the shot peening area from the center of the local correction area towards the edge area with a coverage rate of 10% to 20%. Do not perform large-area shot peening at once. During the correction process, check the fitting gap with the chordal template 7 in a timely manner to avoid over-correction. The local correction area can be appropriately expanded until the fitting gap between the chordal template 7 and the outer surface of the thin-walled area 3 is less than or equal to 0.5 mm.

[0052] Step 5.3: Use the spanning template 12 to fit against the outer surface of the thin-walled region 3, and measure the fitting gap between the spanning template 12 and the outer surface of the thin-walled region 3. The fitting gap should be less than or equal to 0.5 mm. At this point, the fitting gaps between the chordal template 7 and the spanning template 12 and the outer surface of the thin-walled region 3 are both less than or equal to 0.5 mm, and the forming is complete.

[0053] This specification uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A method for shot peening and shaping a double-convex thin-walled region between the frame and the opening of a wall panel, characterized in that... include: The deformation zone is defined as the area where the gap between the template and the biconvex thin-walled region is greater than the delivery tolerance requirement when the template is applied to the biconvex thin-walled region using chordal and spanning templates. The chordal template is applied to the outer surface of the biconvex thin-walled region after shot peening along the chordal direction, and the chordal critical point of the deformation zone is marked. A first curve is drawn along the spanning direction through the chordal critical point. The spanning template is applied to the outer surface of the biconvex thin-walled region after shot peening along the spanning direction, and the first spanning critical point of the deformation zone is marked. A second curve is drawn along the chordal direction through the first spanning critical point. The intersection of the first curve and the second curve forms the deformation zone, which is then marked. The deformed area is chordally shot-peened until the fitting gap between the double-convex thin-walled area and the chordal template meets the delivery tolerance requirements. The stretching template is used to fit the deformation zone along the stretching direction, and the second stretching critical point of the deformation zone is marked. The second stretching critical point is then connected to form a third curve. Several alignment lines perpendicular to the third curve are drawn at equal intervals. The span curvature of the alignment lines is measured. The start and end points of the unqualified curvature areas on each alignment line are marked. The line segments between the start and end points of the unqualified curvature areas on each alignment line are extended along the chord direction to form an alignment strip. When drawing several alignment lines perpendicular to the third curve, if the distance between the second span critical points is less than 50 mm, an alignment line is drawn in the middle. If the distance between the second span critical points is greater than 50 mm, an alignment line is drawn at 50 mm intervals. The distance between the alignment line and the second span critical point must be greater than 25 mm. After pre-bending the biconvex thin-walled area in the spanwise direction, all the correction strips are shot-peened in the spanwise direction until the fitting gap between the biconvex thin-walled area and the spanwise template meets the delivery tolerance requirements. The chordal template is used to measure the biconvex thin-walled region. Local areas where the chordal curvature does not meet the delivery tolerance requirements are locally shot-peened until the fit gap between the biconvex thin-walled region and the chordal template meets the delivery tolerance requirements.

2. The method for shot peening and shaping of the double-convex thin-walled area between the frame and the wall panel according to claim 1, characterized in that... When performing the first chordal shot peening correction on the deformed area, the rotary vane shot peening machine uses a 9 / 16-inch × 1-1 / 4-inch rotary vane, a rotation speed of 6000-7000 rpm, and a coverage of 20%-30% for shot peening.

3. The method for shot peening and shaping of the double-convex thin-walled area between the frame and the wall panel according to claim 1, characterized in that... After the first chordal shot peening of the deformed area, a chordal template is used to check the shaping effect. If the gap between the chordal template and the double-convex thin-walled area is greater than the part delivery tolerance, the deformed area needs to be determined again. The coverage is adjusted according to the previous shaping effect until the gap between the chordal template and the double-convex thin-walled area meets the part delivery tolerance.

4. The method for shot peening and shaping of the double-convex thin-walled area between the frame and the wall panel according to claim 1, characterized in that... When making the calibration strip, the strip width is 20mm.

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