Crack-propagation preventing structure, method for preventing crack propagation, crack-propagation preventing apparatus, and method for producing skin panel for aircraft
a technology of crack propagation and preventing structure, applied in the field of crack propagation preventing structure, crack propagation preventing apparatus, method for preventing crack propagation, etc., can solve the problems of over-known techniques, insufficient suppression or preventing crack propagation of cold working, and insufficient suppression of crack propagation. , to achieve the effect of preventing crack propagation
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first embodiment
[0059] a crack-propagation preventing structure shown in FIGS. 1A and 1B suppresses or prevents the propagation of a crack 2 generated in a metal component 1, such as the above-described skin panel 11. In this structure, an appropriate position on the surface of the metal component 1, which is subjected to crack-propagation prevention processing, is pressed under a load F with a rigid sphere 3 serving as a rigid body. Thereby, a point dimple 4 is provided so that the surface of the metal component 1 is dented substantially in the form of a hemisphere. This point dimple 4, which is formed by a local plastic deformation of the metal component 1, is appropriately provided near the tip of the crack 2, since the crack usually linearly propagates. FIG. 8 shows an example of the relationship between the dimple diameter d and the load F applied to the rigid sphere 3. As shown in FIG. 8, as the load F increases, the dimple diameter d due to the plastic deformation also increases.
[0060] Regar...
second embodiment
[0063] In a crack-propagation preventing structure shown in FIGS. 2A and 2B, instead of the point dimple 4 formed using the rigid sphere 3, a continuous linear dimple 4A is formed using a roller 3A as a rigid body. In this case, when the roller 3A is pressed at an appropriate position in the vicinity of a crack 2 and is moved in the direction shown by the arrow 5a6l , the linear dimple 4A is formed while the roller 3A is rotated as shown by the arrow 5b. For example, as shown in FIG. 2A, the linear dimple 4A is formed so as to intersect the extension of the propagation direction of the crack 2.
[0064] In this crack-propagation preventing structure, the linear dimple 4A, which is formed simply by plastic deformation processing without increasing the weight, is provided on the extension of the crack 2. Consequently, the plastic deformation is occurred in the linear dimple, and the compressive residual stress is induced in the dimple and the vicinity area, and thus the propagation of th...
third embodiment
[0066] shown in FIG. 4, in a newly produced body 10 having a rivet structure, point dimples 4 are formed in advance at appropriate positions of a skin panel 11. In this case, on the skin panel 11, which is surrounded by frames. 12 and stringers 13, a large number of point dimples 4 are arranged with a predetermined pitch in the directions parallel to the frames 12 and the stringers 13. In the example shown in the figure, the point dimples 4 are linearly arranged from one end to the other end so as to form two lines in each of the horizontal direction and the vertical direction in a grid, but the arrangement is not limited thereto.
[0067] By forming such point dimples 4 in advance, the propagation of a crack 2 that is generated at an unpredictable position after commencing use can be minimized.
[0068] Specifically, for example, when cracks 2a and 2c are generated in the direction perpendicular to the frames 12 and the cracks 2a and 2c propagate, since a large number of the point dimp...
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Abstract
Description
Claims
Application Information
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