Crack-propagation preventing structure, method for preventing crack propagation, crack-propagation preventing apparatus, and method for producing skin panel for aircraft

Abstract

A crack-propagation preventing structure that can suppress or prevent the propagation of cracks that would be generated in a metal component or that have been generated in a metal component is provided. The crack-propagation preventing structure includes a point dimple formed by pressing a rigid sphere of a rigid body at an appropriate position on the surface of a metal component, which is subjected to crack-propagation prevention processing.

1 . A crack-propagation preventing structure comprising: 
 a dimple formed by pressing a rigid body at an appropriate position on the surface of a metal component, which is subjected to crack-propagation prevention processing.    
     
     
         2 . The crack-propagation preventing structure according to  claim 1 , wherein the dimple is disposed at at least one position in the form of a point.  
     
     
         3 . The crack-propagation preventing structure according to  claim 1 , wherein the dimple is disposed in the form of a continuous line.  
     
     
         4 . A method for preventing crack propagation comprising forming a dimple by pressing a rigid body at an appropriate position on the surface of a metal component, which is subjected to crack-propagation prevention processing.  
     
     
         5 . The method for preventing crack propagation according to  claim 4 , wherein the dimple is formed in the form of a point or in the form of a line.  
     
     
         6 . The method for preventing crack propagation according to  claim 4 , wherein the dimple is formed near the tip of a crack generated on the surface of the metal component.  
     
     
         7 . The method for preventing crack propagation according to  claim 6 , wherein the dimple is formed on an extension of the crack or a pair of the dimples are formed so as to sandwich the extension.  
     
     
         8 . A crack-propagation preventing apparatus for forming a dimple by pressing a rigid body at an appropriate position on the surface of a metal component, which is subjected to crack-propagation prevention processing, the apparatus comprising: 
 an indenter part serving as the rigid body that is pressed on the surface of the metal component to apply a compressive load;    a control part that detects the magnitude of the compressive load and that adjusts the compressive load; and    a load-generating part for pressing the indenter part on the surface of the metal component.    
     
     
         9 . A method for producing a skin panel for an aircraft, comprising forming a dimple by pressing a rigid body at an appropriate position on the surface of an aircraft skin panel, which is subjected to crack-propagation prevention processing.