Structural element

Abstract

A structural element ( 1, 20, 30, 40 ) comprises a web ( 2 ) extending between a pair of flanges ( 3, 4 ). The areas of particular structural importance are the portions ( 5, 6 ) of the web and flanges adjacent to the junction between the web and the flanges. Material is gathered into these structurally important areas of an otherwise thin component. This is achieved by providing a plurality of small ribs ( 10 ) to absorb the material in these structurally important areas ( 5, 6 ). The ribs ( 10 ) are on a pitch of 2 to 8 times the wall thickness t. The pitch is approximately the same as a typical self drilling, self tapping fastener to prevent skating of the fastener, on fixing. The ribs ( 10 ) are of a depth of between 1.5t and 3.0t, where t is the metal thickness. These parameters ensure that in terms of fixing, the ribs allow a fastening screw to be used and to perform in the same manner as with a flat faced flange or web.

1 . A structural element comprising a web and at least one flange extending from the web, the element comprising a plurality of curved stiffening ribs extending along the longitudinal length of the element, the ribs being formed in the structural element at regions of structural importance of the element without substantially reducing the wall thickness, the pitch of the ribs being from 2 to 8 times the wall thickness of the structural element.  
   
   
       2 . A structural element as claimed in  claim 1  wherein the pitch of the ribs is from 3 to 7 times the wall thickness of the structural element.  
   
   
       3 . A structural element as claimed in  claim 1  wherein the pitch of the ribs is from 3 mm to 8 mm.  
   
   
       4 . A structural element as claimed in  claim 1  wherein the pitch of the ribs is from 3.8 mm to 7.8 mm.  
   
   
       5 . A structural element as claimed in  claim 1  wherein the depth of the ribs is from 1.5 to 3 times the wall thickness of the structural element.  
   
   
       6 . A structural element as claimed in  claim 1  wherein the bend radius of the ribs is from 0.5 to 3 times the wall thickness of the structural element.  
   
   
       7 . A structural element as claimed in  claim 6  wherein the bend radius of the ribs is substantially equal to the wall thickness of the structural element.  
   
   
       8 . A structural element as claimed in  claim 1  wherein the rib has a bottom radius which subtends an arc of between 20° and 128°.  
   
   
       9 . A structural element as claimed in  claim 8  wherein the radius subtends an arc of between 70° and 100°.  
   
   
       10 . A structural element as claimed in  claim 1  wherein the structural element comprises a pair of flanges and the web extends between the flanges.  
   
   
       11 . A structural element as claimed in  claim 1  wherein the ribs are provided in the or each flange of the structural element.  
   
   
       12 . A structural element as claimed in  claim 1  wherein the ribs are provided on the web of the structural element.  
   
   
       13 . A structural element as claimed in  claim 1  wherein the ribs are provided adjacent a corner portion between the web and at least one of the flanges.  
   
   
       14 . A structural element as claimed in  claim 13  wherein the ribs are provided adjacent corner portions between the web and the flanges.  
   
   
       15 . A structural element as claimed in  claim 1  wherein the flanges extend from the web in the same direction.  
   
   
       16 . A structural element as claimed in  claim 1  wherein the flanges extend from the web in opposite directions.  
   
   
       17 . A structural element as claimed in  claim 1  wherein the web is substantially straight.  
   
   
       18 . A structural element as claimed in  claim 1  wherein the web has one or more bends therein.