| 摘要 |
A sheet of material ( 111 ) having a plurality of bend-inducing structures ( 113 ) configured and positioned to produce bending along a bend line ( 115 ). The bend-inducing structures ( 113 ) have arcuate return portions ( 122 ) extending from opposite ends ( 121 ) back along the bend-inducing structures ( 113 ) toward the other return portion ( 122 ) and each return portion ( 122 ) has a length dimension and a radius of curvature reducing stress concentrations. Preferably, the length dimension of the arcuate return portion ( 122 ) is in excess of twice the thickness. The lateral distance, LD, to which the bend-inducing structures ( 113 ) is formed in the sheet away from the bend line ( 115 ) is preferably minimized by small radius arcs ( 125 ) which connect the return portions ( 122 ) to the remainder of the bend-inducing structures ( 113 ). A method of forming a structure ( 131 ) from a sheet of material ( 111 ) to resist cyclical loading is also disclosed, as is a method to increase the fatigue resistance of a structure ( 131 ) formed by bending a sheet of material ( 111 ) along a bend line ( 115 ) having a plurality of bend-inducing structures ( 113 ). |
