Aircraft Wing Rib Bead for Shear Buckling
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Solution Overview
Problem
The existing wing structure of aircrafts faces reduced buckling strength against shear loads due to stringer through holes in the rib, leading to potential deformation and shape changes under lift or drag, which cannot be adequately compensated by increasing the rib's wall thickness without adding weight.
Innovation Solution
A bead is formed on the rib extending in the vertical direction with arcuate ends surrounding the stringer through holes, enhancing the buckling strength against shear loads without increasing the rib's thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If stringer through holes are formed on the rib to allow stringers to pass through, then the wing structure can be assembled with stringers connected to the rib, but the buckling strength of the rib against shear load is reduced
Solution Approach 1:
The rib structure employs local quality enhancement by forming a bead protruding from the outer surface of the rib at the location where the stringer through hole is formed. This localized reinforcement concentrates structural strength precisely where the hole creates weakness, without requiring uniform thickening of the entire rib. The bead creates a local quality change that compensates for the strength loss at the specific critical location while maintaining overall structural efficiency.
Solution Approach 2:
The invention addresses the two-dimensional weakness created by the through hole by adding a third dimensional element - the bead protruding from the rib's outer surface. This dimensional addition creates a three-dimensional reinforcement structure that surrounds and strengthens the hole area, transforming the problem from a planar weakness to a volumetric strength enhancement that resists buckling loads more effectively.
2Strength
If the wall thickness of the rib is increased to compensate for strength reduction due to stringer through holes, then the buckling strength is improved, but the weight of the wing structure increases
Solution Approach 1:
Instead of uniformly increasing the rib's wall thickness throughout, the invention applies local quality enhancement by forming a bead only at the specific location where the stringer through hole is formed. This localized reinforcement provides the necessary buckling strength compensation precisely where the hole creates weakness, while leaving the rest of the rib at its original optimized thickness, thereby avoiding unnecessary weight increase.
Solution Approach 2:
The invention changes the geometric parameter of the rib by adding a bead with specific dimensions (protruding from the outer surface) at the critical location. This parameter change locally increases the section modulus and moment of inertia where needed, providing buckling resistance without requiring a global increase in wall thickness that would add unnecessary weight to the entire wing structure.
3Strength
If a bead extending in the vertical direction is formed on the rib to increase buckling strength, then the resistance against shear load is improved, but it is difficult to compensate for the strength reduction due to stringer through holes
Solution Approach 1:
The bead is positioned at the specific location where the stringer through hole is formed, creating local quality enhancement precisely where the strength compromise occurs. This targeted reinforcement ensures that the bead's buckling resistance capability is applied where it is most needed - at the hole location - rather than distributing reinforcement material throughout the entire rib, thereby achieving sufficient strength compensation more effectively.
Data Source
AI summary
In a wing structure for an aircraft, a rib extends in a chord direction for connecting spars to each other with upper and lower stringer through holes through which stringers of skins pass being formed in upper and lower edges of the rib. A bead is formed on the rib so as to extend between the upper and lower stringer through holes. Upper and lower ends of the bead are formed into arcuate shapes so as to surround the upper and lower stringer through holes, respectively. Thus, it is possible to enhance the buckling strength of the rib against a shear load acting on the wing of the aircraft.