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Centre Joint Concept for a Torsion Box

IP.com Disclosure Number: IPCOM000236499D
Publication Date: 2014-Apr-30
Document File: 2 page(s) / 205K

Publishing Venue

The IP.com Prior Art Database

Abstract

For HTPs in which the upper and lower covers are continuous along the span of the HTP, a new solution for a central joint is proposed. This invention is applicable to any lifting surface even though the example illustrated is based on a horizontal stabiliser design. The invention proposes a torsion box joint concept that replaces the mentioned I-shape central rib. This centre box joint has a square-shape and lower and upper walls whose shape must adapt to the curvature of the skin right at the centre of the box

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Centre Joint Concept for a Torsion Box

PRIOR ART

Traditionally, horizontal stabilizer (HTP from now onwards) torsion boxes are joined by means of a central "I" shaped rib. In the case of CFRP torsion boxes, the rib, which is made of CFRP, may suffer mainly of delamination and corner disbonding problems due to its shape and the material it is made of. The configuration cover-rib produces a poor load transfer right at the symmetric axis of the HTP where there is a high peak of stress concentration.

Moreover, the HTP curvature poses a major problem when it comes to manufacturing the skin, the rib, the spars and the stringers.

INVENTION

For HTPs in which the upper and lower covers are continuous along the span of the HTP, a new solution for a central joint is proposed. This invention is applicable to any lifting surface even though the example illustrated is based on a horizontal stabiliser design.

The invention proposes a torsion box joint concept that replaces the mentioned I-shape central rib.

This centre box joint has a square-shape and lower and upper walls whose shape must adapt to the curvature of the skin right at the centre of the box (see Figure 1).

The lateral walls may improve the stiffness of the structure in the chord wise direction.

This concept is structurally designed so as to step on the feet of the stringer run outs. Therefore, it box has the possibility to be attached to the stringer run outs by means of fasteners.

This configuration provides an...