Clevis-Tang Connection

The clevis-tang connection at interface between two cylindrical Segments has to ensure that under specified loading conditions an absolute tightness of the booster case to out-side, and safe and homogeneous force transmission is achieved.

The investigation of different previous designs at the beginning of the ARIANE 5 development identified a couple of the weaknesses which could be relatively easily eliminated, for example by:

• control of the gaps between the components to limit rotation in the connection

• the use of some kind of the capture device to prevent unstable conditions and excessive rotation, and

• positioning other attachments on the case away from the joint not too close to prevent possible interaction of the effects.

Furthermore, different possibilities to improve the connection, which were considered in our design, were established:

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  Reducing the difference in thickness between the connection and cylinder wall will also reduce the difference in radial elongation and corresponding joint rotation. This results in higher bearing loads for pin connection and should be compensated by a larger pin diameter or an increased number of pins.
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  If the transition in thickness is moved far away from the connection (through prolonged cones on both sides) the effect of wall relative expansion (ca 8 mm), causing rotation and higher loads at the capture device, can be controlled. The transition at the tang side is more important in this respect.

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  A capture device can control the gap opening. It can prevent any eccentric movement in the connection and helps in other less predictable situations as for example in the case of thermal and mechanical distortions.

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  Increasing the length and reducing the height of the sealing branch causes higher bending effects induced by pressure loads, acting in the opposite direction to the joint rotation.

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  Two sealing surfaces at the branch side make assembling the seal easier and more reliable. If, for example a surface scratch produces seal damage, in the case of only one seal surface the possibility of damage to both rings is very high.

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  Equal pin load distribution and reduced pin position eccentricity in the sealing branch will prevent gap opening due to the branch bending.