Viscoelastic Damping Ring for Turbomachine Stator Vane Pivot
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Solution Overview
Problem
High vibration levels in high-power engines cause cracks in the triple connection radius zones of variable pitch stator vanes, leading to structural weakening and potential blade breakage.
Innovation Solution
A vibration damping ring is designed to be mounted around the pivot of the variable pitch stator vane, comprising a rigid external shroud and a flexible viscoelastic internal part, which secures to the pivot rod and absorbs vibrations, allowing for rotation while dissipating mechanical energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high-power engines are used to improve power output, then power increases, but vibration levels increase causing cracks in the triple connection radius zones
Solution Approach 1:
The patent applies viscoelastic material in the damping ring to convert harmful vibrations into beneficial energy dissipation through hysteresis damping. The viscoelastic material absorbs vibrational energy and dissipates it as heat, transforming the harmful vibration effect into a protective damping function that prevents crack formation in the triple connection radius zones
2Object-affected harmful factors
If a damping ring with viscoelastic material is added to reduce vibrations, then vibration damping improves, but device complexity increases
Solution Approach 1:
The damping ring is nested within the existing bearing structure, with the viscoelastic material positioned between the pivot rod and the bearing outer race. This nested configuration allows the damping function to be integrated into the existing bearing assembly without requiring separate mounting operations or additional external components, thereby minimizing the increase in device complexity while achieving effective vibration reduction
3Ease of operation
If the pivot rod rotates freely in the bearing, then rotation smoothness improves, but vibration transmission increases causing structural cracks
Solution Approach 1:
The viscoelastic material in the damping ring acts as an intermediary element between the rotating pivot rod and the stationary bearing housing. This intermediary layer provides the necessary rotational interface while simultaneously filtering and dissipating vibrational energy, allowing smooth rotation to occur without transmitting harmful vibrations to the bearing structure and preventing crack formation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The damping ring effectively reduces vibrations within the vane, preventing cracks and ensuring structural integrity by absorbing and dissipating energy, thus enhancing the durability of the variable pitch stator vanes.
Implementation Method 1
an internal part solidly connected to the external part and ensuring a damping function... The material of the hollow cylindrical part is a viscoelastic material... which absorbs vibrations, allowing for rotation while dissipating mechanical energy
Data Source
AI summary
A bearing for a turbomachine variable pitch stator vane pivot mounted in a bore of a casing of the turbomachine and including a bushing integral with the bore and allowing rotation of a pivot rod within the casing, and additionally a ring mounted so as to be integral with the pivot rod inside the bushing and including an outer part providing the stiffening of the ring and an inner part integral with the outer part and providing a damping function.