Turbomachine Stator Vaned Ring Frangible Pin Design

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Solution Overview

Problem

Turbomachine outlet guide vanes experience significant mechanical stresses due to unbalance, potentially leading to damage, especially when foreign objects are ingested, and existing designs lack effective stress relief mechanisms.

Innovation Solution

A vaned ring design featuring conical seatings and frangible pins that maintain vane position under normal conditions but rupture to release stress when excessive radial force is applied, preventing damage and allowing for easy dismantling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the vane is fixed rigidly to the outer shell to maintain position stability, then the vane position stability is improved, but the vane is susceptible to damage under excessive radial compressive stress

Engineering Contradiction:

Improvevane position stabilityVSAvoidvane resistance to radial compressive stress

Core Design Contradiction:

Stability of the object's compositionVSStrength

Solution Approach 1:

The frangible pin is designed with a predetermined break point that allows it to rupture under excessive radial compressive stress, preventing damage to the vane and outer shell. This cushioning mechanism is built into the structure beforehand to absorb extreme loads that would otherwise cause catastrophic failure.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The connection system transitions from a purely rigid fixed connection to a conditional connection that changes state based on applied stress. The frangible pin maintains rigid connection under normal operating stresses but changes to a ruptured state under excessive stress, allowing the vane to be saved.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the vane is fixed securely to the outer shell to prevent displacement, then the vane fixation reliability is improved, but the structural complexity increases due to additional fastening components

Engineering Contradiction:

Improvevane fixation reliabilityVSAvoidfastening system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The fastening system is segmented into two functional components: the frangible pin that provides the primary secure fixation, and the conical seatings that provide positioning and guide the pin. This segmentation allows each component to be optimized for its specific function while maintaining overall reliability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The frangible pin acts as an intermediary element between the vane and the outer shell. It provides the necessary fixation under normal conditions but can fail safely under excessive load, mediating between the need for secure fixation and the need for stress relief.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of manufacture

If traditional through fasteners are used to fix the vane head to the outer shell, then the manufacturing simplicity is maintained, but the stress concentration and potential for vane damage occur

Engineering Contradiction:

Improvevane assembly simplicityVSAvoidstress concentration on vane

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The design converts the potentially harmful effect of stress concentration into a beneficial safety mechanism. The frangible pin is designed to rupture at a predetermined location under excessive stress, transforming what would be a catastrophic failure mode into a controlled failure that protects the vane and extends the component lifetime.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The frangible pin is designed as a sacrificial component that can be easily replaced if it ruptures. Rather than protecting the expensive vane and outer shell at all costs, the design accepts that the pin may fail under extreme conditions, providing economic protection through the use of a replaceable, lower-cost component.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Data Source

PatentUS10907489B2Vaned ring for turbomachine stator having vanes connected to an outer shell by conical seating and frangible pin

Publication Date: 2021.02.02 SAFRAN AIRCRAFT ENGINES SAS

AI summary

A vaned ring for a turbomachine stator includes an outer shell, a vane having a vane head, and two platforms arranged circumferentially on either side of the vane head, and fixed on a radially inner face of the outer shell by detachable fasteners. The vane head has first conical seatings bearing on respective second conical seatings of the two platforms so as to prevent a displacement of the vane radially inwards and along the circumferential direction. The vaned ring includes a frangible pin including a base mounted on the outer shell and a head projecting radially inwards with respect to the outer shell and having a head surface forming, vis-à-vis a top surface of the vane head, a stop opposing a displacement of the vane radially outwards.