Piezoelectric Variable-Section Nozzle Actuation

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Solution Overview

Problem

Conventional actuating mechanisms for variable-section nozzles in aircraft engine nacelles, such as hydraulic or electromechanical actuators, add weight, bulk, and cost, and pose integration challenges due to their complexity.

Innovation Solution

The use of piezoelectric actuators, arranged on both sides of a movable part or end-to-end as actuating rods, with movement amplification means and control modules, allows for compact and lightweight actuation of the nozzle sections, enabling section variation through electrical voltage control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If hydraulic or electromechanical actuators are used to vary the nozzle section, then the actuation function is achieved, but the weight, bulk, and cost increase

Engineering Contradiction:
Improvenozzle section variation capabilityVSAvoidactuator weight
Core Design Contradiction:
Adaptability or versatilityVSWeight of moving object

Solution Approach 1:

The patent replaces conventional hydraulic or electromechanical actuators with piezoelectric actuators. Piezoelectric materials convert electrical voltage directly into mechanical displacement, eliminating the need for complex mechanical actuation systems. This substitution dramatically reduces the weight and bulk of the actuation system while maintaining the capability to vary the nozzle section area, directly resolving the contradiction between adaptability and weight.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent utilizes the property of piezoelectric materials to change their physical dimension (length) in response to changes in electrical voltage parameters. By applying different voltages to the piezoelectric actuators, the nozzle section area is varied without requiring heavy mechanical actuators. This parameter-based control approach enables lightweight adaptation of the nozzle geometry.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If hydraulic or electromechanical actuators are used to vary the nozzle section, then the actuation function is achieved, but the device complexity and integration difficulty increase

Engineering Contradiction:
Improvenozzle section variation capabilityVSAvoidactuator system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent replaces complex hydraulic or electromechanical actuation systems with simple piezoelectric actuators that directly convert electrical signals into mechanical motion. This substitution eliminates numerous intermediate components, fluid systems, and mechanical linkages, thereby dramatically simplifying the overall device complexity and easing integration into the nacelle structure.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The piezoelectric actuators serve multiple functions: they act as both the actuating mechanism and the control element. The same piezoelectric material that produces motion can also serve as a sensor for position feedback, reducing the need for separate sensing systems and further simplifying the overall actuation system architecture.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Weight of moving object

If piezoelectric actuators are used, then the weight and compactness are improved, but the actuation force must be sufficient for nozzle movement

Engineering Contradiction:
Improveactuator weightVSAvoidactuation force
Core Design Contradiction:
Weight of moving objectVSForce

Solution Approach 1:

The patent divides the actuation system into multiple piezoelectric actuators distributed around the nozzle structure. Rather than relying on a single large-force actuator, multiple smaller piezoelectric elements work in parallel to collectively generate the necessary actuation force. This segmentation approach maintains the lightweight advantage of piezoelectric materials while achieving sufficient total force output.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent combines multiple piezoelectric actuators to work together on a common function (varying the nozzle section). By merging the output of several actuators, the system achieves the required actuation force while maintaining the inherent weight and compactness advantages of piezoelectric technology. The combined effect of multiple small actuators equals or exceeds the force of a single conventional actuator without the associated weight penalty.

Inventive Principle:
Principle #5Merging (Combining)

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

This solution provides a lightweight, compact, and efficient means to vary the nozzle section, reducing weight and cost compared to conventional actuators while maintaining necessary actuation forces, suitable for high-bypass engines.

Implementation Method 1

piezoelectric actuators, and on the other hand means for controlling these actuators

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

piezoelectric sensors are positioned to detect the position of said moving part: one property of the piezoelectric elements is in fact that they can be used in the opposite direction

Methodology Applied
Scientific EffectConverse piezoelectric effect: Converse Piezoelectric Effect

Data Source

PatentEP2828490B1Variable-section jet pipe and aircraft turbojet engine nacelle equipped with such a jet pipe
Publication Date: 2020.02.05 SAFRAN NACELLES
  • EP2828490B1 patent drawingFigure 1~2
  • EP2828490B1 patent drawingFigure 3~4
  • EP2828490B1 patent drawingFigure 5~6

AI summary

A variable-section nozzle for an aircraft nacelle includes a deformable portion of which is movable between a narrow section position and a wide section position. In particular, the variable-section nozzle includes piezoelectric actuators and a controller to control the piezoelectric actuators in order to displace the deformable portion between the narrow and wide section positions. The piezoelectric actuators can be disposed on at least one faces of the deformable portion or be disposed end-to-end to form actuating rods.