Rotor Blade Damping for Impact Energy Absorption

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Solution Overview

Problem

Conventional rotor blades suffer significant damage and structural issues upon impact due to residual deformation of the fairing and working shell, leading to delamination and damage to electrical deicing devices, which are also prone to heat-related damage.

Innovation Solution

Incorporation of flexible damping materials within the blade's structure, including first and second damper means with meltable properties and embedded electrical connections, to absorb impact energy and protect both the structural integrity and electrical components, allowing for controlled deformation and easy access for maintenance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a rigid working shell and fairing are used to protect the blade, then structural strength is improved, but damage propagation and delamination occur upon impact

Engineering Contradiction:

Improvestructural strengthVSAvoiddamage resistance

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent applies beforehand cushioning by placing a compressible foam material between the fairing and the working shell. This cushioning layer is pre-installed to absorb impact energy before it reaches the rigid working shell, preventing residual deformation and delamination that would occur with rigid structures alone. The foam material is specifically positioned to cushion the leading-edge zone where impacts are most likely to occur.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent employs composite materials by combining the rigid working shell (made of composite material with fibers and matrix) with the compressible foam material. This creates a composite structure that benefits from both the strength of the rigid shell and the energy-absorbing properties of the foam, resolving the contradiction between structural strength and impact damage resistance.

Inventive Principle:

Principle #40Composite materials

2Adaptability or versatility

If electrical deicing devices are integrated into the fairing, then deicing functionality is improved, but electrical connections become vulnerable to heat damage

Engineering Contradiction:

Improvedeicing functionalityVSAvoidelectrical connection integrity

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The compressible foam material serves as an intermediary between the electrical deicing devices and the external environment. It provides thermal insulation that protects the electrical connections from heat damage while still allowing the deicing functionality to operate. The foam acts as a protective barrier that mediates between the electrical components and the harsh operational conditions.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If the fairing is made rigid to protect against impacts, then protection capability is improved, but residual deformation occurs upon impact

Engineering Contradiction:

Improveimpact protectionVSAvoidstructural stability

Core Design Contradiction:

Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The rigid fairing is combined with a compressible foam material that provides beforehand cushioning. The foam is positioned between the fairing and the working shell to absorb impact energy before it transfers to the rigid structures. This prevents residual deformation of the fairing and working shell while maintaining their protective function.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 solution effectively limits damage to the blade by absorbing impact energy and preventing electrical connection breakage, while enabling easy access for repair by heating the damping material, thus enhancing the blade's vulnerability reduction and maintenance capabilities.

Implementation Method 1

first damper means firstly provided with damping material and secondly arranged in an outer space extending between the central part of the fairing and the central portion of the shell

Methodology Applied

Scientific EffectDamping: Damping

Implementation Method 2

the damping material being meltable at a temperature higher than a first predetermined temperature

Methodology Applied

Scientific EffectMelting: Melting

Data Source

PatentUS9011102B2Blade with minimized vulnerability

Publication Date: 2015.04.21 EUROCOPTER FRANCE SA

AI summary

A blade (1) having a working shell (10) defining an inner space (16). The blade has a leading-edge space (31) and at least one filler means (40, 50) in said inner space (16) and a leading-edge fairing (20) protecting the working shell (10). The fairing (20) extends from a pressure-side part (21) to a suction-side part (22) via a central part (23). The working shell (10) has in the first zone (13): a pressure-side portion (131), a central portion (133), and a suction-side portion (132). The pressure-side portion (131) is secured to the pressure-side part (21). The suction-side portion (132) is secured to the suction-side part (22). The blade (10) includes first damper means (60) with damping material.