Compartmentalized Rotor Blade Spar for Impact Energy Absorption
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Solution Overview
Problem
Conventional rotor blades face challenges in withstanding accidental impacts due to the concentration of forces and moments, leading to potential structural failure and loss of mechanical strength.
Innovation Solution
The rotor blade features a compartmentalized spar structure with a centrifugal force take-up mechanism and a torsional stress take-up envelope, comprising multiple boxes with retention belts made of unidirectional and inclined fibers, which distribute and absorb forces effectively, and an outer skin for aerodynamic continuity and impact protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional rotor blade structure is used, then the blade can be manufactured with standard design, but the blade is vulnerable to catastrophic failure when subjected to accidental impacts due to concentration of forces and moments
Solution Approach 1:
The blade is divided into multiple independent boxes (first box, second box, third box) that are arranged along the span of the blade. Each box can independently absorb impact energy through controlled deformation, preventing catastrophic failure of the entire blade structure when one box is damaged
Solution Approach 2:
The boxes are designed with predetermined deformation characteristics that allow them to absorb impact energy in a controlled manner. The structure includes energy absorption means within each box that activates upon impact, cushioning the blade against harmful forces before they can propagate through the entire structure
2Strength
If the blade structure is reinforced to withstand higher forces, then the mechanical strength is improved, but the weight of the blade increases
Solution Approach 1:
The blade employs composite material construction with fibers arranged in specific orientations within each box structure. The extrados and intrados walls are formed using composite laminates that provide high strength-to-weight ratio, maintaining mechanical strength while minimizing weight increase
Solution Approach 2:
The reinforcement is localized to specific regions where forces are concentrated. The boxes are strategically positioned at the leading edge, trailing edge, and center of the blade where structural support is most needed, rather than uniformly reinforcing the entire blade
3Reliability
If a single-box spar structure is used, then the manufacturing process is simpler, but the blade lacks redundancy and is more susceptible to catastrophic failure
Solution Approach 1:
The spar is segmented into multiple boxes (first box, second box, third box) that are distributed along the blade span. This segmentation provides structural redundancy where if one box fails, the other boxes continue to support the blade, preventing catastrophic failure
Solution Approach 2:
The boxes are nested within the blade structure with each box containing energy absorption means. The first box is positioned at the leading edge, the second box at the center, and the third box at the trailing edge, creating a nested configuration that maximizes structural efficiency
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 design enhances the blade's ability to absorb impact energy and maintain structural integrity by distributing forces across multiple boxes, reducing the risk of catastrophic failure and allowing continued performance even if one box is damaged.
Implementation Method 1
each retention belt being provided with unidirectional fibers wound around said broaching sleeve, said casing being provided with inclined fibers presenting an angle with respect to said unidirectional fibers
Implementation Method 2
the blade's ability to absorb impact energy and maintain structural integrity by distributing forces across multiple boxes
Implementation Method 3
This design enhances the blade's ability to absorb impact energy and maintain structural integrity by distributing forces across multiple boxes, reducing the risk of catastrophic failure
Data Source
Figure 1~3
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AI summary
The present invention relates to a rotor blade (1) provided with an outer coating (2) and at least one load-bearing spar (10) associated with at least one broaching sleeve (3).Each spar (10) is a compartmentalized spar comprising a centrifugal force resistor (20) inscribed in a torsional stress resistor envelope (30), said centrifugal force resistor (20) comprising at least two boxes (21, 22) each traversed by said pinning sleeve (3) of the spar (10), each box (21, 22) comprising a closed retention belt (23) extending along the span of the blade, the retention belt (23) of one box (22) surrounding the retention belt (23) of another box (21), each retention belt (23) being provided with unidirectional fibers (24) wound around said pinning sleeve (3), said envelope (30) being provided with inclined fibers (31) having an angle with respect to said unidirectional fibers (24).