Thermoplastic-Beam Rotary Blade with RTM-Bonded Fibrous Shell
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing composite blades for aircraft are heavy, costly to manufacture, and have low impact strength due to the use of thermoset resins, which are irreversible and require long cure times, leading to inefficient production and the need for entire blade replacement upon damage.
Innovation Solution
Aircraft blades made with thermoplastic structural beams, a fibrous shell, and a filler material, using Resin Transfer Molding (RTM) to integrate a thermoset resin, allowing for faster production and repairability, with improved impact strength and weight-to-strength ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thermoset resin is used for composite blades, then strength and creep resistance are improved, but manufacturing time increases and repairability decreases
Solution Approach 1:
The blade is divided into multiple components: thermoplastic structural beams, filler material, fibrous reinforcement layers, and thermoset resin matrix. These segments are manufactured separately and then assembled through RTM, allowing parallel production and reducing overall manufacturing time while maintaining the strength benefits of thermoset composites.
Solution Approach 2:
The thermoplastic structural beams and filler material are pre-formed and assembled into a core structure before the RTM process. This preliminary preparation allows the time-consuming curing process to occur during the final resin injection stage rather than requiring extended cure times throughout the entire manufacturing process.
2Strength
If thermoset resin is used for composite blades, then strength is improved, but ease of repair worsens due to irreversible setting
Solution Approach 1:
By segmenting the blade into thermoplastic beams and thermoset resin matrix, the design allows the thermoplastic components to be removed, replaced, or repaired independently. The thermoset resin provides the necessary strength while the modular structure enables targeted repairs without scrapping the entire blade.
Solution Approach 2:
The design facilitates selective replacement of damaged components. If a thermoplastic beam or filler section is damaged, only that specific segment needs to be removed and replaced, while the remaining thermoset resin structure is retained and reused, reducing material waste and repair costs.
3Strength
If traditional composite manufacturing is used, then blade strength is achieved, but productivity decreases due to long cure times
Solution Approach 1:
The blade manufacturing process is segmented into independent stages: thermoplastic beam formation, filler assembly, fibrous layer application, and final RTM curing. This segmentation enables parallel processing of different blade components and eliminates the need for extended cure times across the entire structure, significantly improving productivity.
Solution Approach 2:
The RTM process uses controlled resin injection parameters and optimized curing conditions to reduce the effective cure time. By adjusting temperature, pressure, and resin flow rate parameters during RTM, the manufacturing process achieves full strength development in shorter time compared to traditional layup and cure methods.
4Weight of moving object
If thermoset composite blades are used, then weight to strength ratio is improved, but impact strength decreases
Solution Approach 1:
The blade employs a multi-material composite structure combining thermoplastic materials for structural beams, foam or honeycomb filler material for core support, fibrous reinforcement layers for tensile strength, and thermoset resin matrix for binding. This composite approach achieves superior impact resistance while maintaining light weight, as each material contributes its optimal properties to the overall blade performance.
Solution Approach 2:
Different regions of the blade use different materials optimized for their specific functions: thermoplastic beams provide local structural support and impact absorption, filler material provides core rigidity, fibrous layers provide tensile strength, and thermoset resin provides matrix binding. This localized material optimization achieves high impact strength without compromising the overall weight-to-strength ratio.
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 provides lighter, stronger blades with enhanced impact resistance and faster manufacturing, enabling efficient production and repair, reducing material waste and costs.
Implementation Method 1
performing Resin Transfer Molding, RTM, on the assembly in the fiber shell, wherein the RTM includes injecting a thermoset resin into the shell and the assembly and solidifying the resin
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A rotary blade, the blade comprising one or more structural beams (14, 16) extending generally in a direction from a root end of the blade to a tip of the blade, a shell (12) enclosing the one or more structural beams and defining the outer shape of the blade, wherein the one or more structural beams is made of a thermoplastic material and the shell comprises a fibrous material, the blade further comprising a thermoset resin injected into the shell fibrous material to strengthen the shell and to bond the shell to the one or more beams.