Composite Fiber Torsion Carrier With Decoupled Spiral Coil Layers
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Solution Overview
Problem
Composite fiber materials used in torsion-loaded components are sensitive to multi-axial states of stress, leading to unfavorable interactions between laminate layers, interlaminar cracks, and reduced load-bearing capability, which results in inefficient material utilization and potential component failure.
Innovation Solution
The proposed solution involves a structure with separate layers of individual spiral coils with opposed winding directions, decoupled by an intermediate layer that allows for uniaxial states of stress, enabling the spiral coils to withstand predominantly tensile or compressive loads, thus reducing transverse extensions and enhancing deformation capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If laminate layers are laid in the main directions of stress (+45° and -45° fibers) to carry tensile and compressive stresses, then the load-bearing capability in principal stress directions is improved, but unfavorable interactions occur between layers leading to interlaminar cracks and reduced stability
Solution Approach 1:
The laminate is segmented into separate layers with identical fiber orientations (all +45° or all -45°) rather than alternating orientations. Each layer independently carries stress in its fiber direction, eliminating the problematic interaction between orthogonally oriented layers that causes interlaminar cracks.
Solution Approach 2:
The patent applies different fiber orientations to different local regions (layers) of the composite structure. Each layer is optimized for its specific stress state, with all layers having the same orientation to avoid transverse extension constraints that would otherwise cause cracking at layer interfaces.
2Strength
If a continuous laminate structure with orthogonally oriented fibers is used, then both tensile and compressive stresses are carried, but transverse extension is constrained leading to matrix overstretching and fiber damage
Solution Approach 1:
The continuous laminate is divided into separate layers that are not continuously bonded. This segmentation allows each layer to extend freely in the transverse direction without being constrained by adjacent layers with orthogonal fiber orientations, preventing matrix overstretching and fiber damage.
Solution Approach 2:
A decoupling layer is introduced between the laminate layers to act as an intermediary that allows independent deformation. This decoupling layer permits transverse extension of individual layers without transferring constraint stresses to adjacent layers, eliminating the harmful transverse extension constraint.
3Reliability
If high fatigue allowances are applied to accelerate crack propagation prevention, then component reliability is improved, but significantly more material must be used to limit extensions and stresses
Solution Approach 1:
The patent extracts and removes the source of crack propagation (interlaminar constraints between orthogonally oriented layers) rather than adding material to compensate for potential cracking. By eliminating the constraint mechanism that leads to crack initiation and propagation, high fatigue resistance is achieved with minimal material usage.
Solution Approach 2:
The patent changes the fundamental parameter of fiber orientation arrangement from alternating orthogonal layers to uniform orientation layers. This parameter change fundamentally alters the stress distribution and deformation behavior, allowing the component to withstand fatigue loads without requiring excessive material to limit extensions and stresses.
4Weight of moving object
If composite fiber materials are used in torsion-loaded components, then weight is reduced compared to amorphous materials, but the materials are particularly sensitive to multi-axial states of stress leading to reduced material utilization
Solution Approach 1:
The patent optimizes the local quality of each laminate layer by assigning uniform fiber orientations that match the principal stress directions in torsion-loaded components. This local optimization ensures that each layer efficiently carries stress along its fiber direction, maximizing material utilization efficiency while maintaining the weight advantages of composite materials.
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 approach allows for significantly higher stress levels (up to 600 MPa) in composite fiber torsion components, reducing material usage by half for torsion-transferring components and by a quarter for torsion springs, while also improving energy storage capacity and reducing construction space requirements.
Implementation Method 1
adjacent laminate layers 1, 3 are decoupled from one another by means of an intermediate layer 2, as a result of which a longitudinal extension of the spiral coils of one layer leads only slightly to a transverse extension of the spiral coils of the adjacent layer
Implementation Method 2
The torsion loading is converted into tensile load(s) in the outer spiral coil(s) (1) and compressive load(s) in the inner spiral coil(s) (3)
Data Source
AI summary
The invention relates to a torsion carrier, particularly a torsion spring, helical spring, drive shaft or balance shaft, which enables significant material and installation space savings compared to the prior art. The torsion carrier consists of a plurality of, but at least two supporting layers lying radially one above the other, each of which consists of at least one spiral coil (1, 3), but preferably of a plurality of spiral coils made of predominantly unidirectional composite fiber material, wherein at least two of the supporting layers have a counterrotating spiral coil orientation relative to one other. An elastic intermediate spacer layer (2) is arranged between adjacent spiral coil layers, by means of which a decoupling of the spiral coil expansions of adjacent spiral coil layers is achieved. This achieves particularly favorable, predominantly single-axis states of stress which allow for a high level of material utilization.