Woven Composite Preform Layout for Off-Centering Compensation
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Solution Overview
Problem
Existing methods fail to account for off-centering angles in woven composite materials during part manufacturing, leading to inefficiencies, material wastage, and increased mass due to oversized designs, as behavior laws become invalid with loss of orthogonality.
Innovation Solution
A method that models the behavior of off-centered woven composite materials by defining orthogonal and natural local frames of reference, expressing stiffness and deformation tensors, and calculating stress tensors to optimize fiber orientations before impregnation, allowing for accurate prediction and adaptation of mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If behavior laws are used to model woven composite material without accounting for off-centering angles, then the material can be considered orthotropic and standard orthotropic behavior laws apply, but the model becomes inaccurate when warps and wefts slip and rotate during shaping, causing loss of orthogonality
Solution Approach 1:
The patent applies preliminary action by predicting off-centering angles before the actual shaping process occurs. The method calculates anticipated off-centering angles based on the desired 3D shape, then uses these predictions to adjust the layup configuration in advance. This allows the behavior law model to remain accurate without requiring complex real-time adjustments during shaping, as the compensation is already built into the initial design.
Solution Approach 2:
The patent changes parameters by introducing off-centering angles as a new parameter in the behavior law model. Instead of using standard orthotropic assumptions, the method modifies the constitutive equations to include terms that account for fiber misalignment. This parameter change allows the model to accurately represent the anisotropic behavior that occurs during shaping without requiring entirely new modeling approaches.
2Reliability
If margins are provided in part design to accommodate off-centering effects, then mechanical property losses are compensated, but material wastage increases and part mass increases significantly
Solution Approach 1:
The patent applies local quality by adjusting fiber orientation and layup configuration specifically in regions where off-centering effects are predicted to be most significant. Rather than uniformly oversizing the entire part, the method locally optimizes fiber placement in critical areas such as curved surfaces and transition zones. This targeted approach compensates for mechanical property losses only where needed, avoiding unnecessary material addition in areas where off-centering is minimal.
Solution Approach 2:
The method performs preliminary compensation by calculating anticipated off-centering angles and adjusting the layup design before manufacturing. This allows for precise material utilization where margins are provided only where mechanically necessary, rather than uniformly throughout the entire part. The preliminary calculation enables optimal material distribution that compensates for expected property losses without excessive material wastage.
3Reliability
If behavior laws are made valid for off-centered materials, then accurate prediction of mechanical behavior is possible, but the number of valid behavior laws decreases and material parameters must be identified for each off-centering angle
Solution Approach 1:
The patent changes parameters by formulating a unified behavior law that uses off-centering angle as an explicit parameter. Instead of requiring separate material parameters for each angle, the method modifies the constitutive equations to include trigonometric terms that automatically account for any off-centering angle. This parameter transformation allows a single set of material constants to remain valid across the full range of off-centering conditions, eliminating the need for angle-specific parameter identification.
Solution Approach 2:
The patent achieves universality by creating a behavior law model that functions across both orthotropic and anisotropic conditions. The modified constitutive equations can handle any off-centering angle from 0° to 45° using the same material parameters, making the model universally applicable to woven composite materials during shaping. This multi-functional approach eliminates the need for separate behavior laws for different angle ranges, significantly reducing the complexity of material characterization.
Data Source
AI summary
Methods are provided for creating a component from a preform having a network of fibers having, after the shaping of the preform, an out-of-register angle. The methods include: defining an orthogonal local frame of reference, defining a natural local frame of reference, defining a linked frame of reference, expressing a tensor of the stiffnesses of the woven composite material in said natural local frame of reference, constructing a tensor of the deformations in the orthogonal local frame of reference, expressing, in the linked frame of reference, the tensor of the deformations, calculating a tensor of the stresses in the natural local frame of reference, expressing, in the orthogonal local frame of reference, the stresses tensor, expressing the stiffnesses tensor, constructing a tangent operator, establishing an optimized configuration for the network, and locally adapting the network before impregnating said network.