Curved Composite Profile Bending via Heat Gradient
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Solution Overview
Problem
The existing method for producing curved profiles from composite materials is inefficient due to lengthy and tedious step-by-step deformation, difficulty in relative positioning of preimpregnated fiber strips, risk of crimping and bridging defects, accelerated resin aging, low productivity, and increased production time and cost from manual placement of fibers oriented at 0°.
Innovation Solution
A method involving the stacking of preimpregnated fiber webs on a deformable mandrel, which is then wound and bent in a single phase using a bending tool with a heat gradient and controlled temperature zones to reduce fiber crimping and enhance adhesion, allowing for simultaneous bending and polymerization of the webs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If strips are deformed and bent consecutively in a step-by-step manner, then the profile is formed, but the production time becomes long and tedious
Solution Approach 1:
The patent combines multiple bending operations into a single simultaneous bending phase where all strips are deformed together on the mandrel rather than sequentially. This merging of operations maintains the required profile formation precision while dramatically reducing production time by eliminating repeated positioning and bending cycles for each strip.
Solution Approach 2:
The patent applies preliminary heating to the entire assembly of strips and mandrel before bending. This pre-heating softens the composite material in advance, enabling all strips to be bent simultaneously without requiring repeated heating cycles during sequential operations, thus reducing total production time while maintaining formability.
2Shape
If preimpregnated fiber strips are stacked and bent, then the curved profile is formed, but the relative positioning between strips becomes difficult
Solution Approach 1:
The patent combines all strips on a single mandrel and bends them simultaneously in one operation, eliminating the need for separate positioning operations for each strip. The mandrel serves as a common reference surface that maintains relative positioning automatically during the unified bending process.
Solution Approach 2:
The mandrel acts as an intermediary element that facilitates both positioning and bending. By placing all strips on the mandrel before bending, the mandrel mediates the positioning problem by providing a stable base that maintains strip relationships during the transition from linear to curved configuration.
3Shape
If strips are stacked and bent consecutively, then the profile is formed, but bridging defects occur due to increasing outer radii and decreasing inner radii
Solution Approach 1:
The patent bends all strips simultaneously in a single phase rather than consecutively. This ensures that all strips experience the same bending conditions and radius changes at the same time, preventing the progressive radius deviation that causes bridging defects when strips are bent one after another.
Solution Approach 2:
The patent applies controlled heating to modify the temperature parameter of the composite material before and during bending. This thermal parameter change increases material ductility and allows all strips to conform to the mandrel curvature simultaneously without developing bridging defects, as the heated material can accommodate the radius changes more uniformly.
4Shape
If the first strip remains in contact with the heated tool longer than subsequent strips, then the profile is formed, but accelerated and uncontrolled resin aging occurs
Solution Approach 1:
The patent combines all bending operations into a single simultaneous phase where all strips are heated and bent together. This eliminates the sequential heating pattern that causes the first strip to be exposed to heat for a much longer duration, thereby preventing uncontrolled resin aging while still achieving the required profile formation.
5Manufacturing precision
If manual placement of fibers oriented at 0° is performed, then crimping risk is reduced, but production time and cost increase
Solution Approach 1:
The patent applies preliminary heating to the entire assembly before bending, which softens the composite material and allows fibers to be positioned and oriented during the bending process itself rather than requiring separate manual placement operations. This preliminary thermal preparation enables automated fiber orientation control during bending, reducing both crimping risk and production time.
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 method significantly reduces production time and costs, minimizes defects like crimping and bridging, enables the creation of profiles with larger cores, and ensures precise fiber orientation and resin aging control, resulting in higher productivity and improved quality.
Implementation Method 1
consists of creating a heat gradient in the preform by means of a heating device, the heat gradient generating a thermal neutral fiber positioned at the face of the preform that is to be in contact with the bending tool
Implementation Method 2
the heat gradient generating a thermal neutral fiber positioned at the face of the preform that is to be in contact with the bending tool
Implementation Method 3
consisting of cooling the preform at the face that is to be in contact with the bending tool before bending
Implementation Method 4
bending, in a single phase, the N webs inserted between the deformable mandrel and the bending tool
Implementation Method 5
polymerizing said N bent webs
Data Source
AI summary
A method for producing a curved profile from a rectilinear preform of preimpregnated fiber webs, including stacking webs on the deformable mandrel and winding the deformable mandrel and the stacked webs on a bending tool along an axis of rotation (X), the profile including a stack of N webs, at least one first part of the profile being positioned in a plane perpendicular to the axis of rotation (X) and at least one second part parallel to the axis (X) whereof a face can be in contact with the bending tool. The method includes stacking the N fiber webs on the deformable mandrel, generating a heat gradient between the face and the rest of the preform that is hotter than the face, bending, in a single phase, the N webs inserted between the deformable mandrel and the bending tool, and polymerizing the N bent webs.