Thermoplastic Composite Connecting Rod Design
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Solution Overview
Problem
Current structural composite connecting rods for reacting axial forces have high mass and manufacturing costs due to discontinuous manufacturing methods and the need for extensive reinforcement to achieve impact strength, primarily using thermosetting resins with weak elongation at break.
Innovation Solution
A composite connecting rod design featuring continuous shell fibers impregnated with a thermoplastic matrix, assembled using inclined assembly fibers and a thermoplastic assembly matrix, which reduces material thickness and processing time through thermowelding, and incorporates a sacrificial damping layer for impact resistance and damage indication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thermosetting resins are used to manufacture composite connecting rods, then the rods can achieve sufficient structural strength, but the mass increases due to the need for extensive reinforcement plies to compensate for weak elongation at break
Solution Approach 1:
The patent changes the material parameter from thermosetting resin to thermoplastic resin, which fundamentally alters the elongation at break characteristic. Thermoplastic resins inherently possess higher elongation at break without requiring additional reinforcement plies, thus reducing mass while maintaining structural strength. This parameter change resolves the contradiction by eliminating the need for compensatory reinforcement.
Solution Approach 2:
The patent employs a composite material system consisting of continuous fibers embedded in a thermoplastic resin matrix. This composite structure provides both the required structural strength and the necessary ductility through the thermoplastic matrix, avoiding the need for excessive reinforcement plies that would increase mass.
2Ease of manufacture
If discontinuous thermoforming and assembly of semi-cylindrical shells by lateral overlapping is used, then the connecting rod can be manufactured, but the mass increases due to doubling of thickness and the manufacturing cost increases
Solution Approach 1:
The patent extracts and eliminates the unnecessary lateral overlapping assembly step from the manufacturing process. Instead of assembling two shells with overlapping edges that double the thickness, the invention uses a single continuous shell formed directly by wrapping a flat preform around a mandrel, thereby removing the redundant material and simplifying the manufacturing process.
Solution Approach 2:
The patent segments the manufacturing process into continuous steps: cutting the flat preform to length, wrapping it around a mandrel to form the cylindrical shell, and curing the resin in one continuous operation. This segmented approach eliminates the need for separate assembly of multiple shell components, reducing both mass and complexity.
3Ease of manufacture
If lateral overlapping assembly of shells is used, then the shells can be connected, but the manufacturing cost increases due to the need for additional materials and complex assembly procedures
Solution Approach 1:
The patent merges the shell formation and assembly operations into a single continuous process. The flat preform is wrapped around the mandrel and cured in one operation, combining what would traditionally be separate forming and assembly steps. This eliminates the need for lateral overlapping and reduces manufacturing complexity while maintaining assembly capability.
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 design achieves improved mechanical properties for axial force reaction and impact resistance, leading to mass savings and reduced manufacturing costs while maintaining or exceeding required performance standards.
Implementation Method 1
the assembly web(s) comprising assembly fibers primarily inclined by an angle ±α relative to the axis of symmetry (i.e., relative to the predominantly axial shell fibers) and impregnated with a thermoplastic assembly matrix remelted in contact with the shell matrix
Data Source
AI summary
A connecting rod comprises a convex elongated body around a longitudinal axis of symmetry and two connecting ends for connecting to adjacent structures. The connecting rod includes two shells with two longitudinal edges that are assembled in these edges and that each have a base of at least one shell web including continuous shell fibers primarily parallel to this axis of symmetry and impregnated with a thermoplastic shell matrix. The connecting rod incorporates at least one assembly web wound around and along the shells, and assembly fibers primarily inclined relative to the axis and impregnated with a thermoplastic assembly matrix remelted in contact with the shell matrix.