Jig for CFRP Tubular Molding with Pressure-Regulating Bladder
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Solution Overview
Problem
The existing methods for integrating thermoplastic CFRP skin and stringer using a mandrel face challenges in maintaining the shape of the inner peripheral surface of tubular portions due to high pressure requirements, leading to potential deformation and difficulties in removing the core or bladder, especially when the stringer has a non-linear or curved shape.
Innovation Solution
A jig comprising mold portions with contact surfaces matching the inner peripheral shape, a bladder for fluid accommodation, and connecting portions to regulate the interval between mold portions, allowing for precise shaping and easy removal by controlling fluid pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a bladder is inserted into the hollow portion to prevent recessed deformation, then the shape stability is improved, but the bladder excessively inflates under high pressure causing the skin position to deviate from the specified surface
Solution Approach 1:
The bladder is divided into multiple independent bladder portions (first bladder portion and second bladder portion) arranged along the longitudinal direction. Each bladder portion independently supports the inner peripheral surface at different locations, preventing excessive inflation at any single point while maintaining overall shape stability under high pressure.
Solution Approach 2:
Different bladder portions are positioned at specific locations corresponding to different sections of the hollow portion. This allows localized pressure distribution and support, where each bladder portion maintains the shape at its specific position without causing deviation elsewhere, achieving both shape stability and position precision.
2Shape
If a core is used to maintain the hollow portion shape, then the shape definition is improved, but the demolding work becomes difficult and time-consuming
Solution Approach 1:
The bladder portions are made flexible and capable of deformation. After molding, the bladder portions can be easily deflated and removed from the hollow portion, transforming from a rigid support structure to a removable flexible element, thereby reducing demolding time and effort.
Solution Approach 2:
The bladder portions are constructed from flexible material that can be inflated during molding to define the hollow portion shape, then deflated and easily removed afterward. This flexible shell approach replaces the traditional rigid core, enabling both precise shape definition and easy demolding.
3Strength
If high pressure is applied by the roller to laminate thermoplastic CFRP, then the blending of synthetic resin and fiber is improved, but the inner peripheral surface of the tubular portion deforms excessively
Solution Approach 1:
The inflated bladder portions act as a counterforce to the high pressure applied by the roller. The internal pressure from the bladders balances the external compression force, preventing the inner peripheral surface from deforming excessively while allowing sufficient pressure for proper resin-fiber blending.
Solution Approach 2:
The system dynamically adjusts pressure parameters by controlling the inflation level of the bladder portions. The bladders maintain internal pressure that counterbalances the external rolling pressure, optimizing both the blending quality and shape preservation during the molding process.
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 jig effectively defines the internal shape of the material and facilitates easy removal after molding, preventing excessive inflation and deformation, even under high pressure conditions, and is applicable to both thermosetting and thermoplastic resin-based CFRP molding.
Implementation Method 1
a bladder (3) that is provided on an opposite side to the contact surfaces of the plurality of mold portions with respect to the mold portions, is capable of accommodating a fluid (10) therein, and is capable of expanding and contracting according to a pressure of the accommodated fluid
Data Source
AI summary
A jig includes mold parts that have a contact surface of a cylindrical part of a material to be molded having a shape complying with the inner peripheral surface of the cylindrical part and are arranged in a direction crossing one direction; a bladder that is provided on a side opposite to the contact surfaces of the plurality of mold parts relative to the mold parts, capable of accommodating a fluid therein, and expandable/retractable according to a pressure of the accommodated fluid; a joining part that joins the plurality of mold parts and the bladder; and a connection part that connects a one-side mold part and an another side mold part adjacent to the one-side mold part among a plurality of mold parts to each other and restricts an interval between the one-side mold part and the other-side mold part in a direction crossing the one direction with a prescribed range.