Dis-bond membrane prevents liner bonding in pressure vessels
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Solution Overview
Problem
The mechanical performance of composite pressure vessels is compromised by undesired stress concentrations due to bonding between thermoplastic liners and thermoset outer walls, which occurs when the thermoplastic softens and migrates into the reinforcing fibers during the curing process of the thermoset resin, leading to reduced performance and service life.
Innovation Solution
A dis-bond membrane, typically a thermoplastic barrier film with a higher softening temperature than the thermoset resin, is installed between the inner liner and the outer structural wall to prevent bonding, achieved by attaching cylinder and dome sections of the barrier film using adhesive tape, ensuring the liner can expand and contract freely without stress points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the thermoplastic liner is used with thermoset outer wall during curing, then the pressure vessel can be fabricated, but stress concentrations occur due to co-mingling of thermoplastic with reinforcing fibers
Solution Approach 1:
A dis-bond membrane is introduced as an intermediary layer between the thermoplastic liner and the thermoset outer wall. This membrane prevents direct contact and co-mingling between the thermoplastic material and reinforcing fibers during curing, thereby eliminating the source of stress concentrations while allowing the pressure vessel to be fabricated as intended
2Ease of operation
If the thermoplastic liner softens at cure temperature, then the liner can be formed, but the liner migrates into the outer wall causing random bonds
Solution Approach 1:
The dis-bond membrane serves as a mediator that allows the thermoplastic liner to soften and be formed during curing without migrating into the outer wall. The membrane barrier prevents the liner material from contacting the reinforcing fibers, thus avoiding random bond formation while maintaining the ease of liner formation
Solution Approach 2:
The dis-bond membrane is installed beforehand to prevent the harmful migration of thermoplastic into the outer wall before it occurs. By establishing this barrier in advance, the system prevents the formation of unwanted random bonds during the curing process
3Adaptability or versatility
If the liner expands and contracts during use, then the pressure vessel functions, but stress points are created at bonding locations
Solution Approach 1:
The dis-bond membrane acts as a mediator that allows the liner to expand and contract freely during pressure cycling without creating stress points. By preventing direct bonding between the liner and outer wall, the membrane eliminates the constraint that would otherwise create stress concentrations at bonding locations, thereby maintaining structural integrity
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 dis-bond membrane effectively reduces or eliminates bonding between the liner and the outer wall, enhancing the mechanical performance and service life of the pressure vessel by preventing stress concentrations and allowing the liner to expand and contract without interference.
Implementation Method 1
Attaching the cylinder section of the barrier film is performed using an adhesive tape
Data Source
AI summary
A dis-bond membrane prevents co-mingling between a thermoplastic liner and a fiber reinforced thermoset outer wall of a pressure vessel during thermal curing of the outer wall.