Composite Projectile Barrel Thermal Stress Reduction
Solution Overview
Problem
Traditional composite gun barrels face challenges such as burst strength, thermal management, and accuracy issues due to thermal expansion differences between the composite outer shell and inner liner, leading to potential delamination and reduced accuracy.
Innovation Solution
A composite projectile barrel design featuring a metal alloy inner barrel section and an outer composite structure with carbon fiber prepreg layers and non-woven nanofiber web membranes, where the carbon fiber prepreg has a low resin content and the layers are oriented in specific patterns to enhance strength, stiffness, and heat dissipation, while the nanofiber web membranes improve interlaminar strength and reduce thermal stresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If additional layers of CFC windings are added to improve burst strength and axial strength, then the mechanical strength and stiffness are improved, but the heat removal capability deteriorates and the barrel becomes bulkier
Solution Approach 1:
The patent changes the material parameters by substituting carbon fiber with graphene foam, which has fundamentally different thermal and mechanical properties. Graphene foam provides both high strength and superior thermal conductivity, resolving the trade-off between mechanical strength and heat removal capability that plagues traditional CFC barrels
Solution Approach 2:
The patent uses composite materials by combining graphene foam with metal alloys (such as aluminum or copper) to create a hybrid structure that leverages the high strength-to-weight ratio of graphene and the excellent thermal conductivity of metals, achieving both mechanical strength and thermal management in a single barrel structure
2Weight of moving object
If continuous fiber composite material is used for the outer shell, then the weight is reduced and strength is improved, but thermal management deteriorates due to poor heat conduction
Solution Approach 1:
The patent creates a composite structure by integrating graphene foam with metal materials. This composite approach allows the barrel to maintain the lightweight advantage of composites while gaining the superior thermal conductivity of metals, effectively resolving the thermal management issue
Solution Approach 2:
The patent fundamentally changes the thermal conduction parameter by introducing graphene foam, which has exceptionally high thermal conductivity compared to traditional polymer matrices. This parameter change enables effective heat removal while maintaining the structural advantages of composite materials
3Weight of moving object
If carbon fiber-reinforced polymer matrix composite is used, then the weight is reduced compared to steel, but thermal expansion differences cause thermal stresses and potential delamination
Solution Approach 1:
The patent changes the coefficient of thermal expansion parameter by using graphene foam and metal alloys that have thermal expansion properties more compatible with steel liners. This reduces the thermal mismatch and associated stresses during temperature cycling
Solution Approach 2:
The patent employs composite materials with tailored thermal properties, combining graphene foam's dimensional stability with metal's ductility to create a structure that can accommodate thermal expansion differences without delamination or failure
4Strength
If more layers of windings are added to ensure burst strength, then the strength is improved, but manufacturing complexity and material expense increase
Solution Approach 1:
The patent changes the material strength parameter by using graphene foam, which provides exceptional mechanical strength at lower densities. This allows achieving the required burst strength with fewer layers or thinner walls, simplifying the manufacturing process and reducing material expense
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 results in a lightweight barrel with improved heat dissipation, increased rigidity, reduced delamination, and enhanced accuracy by minimizing thermal stresses and resonance, leading to better performance and durability.
Implementation Method 1
the nanofiber web membranes improve interlaminar strength and reduce thermal stresses
Implementation Method 2
improved heat dissipation
Implementation Method 3
enhanced accuracy by minimizing thermal stresses and resonance
Data Source
AI summary
A composite projectile barrel having an inner barrel section and a composite outer barrel shell aligned coaxially with the inner barrel section is described. The inner barrel section may be made from a metal or metal alloy. The composite outer barrel shell may include two or more layers of carbon fiber prepreg and a layer of non-woven nanofiber web membrane disposed between adjacent layer of carbon fiber prepreg. The carbon fiber prepreg can include a weave of carbon fibers in a nanoparticle-reinforced resin matrix, with the resin content being less than or equal to 35 wt % of the carbon fiber content. The non-woven nanofiber web membrane can be Xantu.layr™.