Composite Gasket Slip Planes for Shear Load Dissipation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing multi-layer composite gaskets used in internal combustion engines face issues with sheer loads caused by differential expansion and movement between mating members, leading to weakened adhesive layers and compromised sealing performance over time.
Innovation Solution
Incorporating paper layers between the perforated cores and the center core to act as slip planes, which dissipate sheer loads and maintain the sealing function by allowing slight lateral shifting, while graphite layers maintain their seal against mating members under dynamic conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If rigid adhesive layers are used to bond the center core to the perforated metal layers, then the gasket maintains structural integrity and sealing function, but the adhesive layers weaken and break under sheer loads from differential expansion and combustion forces
Solution Approach 1:
A viscoelastic buffer layer is introduced as an intermediary between the rigid adhesive layers and the center core. This buffer layer absorbs and dissipates sheer loads through its viscoelastic properties, preventing direct transmission of stress to the adhesive layers. The buffer layer acts as a stress-absorbing mediator that protects the adhesive bond from failure under dynamic combustion forces and thermal expansion differential.
Solution Approach 2:
The invention changes the mechanical parameters of the gasket structure by introducing a layer with viscoelastic properties that can dynamically adjust its stiffness. Under static conditions, the buffer layer maintains adequate bonding; under dynamic sheer loading, it softens to absorb stress, thereby changing the stress distribution parameters throughout the gasket assembly and preventing adhesive failure.
2Strength
If the gasket structure is made rigid to maintain sealing under compression, then sealing capability is improved, but the gasket cannot accommodate differential thermal expansion and combustion forces without compromising the seal
Solution Approach 1:
The gasket structure is made dynamic by incorporating a viscoelastic buffer layer that can adapt its mechanical properties in response to varying loads. This layer provides rigidity under static compression to maintain sealing, but becomes more compliant under dynamic sheer loads from thermal expansion and combustion forces, allowing the gasket to accommodate dimensional changes while maintaining the seal.
Solution Approach 2:
The invention uses a composite structure combining rigid components (adhesive layers, metal cores) with a viscoelastic buffer layer. This composite construction allows different parts of the gasket to perform different functions: the rigid parts provide structural integrity and sealing pressure, while the viscoelastic part provides adaptability to dynamic forces, achieving both sealing capability and accommodation of expansion forces.
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 gasket effectively accommodates dynamically changing compressive and sheer forces, extending its service life and maintaining excellent sealing capabilities over an extended duty range without fluid leaks.
Implementation Method 1
The paper layers disposed between the respective perforated cores and the center core can function as slip planes to enable slight lateral shifting of the perforated cores relative to the center core which thereby relieve sheer loads in use
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A multi-layered composite gasket (10) includes three, preferably metallic cores ( 12, 14). A solid center core ( 12) is flanked on both sides by bonded paper layers (30). Perforated cores (14) mechanically interlock with each paper layer (30) through inwardly directed tangs (22). Graphite layers (26) are disposed outside of each perforated core (14) and are mechanically interlocked thereto by outwardly directed tangs (20) extending from the perforated cores (14). When using the gasket (10) material for sealing cylinder heads in internal combustion engines, a fire ring (46) may be affixed with a fire ring holder (48). The gasket (10) can be manufactured by making first and second preform sheets (32) comprised of one perforated core (14) sided with one paper layer (30) and one graphite layer (26). The preform sheets (32) are then bonded to a center core (12) using a heat activated adhesive. Combining rollers (42) compress and densify the layers to form the completed material set which can be stored on a coil (44) or cut into sheets.