Sealed Joint Life Prediction Using Combined Cycle Load Analysis
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Solution Overview
Problem
Conventional methods for mitigating low and high cycle loads on sealants in vehicle components either under-design or over-design the sealed joints, leading to premature failure of the sealant.
Innovation Solution
A method using finite elemental analysis (FEA) to subject a sealed joint to both high cycle and low cycle loads, determining the maximum displacements under each condition, and calculating the estimated life of the joint using a specific formula that incorporates material constants of the sealant.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional methods address only low cycle loads or only high cycle loads, then the design process is simplified, but the sealed joint becomes either under-designed or over-designed
Solution Approach 1:
The patent combines both low cycle load analysis and high cycle load analysis into a single integrated design methodology. The system simultaneously evaluates both load types and their interaction effects on the sealed joint, allowing designers to account for combined loading conditions without performing separate design iterations for each load type.
Solution Approach 2:
The patent introduces a load ratio parameter (R = low cycle load / high cycle load) that characterizes the relative magnitude of low cycle loads compared to high cycle loads. By varying this parameter, the methodology can predict sealant performance across different operating conditions and loading scenarios, enabling accurate prediction without complex separate analyses.
2Weight of stationary object
If the sealed joint is under-designed, then the component mass is reduced, but the sealant fails prematurely
Solution Approach 1:
The patent performs preliminary prediction of sealant performance under combined low and high cycle loads before finalizing the design. By using the proposed methodology to estimate sealant life and identify potential failure risks early in the design process, engineers can optimize the sealed joint design to achieve adequate reliability without excessive mass, avoiding both under-design and over-design scenarios.
3Reliability
If the sealed joint is over-designed, then the sealant service life is extended, but the component mass increases due to unnecessary structural stiffness
Solution Approach 1:
The patent uses the load ratio parameter and predicted sealant life to optimize the sealed joint design. By adjusting design parameters based on the predicted performance under combined loading, engineers can achieve the minimum necessary structural stiffness and mass to meet reliability requirements, eliminating unnecessary over-design while ensuring adequate sealant service life.
Data Source
AI summary
A method for determining the predicting sealing performance of a joint having a sealant positioned between a first member and a second member. The method includes selecting a sealant material for the sealant, selecting a first member material for the first member and a second member material for the second member, and subjecting the joint, using finite elemental analysis (FEA), to high cycle loads and low cycle loads. After subjecting the joint to the high cycle loads and the low cycle loads, the method includes determining a maximum high cycle displacement of the joint and determining a maximum low cycle displacement of the joint, and determining an estimated life of the joint using the following formula (1):(maximum low cycle displacement+1)×(maximum high cycle displacement2)=C·(2Nf)2b,where in formula (1) C represents a constant of the sealant material, Nf represents the estimated life of the joint, and b represents a slope.