Electrical Connector Failure Rate Estimation via Degraded Vibration Samples
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Solution Overview
Problem
Existing methods for determining the failure rate of electrical connectors are inefficient, requiring extensive time, high costs, and unreliable due to the difficulty in simulating sufficient operating hours while avoiding false results and additional degradation mechanisms.
Innovation Solution
A method involving degrading a sample connector to a reduced normal force threshold, determining its probability within a batch, applying a vibrating test, and calculating the failure rate by multiplying the sample's failure rate by this probability, using a normal distribution and automotive norms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a standard connector vibration test is performed to simulate operating hours, then the test duration is reduced to around 3 weeks, but the number of failures obtained is insufficient for significant statistical analysis
Solution Approach 1:
The invention applies preliminary degradation treatments (thermal cycling, mechanical wear, or chemical exposure) to connector samples before conducting the vibration test. This pre-degradation reduces the contact normal force and accelerates the formation of micro-movements between terminals, causing failures to occur earlier during the vibration test. As a result, sufficient failures are obtained within a shortened test duration of around 3 weeks, resolving the contradiction between test time and statistical significance.
2Productivity
If test severity is increased by raising temperature or vibration amplitude to cause earlier failures, then the failure rate is accelerated, but other degradation mechanisms are activated that cannot be correlated to field experience
Solution Approach 1:
The invention changes the contact normal force parameter through controlled preliminary degradation treatments (thermal cycling, mechanical wear, or chemical exposure) rather than increasing vibration amplitude or temperature excessively. This parameter change accelerates the degradation process by creating conditions that promote micro-movements and contact resistance increase, while keeping the vibration test conditions within realistic field ranges. This resolves the contradiction by achieving failure acceleration through a different physical mechanism that remains correlated to actual field degradation.
3Reliability
If the quantity of samples in test is increased to obtain significant failure statistics, then the statistical confidence is improved, but the test cost increases significantly
Solution Approach 1:
The invention applies preliminary degradation treatments to accelerate the aging process of connector samples before vibration testing. This pre-treatment creates non-uniform degradation states across the sample population, with some samples already接近 to failure conditions. As a result, failures occur at higher rates during the vibration test, allowing statistically significant failure rate determination with a moderate number of samples (e.g., 50-100), thereby reducing the total quantity of connectors needed compared to conventional testing.
4Measurement precision
If vibration test conditions are optimized to match field degradation mechanisms, then the test accuracy is improved, but the test duration extends to simulate 10 years of operation
Solution Approach 1:
The invention applies preliminary degradation treatments (thermal cycling, mechanical wear, or chemical exposure) that specifically target the contact interface degradation mechanisms observed in field applications. These treatments create micro-movements, reduce contact normal force, and initiate contact resistance increase before the vibration test begins. This allows the subsequent vibration test to be conducted at realistic field conditions while still achieving accelerated failure rates, thereby maintaining measurement precision while reducing test duration from 10 years equivalent to around 3 weeks.
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
Accelerates the failure rate determination process, enhances confidence in results, and reduces costs by simulating a significant number of operating hours efficiently.
Implementation Method 1
applying a vibrating test to said at least one sample
Implementation Method 2
applying a vibrating test to said at least one sample
Implementation Method 3
the possible micro-movement between the male and female terminals due to system vibrations or thermal expansion cycles
Implementation Method 4
the possible micro-movement between the male and female terminals due to system vibrations
Data Source
Figure 1~2
AI summary
The invention is directed to a method for determining a failure rate (%B) of a batch (B) of electrical connectors (C), comprising the following steps: - making at least one sample (S) of electrical connector (C) degraded so as to exhibit a contact normal force (F) lesser than a force threshold (FT), lesser than the mean force (FM) of the batch (8), - determining a probability (P) of occurrence of said at least one sample (S) within the batch (8), in function of the threshold force (FT), - applying a vibrating test to said at least one sample (S), - obtaining a failure rate (%S) of the sample (S), - calculating a failure rate (%B) of the batch (B) by multiplying the failure rate (%S) of the sample (S) by the probability (P).