The life assessment of wire harnesses is a complex process that requires comprehensive consideration of multiple factors and testing methods. The following are several main evaluation methods:

1. Electrical performance testing

Electrical performance testing includes resistance, capacitance, inductance, and withstand voltage tests. Through these tests, it can be determined whether the conductivity of the wiring harness is good and whether there are any issues such as open circuits or short circuits

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2. Mechanical performance testing

Mechanical performance testing includes tensile, bending, and vibration tests. These tests can evaluate the tensile, bending, and vibration resistance of the wiring harness, thereby determining its durability performance

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3. Thermal performance testing

Thermal performance testing includes tests for heat resistance, cold resistance, and heat shock resistance. By testing the performance of the wiring harness under different temperature conditions, the durability of the wiring harness in different working environments can be evaluated

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4. Mechanical vibration testing

Mechanical vibration testing can test the performance of wiring harnesses in mechanical vibration environments. By conducting vibration tests at different frequencies and amplitudes, it is possible to simulate the vibration of wiring harnesses in industrial environments such as vehicles and robots, and evaluate their anti vibration performance

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5. Salt spray corrosion test

Salt spray corrosion testing is mainly used to evaluate the corrosion resistance of wire harnesses in harsh environments. By placing the wiring harness in a salt spray environment and observing its resistance to corrosion, evaluate its lifespan and durability

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6. Accelerated test design and life model evaluation

Accelerated test design is a method of accelerating product failure by applying stresses (such as temperature, mechanical stress, etc.) that are higher than normal usage conditions. By establishing failure physical models such as S-N curves for material fatigue and Arrhenius formulas for material aging, the fatigue life of wire harnesses can be quantitatively estimated

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7. Failure criteria and failure detection methods

Failure criteria and failure detection methods are important aspects of accelerated test design. For example, by measuring the impedance value of the wire harness at a high sampling frequency to monitor the damage inside the harness, an impedance analyzer is selected as the test instrument, and an AC signal is applied to both ends of the wire harness at a testing frequency of 1kHz to measure the impedance values at different times

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8. Fatigue life assessment

By conducting accelerated life tests on automotive wiring harnesses through an accelerated testing scheme, the fatigue life of the wiring harness can be quantitatively estimated. For example, conducting 100000 fatigue durability tests can simulate a fatigue life of 15.9 years for automotive wiring harnesses, and conducting 1000 hours of 125 high temperature aging tests can simulate a 2.6-year aging life for automotive wiring harnesses

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9. Regular maintenance and inspection

Regular maintenance and inspection of the appearance and performance of the wiring harness, timely detection and handling of potential problems, can effectively extend the service life of the wiring harness. For example, the maintenance cycle for engine wiring harnesses is generally once every 40000 to 50000 kilometers