SC/T 7002.8-2018 in English

Standard Evolution and Scope of Application

SC/T 7002.8-2018 is an upgraded version of the 1992 version of the standard. It mainly adds test specifications for automation equipment, modifies the vibration response inspection process, and refines the dangerous frequency processing mechanism. It is suitable for reliability verification of electronic equipment used in fishing vessels in a simulated ship vibration environment.

Comparison of core test parameters

Analysis of key technical points

1. Dangerous frequency processing mechanism

When a dangerous frequency appears in the vibration response check, the standard requires:
(1) Record the resonance point with Q value > 2
(2) Prioritize structural optimization to eliminate the resonance
(3) If the resonance cannot be eliminated, a 2-hour specific frequency vibration resistance test is required

2. Principles for selecting test directions

The standard stipulates that three orthogonal axial vibration responses must be tested, but for symmetrical structural equipment, one axial test can be reduced. In actual implementation, please note:
- Documentation proving structural symmetry must be provided
- The retained test directions should include the main load-bearing axes

Implementation recommendations

1. Equipment selection guide

It is recommended to give priority to equipment models that have passed the 30Hz/90min benchmark vibration resistance test. This condition is listed in the standard as the default test plan when there is no hazardous frequency.

2. Test process optimization

1. Pre-scan stage: It is recommended to use 0.5 octave/minute low-speed scanning to improve the recognition rate of dangerous frequencies
2. Fixture verification: Ensure that the first-order natural frequency of the installed fixture is greater than 100Hz
3. Intermediate detection: Perform real-time performance monitoring according to CB 1146.9 standard

3. Application of quality exemption clauses

For heavy equipment (general cabin ≥100kg/machinery cabin ≥10kg):
- Weight certification documents must be submitted
- The minimum acceleration amplitude must not be less than 50% of the standard value
- The test report must indicate the exemption clause number