What validation tests should be performed on a wave spring assembly to ensure 'Zero-Failure' in mission-critical aerospace valves?

Validation should include: 1) Load-Deflection Verification: Measuring the load at the specified work height using a precision tester. 2) Free Height Consistency: Checking for permanent set after 5-10 cycles to solid height. 3) Cycle Testing: Stress-cycling the spring at operating temperature to 1.5x the design life. 4) Resonant Frequency Analysis: Ensuring the system's vibration frequency does not match the spring's natural frequency $f_n = _x000c_rac{1}{2\pi} imes _x000c_rac{k}{m}$, as resonance causes rapid fatigue. 5) Cleanliness Verification: Utilizing microscopic inspection (per ISO 16232) to ensure no metallic particulates from the spring coiling process remain, which could foul valve seats.