Vibration Requirement
Accelerated mechanical testing quantifies random vibration exposure across broad frequency spectra. Environmental testing specifications utilize g rms power spectral density to define the root-mean-square acceleration energy delivered to electronic assemblies during random vibration testing. Integrating spectral acceleration power density across specified excitation bandwidths yields total root-mean-square acceleration loading.
The metric defines input excitation energy, stopping short of predicting local board resonance or component stress without dynamic structural modeling.
Spectral Calculation
Power spectral density plots display acceleration power per unit frequency across defined spectrum bands. Test systems drive electrodynamic shakers using closed-loop accelerometers, shaping random noise profiles to match target spectral density curves. High spectral peaks focused near circuit board structural resonances induce rapid bending stress in solder joints and surface mount pins.
Designers inspect power spectral density profiles to identify high-energy frequency bands capable of exciting circuit assembly resonance modes. Fast Fourier transform algorithms process accelerometer outputs to verify spectrum compliance during vibration screening. Controlling spectral distribution prevents premature fatigue failures caused by narrowband resonance amplification.
Strain Response
Random vibration profiles generate complex cyclic loading across component leads. High root-mean-square values accelerate mechanical fatigue in fragile solder structures. Vibration profiles apply exclusively to specified shaker orientation axes.
