A hybrid frequency-time-domain approach to determine the vibration fatigue life of electronic devices

A hybrid frequency-time-domain model is presented to holistically predict the mechanical effects of vibrational loads on microelectronic devices placed in complex geometrical systems. Dynamic system loads in the frequency domain are spatially reduced to local devices and transformed into the time domain allowing for nonlinear material modelling and lifetime assessment. The electronic system and its components are interpreted as an equivalent multi-degree-of-freedom oscillator to analytically set up the equation of motion, whose modal stiffness and damping coefficients are experimentally determined. The displacements of the point oscillators are translated to a simplified finite element model, which identifies critical components in the frequency domain based on the mass participation factor. Numerical submodelling techniques are applied to asses statistical stress configurations and reveal critical electrical devices susceptible to material fatigue. The frequency response function of the device is inverse Fast Fourier transformed into the time domain to quantify fatigue strength and calculate the damage accumulated throughout the vibrational load cycles.