Accelerated prediction of shear fatigue life of soft adhesive based on the time-temperature superposition principle

Long-term service lifetime estimation of soft adhesives is critical for their reliability and durability but is often expensive and time-consuming. The applicability of the time-temperature superposition principle (TTSP) to predict the shear fatigue life of the soft adhesive was investigated by systematic experiments. Through the analysis of energy dissipation mechanism, it was found that the viscoelastic dissipation stage played a dominant role in the shear fatigue process of the soft adhesive in the lap shear configuration. The master curve of the shear fatigue life at reference temperature could be successfully constructed by using the shift factor obtained from the rheological test. The shear fatigue life at low temperatures could be equivalently predicted based on short-term testing at relatively high temperatures. The TTSP method is effective in predicting the shear fatigue life of the soft adhesive under wide lifetime ranges and temperatures, which could save testing time and cost greatly. Viscoelastic dissipation dominant mechanism exists in the shear fatigue process.The TTSP method is extended to the shear fatigue behavior of soft adhesive.The master curves of the shear creep life and shear fatigue life are constructed.The long-term service lifetime of soft adhesive obtains an accelerated prediction.