Reliability of Adhesive Joints Under Piezomechanical Loading

摘要

Models were developed, validated by experiments for the cyclic loading and fatigue failure of adhesives between piezo-ceramic adherends. An analytical shear lag model and a numerically-implemented cohesive zone model were developed. The equivalence of the loading state in piezo-mechanical loading to thermomechanical actuation was established Experiments were conducted on Lead Zirconium Titanate (PZT) substrates bonded by Lead-Tin eutectic solders. Some experiments were also conducted with a polymer adhesive. A novel test specimen, test fixture and associated power electronics were designed and fabricated. Digital image correlation was used to obtain in situ strain distributions during actuation. Damage growth and stress-life data was obtained and compared with model predictions. Once calibrated, good agreement was achieved between strain levels and fatigue life times predicted by the models and experimental data. The modeling and experimental results are significant as they provide a means to estimate the fatigue lifetime of surface- mounted piezo-actuators.