摘要
The utilization of piezoelectric materials in MEMS devices under harsh environments has gained affordable appreciations due to its unique mechanical and electrical material properties.However,the reliability of MEMS devices triggered by fatigue damage remains elusive and needs to be further explored.Here,we present a continuum constitutive model for piezoelectric materials containing a substantive amount of randomly dispersed microcracks.The constitutive equation of the piezoelectric materials with microcracks is formulated via Helmholtz free energy by combining the Kachanvo damage evolution law and the Chaboche fatigue damage development to express the fatigue damage growth.A case of the fatigue damage analysis of the piezoelectric microplate with transverse matrix cracks in the status of plane stress is presented by adopting the von Karman’s plate theory.With numerical schemes employed,the effect of cyclic impulsive loadings and electrical loadings on the fatigue damage and fatigue life prediction of a piezoelectric microplate is investigated and discussed.The findings provide valuable insights into the fundamental mechanism of reliability in piezoelectric MEMS devices due to cyclic loadings,thereby offering new ways to exploit and fabricate the piezoelectric-based MEMS devices suitable for harsh conditions.
