Rheological properties and viscoelastic model of sensor-enabled piezoelectric geocable Available to Purchase

Sensor-enabled piezoelectric geocables (SPGC) have attracted widespread attention as an emerging technology due to their effective strain and vibration monitoring effects. However, the mechanical and electrical properties of SPGC during long-term rheological processing remain unclear. In this study, the stepped isothermal method (SIM) was used to perform creep tests under different constant loads, and stress relaxation tests were conducted under different initial strains and strain rates. The creep test results show that SPGCs exhibit a decaying creep curve and are a typical viscoelastic-plastic material. The time-strain and the time-normalized impedance change value curves of SPGC conform to the logarithmic creep empirical model and viscoelastic constitutive model. The normalized impedance change value of SPGC increased with the increase of initial stress level and creep strain. At initial stress levels of 30%, 50%, and 60%σ_T, the creep strains of SPGC after 51.3  years were expected to reach 1.08%, 3.29%, and 5.31%, and the corresponding normalized impedance change values would reach 0.0771, 0.1704, and 0.2246. The results of the stress relaxation test showed that the normalized impedance change value of SPGC decreased with stress relaxation. The normalized impedance change value had a linear functional relationship with both the initial strain and the strain rate. The tensile strain and strain rate of SPGC caused by the sliding surface of the soil can be determined by monitoring the rate of growth of the normalized impedance change value. The research results fill a gap in the long-term rheological properties of SPGC and provide support for further practical applications of SPGC.