Study On Electromechanical Response Characteristics Of PZT Under Synergistic Effect Of Temperature Stimulation And Shock

Hypersonic weapons and space-based platform launch are the key development directions of weapons in the world.Accelerometers,piezoelectric power supplies or disposable high-voltage pulse devices with PZT as the core device will face more stringent working conditions in future weapon systems.In foreign countries,lead zirconate titanate（PZT）is widely used in intelligent fuze because of its good long storage,high reliability and excellent electromechanical conversion characteristics.However,the electromechanical response characteristics of piezoelectric ceramics（PZT-5H）are still unclear due to the sudden change of temperature,which seriously hinders the application of piezoelectric ceramics in related fields.In this paper,PZT-5H is taken as the research object.The electromechanical response characteristics of PZT under different given temperatures,different temperature change rates and impact are studied by means of experimental research,theoretical analysis and numerical simulation.The main work and achievements of this paper are as follows:（1）By measuring the static electrical parameters of PZT-5 H at different given temperatures and different temperature change rates,the average pyroelectric coefficient of polarized lead zirconate titanate ceramics is 4.16×10^-8C/cm²°C in the temperature range of 25-160°C.（2）Under the condition of electrical open circuit,the stress load and electrical output characteristics of piezoelectric ceramics under different temperatures and different temperature change rates are measured.It can be seen that the piezoelectric ceramics still maintain the mechanical properties and show an enhanced trend at25-160°C.However,when the piezoelectric ceramics are impacted and broken,the pore defects and cracks at the fracture are one of the reasons for the difference between the two peak values of the output voltage.At room temperature,when the impact velocity is constant,the peak value of the output voltage of the piezoelectric ceramics（PZT-5H）is positively correlated with the load resistance.With the increase of ambient temperature,the mechanical and electrical properties of piezoelectric ceramics have changed.The piezoelectric voltage constant g₃₃（σ,ΔT）was calculated at different heating rates under electrical open circuit.Under the condition of similar stress and temperature,the piezoelectric voltage constant decreases with the increase of heating rate.In the temperature range of 25-100°C,the piezoelectric voltage constant increases with the increase of temperature.When the temperature exceeds 100°C,the piezoelectric voltage constant decreases with the increase of temperature.（3）The piezoelectric strain constant d₃₃（σ,ΔT）was calculated based on experiments under the conditions of electrical short circuit,different given temperatures and different temperature rise rates.Under the condition that the electric displacement is constant and the stress is the same,with the increase of temperature change rate,the electric displacement caused by pyroelectric effect becomes larger,so the piezoelectric strain constant becomes smaller.Under the condition of the same temperature change rate and the same stress,with the increase of temperature,the piezoelectric strain constant first increases slightly and then decreases sharply.The change of temperature will lead to the change of mechanical loss and electromechanical coupling of piezoelectric ceramics.Based on different given temperature,different temperature change rate and different electrical boundary（open circuit and short circuit）conditions,the elastic compliance coefficient S^Eunder short circuit condition,the elastic compliance coefficient S^Dunder open circuit condition and the electromechanical coupling coefficient k of piezoelectric ceramics are calculated.The elastic compliance coefficients of short circuit and open circuit with temperature of 160°C and temperature change rate of 150°C/min are the lowest.With the increase of temperature and temperature change rate,the electromechanical coupling ability increases first and then decreases.（4）Combined with the finite element software COMSOL Multiphysics,the numerical simulation of the internal potential calculation of piezoelectric ceramicswith different temperature change rates at different given temperatures is carried out.The internal potential of piezoelectric ceramics during heating is calculated.During the heating process of piezoelectric ceramics,there is a temperature difference inside the ceramics.With the increase of the given temperature,the temperature difference inside the ceramics gradually increases.The internal thermoelectric effect and pyroelectric effect caused by the temperature difference inside the ceramics are calculated by numerical simulation.The potential generated by the pyroelectric effect is under the influence of different given temperatures and different temperature change rates.The potential generated by the internal temperature difference of piezoelectric ceramics is much smaller than the voltage generated by the impact discharge of piezoelectric ceramics.Therefore,the pyroelectric effect can be ignored in the whole process of impulse discharge.