This equation helps to improve the relative sensitivity of the piezoelectric accelerometer by reducing the error. The expression of cutoff pulse ωC is given by the following relation: ω C tan δ listed in Table 1 [21]. Simulation Results The parameters of the piezoelectric sensor used for simulation of the developed model are: a sensor natural frequency equal 10000 Hz; damping ratio equal 0.6, 0.63, 0.65, 0.68 and 0.7; relative frequency of movement varies from 0 to 4200 Hz; and amplitude of the movement is 0.5 mm. Table 2 and Fig. 3 show the displacement of the movement Fig. 3. Displacement according to relative frequency of movement (from [21], ©2018 Springer, used with permission). Sr 1 1 c 2 Y 2 . z 2 (18) The replacement of (13) in (17) allows new relation to be written that connects the relative sensitivity according to the measurement error: Sr 1 1 c 2 .1 E (19) (z) according to the variation of relative frequency and for different values of the accelerometer damping ratio. The values listed in the table show that the displacement has slightly varied with the damping rate variation. There is a little difference between the five curves in Fig. 3, which implies the effect of the damping rate variation on the piezoelectric sensor measurement error. For this purpose, the equation of measurement error is simulated to extract the suitable damping ratio to reduce it. The results are illustrated in Table 3 and Fig. 4. Table 3 presents the results of error according to relative frequency for five damping ratios. These results indicate that: ◗ For a relative frequency variation of 0 to 4200 Hz and a damping rate choice equals to 0.6, the error does not exceed a value which equals 3.57%. (20) The parameters of the piezoelectric material PZT (PZ27) are Table 3 - Measurement error results Error (%)