Ue to a delay within the measuring system, and not given by a damaging damping coefficient. Figure 11 shows the calibrated frequency response functions AM, MI, AS and its phase for two compliant elements: 1 with double rubber buffer in each stack (Figure 4a) as well as the other one particular with a single rubber buffer in every single stack (Figure 4b). Halving the stacks of your rubber buffer doubles the stiffness from compliant element A to B. This could be clearly seen in the low frequency range of ASmeas. and increases as well the all-natural frequency. Both compliant elements show a stiffness dominated behavior. The stiffness of element B with 540 N/mm is just not twice as significant as that of element A with 300 N/mm. That is most likely because of the nonlinear behavior on the rubber buffers themselves, since the single stacks are compressed twice as substantially as the double stacks in the same amplitude. The phase DPX-H6573 supplier difference of each compliant components are practically equal in front from the first natural frequency.Appl. Sci. 2021, 11,15 ofFigure 10. Apparent Stiffness directly measured ASmeas. and calibrated AStestobj. of your compliant element A in the low frequency test bench.The calibrated measurement of compliant element A has its organic frequency at around 190 Hz (Figure 11 blue dots) and compliant element B at 240 Hz (Figure 11 black dots). For element A it is shown that the non-calibrated measurement supplies a natural frequency of about 80 Hz (Figure 9) and the non-calibrated measurement from the compliant element B determines a natural frequency of 110 Hz. The relative difference between the non-calibrated towards the calibrated measurement for the offered elements is larger than the difference in between the two elements themselves. This once more shows the higher sensitivity from the test results by mass cancellation and measurement systems FRF H I pp . three.five. Findings from the Performed Dynamic Calibration The compliant structures presented in literature (Section 1) happen to be investigated in precise test ranges. For the use of AIEs as interface components in vibration testing further application needs have to be fulfilled. An increase in the investigated force, displacement and frequency range of the test object leads to the necessity to calibrate the test benches within the complete test range. Investigations with the FRFs AS, MI and AM show deviations in the best behavior of a freely vibration mass. Calibration quantities is usually calculated by the known systematic deviation from the best behavior. The investigations around the vibrating mass plus the compliant elements have shown the influence and resulting possibilities around the measurement final results by mass cancellation and measurement systems FRF H I pp . To be sure that these influences do not only apply to a single precise sensor and measuring technique, the investigation was carried out around the two clearly various systems presented. This led to distinct calibration values for H I pp and msensor . Consequently, the calibration quantities should be determined for every configuration. Even when the test setup isn’t changed, “frequent checks on the calibration elements are strongly recommended” [26]. The measurement systems FRF H I pp is determined only for the test information of the freely vibration mass, and is limited at its ends. Moreover, the function H I pp ( f ) is determined by the data accuracy from which it really is made. The residual should be determined from applying adequate data and also the accuracy really should be evaluated. The measurement systems FRF H I pp and.
