Correction: Lange et al. Performance of a Piezoelectric Energy Harvesting System for an Energy-Autonomous Instrumented Total Hip Replacement: Experimental and Numerical Evaluation. Materials 2021, 14, 5151.

The authors wish to make the following corrections to their paper [...].

Error in Figure

The authors wish to make the following corrections to their paper [1]. In the original publication, there was a mistake in Figure 4 as published. A conversion problem led to a corrupted left line in the circuit diagram. The corrected Figure 4 appears below.

Figure 4

Measuring circuit of the piezoelectric element (PZT) for different load resistances with a voltage divider and an oscilloscope.

Text Correction

A correction has been made to Section 2.2.3. Mechanical Testing. There was an error in the original publication. In Equation (5), V was used instead of V:

Furthermore, there was an error introduced in the original publication after our proofreading. The text belonging to Appendix B was misleadingly placed in Appendix A. We reduced our Appendix to only one main section with two sub-sections and adopted the references in the main text.

A correction has been made to as follows:

The reference has been adopted in Section 3.1. Results of Finite Element Analysis: Deformation, Loading, and Sensitivity:

The results of the sensitivity analysis are described below, revealing the relevant input parameters influencing the output. The full result data are shown in Figure A1, Appendix A.1.

Figure A1

Results of the sensitivity analysis (absolute values in blue and percent deviation in red). The dashed line represents the original value of the reference model. For convenience, the absolute values of the percentages are shown. (a) Simulated strain for the strain gauge (µm/m); (b) displacement of point C in vertical direction of the uniaxial testing machine (direction of the acting force) (mm); (c) contact force F33 acting on the piezoelectric element’s end faces in the direction of its cylinder axis (N); (d) generated power calculated from F33 (µW); (e) maximum von Mises stress in the implant cavity σimp (MPa); and (f) maximum von Mises stress in the piezoelectric element mid plane cross-section σpiez (MPa). (Abbreviations: E—Young’s modulus; AP—antero-posterior; ML—medio-lateral).

The results of the sensitivity analysis show that the contact force F33 and the open-circuit voltage VOC were identically influenced; therefore, only the contact force F33 is presented and shown in Figure A1, Appendix A.1.

The reference has been adopted in Section 4.2.3. Interpretation of Numerical Model and Relation with Experiments:

Model calibration can also be considered, promising a solution with less effort. This is shown in Appendix A.2. Based on a simple loading regime and experimental measurements, the numerical data could be fitted and the calibrated model could predict the voltage curves and power output for a more complex force profile.

The reference has been adopted in Section 5. Conclusions:

Depending on the research question, the numerical model requires an extension to enhance its predictive power. A first step could be calibration, as shown in Appendix A.2.

A correction has been made to the Appendix A: