https://link.springer.com/content/pdf/10.1007/s13198-021-01404-4.pdf

AI based study on product development and process design

FEM implementation of the nonlinear damage evolution model for piezoelectric material under bipolar electrical fatigue load

This article first reviews the position control of piezoelectric actuators, particularly charge-based sensorless control systems, which often include a charge estimator as a key component. The rest of the paper is about charge estimators for piezoelectric actuators. Two of the most recent/effective types of these estimators utilise either a sensing capacitor (type I in this paper) or a sensing resistor (type II); the latter (and the newer) type is broadly known as a digital charge estimator. Some experimental results in the literature show that, with the same loss in excitation voltage, a considerably higher amount of charge can be estimated with a type II estimator in comparison with a type I estimator; therefore, the superiority of type II estimators was acknowledged. In order to re-assess this conclusion, this paper equitably compares type I and II estimators through analytical modelling and experimentation. The results indicate that type II estimators have only a slight advantage in estimating higher amounts of charge, if both type I and II estimators are designed appropriately. At the same time, type II estimators have disadvantages; e.g., the resistance of type II estimators has to be tuned to suit different excitation frequencies. This research concludes that capacitor-based (type I) charge estimators for piezoelectric actuators, with pertinent design and implementation, can be still the prime solution for many charge estimation problems despite claims in the literature in the last decade.

/pdf/charge-estimation-of-piezoelectric-actuators-a-comparative-2wdg5au6.pdf

Charge Estimation of Piezoelectric Actuators: A Comparative Study

A new piezoelectric actuator combining interdigitated ring electrodes and a PZT-52(Lead Zirconate Titanate) disk was investigated for the large displacement requirements of piezoelectric actuators. Finite element models were established according to the structural characteristics of the actuator and static analysis was carried out based on ANSYS software. Then Ø25 mm × 2 mm samples were prepared. The displacement detection system was established, and the influence of electrode structure on radial displacement was studied experimentally. A comparison between the experimental results and the finite element analysis confirmed that the finite element model was correct. The results showed that the effect of electrode width on displacement was small. With decrease in electrode center distance and increase in the number of electrodes pairs, the radial displacement increased correspondingly. The peak of radial displacement was 1.63 μm under a 200 V voltage excitation voltage of 0.2 Hz. This was 2.5 times that for a conventional electrode piezo disk with the same structure. The actuator demonstrated better displacement properties. The piezoelectric disk could be valuable in applications involving micro-nano devices.

/pdf/finite-element-modeling-and-test-of-piezo-disk-with-local-w6yuqae4.pdf

Finite Element Modeling and Test of Piezo Disk with Local Ring Electrodes for Micro Displacement

Abstract The service life of piezoelectric devices is significantly affected by the electric fatigue load. The randomness of loads and nonuniformity of material properties caused by random distribution of internal defects in piezoelectric body will lead to the dispersion of the failure life of piezoelectric devices. Predicting failure probability of piezoelectric materials under electric fatigue load is essential for the reliability and life prediction of piezoelectric structures and devices. In this paper, the initial damage of piezoelectric materials is modeled as a random variable. Based on the methods of probability theory and statistics, the failure probability assessment model of piezoelectric materials under electric fatigue load is proposed. The probability density function of initial damage is obtained by observation and statistics of initial defect area. The failure probability assessment model of piezoelectric materials under electric fatigue load can be obtained by probability theory and integral method. Meanwhile, the failure probability evolution of piezoelectric materials under various electric fatigue loads is considered. The results show that the failure life and dispersion of piezoelectric materials is significantly affected by electric fatigue load, and the variation of failure probability under various electric loads is similar. Based on the proposed failure probability assessment models, the randomness of the electric load and randomly distributed initial defects of materials are considered in the damage evolution and performance prediction of piezoelectric structures, which is an important supplement to the reliability prediction and application of piezoelectric devices.

The failure probability assessment model of piezoelectric materials under electric fatigue load

In order to process micro scale parts more conveniently, especially the micro parts with complex shape, a new micro blanking equipment based on piezoelectric ceramic driving is proposed in this paper. Compared with other large precision machining equipment, the equipment cost has been greatly reduced. Using displacement sensor to detect the change of output displacement and feedback control piezoelectric actuator to control the change of relevant parameters, the control precision is high. The micro gear parts with diameter less than 2 mm are obtained through the blanking experiment on the experimental equipment. From the relationship between the obtained time and the punch output force, output displacement and die adjustment, it can be seen that the designed equipment has good processing performance and can complete the blanking forming of micro parts well.

https://www.mdpi.com/2072-666X/12/2/200/pdf

Changjun Hu

Papers

Research on Precision Blanking Process Design of Micro Gear Based on Piezoelectric Actuator.