Electrical Properties of PZT Under High-Pressure Stress Pulse Effects of Loading Frequency and Circuit Load

2021 ◽  
Author(s):  
Ruizhi Wang ◽  
enling tang ◽  
Guolai Yang ◽  
Yafei Han ◽  
Chuang Chen ◽  
...  
Keyword(s):  
High Pressure ◽  
Strain Rate ◽  
Output Voltage ◽  
Load Resistance ◽  
Open Circuit ◽  
Loading Frequency ◽  
Stress Pulse ◽  
Pressure Stress ◽  
The Relationship ◽  
Electrical Output

Abstract The research on the discharge characteristics of PZT under conventional applications has made good progress. In theory, the piezoelectric equation can be used to describe the relationship between stress and electrical output. However, existing studies have shown that the relationship becomes nonlinear under high-pressure stress pulses. To study the effect of loading frequency and circuit load on the electrical output performance of PZT under high-pressure stress pulse, the experiment was carried out based on the split Hopkinson pressure bar and a dynamic & static universal test machine. The effects of different circuits load on the output voltage under high-frequency and low-frequency high-pressure stress pulses are analyzed. Both theory and experiments prove that the critical open-circuit measurement resistance (Rcritial) of PZT decreases with the load frequency. The output voltage is positively correlated with the load resistance when the load resistance is less than Rcritial. It is confirmed by loading different circuits (diodes are added in different positions) that reverse positive charge appears at the negative pole of the material during the stress unloading stage. PZT have the maximum dischargeable strain Tunder the high-pressure stress pulses. PZT no longer generates induced charges when the strain is greater than h. When constant strain rate loading makes PZT completely release energy, its open-circuit output voltage is proportional to the strain rate.

Difference between the cell wall roughnesses of mothers and daughters of Saccharomyces cerevisiae subjected to high pressure stress

Micron ◽  
2021 ◽  
pp. 103091
Author(s):  
Raissa D. Moura ◽  
Lauanda M. Carvalho ◽  
Brígida A.A. Spagnol ◽  
Tarcio Carneiro ◽  
Ane Catarine Tosi Costa ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
High Pressure ◽  
Cell Wall ◽  
Mothers And Daughters ◽  
Pressure Stress

scholarly journals Analytical Modeling of a Doubly Clamped Flexible Piezoelectric Energy Harvester with Axial Excitation and Its Experimental Characterization

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3861
Author(s):  
Jie Mei ◽  
Qiong Fan ◽  
Lijie Li ◽  
Dingfang Chen ◽  
Lin Xu ◽  
...  
Keyword(s):  
Output Power ◽  
Power Output ◽  
Output Voltage ◽  
Energy Harvester ◽  
Load Resistance ◽  
Engineering Practice ◽  
Maximum Output ◽  
Widespread Application ◽  
Piezoelectric Energy ◽  
Axial Excitation

With the rapid development of wearable electronics, novel power solutions are required to adapt to flexible surfaces for widespread applications, thus flexible energy harvesters have been extensively studied for their flexibility and stretchability. However, poor power output and insufficient sensitivity to environmental changes limit its widespread application in engineering practice. A doubly clamped flexible piezoelectric energy harvester (FPEH) with axial excitation is therefore proposed for higher power output in a low-frequency vibration environment. Combining the Euler–Bernoulli beam theory and the D’Alembert principle, the differential dynamic equation of the doubly clamped energy harvester is derived, in which the excitation mode of axial load with pre-deformation is considered. A numerical solution of voltage amplitude and average power is obtained using the Rayleigh–Ritz method. Output power of 22.5 μW at 27.1 Hz, with the optimal load resistance being 1 MΩ, is determined by the frequency sweeping analysis. In order to power electronic devices, the converted alternating electric energy should be rectified into direct current energy. By connecting to the MDA2500 standard rectified electric bridge, a rectified DC output voltage across the 1 MΩ load resistor is characterized to be 2.39 V. For further validation of the mechanical-electrical dynamical model of the doubly clamped flexible piezoelectric energy harvester, its output performances, including both its frequency response and resistance load matching performances, are experimentally characterized. From the experimental results, the maximum output power is 1.38 μW, with a load resistance of 5.7 MΩ at 27 Hz, and the rectified DC output voltage reaches 1.84 V, which shows coincidence with simulation results and is proved to be sufficient for powering LED electronics.

scholarly journals A ΔSOC-based equalization strategy applied to industry

2020 ◽  
Author(s):  
Maonan Wang ◽  
Chun Chang ◽  
Feng Ji
Keyword(s):  
Open Circuit ◽  
Battery Pack ◽  
Battery Management System ◽  
Battery Management ◽  
Battery Cell ◽  
New Strategy ◽  
The Difference ◽  
Relative Errors ◽  
The Relationship ◽  
Battery Cells

Abstract The voltage-based equalization strategy is widely used in the industry because the voltage (U) of the battery cell is very easy to obtain, but it is difficult to provide an accurate parameter for the battery management system (BMS). This study proposes a new equalization strategy, which is based on the difference between the state of charge (SOC) of any two battery cells in the battery pack, that is, a ΔSOC-based equalization strategy. The new strategy is not only as simple as the voltage-based equalization strategy, but it can also provide an accurate parameter for the BMS. Simply put, using the relationship between the open circuit voltage and the SOC of the battery pack, the proposed strategy can convert the difference between the voltage of the battery cells into ΔSOC, which renders a good performance. Additionally, the required parameters are all from the BMS, and no additional calculation is required, which makes the strategy as simple as the voltage-based balancing strategy. The four experiments show that the relative errors of ΔSOC estimated by the ΔSOC-based equalization strategy are 0.37%, 0.39%, 0.1% and 0.17%, and thereby demonstrate that the ΔSOC-based equalization strategy proposed in this study shows promise in replacing the voltage-based equalization strategy within the industry to obtain better performance.

scholarly journals Coupled Thermomechanical Response Measurement of Deformation of Nickel-Based Superalloys Using Full-Field Digital Image Correlation and Infrared Thermography

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2163
Author(s):  
Krzysztof Żaba ◽  
Tomasz Trzepieciński ◽  
Sandra Puchlerska ◽  
Piotr Noga ◽  
Maciej Balcerzak
Keyword(s):  
Surface Temperature ◽  
Strain Rate ◽  
Rolling Direction ◽  
Image Correlation ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Response Measurement ◽  
Sheet Rolling ◽  
Inconel Alloys ◽  
The Relationship

The paper is devoted to highlighting the potential application of the quantitative imaging technique through results associated with work hardening, strain rate and heat generated during elastic and plastic deformation. The aim of the research presented in this article is to determine the relationship between deformation in the uniaxial tensile test of samples made of 1-mm-thick nickel-based superalloys and their change in temperature during deformation. The relationship between yield stress and the Taylor–Quinney coefficient and their change with the strain rate were determined. The research material was 1-mm-thick sheets of three grades of Inconel alloys: 625 HX and 718. The Aramis (GOM GmbH, a company of the ZEISS Group) measurement system and high-sensitivity infrared thermal imaging camera were used for the tests. The uniaxial tensile tests were carried out at three different strain rates. A clear tendency to increase the sample temperature with an increase in the strain rate was observed. This conclusion applies to all materials and directions of sample cutting investigated with respect to the sheet-rolling direction. An almost linear correlation was found between the percent strain and the value of the maximum surface temperature of the specimens. The method used is helpful in assessing the extent of homogeneity of the strain and the material effort during its deformation based on the measurement of the surface temperature.

Viscous Rayleigh-Taylor Instability Experiments at High Pressure and Strain Rate

2010 ◽  
Vol 104 (13) ◽  
Author(s):  
Hye-Sook Park ◽  
K. T. Lorenz ◽  
R. M. Cavallo ◽  
S. M. Pollaine ◽  
S. T. Prisbrey ◽  
...  
Keyword(s):  
High Pressure ◽  
Strain Rate ◽  
Taylor Instability ◽  
Rayleigh Taylor Instability

Maximal Oxygen Uptake and Daily Physical Activity in 7- to 12-Year-Old Boys

1993 ◽  
Vol 5 (4) ◽  
pp. 357-366 ◽  
Author(s):  
Hazzaa M. Al-Hazzaa ◽  
Mohammed A. Sulaiman
Keyword(s):  
Physical Activity ◽  
Heart Rate ◽  
Oxygen Uptake ◽  
Maximal Oxygen Uptake ◽  
Open Circuit ◽  
Daily Physical Activity ◽  
Activity Level ◽  
Activity Levels ◽  
School Time ◽  
The Relationship

The present study examined the relationship between maximal oxygen uptake (V̇O2max) and daily physical activity in a group of 7- to 12-year-old boys. V̇O2max was assessed through the incremental treadmill test using an open circuit system. Physical activity level was obtained from heart rate telemetry outside of school time for 8 hrs during weekdays and during 40 min of physical education classes. The findings indicated that the absolute value of V̇O2max increased with age, while relative to body weight it remained almost the same across age, with a mean of 48.4 ml · kg−1 · min−1. Moreover, heart rate telemetry showed that the boys spent a limited amount of time on activities that raise the heart rate to a level above 160 bpm (an average of 1.9%). In addition, V̇O2max was found to be significantly related to the percentage of time spent at activity levels at or above a heart rate of 140 bpm, but not with activity levels at or above a heart rate of 160 bpm.

Broadband Rotational Energy Harvesting Using Micro Energy Harvester

2018 ◽  
Author(s):  
Jui-Ta Chien ◽  
Yung-Hsing Fu ◽  
Chao-Ting Chen ◽  
Shun-Chiu Lin ◽  
Yi-Chung Shu ◽  
...  
Keyword(s):  
Energy Harvesting ◽  
Output Voltage ◽  
Energy Harvester ◽  
Low Frequency ◽  
Rotational Energy ◽  
Open Circuit ◽  
Maximum Output ◽  
Rotational Excitation ◽  
Rotating Speed ◽  
Piezoelectric Energy

This paper proposes a broadband rotational energy harvesting setup by using micro piezoelectric energy harvester (PEH). When driven in different rotating speed, the PEH can output relatively high power which exhibits the phenomenon of frequency up-conversion transforming the low frequency of rotation into the high frequency of resonant vibration. It aims to power self-powered devices used in the applications, like smart tires, smart bearings, and health monitoring sensors on rotational machines. Through the excitation of the rotary magnetic repulsion, the cantilever beam presents periodically damped oscillation. Under the rotational excitation, the maximum output voltage and power of PEH with optimal impedance is 28.2 Vpp and 663 μW, respectively. The output performance of the same energy harvester driven in ordinary vibrational based excitation is compared with rotational oscillation under open circuit condition. The maximum output voltage under 2.5g acceleration level of vibration is 27.54 Vpp while the peak output voltage of 36.5 Vpp in rotational excitation (in 265 rpm).

scholarly journals Effect of the Strain Rate on the Fracture Behaviour of High Pressure Pre-Charged Samples

Proceedings ◽  
2018 ◽  
Vol 2 (23) ◽  
pp. 1417
Author(s):  
Guillermo Álvarez Díaz ◽  
Tomás Eduardo García Suárez ◽  
Cristina. Rodríguez González ◽  
Francisco Javier Belzunce Varela
Keyword(s):  
Fracture Toughness ◽  
High Pressure ◽  
Hydrogen Embrittlement ◽  
Strain Rate ◽  
Fracture Behaviour ◽  
Structural Steels ◽  
Gaseous Hydrogen ◽  
Displacement Rate ◽  
Steel Strength ◽  
Fracture Tests

The aim of this work is to study the effect of the displacement rate on the hydrogen embrittlement of two different structural steels grades used in energetic applications. With this purpose, samples were pre-charged with gaseous hydrogen at 19.5 MPa and 450 °C for 21 h. Then, fracture tests of the pre-charged specimens were performed, using different displacement rates. It is showed that the lower is the displacement rate and the largest is the steel strength, the strongest is the reduction of the fracture toughness due to the presence of internal hydrogen.

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