Imperfect Elasticity of Rock: Its Influence on the Velocity of Stress Waves

A Concise Review on the Interaction Between Stress Waves and Cracks

10.21236/ada499445 ◽

2009 ◽

Author(s):

Cyril Williams

Keyword(s):

Stress Waves ◽

Concise Review

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Analysis of the expansion process of cracks caused by blasting stress waves in a PMMA medium with filled defects

Materials Today Communications ◽

10.1016/j.mtcomm.2021.102396 ◽

2021 ◽

pp. 102396

Author(s):

Yanbing Wang ◽

Jiaqing Dong ◽

Zhaoyang Wang ◽

Yabin Zhao

Keyword(s):

Stress Waves ◽

Expansion Process

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Design and Analysis of a Novel Piezoceramic Stack-based Smart Aggregate

Sensors ◽

10.3390/s20226438 ◽

2020 ◽

Vol 20 (22) ◽

pp. 6438

Author(s):

Guangtao Lu ◽

Xin Zhu ◽

Tao Wang ◽

Zhiqiang Hao ◽

Bohai Tan

Keyword(s):

Resonance Frequency ◽

Electromechanical Coupling ◽

Structural Parameters ◽

Electromechanical Coupling Factor ◽

Coupling Factor ◽

Stress Waves ◽

Parallel Connection ◽

Smart Aggregate ◽

In Series ◽

Piezoelectric Wafers

A novel piezoceramic stack-based smart aggregate (PiSSA) with piezoceramic wafers in series or parallel connection is developed to increase the efficiency and output performance over the conventional smart aggregate with only one piezoelectric patch. Due to the improvement, PiSSA is suitable for situations where the stress waves easily attenuate. In PiSSA, the piezoelectric wafers are electrically connected in series or parallel, and three types of piezoelectric wafers with different electrode patterns are designed for easy connection. Based on the theory of piezo-elasticity, a simplified one-dimensional model is derived to study the electromechanical, transmitting and sensing performance of PiSSAs with the wafers in series and parallel connection, and the model was verified by experiments. The theoretical results reveal that the first resonance frequency of PiSSAs in series and parallel decreases as the number or thickness of the PZT wafers increases, and the first electromechanical coupling factor increases firstly and then decrease gradually as the number or thickness increases. The results also show that both the first resonance frequency and the first electromechanical coupling factor of PiSSA in series and parallel change no more than 0.87% as the Young’s modulus of the epoxy increases from 0.5 to 1.5 times 3.2 GPa, which is helpful for the fabrication of PiSSAs. In addition, the displacement output of PiSSAs in parallel is about 2.18–22.49 times that in series at 1–50 kHz, while the voltage output of PiSSAs in parallel is much less than that in parallel, which indicates that PiSSA in parallel is much more suitable for working as an actuator to excite stress waves and PiSSA in series is suitable for working as a sensor to detect the waves. All the results demonstrate that the connecting type, number and thickness of the PZT wafers should be carefully selected to increase the efficiency and output of PiSSA actuators and sensors. This study contributes to providing a method to investigate the characteristics and optimize the structural parameters of the proposed PiSSAs.

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