The effect of applied stress on the phase and group velocity of guided waves in anisotropic plates

2017 ◽  
Vol 142 (6) ◽  
pp. 3553-3563 ◽  
Author(s):  
Brennan Dubuc ◽  
Arvin Ebrahimkhanlou ◽  
Salvatore Salamone
Keyword(s):  
Group Velocity ◽  
Applied Stress ◽  
Guided Waves ◽  
Anisotropic Plates

scholarly journals Automated In-Process Cure Monitoring of Composite Laminates Using a Guided Wave-Based System With High-Temperature Piezoelectric Transducers

2018 ◽  
Vol 1 (2) ◽  
Author(s):  
Tyler B. Hudson ◽  
Fuh-Gwo Yuan
Keyword(s):  
High Temperature ◽  
Group Velocity ◽  
Guided Waves ◽  
Glassy State ◽  
Guided Wave ◽  
Piezoelectric Transducers ◽  
State Transitions ◽  
Degree Of Cure ◽  
Cure Cycle ◽  
Cure Monitoring

An in-process cure monitoring technique based on “guided wave” concept for carbon fiber reinforced polymer (CFRP) composites was developed. Key parameters including physical properties (viscosity and degree of cure) and state transitions (gelation and vitrification) during the cure cycle were clearly identified experimentally from the amplitude and group velocity of guided waves, validated via the semi-empirical cure process modeling software RAVEN. Using the newly developed cure monitoring system, an array of high-temperature piezoelectric transducers acting as an actuator and sensors were employed to excite and sense guided wave signals, in terms of voltage, through unidirectional composite panels fabricated from Hexcel® IM7/8552 prepreg during cure in an oven. Average normalized peak voltage, which pertains to the wave amplitude, was selected as a metric to describe the guided waves phenomena throughout the entire cure cycle. During the transition from rubbery to glassy state, the group velocity of the guided waves was investigated for connection with degree of cure, Tg, and mechanical properties. This work demonstrated the feasibility of in-process cure monitoring and continued progress toward a closed-loop process control to maximize composite part quality and consistency.

General formalism for plane guided waves in transversely inhomogeneous anisotropic plates

Wave Motion ◽  
2004 ◽  
Vol 40 (4) ◽  
pp. 413-426 ◽  
Author(s):  
A.L. Shuvalov ◽  
O. Poncelet ◽  
M. Deschamps
Keyword(s):  
Guided Waves ◽  
Anisotropic Plates

Parameters Choice in Detection of Viscous Liquid-Filled Pipelines With Axial Power Flow Distributions of Ultrasonic Guided Waves

2004 ◽  
Author(s):  
Dean Ta ◽  
Zhenqing Liu
Keyword(s):  
Group Velocity ◽  
Viscous Liquid ◽  
Power Flow ◽  
Guided Waves ◽  
Amplitude Distribution ◽  
Propagation Characteristic ◽  
The Other ◽  
Wave Number ◽  
Elastic Pipes ◽  
Complex Dispersion

The propagation characteristic of ultrasonic longitudinal guided waves in viscous liquid-filled elastic pipes is investigated. The complex dispersion curves were computed on the assumption that the frequency is real number and wave number is complex number. Then an analysis is carried out of the Axial Power Flow (APF) amplitude and attenuation distributions. Finally, the optimal location, optimal mode and its frequency-thickness products (fd) of testing for pipes filled with viscous liquid are chosen by the APF and attenuation distributions. The results showed that the APF amplitude distribution is an effective parameter to choose modes and parameters of testing for pipes. On the other hand, at the ranges of fd of larger group velocity of each mode, this mode has feeble dispersion, while the other modes have smaller group velocity and stronger dispersion. And in that range, the mode has a larger APF at the wall of pipes. Therefore, at the range of fd of larger group velocity of each mode, this mode is used to test elastic pipes filled with viscous liquid should be more effective, the results agree with each other.

scholarly journals Effects of Adhesive Parameters on Dispersion Characteristics of Ultrasonic Guided Waves in Composite Pipes

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Juanjuan Li ◽  
Yan Han
Keyword(s):  
Group Velocity ◽  
Guided Waves ◽  
Velocity Dispersion ◽  
Group Velocity Dispersion ◽  
Adhesive Layer ◽  
Dispersion Curves ◽  
Ultrasonic Guided Waves ◽  
Bonding Quality ◽  
Mode Identification ◽  
Composite Pipes

The aim of the investigation presented here was to understand how the viscosity parameters of an adhesive layer affect group velocity and attenuation of the double-layer adhered pipe. Various parameter combinations (attenuation of longitudinal wave and shear wave, pαL and qαT; thickness, d; and density, nρ) were utilized in order to generate different uncured degrees of the adhesive layer. In the frequency range 0∼500 kHz, the group velocity dispersion curves and attenuation dispersion curves were obtained from these models. Then, the group velocity and attenuation of the two commonly used modes, L0,2 and T0,1, were compared and analyzed. The results have shown that it is important to remark that little effect on group velocity was caused, and significant linear increases of attenuation occur with increase in q, d, and n. However, variable p had little effect on attenuation; more modes emerged when d increased or n decreased, causing difficulties on mode identification and signal processing. The numerical results provided a useful way to evaluate bonding quality by measuring the group velocity and attenuation in the pipelines.

New approach to detection of guided waves with negative group velocity: Modeling and experiment

2019 ◽  
Vol 442 ◽  
pp. 155-166 ◽  
Author(s):  
Boris Zaitsev ◽  
Iren Kuznetsova ◽  
Ilya Nedospasov ◽  
Andrey Smirnov ◽  
Alexander Semyonov
Keyword(s):  
Group Velocity ◽  
Guided Waves ◽  
Negative Group ◽  
New Approach ◽  
Velocity Modeling ◽  
Negative Group Velocity

scholarly journals Static component generation and measurement of nonlinear guided waves with group velocity mismatch

2021 ◽  
Vol 1 (5) ◽  
pp. 055601
Author(s):  
Chang Jiang ◽  
Weibin Li ◽  
Mingxi Deng ◽  
Ching-Tai Ng
Keyword(s):  
Group Velocity ◽  
Guided Waves ◽  
Static Component ◽  
Group Velocity Mismatch ◽  
Velocity Mismatch
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