scholarly journals Numerical Study of Concrete Mesostructure Effect on Lamb Wave Propagation

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2570 ◽  
Author(s):  
Beata Zima ◽  
Rafał Kędra
Keyword(s):  
Particle Size ◽  
Wave Propagation ◽  
Lamb Wave ◽  
Lamb Waves ◽  
Numerical Study ◽  
Diagnostic Methods ◽  
Material Parameters ◽  
The Difference ◽  
Dispersion Solution ◽  
Lamb Wave Propagation

The article presents the results of the numerical investigation of Lamb wave propagation in concrete plates while taking into account the complex concrete mesostructure. Several concrete models with randomly distributed aggregates were generated with the use of the Monte Carlo method. The influence of aggregate ratio and particle size on dispersion curves representing Lamb wave modes was analyzed. The results obtained for heterogeneous concrete models were compared with theoretical results for homogeneous concrete characterized by the averaged macroscopic material parameters. The analysis indicated that not only do the averaged material parameters influence the dispersion solution, but also the amount and size of aggregate particles. The study shows that Lamb waves propagate with different velocities in homogeneous and heterogeneous models and the difference increases with aggregate ratio and particle size, which is a particularly important observation for wave-based diagnostic methods devoted to concrete structures.

Lamb Wave Propagation in Anisotropic Laminates

1990 ◽  
Vol 57 (4) ◽  
pp. 923-929 ◽  
Author(s):  
G. R. Liu ◽  
J. Tani ◽  
K. Watanabe ◽  
T. Ohyoshi
Keyword(s):  
Wave Propagation ◽  
Energy Distribution ◽  
Hybrid Composite ◽  
Lamb Wave ◽  
Composite Laminates ◽  
Strain Energy ◽  
Lamb Waves ◽  
Energy Distributions ◽  
Phase Velocities ◽  
Lamb Wave Propagation

The wave propagation in arbitrary anisotropic laminates is investigated on the basis of an exact theory. The dispersion relations of Lamb waves are determined for graphite/epoxy symmetric angle-ply laminates and hybrid composite ones which consist of carbon/epoxy and glass/epoxy layers. The dispersion and anisotropy of phase velocities for fundamental modes are discussed in detail. The energy distributions in the thickness direction of laminates are calculated for each kind of Lamb wave. A hybrid composite laminate is found to have better capability in absorbing impact energy by analyzing the strain energy distribution during the wave propagation. The results of the strain energy distribution are useful in determining the arrangement and the fiber orientation of the layers of hybrid composite laminates.

Cauchy formalism for Lamb waves in functionally graded plates

2018 ◽  
Vol 25 (6) ◽  
pp. 1227-1232 ◽  
Author(s):  
Sergey V. Kuznetsov
Keyword(s):  
Wave Propagation ◽  
Functionally Graded Materials ◽  
Lamb Wave ◽  
Lamb Waves ◽  
Functionally Graded ◽  
Functionally Graded Plates ◽  
Graded Materials ◽  
Anisotropic Plates ◽  
Transverse Inhomogeneity ◽  
Lamb Wave Propagation

Propagation of harmonic Lamb waves in plates made of functionally graded materials with transverse inhomogeneity is analyzed by applying Cauchy six-dimensional formalism previously developed for the study of Lamb wave propagation in homogeneous or stratified anisotropic plates. For anisotropic plates with arbitrary transverse inhomogeneity a closed form implicit solution for the dispersion equation is derived and analyzed.

Impact of Changing Temperature on Lamb Wave Propagation for Damage Detection

2013 ◽  
Vol 588 ◽  
pp. 140-148 ◽  
Author(s):  
Rafal Radecki ◽  
Wieslaw Jerzy Staszewski ◽  
Tadeusz Uhl
Keyword(s):  
Wave Propagation ◽  
Damage Detection ◽  
Lamb Wave ◽  
Structural Damage ◽  
Clustering Algorithm ◽  
Lamb Waves ◽  
Ultrasonic Waves ◽  
Effect Of Temperature ◽  
Propagation Parameters ◽  
Lamb Wave Propagation

Lamb waves are the most widely used guided ultrasonic waves for structural damage detection. One of the major problems associate with Lamb wave propagation is the effect of temperature on wave propagation parameters. It is important that these parameters are more sensitive to damage than to varying temperature. The paper demonstrates how amplitude and arrival time of Lamb waves are affected by temperature. The analysis is performed for the experimental data gathered from Lamb wave propagation in a damaged aluminium plate. A simple clustering algorithm is used to distinguish between "undamaged" and "damaged" conditions in the presence of changing temperature.

Lamb Wave Propagation Through Off-Axis Media

2011 ◽  
Author(s):  
Jacob Brown ◽  
Whitney Reynolds ◽  
Derek Doyle ◽  
Andrei Zagrai
Keyword(s):  
Wave Propagation ◽  
Elastic Wave ◽  
Wave Velocity ◽  
Lamb Wave ◽  
Composite Structures ◽  
Lamb Waves ◽  
Resin Matrix ◽  
Space Structures ◽  
Propagation Characteristics ◽  
Lamb Wave Propagation

The use of elastic wave based Structural Health Monitoring has shown its usefulness in both characterizing and diagnosing composite structures. Techniques using elastic wave SHM are being developed to allow for improved efficiency and assurance in all stages of space structure development and deployment. These techniques utilize precise understanding of wave propagation characteristics to extract meaningful information regarding the health and validity of a component, assembly, or structure. However, many of these techniques focus on the diagnostic of traditional, isotropic materials, and questions remain as to the effect of the orthotropic properties of resin matrix composite material on the propagation of elastic waves. As the demands and expectations placed upon composite structures continue to expand in the space community, these questions must be addressed to allow the development of elastic wave based SHM techniques that will enable advancements in areas such as automated build validation and qualification, and in-situ characterization and evaluation of increasingly complex space structures. This study attempts to aid this development by examines the effect of cross ply, off-axis fiber orientation on the propagation characteristics of lamb waves. This is achieved by observing the result of symmetric and anti-symmetric wave propagation across materials in cases containing both off-axis and axially-aligned elements. In both cases the surface plies of the test specimen are axially aligned with the wave propagation direction. Using these results, the relative effect of core ply orientation on lamb wave propagation, and lamb wave sensitivity to bulk properties, or alternatively, the dominance of surface properties on propagation characteristics, can be seen, and this information can be used to aid in future research and application of lamb waves for interrogation of advanced, high-strain composite space structures. It was found that the core orientation caused significant variation in the S0 wave velocity, while yielding little influence on the A0 wave velocity.

Temperature Influence Compensation for Lamb Wave Damage Detection

2011 ◽  
Vol 105-107 ◽  
pp. 621-625
Author(s):  
Wen Zhong Qu ◽  
D.J. Inman
Keyword(s):  
Wave Propagation ◽  
Lamb Wave ◽  
Elevated Temperatures ◽  
Lamb Waves ◽  
Guided Wave ◽  
Diagnostic Tools ◽  
Temperature Influence ◽  
Compensation Approach ◽  
Lamb Wave Propagation ◽  
Piezoelectric Wafers

Among structural health monitoring (SHM) techniques, Lamb waves is frequently used as diagnostic tools to detect damage in plate-like structures. Temperature variation can cause significant changes in guided-wave propagation and transduction for SHM. In this paper, controlled experiments examine changes in Lamb wave propagation and transduction using PZT-5A piezoelectric wafers under quasi-statically varying temperature (from 5°C to 60°C). The baseline selection method and baseline signal stretch method are used to compensate the temperature influence on Lamb wave propagation. The results of the experiments demonstrate the effectiveness of the temperature compensation approach and the simulated damage on the plate can be detected effectively under elevated temperatures environment.

Gas Accumulation Detection in a Water Tank Using Lamb Waves

2012 ◽  
Author(s):  
Lingyu Yu ◽  
Zhenhua Tian ◽  
Liuxian Zhao
Keyword(s):  
Wave Propagation ◽  
Lamb Wave ◽  
Lamb Waves ◽  
Experimental Tests ◽  
Solid Material ◽  
Nuclear Regulatory Commission ◽  
Gas Detection ◽  
Water Tank ◽  
Gas Accumulation ◽  
Lamb Wave Propagation

According to U.S. Nuclear Regulatory Commission (NRC) Generic Letter 2008, the gas accumulation in the nuclear emergency core cooling systems is concerned since it may critically damage pipes, pumps and valves. There is a need to detect the inside gas accumulation including the quantification of gas location and volume. In this paper, we propose a in-situ technique for gas detection in a gas tank by using Lamb waves. Lamb wave propagation in a plate-like structure is affected by the boundary conditions. For structures in air or submerged in liquid, wave propagations are different. When the structure is in contact with liquid such as water, wave energy leaks into it from the solid material. Therefore, the way of gas detection is related to the detection of change in wave propagation characteristics. Experimental tests in a steel water tank were conducted and shown the Lamb wave’s response to the water presence. Theoretical study of Lamb waves propagation on a free plate in air and on a plate with one surface submerged in liquid were then conducted and compared. Further investigation to understand the change in Lamb wave propagation when water is present was conducted with frequency-wavenumber analysis. In the frequency-wavenumber space, it was found that a new plate wave mode, quasi-Scholte wave showed up. A0 Lamb mode showed a decreased propagation while S0 Lamb wave showed no changes. The change in the Lamb wave propagation is found to be frequency dependent.

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