The Elastic Wave Of Layered Structures In Engineering And Its Application

Layered structure is widespread in geotechnical engineering, interface is critical part of layered structure in geotechnical engineering, bonding quality of the interface directly affects the service life and application safety. Therefore, the detection on bonding quality of the interface is important guarantee to strengthen construction quality control and necessary means to eliminate potential safety hazard, like settlement, leakage, collapse and effective steps to ensure the service life. The method of elastic wave test is main nondestructive testing method to detect interface bonding quality in layered structure, Researching on the elastic wave propagation law in layered structures is help to design and implement the testing plan. In this paper, the main research contents and results as follows:(1) Wave impedance ratio have effects on elastic wave propagation in layered structure. Using the transient dynamics in ANSYS to establish models with different layered material types of engineering structure, the models divided by the interface bonding quality. The results showed that: Compared with homogeneity, propagation of elastic wave has minimal interference, the reflection signal is outstanding on the condition of heterogeneous, and more obvious as the decreasing of wave impedance ratio; Because of the existence of defects, the stress wave transmit energy with going around the defect under the surfac, but when the wave impedance surface is obvious, transmission energy reducing.(2) Interface roughness have effects on elastic wave propagation in layered structure. Using the transient dynamics in ANSYS to establish five groups models with different interface roughness that different by curvature with 0、0.25、0.5、0.75、1. Division with interface morphology difference, to establish different defects models. The results show that: As the roughness increase gradually, the multiple reflection times gradually reduce, time gradually shortened, when roughness reaches special degree, the reflect wave form show up, explained that signal form delay is not caused by detection object exists defects such as holes, but the interface roughness is higher.(3) Interface defects have effects on elastic wave propagation in layered structure. Through ANSYS to establish three layers reinforced concrete structure, first of all, in order to judge the influence of defect size on elastic wave propagation, established four groups of model with the lateral changes and four groups of model with longitudinal changes, secondly, in order to determine influence of defect location relative reception position on elastic wave propagation, setting up three groups models with different defect location, The results show that as the horizontal length is longer, the first jump time of reflection wave ahead of schedule. as defects location is far from receiving sensor location, spectrum diagram corresponding amplitude increase higher than the frequency of the resonant frequency.Through the study of this article, it has certain reference and guidance significance for implementation and data analysis of detecting the layered interface bonding quality in geotechnical engineering with elastic wave method.