预应力孔道超声检测回波法数值模拟的频散特性分析  

Analysis of Dispersion Characteristics of Numerical Simulation of Prestressed Duct Using Ultrasonic Detection Echo Method

作　　者：肖建平[1] 王凡[1] 朱自强[1] 余涛[1] 

机构地区：[1]中南大学地球科学与信息物理学院,湖南长沙410083

出　　处：《公路交通科技》2014年第2期74-80,127,共8页Journal of Highway and Transportation Research and Development

基　　金：国家自然科学基金项目(41274122);湖南省自然科学基金项目(12JJ6033);中南大学中央高校基本科研业务费专项资金项目(2011QNZT019)

摘　　要：利用有限差分超声脉冲回波法对预应力梁压浆孔道的注浆密实性进行数值模拟时,波动方程的数值频散会严重影响波场模拟的精度和分辨率。针对所采用的交错网格有限差分方法,本文从空间网格离散、时间网格离散两方面分析了网格间距、差分精度、介质速度和时间步长等因素对数值频散的影响,指出由频散导致的假频现象及其主要特点。数值算例和模型正演结果表明:高阶交错网格有限差分用于预应力梁中的超声脉冲数值模拟可压制回波频散,有利于提高波场数值模拟的精度和效率。In the process of using finite-difference ultrasonic pulse echo method to numerical simulate the grouting fullness in duct of prestressed beam, the phenomenon of numerical dispersion of wave equation will seriously affect the accuracy and resolution of the wave field. For the staggered grid finite difference method adopted in numerical simulation using ultrasonic pulse echo method, the influence of grid spacing, difference accuracy, medium speed and time step on numerical dispersion caused by space grid discrete and time grid discrete are analysed, and the alias phenomenon caused by dispersion and the main features are pointed out. the Numerical example and the forward modeling results show that High-order staggered-grid finite difference scheme can be used for reducing the echo dispersion characteristics of ultrasonic pulse numerical simulation for prestressed beam, and helping to improve the accuracy and efficiency of the wave field simulation.

关 键 词：桥梁工程 频散特性分析 超声脉冲数值模拟 预应力孔道 无损检测 高阶交错网格 

分 类 号：U445.57[建筑科学—桥梁与隧道工程]