...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>NDT & E international >Modeling of delamination detection utilizing air-coupled ultrasound in wood-based composites
【24h】

Modeling of delamination detection utilizing air-coupled ultrasound in wood-based composites

机译：基于空气耦合超声的木质复合材料脱层检测建模

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

In this work, we model ACU transmission in delaminations, with focus in the interference effects resulting from multiple ultrasonic reflections within the delamination layers and the resulting changes in the amplitude and time of flight. For this purpose, we propose a simplified analytical model, which we cross-validate with full-wave finite-difference time-domain (FDTD) simulations. Both models show a very high agreement on the predicted ultrasound waveforms, with amplitude deviations less than 0.15 dB and time deviations below 0.1 μs. The reduction of ultrasound signal amplitude at debonding was validated with experiments. A simple engineering formula in function of delamination gap and transducer frequency was sufficient to model experimental transmission values for a gap thickness range from 70 to 2000 μm with an uncertainty below 2 dB. Furthermore, consistent resonance frequencies were identified in both experiments and simulations. The use of pulsed ultrasound signals reduces undesired resonances and provides a consistent amplitude reduction across the full range of delamination gaps. Apart from interference effects, the effect of the finite size of the ultrasound transducers as well as diffraction effects were empirically investigated. As a result of these, the lateral resolution is reduced and the sound tends to propagate through the bonded region next to the delamination. Diffraction effects are strongly influenced by wood anisotropy, with lower lateral resolution in the grain direction.
机译：在这项工作中，我们对分层中的ACU传输进行建模，重点是分层层中多次超声反射以及所产生的振幅和飞行时间变化所产生的干扰效应。为此，我们提出了一种简化的分析模型，该模型与全波有限差分时域（FDTD）仿真进行交叉验证。两种模型在预测的超声波形上都显示出很高的一致性，幅度偏差小于0.15 dB，时间偏差小于0.1μs。通过实验验证了剥离时超声信号幅度的减小。一个简单的工程公式，即分层间隙和换能器频率的函数，足以模拟间隙厚度范围为70至2000μm且不确定度低于2μdB的实验透射值。此外，在实验和模拟中都确定了一致的共振频率。脉冲超声信号的使用减少了不希望的共振，并在整个分层间隙范围内提供了一致的幅度减小。除了干扰效应，还对超声换能器的有限尺寸以及衍射效应进行了经验研究。结果，横向分辨率降低，并且声音趋于通过紧邻分层的结合区域传播。木材各向异性对衍射效应有很大影响，而在晶粒方向上的横向分辨率较低。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号