The ground penetrating radar(GPR) forward simulation all aims at the singular and regular models, such as sandwich model, round cavity, square cavity, and so on, which are comparably simple. But as to the forward of c...The ground penetrating radar(GPR) forward simulation all aims at the singular and regular models, such as sandwich model, round cavity, square cavity, and so on, which are comparably simple. But as to the forward of curl interface underground or “v” figure complex model, it is difficult to realize. So it is important to forward the complex geoelectricity model. This paper takes two Maxwell’s vorticity equations as departure point, makes use of the principles of Yee’s space grid model theory and the basic principle finite difference time domain method, and deduces a GPR forward system of equation of two dimensional spaces. The Mur super absorbed boundary condition is adopted to solve the super strong reflection on the interceptive boundary when there is the forward simulation. And a self-made program is used to process forward simulation to two typical geoelectricity model.展开更多
大体积混凝土结构被广泛应用于土木、水利等领域的重大工程中,而混凝土抗拉强度低的力学特性决定了其易产生裂纹,因此,发展高效的检测方法,识别大体积混凝土结构中的裂纹信息十分必要.论文提出了一种新的方法,通过提取响应信号频谱中特...大体积混凝土结构被广泛应用于土木、水利等领域的重大工程中,而混凝土抗拉强度低的力学特性决定了其易产生裂纹,因此,发展高效的检测方法,识别大体积混凝土结构中的裂纹信息十分必要.论文提出了一种新的方法,通过提取响应信号频谱中特定频率的幅值特征,基于BP人工神经网络建立幅值特征与裂纹信息间的映射关系,从而有效识别出裂纹信息.首先采用扩展有限元法(eXtended Finite Element Methods, XFEM)和人工吸收边界模型,分别模拟了单裂纹和双裂纹情形下,大量不同裂纹信息下特定位置传感器的响应,分析其频谱曲线并提取特征,建立频谱特征—裂尖位置数据集,以训练人工神经网络,测试集的反演效果显示,该方法具有较好的准确度,可有效识别出裂纹信息.展开更多
文摘The ground penetrating radar(GPR) forward simulation all aims at the singular and regular models, such as sandwich model, round cavity, square cavity, and so on, which are comparably simple. But as to the forward of curl interface underground or “v” figure complex model, it is difficult to realize. So it is important to forward the complex geoelectricity model. This paper takes two Maxwell’s vorticity equations as departure point, makes use of the principles of Yee’s space grid model theory and the basic principle finite difference time domain method, and deduces a GPR forward system of equation of two dimensional spaces. The Mur super absorbed boundary condition is adopted to solve the super strong reflection on the interceptive boundary when there is the forward simulation. And a self-made program is used to process forward simulation to two typical geoelectricity model.
基金Project supported by China Postdoctoral Science Foundation （20100481488）, Key Fund Project of Advanced Research of the Weapon Equipment （9140A33040512JB3401）.
文摘大体积混凝土结构被广泛应用于土木、水利等领域的重大工程中,而混凝土抗拉强度低的力学特性决定了其易产生裂纹,因此,发展高效的检测方法,识别大体积混凝土结构中的裂纹信息十分必要.论文提出了一种新的方法,通过提取响应信号频谱中特定频率的幅值特征,基于BP人工神经网络建立幅值特征与裂纹信息间的映射关系,从而有效识别出裂纹信息.首先采用扩展有限元法(eXtended Finite Element Methods, XFEM)和人工吸收边界模型,分别模拟了单裂纹和双裂纹情形下,大量不同裂纹信息下特定位置传感器的响应,分析其频谱曲线并提取特征,建立频谱特征—裂尖位置数据集,以训练人工神经网络,测试集的反演效果显示,该方法具有较好的准确度,可有效识别出裂纹信息.
