Crack Identification by Source Inversion Analysis of AE Wave Motions

通过声发射波运动源反演分析识别裂纹

• 批准号: 01850111
• 负责人: OHTSU Masayasu
• 金额: $ 1.15万
• 依托单位: Kumamoto University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Developmental Scientific Research (B).
• 财政年份: 1989
• 资助国家: 日本
• 起止时间: 1989 至 1990
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-01850111/
• 关键词: Acoustic Emission; Source Inversion Analysis; Crack Mechanisms

The aim of the present research is to develop a technique which can identify crack kinematics from acoustic emission (AE) wave motions. Theoretically, AE waveforms are represented by an integral formulation based on the boundary element method (BEM). Introducing a dislocation model as a mathematical model for a crack, the moment tensor representation is derived.The moment tensor consists of elastic constants, a direction vector of the unit normal to crack surface, and a direction vector of crack motion. Thus, crack kinematics on crack type and crack orientation are recovered, provided that six independent tensor components are fully determined. For this purpose, a computer software named SiGMA (Simplified Green's function for Moment tensor Analysis) is developed. Following the eigenvalue analysis of moment tensor components and a unified decomposition, AE sources are classified into tensile cracks and shear cracks. Crack opening direction of the tensile crack is obtained from the direction of the first eigenvector. The direction of shear motion is recovered from the directions of the first and the third eigenvectors.The inversion procedure developed is applied to AE data on in situ hydrofracturing tests and fracture tests in concrete. Numerical studies on hydrofracturing tests confirm the reasonable accuracy of the proposed procedure. Results of cylinder-tensile tests and pullout tests of anchor bolt show a great promise for identifying crack kinematics by AE inversion procedure.

本研究的目的是开发一种从声发射波运动中识别裂纹运动学的技术。理论上，声发射波形用边界元法（BEM）的积分公式表示。引入位错模型作为裂纹的数学模型，导出了矩张量表示。矩张量由弹性常数、单位法向裂纹表面的方向矢量和裂纹运动的方向矢量组成。因此，在完全确定六个独立张量分量的情况下，恢复了裂纹类型和裂纹方向上的裂纹运动学。为此，开发了一个计算机软件SiGMA （Simplified Green’s function For矩张量分析）。通过矩张量分量的特征值分析和统一分解，将声发射源划分为拉伸裂纹和剪切裂纹。拉伸裂纹的张开方向由第一特征向量的方向得到。从第一个和第三个特征向量的方向恢复剪切运动方向。将所开发的反演方法应用于现场水力压裂试验和混凝土断裂试验的声发射数据。水力压裂试验的数值研究证实了该方法的合理性和准确性。锚杆筒体拉伸试验和锚杆拉拔试验结果表明，声发射反演方法在识别锚杆裂纹运动学方面具有广阔的应用前景。

项目成果

重石 光弘,大津 政康: "AE逆解析による円筒引張試験の観察" コンクリ-ト工学年次論文報告集. 12. 185-190 (1990)

Mitsuhiro Shigeishi、Masayasu Otsu：“通过AE逆分析观察圆柱形拉伸试验”混凝土工程年论文报告12. 185-190 (1990)

M. Ohtsu: "Simplified Moment Tensor Analysis and Unified Decomposition of Acoustic Emission Source : Application to In Situ Hydrofracturing Test" J. of Geophys. Res.

M. Ohtsu：“声发射源的简化矩张量分析和统一分解：在原位水力压裂试验中的应用”J. of Geophys。

M.Shigeishi and M.Ohtsu: "Crack Kinematics by Simplified Moment Tensor Inversion of AE" Progress in Acoustic Emission. 5. 211-216 (1990)

M.Shigeishi 和 M.Ohtsu：“通过 AE 简化矩张量反演的裂纹运动学”声发射方面的进展。

M.Ohtsu: "Simplified Moment Tensor Analysis and Unified Decomposition of Acoustic Emission Source:Application to In Situ Hydrofracturing Test" Journal of Geophysical Research.

M.Ohtsu：“声发射源的简化矩张量分析和统一分解：在原位水力压裂试验中的应用”地球物理研究杂志。

M.Ohtsu,M.Shigeishi and H.Iwase: "AE Observation in the Pull-Out Process of Shallow Hook Anchors" 土木学会論文集. 408/V-11. 177-186 (1989)

M.Ohtsu、M.Shigeishi 和 H.Iwase：“浅钩锚栓拔出过程中的 AE 观察”日本土木工程师学会论文集 408/V-11 (1989)。