Acoustic Emission Parameter Determination via Moment Tensor Analysis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for determining AE parameters, such as source positions and numbers of microcracks in rock, using moment tensor analysis are limited in their ability to accurately quantify and locate microcrack events in rock specimens during fracturing processes.
Innovation Solution
A method and system that involves constructing a numerical model of a rock specimen using PFC software, simulating the failure process, identifying microcrack positions and times, and applying moment tensor analysis to determine AE parameters, including magnitude and energy, by considering the spatial range and geometric centers of microcracks as source positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If moment tensor analysis is applied to determine AE parameters, then AE magnitude and energy can be obtained, but source positions and numbers of microcracks in single AE events cannot be determined
Solution Approach 1:
The patent segments the AE event analysis into multiple components: it divides the rock specimen into discrete rock grains, identifies individual microcrack events within the AE event, and separates the determination of source position, microcrack number, and AE parameters into distinct analytical steps. This segmentation allows simultaneous extraction of source position, microcrack count, and moment tensor parameters that were previously inaccessible
Solution Approach 2:
The patent transitions from traditional single-dimension AE parameter analysis to multi-dimensional analysis by incorporating spatial information (source position), temporal information (microcrack sequence), and quantitative information (microcrack number) alongside the traditional moment tensor parameters. This dimensional expansion enables comprehensive characterization of AE events
2Reliability
If PFC software is used to simulate rock fracturing process, then microcrack initiation and propagation can be reproduced, but source positions and AE parameters cannot be determined
Solution Approach 1:
The patent introduces moment tensor analysis as an intermediary methodology that bridges the PFC simulation and AE parameter determination. By calculating moment tensors from the simulated contact forces and applying moment tensor inversion, the system extracts source position and AE parameters from the PFC simulation data, enabling quantitative characterization of the simulated microcrack events
Solution Approach 2:
The patent transforms the PFC simulation output parameters (contact forces, grain displacements) into AE-relevant parameters (source position, moment tensor components, AE magnitude) through mathematical transformations and inversion algorithms. This parameter transformation enables direct comparison between simulation results and experimental AE measurements
3Manufacturing precision
If microcracks are identified by bonded contact fractures in PFC model, then fracturing time and positions can be obtained, but AE event classification and source position determination are unavailable
Solution Approach 1:
The patent implements feedback mechanisms where identified microcrack positions and times are used to update the AE event classification, which in turn refines the source position determination. The system continuously refines its classification by comparing simulated microcrack patterns with observed AE waveforms, improving source location accuracy through iterative feedback
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively determines AE source positions and calculates AE parameters, enhancing the understanding of rock fracturing processes by identifying microcracks as the same event based on temporal and spatial criteria, thereby improving the accuracy of AE monitoring.
Implementation Method 1
fractures of bonded points between the rock grains respectively represent the microcracks
Implementation Method 2
The term AE refers to the generation of elastic waves due to release of strain energy from the rock in fracturing process
Implementation Method 3
In PFC simulation, the moment tensors can be obtained by recording variations of surrounding contact forces in bond failure, thus getting the magnitude and energy of the AE
Data Source
AI summary
A method and system for determining acoustic emission (AE) parameters of rock based on moment tensor analysis. The method includes: constructing, according to macroscopic mechanical parameters, a numerical model of a rock specimen to be tested; loading the numerical model through particle flow code software to simulate a failure process of the rock specimen to be tested, and identifying fracturing time and positions of microcracks when the PFC software loads the numerical model; determining, when the PFC software loads the numerical model, if rock grains of two sequentially generated microcracks include common rock grains, and an interval for generating the two microcracks is less than duration time of a present AE event, the two microcracks as a same AE event; taking geometric centers of all microcracks within a spatial range of an AE event as source positions of the corresponding AE event; and determining AE parameters of the AE event.