Wave Propagation Simulation Using Virtual Particles

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Solution Overview

Problem

Simulating wave propagation through media with complex boundaries is computationally expensive, making it challenging to accurately determine defect detectability in ultrasonic testing, particularly in high stress regions of metallic preforms, where existing methods face accuracy vs. efficiency trade-offs and struggle to distinguish boundaries from defects.

Innovation Solution

A computer-implemented method that calculates wave superposition only at the time of interest, using virtual points with adjustable density, and employs a joint distribution function to simulate wave propagation, allowing for high accuracy and efficiency in determining defect detectability without requiring previous time interval calculations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If meshed methods (FDM, FEM) are used to simulate wave propagation, then measurement precision is improved, but productivity deteriorates due to high computational expense

Engineering Contradiction:
Improvewave propagation simulation accuracyVSAvoidcomputational efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent extracts only the essential wave propagation characteristics (position, magnitude, direction) from the full wave equation solution, calculating these specific parameters directly without solving the complete differential equation system. This selective extraction maintains measurement precision for the required parameters while dramatically improving computational efficiency by avoiding the overhead of mesh-based methods.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical mesh-based computational system (FDM/FEM requiring discretization of the entire domain into elements) with a particle-based system where wave properties are tracked through discrete master and virtual particles. This substitution eliminates the computational burden of mesh generation and element-wise calculations while preserving wave propagation accuracy.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If meshless methods (DPSM) are used to improve productivity, then measurement precision deteriorates due to singularities at boundaries and defect areas

Engineering Contradiction:
Improvecomputational efficiencyVSAvoidboundary and defect detection accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent segments the wave propagation problem into distinct particle types (master particles representing wave sources and virtual particles representing field points) with clearly defined roles. This segmentation allows the method to handle boundary and defect areas systematically by treating them as specific virtual particles, avoiding the singularity problems that plague traditional meshless methods while maintaining computational efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces virtual particles as intermediaries between master particles (wave sources) and the physical boundaries/defects. These virtual particles mediate the wave-field interaction, allowing accurate representation of wave behavior at boundaries and defects without creating computational singularities. The virtual particles carry wave information smoothly through the domain, resolving the precision issues of direct boundary modeling in meshless methods.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If full wave equation solving is performed to ensure reliability, then loss of time increases due to computational expense

Engineering Contradiction:
Improvedefect detectability determinationVSAvoidcomputational time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent performs preliminary calculations of wave parameters (position, magnitude, direction) at master particle locations before propagating them to virtual particles. This preliminary action establishes the wave state in advance, allowing rapid subsequent propagation calculations that determine defect detectability reliably without requiring full time-dependent wave equation solutions at every point in the domain.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent calculates only the partial set of wave parameters necessary for defect detectability assessment (position, magnitude, direction at relevant locations) rather than solving for the complete wave field throughout the entire domain. This partial action approach maintains reliability for the specific application goal while significantly reducing computational time by avoiding excessive calculations of unnecessary wave field components.

Inventive Principle:
Principle #16Partial or excessive action

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 method ensures high accuracy and computational efficiency in simulating wave propagation, enabling the detection of defects within metallic preforms during ultrasonic testing, thereby ensuring that defects are not missed during acceptance testing.

Implementation Method 1

calculates wave superposition only at the time of interest

Methodology Applied
Scientific EffectWave superposition:

Implementation Method 2

simulating wave propagation in a medium

Methodology Applied
Scientific EffectWave propagation:

Data Source

PatentEP3023779B1Method of determining the magnitude of a field variable of an energy wave
Publication Date: 2023.10.25 ROLLS ROYCE PLC
  • EP3023779B1 patent drawingFigure 1~2
  • EP3023779B1 patent drawingFigure 3
  • EP3023779B1 patent drawingFigure 3

AI summary

A computer implemented method of determining the magnitude of a field variable of an energy wave at a predetermined time through a domain of interest, the method comprising the steps of: defining a plurality of master particles spaced within the domain, the master particles being representative of field variables of an energy wave at the location of the respective master particle, and defining a supporting domain Ωm for each master particle; computing field variables including the position, magnitude and direction of propagation of each master particle at a predetermined time step; defining a plurality of virtual particles spaced within the domain representative of the magnitude of a field variable of the wave at the location of the respective virtual particle; calculating a magnitude uv of the field variable of each virtual particle at the time of interest by applying the formula: uv=∑m=1Numfq1×gq2Where v∈Ωm Where v ∈Ωm where N is the total number of master particles, um is the magnitude of a respective master particle, f(q1) is an envelope function relating the magnitude of the virtual particle to the distance from the master particle in the direction of propagation of the master particle, and g(q2) is a smoothing function relating the magnitude of the virtual particle to the distance from the master particle normal to the direction of propagation of the master particle.