Cavitation Peening Feedback Control for Stress Consistency

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Solution Overview

Problem

Existing cavitation peening systems lack robust process controls to consistently impart predetermined levels of compressive residual stress to workpieces, which is crucial for their effective use in various applications.

Innovation Solution

A cavitation peening system that includes a fluid delivery system and a feedback system with multiple feedback devices monitoring parameters like sound level, vibration frequency, and oxygen levels, which a controller uses to determine and adjust the peening intensity of cavitation bubbles, ensuring consistent compressive residual stress is imparted to the workpiece.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional cavitation peening systems are used, then compressive residual stress can be imparted to the workpiece, but the process lacks robust controls to ensure predetermined stress levels are consistently achieved

Engineering Contradiction:

Improveconsistency of compressive residual stress levelsVSAvoidprocess control system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a feedback system with sensors that monitor cavitation bubble characteristics (such as acoustic emissions, light emission, or bubble size) and provide real-time data to a controller. The controller adjusts fluid pressure and flow rate based on this feedback to maintain consistent peening intensity and achieve predetermined compressive residual stress levels, directly resolving the reliability issue.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system dynamically changes operational parameters (fluid pressure, flow rate, nozzle-to-workpiece distance) based on monitored cavitation characteristics. By adjusting these parameters in real-time, the system maintains optimal peening conditions and ensures consistent compressive residual stress impartation, addressing the reliability concern while managing complexity through automated control.

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If feedback systems with multiple sensors are implemented, then peening intensity can be precisely controlled, but the system complexity and cost increase

Engineering Contradiction:

Improvepeening intensity control precisionVSAvoidfeedback system complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent employs feedback devices that detect cavitation bubble characteristics (acoustic signals, luminescence, or visual properties) to provide real-time information about peening intensity. The controller uses this feedback to automatically adjust fluid delivery parameters, achieving precise peening control without requiring overly complex manual intervention systems.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system replaces complex mechanical measurement and adjustment mechanisms with sensor-based detection and automated control. By using optical, acoustic, or electrical sensors to monitor cavitation and electronically controlling fluid pressure and flow, the system achieves high precision while managing complexity through non-mechanical means.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If real-time monitoring and adjustment of cavitation parameters is implemented, then consistent compressive residual stress is achieved, but the processing time and system complexity increase

Engineering Contradiction:

Improvecompressive residual stress consistencyVSAvoidprocessing time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The feedback system operates continuously during the peening process, providing real-time monitoring and adjustment without interrupting the cavitation peening action. This continuous control ensures consistent compressive residual stress is achieved while minimizing idle time, as the system makes rapid adjustments without stopping the peening process.

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

The system performs rapid measurements and adjustments in quick succession, using fast-response sensors and controllers that can detect cavitation characteristics and modify fluid parameters almost instantaneously. This allows the system to maintain consistency while minimizing the time penalty associated with monitoring and adjustment.

Inventive Principle:

Principle #21Skipping (Rushing through)

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

The system ensures repeatable and efficient imparting of compressive residual stress and surface enhancement to workpieces, enabling precise control over the peening process, reducing costs and time in manufacturing and maintenance.

Implementation Method 1

discharging a flow of fluid towards the workpiece at a pressure and a flow rate that facilitates forming a plurality of cavitation bubbles

Methodology Applied

Scientific EffectCavitation: Cavitation

Implementation Method 2

Because cavitation bubble collapse creates an implosion and corresponding intense shockwave

Methodology Applied

Scientific EffectShock wave: Shock Wave

Data Source

PatentUS9200341B1Systems and methods of cavitation peening a workpiece

Publication Date: 2015.12.01 THE BOEING CO

AI summary

A method of cavitation peening a workpiece is provided. The method includes discharging a flow of fluid towards the workpiece at a pressure and a flow rate that facilitates forming a plurality of cavitation bubbles, monitoring a feedback parameter associated with the plurality of cavitation bubbles, and determining a peening intensity of the plurality of cavitation bubbles based at least partially on a value of the feedback parameter.