Modal Impact Testing Assembly for Rotating Spindles

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Solution Overview

Problem

Existing modal impact testing methods for rotating elements, such as spindles, are hindered by changes in bearing preload values at elevated speeds, leading to inaccurate operational behavior and parameter determination, and pose risks to operators due to manual impact and connectivity challenges with rotating parts.

Innovation Solution

A modal impact testing assembly and system that includes a remotely-triggered impact hammer with a load cell and a non-contact laser interferometer, allowing for modal impact testing of rotating elements at operational speeds without operator proximity and eliminating the need for wire connections, using a test element aligned between the impact assembly and signal response measuring device secured to a rotating element.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If manual impact testing is performed on rotating elements, then operator proximity is required for operation, but this increases risk to the operator

Engineering Contradiction:

Improvemanual impact operationVSAvoidoperator risk

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

A remotely-operated impact hammer system serves as an intermediary between the operator and the rotating test element. The impact hammer is controlled through a trigger mechanism that allows remote actuation, eliminating the need for operator proximity to the rotating component while maintaining testing capability.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The manual mechanical impact system is replaced with an automated impact hammer mechanism that can be triggered remotely. This substitution eliminates direct operator involvement in the impact delivery process, reducing risk while preserving the essential testing function.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If connector elements such as wires are used to connect accelerometers to the rotating spindle, then measurement capability is achieved, but it is difficult or impossible to attach them to rotating spindles

Engineering Contradiction:

Improveaccelerometer measurement capabilityVSAvoidattachment difficulty

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

Wire-based electrical connections are replaced with wireless measurement technology. The system uses wireless transmission to convey measurement data from accelerometers mounted on the rotating spindle to external recording equipment, eliminating the attachment difficulty of wires to rotating components while maintaining measurement precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The measurement system transitions from wired electrical signal transmission to wireless signal transmission. This parameter change in the connection method allows accelerometers to be mounted on rotating spindles without the mechanical constraint of wire attachment, solving the ease of manufacture problem while preserving measurement capability.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If modal impact testing is performed on stationary spindles, then testing procedure is simple, but bearing preload values change at elevated speeds altering test outcomes

Engineering Contradiction:

Improvetesting procedure complexityVSAvoidoperational behavior determination accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The testing system transitions from static (stationary spindle) to dynamic (rotating spindle at operational speeds) operation. By enabling impact testing on rotating spindles, the system captures the actual bearing preload conditions present during operation, improving measurement precision while managing increased procedural complexity through automated components.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

A remotely-operated impact hammer and wireless measurement system serve as intermediaries that enable accurate testing of rotating spindles. These components bridge the gap between the need for operational-speed testing and the complexity of performing such tests, maintaining measurement precision while managing system complexity.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Reliability

If weeks and months of test manufacturing and production runs are conducted to characterize static and dynamic performance, then comprehensive data is obtained, but testing time is excessive

Engineering Contradiction:

Improvemanufacturing performance characterizationVSAvoidtesting time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The testing system enables continuous data collection during actual production operations. By mounting accelerometers on rotating spindles and using wireless transmission, the system continuously captures dynamic performance data during normal manufacturing runs, eliminating the need for separate extended testing periods and reducing total testing time while maintaining reliability.

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

The system allows the production process itself to generate test data. By instrumenting the rotating spindles and capturing data during operational runs, the manufacturing process serves its own characterization needs, eliminating the need for separate dedicated testing time while ensuring reliable performance data is obtained.

Inventive Principle:

Principle #25Self-service

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

Enables accurate determination of operational behavior and parameters of rotating machining tools at operational speeds, reducing testing time and eliminating operator risks, while allowing for precise analysis of dynamic characteristics without manual intervention or wire connections.

Implementation Method 1

an impact assembly configured to impact the test element with a remotely-triggered excitation impulse

Methodology Applied

Scientific EffectForce sensing: Force

Implementation Method 2

a non-contact laser interferometer configured to measure a response signal

Methodology Applied

Scientific EffectLaser interferometry: LIDAR

Data Source

PatentEP2824440B1Modal impact testing assembly, system and method

Publication Date: 2017.03.08 THE BOEING CO

AI summary

There is disclosed an assembly (10), a system (12) and a method (150) for modal impact testing. The assembly (10) has a first set of components (14). The first set of components (14) include an impact assembly (16), a cycle control element (18) coupled to the impact assembly (16), and a signal response measuring device (20) positioned opposite the impact assembly (16). The assembly (10) further has a second set of components (28) separate from the first set of components (14). The second set of components (28) include a first controller (30) coupled to the cycle control element (18) and a second controller (34) coupled to the signal response measuring device (20). The first set of components (14) and the second set of components (28) form a modal impact testing assembly (10) for modal impact testing. The impact assembly (16) of the modal impact testing assembly (10) is configured to impact a test element (46) rotating at operational speeds.