Soft Reaction Structure for Vibration Isolation in Testing Systems

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Solution Overview

Problem

Existing testing systems experience structural vibration modes that lead to inertial errors in force transducer output signals due to dynamic forces causing columns to stretch and compress, and a box mode of vibration in the crosshead, base, and columns, which affects the accuracy of material testing.

Innovation Solution

Incorporation of compliant devices, such as gas-filled inflatable elements or chambers, between the column assemblies and the base, and optionally between the column assemblies and the crosshead, to act as soft springs, providing adjustable compliance and damping to isolate and decouple the column assemblies from the base, reducing transmitted vibrations and structural mode excitations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a rigid test system construction is used, then structural stability is maintained, but structural vibration modes are excited causing inertial errors in force transducer output signals

Engineering Contradiction:

Improvestructural stabilityVSAvoidforce transducer output signal accuracy

Core Design Contradiction:

Stability of the object's compositionVSMeasurement precision

Solution Approach 1:

Compliant devices are introduced as intermediary elements between the rigid structural components (columns and base). These devices act as mediators that decouple the rigid connections, allowing the structural components to move independently and preventing the transmission of vibrational forces that would otherwise cause inertial errors in the force transducer output.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The mechanical properties of the connection between columns and base are changed from rigid to compliant. By introducing compliant devices with specific compliance characteristics, the system transforms the connection parameters to allow controlled movement and vibration isolation, thereby reducing structural vibration modes while maintaining overall structural stability.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If high frequency testing is performed, then testing efficiency is improved, but dynamic forces increase causing excitation of structural vibration modes

Engineering Contradiction:

Improvetesting efficiencyVSAvoidstructural vibration mode excitation

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The compliant devices convert the harmful effect of high-frequency dynamic forces into a beneficial isolation mechanism. By allowing controlled compliance at the column-base connections, the system enables high-frequency testing while the compliant elements absorb and isolate the vibrational energy, preventing it from exciting structural resonance modes.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Measurement precision

If compliant devices are added to reduce vibrations, then measurement precision is improved, but device complexity increases

Engineering Contradiction:

Improveforce transducer output signal accuracyVSAvoidtest system structural complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

Instead of making the entire test system compliant or complex, the solution applies compliant devices only at specific critical locations - the connections between columns and base. This localized application of compliance provides vibration isolation precisely where needed to prevent inertial errors in the force transducer, without requiring complex modifications throughout the entire system.

Inventive Principle:

Principle #3Local quality

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 compliant devices effectively reduce structural vibration modes, enhancing the accuracy and performance of the testing system by minimizing inertial errors in force transducer output signals, allowing for more precise material testing across a range of frequencies.

Implementation Method 1

Compliant devices are provided to form a compliant coupling between each of the column assemblies and at least one of the base and the crosshead. The compliant devices support the weight of the crosshead.

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

The compliant devices reduce the transmitted vibrations from the crosshead and/or columns into the base.

Methodology Applied

Scientific EffectDamping: Damping

Data Source

PatentEP2041544B1Testing system with soft reaction structure

Publication Date: 2017.03.22 MTS SYSTEMS CORPORATION

AI summary

A testing system (10) includes a soft reaction structure (30) formed by column assemblies (26), a base (22) and a crosshead (30). Compliant devices (44,44') are disposed between the column assemblies (26) and the base (22) and/or the crosshead (30) to isolate interaction of these components and reduce structural vibration mode excitation.