Resonance Bending Fatigue Test Bench with Dynamic Nodal Support Tracking

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Solution Overview

Problem

Existing resonance bending fatigue test benches for tubular components are ineffective as they cannot perform continuous tests dynamically adjusting the position of nodal supports during the test, leading to inaccuracies due to changes in operating conditions.

Innovation Solution

The introduction of at least one intermediate support element along the axis of the tubular element, supported by flexible and movable elements, allows for real-time adjustment of the support position based on feedback from oscillation amplitudes, ensuring accurate stress application throughout the test.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If fixed supports are positioned at initial nodal locations, then test setup is simple, but test accuracy deteriorates due to node position drift during operation

Engineering Contradiction:
Improvetest setup simplicityVSAvoidstress application accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The support system transitions from a static configuration to a dynamic one where at least one support can move along the tubular element's axis. This allows the support to track the nodal position as it shifts during the fatigue test, maintaining accurate stress application without requiring complete repositioning or test interruption.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

A feedback control mechanism is implemented using sensors (such as accelerometers or displacement sensors) that continuously monitor the nodal position. This information is fed to a control system that actuates the movable support to maintain its position at the current node location, ensuring test accuracy throughout the fatigue test duration.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If nodal support position is corrected during test execution, then test accuracy is maintained, but test continuity is interrupted

Engineering Contradiction:
Improvestress application accuracyVSAvoidtest continuity
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The support system is designed with dynamic positioning capability, allowing continuous adjustment of support location during the fatigue test without interruption. This eliminates the need to stop the test for manual repositioning, as the support automatically tracks the nodal position changes in real-time.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The feedback-controlled movable support ensures continuous and accurate stress application throughout the entire fatigue test duration. The system maintains the support at the correct nodal position continuously, preventing any interruption in the useful action of the fatigue test and maximizing productivity.

Inventive Principle:
Principle #20Continuity of useful action

3Measurement precision

If intermediate movable support is introduced, then node position tracking is enabled, but device complexity increases

Engineering Contradiction:
Improvenode position accuracyVSAvoidsupport system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The support system is segmented into fixed supports and at least one movable support with feedback control. This segmentation allows the complex functionality of dynamic positioning to be isolated to specific components rather than requiring the entire support system to be complex, managing overall system complexity while enabling node position tracking.

Inventive Principle:
Principle #1Segmentation

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 solution enables more reliable and accurate resonance bending fatigue tests by continuously correcting the support position in real-time, eliminating the need to interrupt the test and ensuring consistent stress application without spurious harmonics.

Implementation Method 1

supported by flexible and movable elements according to the direction of the axis of the element under test

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

subjected to bending excitation, reaching the resonance condition at the first proper frequency, by means of one or more eccentric masses

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP4534973A1Resonance bending fatigue test bench with position of the controlled tracking supports
Publication Date: 2025.04.09 UNIV DI PISA
  • EP4534973A1 patent drawingFigure 1(a)~1(b)
  • EP4534973A1 patent drawingFigure 2
  • EP4534973A1 patent drawingFigure 3

AI summary

Resonance bending fatigue test bench on tubular components (1), comprising at least two supports (2, 2') configured to support the component under test at the position of the nodes of the deformed part along the axis (a) of the component (1); an eccentric mass (6) removably applicable to a first end (4) of the component (1); a motor (3) connected to the eccentric mass (6) for transmitting a rotational motion by means of a kinematic mechanism (5); further comprising means (11) for continuously detecting the vibrations at the sides of at least one node of the deformed part (1); an electronic unit (U) operatively connected to said detection means (11) for determining the axial position of the nodes of the deformed part of the component (1) based on the detected vibrations; at least one support (2) movable along the axis (a) of the component (1); actuating means (7) operatively connected to the movable support (2) for imparting to said movable support (2) a displacement tracking the position of the corresponding node of the deformed part calculated by the electronic unit (U) during the test.