Movable Test Stand for Wind Turbine Blade Structural Analysis

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Solution Overview

Problem

Testing wind turbine rotor blades poses significant technical and financial challenges due to their length and complex hybrid structures, requiring efficient and controlled application of forces to simulate realistic load conditions, which is difficult with existing test rigs.

Innovation Solution

A test stand with movable clamping devices that apply forces along a predetermined axis, using a carrier connected to a frame or floor via rollers or hinges, allowing for parallel or rotational movement, and incorporating elastic elements to prevent rotation while allowing torsion, along with digital image correlation systems to correct for any rotation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If subcomponents of wind turbines are tested in test rigs to simulate realistic load conditions, then the accuracy of structural parameter measurement is improved, but the complexity of the test rig increases due to the need for precise force application and rotation prevention

Engineering Contradiction:
Improvestructural parameter measurement accuracyVSAvoidtest rig complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The test rig employs a movable support structure that can dynamically adjust its position along a predetermined path (linear or circular) to accommodate different testing requirements. This dynamic capability allows the same apparatus to handle various subcomponent geometries and loading conditions, improving measurement versatility without proportionally increasing overall system complexity

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

An elastic element is introduced as an intermediary component between the support structure and the test specimen. This elastic element serves dual functions: it prevents unwanted rotation of the support structure during loading while simultaneously allowing controlled torsional movement. This intermediary component simplifies the control system by passively managing rotational constraints without requiring complex active control mechanisms

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If the support structure is allowed to rotate freely to accommodate different test configurations, then the adaptability of the test rig is improved, but the reliability of force application deteriorates due to unwanted rotation during testing

Engineering Contradiction:
Improvetest configuration flexibilityVSAvoidforce application accuracy
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The support structure is designed with asymmetric rotational constraints: it can rotate freely to establish the initial test configuration and orientation, but during the actual loading process, the elastic element engages to prevent unwanted rotation. This asymmetric behavior—free rotation for setup, constrained rotation for testing—resolves the contradiction between adaptability and reliability

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The system transitions between different states of rotational freedom by changing the engagement state of the elastic element. During configuration setup, the element is disengaged allowing full rotational freedom. During force application, the element engages to constrain rotation. This parameter change (from free to constrained rotation) allows the system to satisfy both adaptability and reliability requirements at different stages of the testing process

Inventive Principle:
Principle #35Parameter changes

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 efficient and controlled application of forces to simulate realistic load conditions on wind turbine rotor blades, reducing damage and allowing for accurate measurement of deformation, thereby improving the testing process.

Implementation Method 1

Furthermore, a test stand according to the invention incorporates an elastic element, for example in the form of a spring, with which a test specimen is connected to a frame of the test stand or to a wall, so that rotation about a longitudinal axis of the test specimen is restricted or prevented

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3704460B1Device for structure testing
Publication Date: 2023.03.01 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
  • EP3704460B1 patent drawingFigure 1~2
  • EP3704460B1 patent drawingFigure 3a~3c

AI summary

The invention relates to a test stand comprising a support (19, 25) which is moveably connected to a wall (18, 18', 18 "), a base, a frame (26) of the test stand or another part of the test stand and can be moved on a predetermined path; an actuator (22) which is connected to the support and by means of which the support (19, 25) that can be moved on the predetermined path, two clamping devices (13) respectively comprising a ball joint, wherein one of the two clamping devices (13) is secured to the support (19, 25) and the other of the two clamping devices (13) is arranged in an axis (10) with the first of the two clamping devices (13), such that a test body (1) is clamped between the two clamping devices (13) on outer surfaces of the test body and can be maintained by the clamping devices (13), and a test force exerted by a test body by moving the support (19, 25) through the first of the two clamping devices (13) acts essentially along the axis (10). The test body is fixed by means of an elastic element (23) in order to limit a rotation of the test body about the axis (10).