ORE Catapult x Bladena – Full-Scale Torsional Fatigue Testing

WHAT WE’RE TESTING

As blades grow beyond 70, 80 and now 100 metres, they experience forces that shorter blades simply did not. One of the most significant is torsion – the twisting motion a blade experiences as loads act along its span. In modern large blades, torsional loading can drive local deformation in ways that standard certification tests were not designed to capture.

This campaign tests what actually happens when an 88m blade is subjected to controlled torsional fatigue loading – and whether two structural reinforcement solutions developed by Bladena can measurably reduce that deformation.

The Lattice Bar™ is an internal reinforcement system designed to enhance torsional stiffness and control cross-sectional deformation modes observed in large blades under fatigue loading.

The D-Stiffener™ is a lightweight internal feature that strengthens the trailing edge without adding significant weight. It targets edge separation and panel breathing – failure modes especially common near the maximum chord area of long blades under cyclic torsional stress.

We are not only keeping pace with advancing blade scale – we are generating evidence that can support the industry conversation on how full-scale validation methods need to evolve.

TECHNICAL DETAILS

Why torsional loading matters

As blades grow beyond 70 metres, torsion – the twisting motion a blade experiences as loads act along its span – becomes an increasingly important factor in long-term structural performance. In shorter, stiffer blades, torsional effects were less dominant. In modern blades over 80 metres, torsional loading can drive local deformation in ways that standard certification tests were not designed to capture.

Current industry standards acknowledge torsion as part of blade loading but were developed when blades were smaller. As blade technology has scaled rapidly, local deformation modes caused or amplified by torsional loading have become more significant – particularly in fatigue-sensitive areas such as trailing edges, shear webs and adhesive bondlines.

The test setup

The test applies controlled torsional loading to an 88m blade at ORE Catapult’s facility in Blyth. Saddle clamps are positioned around the blade’s maximum chord region to introduce torsional demand under safe and repeatable conditions. The programme comprises approximately one million fatigue cycles – not to reproduce the complete lifetime loading history of the blade, but to activate and measure specific structural responses under controlled conditions.

What we’re measuring

The blade is instrumented with over 70 sensors to capture how it responds under torsional loading. The measurement programme focuses on three key phenomena:

The data directly supports validation and calibration of the structural model, improving confidence in how blade behaviour is predicted and assessed over its lifetime.

The two phases of testing

The campaign runs in two phases. The first establishes a baseline – testing the blade in its unreinforced state to understand its natural structural response before any intervention. The second installs and tests two reinforcement solutions developed by Bladena:

Comparing blade behaviour before and after each solution is installed provides direct evidence of whether the structural effect of reinforcement is measurable at full scale.

What the results will tell us

The campaign will generate a full-scale reference dataset for torsion-induced blade response – including global measurements of twist, rotation and displacement, and local measurements of strain and cross-sectional deformation. The data will be used to validate and calibrate structural models, improving how the industry predicts and manages blade behaviour at scale. Detailed results will be published in a series of technical whitepapers.