non-destructive testing of fiber composite components ...€¦ · mechanical testing techniques...

Y. Petryna Innotesting 2017, Wildau, 24.02.2017 1

Non-destructive Testing of Fiber Composite Components - Case Study: Rotor Blades of Wind Turbines

Y. Petryna Technische Universität Berlin

Thanks to PhD students: M. Kannenberg, A. Künzel, D. Kovacevic


Content

Introduction

Rotor blades, BladeTester

Non-destructive testing

Examples Conclusion and outlook


Motivation: Manufacturing faults and defects

Deformation under dead weight Deforamtion in operation Handwork

Extensive hand work, various materials, blind bondings and cost pressure cause several manufacturing defects in rotor blades, which can be critical in operation


Bladetester

Joint research project BladeTester - Automated approach for serial integrity tests of rotor blades

2011-2015

Partners

Technische Universität Berlin, Verbundkoordinator

BAM Bundesanstalt für Materialforschung und –prüfung

Steinbichler Optotechnik GmbH

Associated Partners

Ingenieurbüro Werkhausen


Rotor blade „tuners“

5 real rotor blades for industrial wind turbine + incorporated manufacturing faults as experimental specimens

13,40 m

Rotating support


Manufacturing faults

relation to components defect type defect causes defect rate consequences for manufacturer relevance w.r.t. RB integrity detectability

Systematic fault analysis by partners is documented in a fault matrix, which categorizes faults with respect to

1 RB without special faults 2 RB with special faults 1 RB possibly fault-free 1 RB with faults (coated)

Rotor blade tuners:

designer

manufacturer certifier


Delamination (foil)

Resin inclusion

Trockenstelle

Resin fault (foam area)

Resin fault (spar area)

Some examples of manufacturing faults


Some examples of manufacturing faults

Voids in bond line

Ondulation

Faulty adhesive joint (spar)

Resin channel

disturbed force flow


Systematic testing of various NDT techniques w.r.t. manufacturing faults

Electromagnetic waves

Mechanical testing techniques

Übersicht über das EM-Spektrum

Ultrasonic waves Shearography guided waves

Ultrasonic testing (MUSE-4)

X-rays

void

Selection criteria

Detectability Repeatability Resolution Testing time / cost

Non-destructive testing


NDT on spesimen

µ-waves C-Scan (FIT-M) 10 GHz, wave length 3 cm

Microwave

THz-Scan (Becker Photonik) 100 GHz, wave length 3 mm

THz

US US-Scan (MUSE Z-400 Dr. Hillger) 0.5-1.0 MHz

Hidden ondulation in composite, stress field disturbance, potential failure source

Elec

tro

-mag

net

ic

wav

es

mec

han

ical

w

aves

Other applied techniques: thermography, shearography, x-rays


adhesive

adhesive

US testing on rotor blade segment

foam

surface damage

composite voids composite

Section of rotor blade with several defects

US scan with reduced colours

foam


NDT on rotor blades

Ondulation in laminate

Resin inclusion

Layer gradation defects


Image processing

Object

Surface photos

Suction side Pressure side

easy access low cost automatable rapid camera + software

visible information close to the surface

Partner: GFAI


Separation acc. to material types

Separation acc. to visible damage

+ geometrical information on edges, areas, positions, etc.

Image processing


Combined NDT on rotor blades

Photos

Image processing of photos

US scan

A combination of rapid image processing and specialized US testing provides a reliable information on the setup and manufacturing faults of rotor blades

US scan

However, the assessment of “effects of defects” remains a challenge without a proper computer simulation.


3D reconstruction of internal structure by use of US waves

bond

Bond lines with defects

bond

Surface repair

Thickness change

Laminate


the same faulty adhesive layer

good adhesive layer faulty adhesive layer


“real” adhesive layer transferred to FE model

The adhesive layer between two laminate surfaces is filled with volume elements and subjected to shear loading by use of FE

simulation


Conclusion and Outlook

This approach (NDT+FEM) shall provide much more realistic predictions of structural integrity since it is based on real/measured data

We are looking for industrial partners for a joint project!


Thank you for your attention

non-destructive testing of fiber composite components ...€¦ · mechanical testing techniques...

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