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CATEGORIES:Engineering - Mechanics and Materials Seminar Seri
 es
SUMMARY:Uncovering fatigue damage development in unidirect
 ional composites using x-ray computed tomography -
  Lars Mikkelsen\, Institute for Wind Energy\, DTU\
 , Denmark 
DTSTART;TZID=Europe/London:20170217T140000
DTEND;TZID=Europe/London:20170217T150000
UID:TALK69642AThttp://talks.cam.ac.uk
URL:http://talks.cam.ac.uk/talk/index/69642
DESCRIPTION:Understanding fatigue damage evolution in the load
  carrying laminates of wind turbine blade play an 
 important role designing longer and lighter turbin
 e blades. Turbine blades which will make it possib
 le to increase the size of wind turbines or to upg
 rade existing turbines for lower wind classes’. Th
 ereby\, it will be possible to lower the cost of e
 nergy for wind energy based electricity. In the pr
 esented work\, a lab-source x-ray computed tomogra
 phy equipment (Zeiss Xradia 520 Versa) has been us
 ed in connection with ex-situ fatigue testing of u
 ni-directional composites in order to identify fib
 re failure during the fatigue loading. The load ca
 rrying laminates in wind turbine blades is typical
 ly based on a number of non-crimp fabrics in where
  the load carrying fibres are oriented in the axia
 l direction of the blades. In order to ease the ha
 ndling of the fabric during the dry fabric layup a
 nd to ensure a good alignment of the final laminat
 es\, approximately 10% of the fibres are oriented 
 in secondary directions as so-called backing bundl
 es and stitched to the uni-directionally oriented 
 bundles. Due to the coarse structure of the non-cr
 imp fabric\, test samples with a larger cross-sect
 ion (compared to other comparable x-ray studies) h
 ave been used in order to ensure a representative 
 test volume during the ex-situ fatigue testing. Us
 ing the ability of the x-ray computed tomography t
 o zoom into regions of interest\, non-destructive\
 , the fatigue damage evolution in a repeating ex-s
 itu fatigue loaded test sample has be explored. Th
 ereby\, the fatigue failure mechanism has been unc
 overed showing fibre breakage regions growing from
  cross-over regions of the backing bundles. Based 
 on those observations\, more realistic micromechan
 ical based fatigue damage models as well as sugges
 tions on bundle arrangement improving the fatigue 
 resistance of non-crimp fabric used in the wind tu
 rbine industry can be made. 
LOCATION:Oatley Seminar Room\, Department of Engineering
CONTACT:Hilde Hambro
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