Environmental Engineering Reference
In-Depth Information
4
Manufacturing Technologies
for Turbine
Power Blades
4.1
Introduction
Many.small.companies.during.the.1970s.built.wind.turbines.for.energy.pro-
duction.. New. manufacturing. technology. was. gradually. developed. during.
the.next.two.decades.(1980s.and.1990s)..Concern.about.the.working.environ-
ment. and. stricter. legislation. pushed. the. technologies. away. from. wet. and.
open. process. toward. prepreg. technology. and. closed. mold. infusion. tech-
niques..In.this.chapter,.we.describe.the.(wet).hand.lay-up.process,.ilament.
winding,.prepreg.technology,.and.resin.infusion.technology.
4.2
WetHandLay-UpProcess
In. the. early. days,. smaller. glass. iber,. reinforced. polyester. turbine. blades.
were. manufactured. using. the. traditional. wet. hand. lay-up. technique. in.
open.molds,.which.had.been.used.for.decades.in.building.boats..The.rein-
forcements. were. all. glass. ibers. and. mainly. chopped. strand. mats. (CSMs).
with. random. iber. orientation.. In. some. cases,. woven. fabric. was. added. to.
increase.stiffness.and.strength..The.upper.and.lower.shells.were.adhesively.
bonded.together.to.form.the.airfoil.shade.blade..As.the.blade.became.longer.
(approaching.8.m),.webs.were.inserted.to.support.the.airfoil.and.to.take.up.
both.bending.and.shear.loads.
A.demand.for.higher.stiffness.and.strength.introduced.a.more.dedicated.
iber.orientation.with.more.ibers.in.the.longitudinal.direction.of.the.blade..
This.was.achieved.either.by.using.unidirectional.woven.fabrics.(unbalanced.
fabrics. with.more.ibers.in.one.of.the.directions,.normally.the.warp.direc-
tion).or.by.laying.down.many.parallel.roving.ibers.in.the.length.direction.in.
between.the.CSMs..In.some.designs,.these.rovings.serve.another.purpose.in.
that.they.were.used.to.form.the.root.end.attachment.as.well..At.the.root.end,.
the. rovings. were. wound. around. steel. bushes. (small. tubes). and. continued.
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