Environmental Engineering Reference
In-Depth Information
Gear rim and pinions
planetary reducer
FIGURE 2.10
A.planetary.gearbox.reducer.
2.8
ProposalforRobustRedesignTurbineBlades
2.8.1 Introduction
Composite. wind. turbine. blades,. helicopter. rotors,. and. fans. are. manufac-
tured.in.a.laminate.form.from.iberglass/carbon.ibers.reinforced.epoxy.or.
vinyl.ester.resins..The.blade.skin.is.made.of.aramid.iber.or.Glass.C,.E,.and.
Kevlar™. iber.. Additional. reinforcement. in. the. leader. and. trailing. edge. of.
the.blade.is.made.for.the.protection.of.the.artiicial.loads..For.this.purpose,.
the.carbon.iber.with.reinforced.epoxy.or.vinyl.ester.resins.has.been.oriented.
in.various.directions.
Changing.the.iber.direction.of.the.layers.can.protect.wind.turbine.blades.
from.the.torsion.and.bending.moments..Therefore,.the.natural.frequencies.of.
wind.power.blades.can.be.favorably.placed.in.an.area.outside.the.operational.
rpm.(revolution.per.minute).range.
The.purpose.of.using.advanced.materials.for.enlarged.rotors.is.to.increase.
power,.improve.structure.and.aero.design,.alter.active.and.passive.controls,.
obtain.higher.tip.speed,.and.lower.acoustic.
2.8.2
Loads Acting Outside Wind Turbine Blades
External.loads.for.wind.turbine.blades.are.exposed.to.wind.and.gravity..The.
speed.of.the.blade.is.75.to.85.m/sec,.which.is.much.higher.than.wind.speed,.
even. at. storm. conditions. (25m/sec.).. The. relative. wind. directions. change.
with. storm. conditions.. The. blades. are. exposed. to. the. wind. that,. through.
the.lift.on.the.aerodynamic.proile,.causes.loads.at.right.angle.to.the.blades,.
which,.therefore,.react.by.bending.lapwise..The.loads.are.both.static,.causing.
a.permanent.bending.of.the.blades,.and.dynamic,.causing.a.fatigue,.lapwise.
Search WWH ::
Custom Search