Dynamic Strength - Hybrid Anisotropic Materials for Wind Power Turbine Blades - page 155

misalignment. of. the. shafts—as. small. as. a. few. thousandths. of. a. degree—
caused. by. the. compliance. of. those. bearings,. inluences. the. gear. contact.
forces. and. cause. unwanted. wear. on. the. gear. teeth.. In. order. to. avoid. this.
wear,.gearbox.manufacturers.can.optimize.the.gear.geometry.(lead.crown.
and.involute.crown).based.on.virtual.simulation. 40

5.10.3 An Integrated Simulation Process

The. LMS ® . Virtual.Lab. Motion. (Leuven,. Belgium),. wind. turbine. engineers.
can. accurately. model. contacts. between. gearbox. components.. This. allows.
them. to. eficiently. predict. the. transmission. of. loads. between. components.
like. gears,. shafts,. or. bearings,. while. taking. the. lexibility. of. these. compo-
nents.into.account.
Based.on.the.wind.load.cases,.LMS.Virtual.Lab.evaluates.the.stresses.on.
each.component.and.predicts.their.structural.static.reliability..Using.the.same.
Virtual.Lab.simulation.environment,.users.can.perform.durability,.vibration,.
and.noise.analyses.in.a.straightforward.way...In.addition,.the.seamless.inte-
gration.and.the.preserved.associativity.within.LMS.Virtual.Lab.avoid.time-
consuming.and.error-prone.transfer.of.data.and.allow.development.team.to.
perform.fast.optimization.loops.

5.10.4 Multibody Simulation to Assess Dynamic Behavior

Multibody.simulation.is.used.to.assess.the.structural.reliability.of.the.gear-
box.and.to.make.sure.it.resists.the.extreme.and.unpredictable.loads.from.the.
wind.and.doesn't.break.under.high.or.concentrated.stresses..In.a.standard.
1.5.MW.wind.turbine,.the.huge.input.torque.of.around.1,000.kNm.coming.
from.the.blades.rotating.at.15.rpm.has.to.be.transferred.to.realize.a.gear.ratio.
between.the.input.and.output.shaft.of.more.than.100.in.order.to.match.the.
rotational.speed.needed.to.generate.electricity.from.the.generator..Typically,.
this. is. done. through. a. three-stage. gearbox. design;. a. irst. stage. with. plan-
etary.gears.(offering.a.large.gear.ratio.and.low.weight.of.the.gears).and.two.
subsequent.parallel.gear.stages..Next.to.the.gears.themselves,.the.bearings.
have.to.be.modeled.in.detail.because.of.the.very.high.loads.they.support.and.
their.key.impact.on.the.overall.reliability.of.the.wind.turbine.
In.the.irst.step.of.the.process,.the.CAD.(computer-aided.design).geometry.
is.imported.or.created.within.LMS.Virtual.Lab.Motion.using.the.embedded.
3D.modeling.capabilities..The.model.includes.the.gears,.shafts,.bearings,.and.
housing.. In. order. to. switch. from. a. pure. kinematic. analysis. to. a. dynamic.
analysis,.the.gearbox.model.is.then.extended.with.lexible.bodies.(with.iner-
tial. parameters),. connections. between. them. (joints,. constraints,. forces). as.
well. as. controls.. At. this. level,. a. dynamic. simulation. is. computed. and. the.
results.can.be.visualized.through.3D.animations.or.2D.graphs.from.any.vari-
able.in.the.model..Various.alternatives.of.the.design.(from.CAD.or.dynamic.
parameters).are.compared.in.order.to.optimize.the.system.with.regards.to.