Introducing the Romax

Product Family

RomaxDESIGNER

CONCEPT

CAD FUSION

Dynamic FUSION

Kristian Kuyumdzhiev – Applications Engineer

July 2016

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System Modelling Approach

+ Effort and Complexity

Romax ModelGeneric Finite Element /

Multi body Dynamics

Basic Gear or Bearing

Calculation Software

Too Complex,

Too Slow (weeks to

build/run a single case)

Difficult to rate

components

Hybrid modelling

approach of full system

Fast, accurate prediction

of load misalignment &

stress

Component rating

Too Simple

No system level analysis

Calculation not

Simulation!

++Productivity

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Radial and axial

clearances defined by

geometric parameters

and represented by

non-linear contact

elements

Detailed bearings from

catalogues or user

defined raceway and

element dimensions

Romax Detailed

Analytical Model

Axisymmetric shafts

described by dimensions

and materials.

Timoshenko Beam

Simple bearings

represented by

user-defined stiffness

values

Complex shafts

represented by

3D FE meshes

Gears represented as

concept: basic parameters or

detailed: full macro- and

micro- geometry definition

Romax Analytical

Representation

Spline described by

dimensions and

3D user-defined stiffness

or from

FE contact analysis

meshes

Non-rotating

complex structures

(e.g. Housing)

represented by

3D FE meshes

System Modelling Approach

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Full model predicts poor tooth load distribution with high

edge loading. Model includes flexible housing, carrier and

advanced bearing models.

Simple model predicts good tooth load distribution. This

demonstrates the large impact of making unrealistic

modelling simplifications.

Importance of Full System Modelling

Accuracy of model affects design conclusions

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Bearings

• Bearing catalog database

• Detailed bearing geometry definition• Load distribution and contact stress

• Life calculations using

latest ISO standards

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Bearings

• Optimise roller and raceway profile for

improved efficiency, durability and NVH

performance

• State of the art flexible FE to

predict bearing distortion

• Manufacturing and assembly

– mounting conditions,

temperatures, preloads, radial

internal clearances

• Highly accurate results

for bearing durability,

efficiency, NVH through

full gearbox analysis

considering whole

system interactions

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Gears

Whole system modelling for fast and

precise:

• Mesh misalignment prediction

• Loaded tooth contact analysis

• Transmission error prediction

• Root stress analysis

• Macro/micro geometry optimisation

• Gear rating to AGMA, ISO, DIN

standards

Interfaces to:

• ANSol HFH and HFM

• Klingelnberg KIMoS

• Windows LDP

Spur Planetary Bevel/Hypoid

Helical Plus planetary Beveloid

Face Ravigneaux Worm

Loading Concept Detailed

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Finite element

• Include an FE representation of: housings,

axisymmetric and non-axisymmetric shafts, planet

carriers, gear blanks, planet pins, etc.

• Automatic meshing of standard shafts into FE

components

• Import, position and connect full FE meshes /

condensed mass and stiffness matrices from

Nastran, ABAQUS and ANSYS

• Condense FE for static or dynamic analysis, or

export to ANSYS, ABAQUS or Nastran

• Leads to increased accuracy of system calculations

including bearing life, gear contact and bending

stress, gear mesh misalignment

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NVH - Whine and Rattle

• Gear whine: quick and accurate vibration

prediction

• Gear rattle: simulation of non-linear torsional

response to external forces

• Predicting transmission error (TE)

o Full system deflections taken into account

o Variation of gear tooth stiffness taken into

account

o Unique capability to analyse gear contact

in planetary gear systems

• Advanced post-processing analysis tools

• Automated optimization algorithms reduce noise

without affecting other design targets

• Interface to AVL Excite

b

Line of action

Driving

Driven

Full System

Dynamic Model

Spur/Helical Planetary Bevel/Hypoid

Romax TCA

OSU LDP

User Defined

Romax Gearbox TE

User Defined

Ansol

Klingelnberg KIMoS

User Defined

General Excitations

Gear Whine Vibrations

Transmission Error

Dynamic System Properties System Vibration Response

Mode shapes and natural frequencies Vibration response order cuts

Modal energy distribution

Modal flexibility

Frequency response functions

…

Dynamic bearing force

Waterfall plots

Operating deflection shapes

…

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NVH - Sidebands

• Frequency domain analysis – fast

• Full system model – captures system

interactions

• Accounts for:

o Manufacturing errors

o Deviations under loading

o Carrier rotation

• Close correlation with test data

• User-friendly interface, independent of

model

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NVHAcoustic Export

• Direct export of housing vibration

• LMS Virtual Lab Acoustics, Ansol Coustyx, etc.

• Radiated noise (a key target metric for gear

whine) can then be predicted for the transmission

• There is no need to use an FEA package as part of

the process

RomaxDESIGNERExport dynamic

bearing forces

Apply forces in

Nastran

Get housing

vibration

Radiation

LMS VL Acoustics

RomaxDESIGNERExport housing

vibration

Radiation

LMS VL Acoustics

Old process:

New process:

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Efficiency

• Predict the efficiency of a system at concept level

• Variety of drag models for bearing friction, gear meshes,

gear blanks and shaft seals

• Industry-standard calculations or user-input efficiency

maps

• Torque, speed, temperature and lubricant level effects

• Fuel consumption and CO2 emissions

• Efficiency optimisation without other compromises

• Pinpoint causes for losses and make educated decisions

Drive cycle data User-defined duty

cycle

Total system efficiency

Fuel consumption

and CO2 emissions

Component losses

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Efficiency Models

• Seal drag model:

• ISO 14179-1 (US based)

• ISO 14179-2 (German based)

o Calculation is dependent on:

• Seal diameter and material

• Roller bearing friction model:

o All models have an empirical approach (same equation with

different coefficients):

• ISO 14179-1

• ISO 14179-2

• Palmgren

o Bearing losses depend on:

• Bearing type and size

• Lubricant

• Bearing load

• Romax has implemented efficiency models for each of the main gearbox components:

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Efficiency Models

• Gear drag model:

o Gear drag losses are the result of:

• Windage losses: due to friction with oil-air mixture

• Churning losses: due to friction with oil in dip region

o Dependent on gear speed and gear immersion depth

• ISO 14179-1 and ISO 14179-2 standards

• Terekhov experimental work with an addition of the Anderson

windage model

Model ISO 14179-1 ISO 14179-2 Terekhov

Approach Analytical Experiments Experiments

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Efficiency Models

• Gear mesh efficiency model:

o The gear mesh drag is the result of:• Sliding losses: due to friction

• Rolling losses: due to elastohydrodynamic effects

o Dependent on gear speed and torque

o ISO 14179-1 and ISO 14179-2 standards

o Romax calculation method based on Anderson’s experimental tests

Model: ISO 14179-1 ISO 14179-2 Anderson

Internal gears Extended Extended

Rolling losses

• In all models gear mesh efficiency is dependent on slipping speed, contact load, and

friction coefficient

• Romax has developed a more accurate method to account for micro geometry

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Efficiency Analysis Results

• Individual load case or entire duty cycle results

o Load case: efficiency is calculated on a single loading

condition.

• Efficiency maps

• Component losses

o Drive Cycle: overall efficiency for a collection of load cases

• Efficiency maps

• Power loss maps

• Fuel and equivalent CO2 consumption

1st gear

5th gear

2nd gear

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Conceptual design

• Early design validation at concept stage with

minimum input

• Fast, user-friendly model creation environment

• Vehicle system simulation

• Example applications

o Layout design for optimum packaging and efficiency

o Component sizing and rating

o Drive cycle simulation of vehicle system

o Fuel consumption

o Gear ratio optimisation

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Video example

Go to the following link to see the video content:

https://youtu.be/HAdvYKCjoFo

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Interface to CAD

• Import/Export model geometry to/from all major CAD

formats

• Enables close collaboration between designers and

analysts

• Ensures model quality, consistency and traceability

• Example applications

o Rapid, accurate Romax model build from existing CAD

o Export Romax model for packaging and housing design

o Import/Export gear data

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Video example

Go to the following link to see the video content:

https://youtu.be/xFT8xJfBscA

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Multibody/Multisystem dynamics

integration• Automated generation of optimised multibody dynamic models

• Automatic translation of models to ADAMS, Modelica, GT-SUITE, Simscape/Simulink

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Video example

Go to the following link to see the video content:

https://youtu.be/Ci-KD7JzEPc

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Enterprise solutions

• Batch running using XML

• Customised reporting – template-based reports

• Interfacing

o Process automation and optimisation

o CAD import/export

o FE import, condensation, export

o Multibody automated model generation,

translation, export

o Acoustic export

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CAD

Product Requirements

Multibody Dynamics

Right First Time Design

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Streamlined and integrated solution seamlessly linking design tools with

simulation and analysis tools

Making better use of CAE throughout the design and development process

- not just a design validation tool

Identifying design problems as early as possible in the development

process so better solutions can be realised

Reducing development time and cost by finalising long-lead items earlier

and by minimising prototyping

We deliver Right First Time™ solutions