2013 SRMv3-2 Supplemental2013

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Volume III | Supplemental Issue - Summer 2013

MANUFACTURING COMPANIES RELY ON MARC

The World

is Nonlinear

SIMULATINGMANUFACTURING PROCESSES

THE HADLEY GROUP

Simulation HelpsIncrease Salesby $4M

COMTES/PILSEN STEEL

Nonlinear FEA Validates NewCold Roll Forming Process

Solving Problems & Improving Processes

Heat Transfer Analysis Helps SolveTough Forging Problem

Getting to the

Root Cause ofCracks

BIG TYRE

New Tire Development & Optimized Engines

Nonlinear FEA AcceleratesDevelopment of Non-Pneumatic,Non-Solid Tire for Mining Industry

Designing theRight Tire

INNOVATINGMOMENTUM IN GROUND VEHICLES


2/162 | MSC Software

IN THIS ISSUE

REALITY

simulating

Leslie Bodnar, [email protected]

Marina Carpenter, Graphic Designer/Assist. [email protected]

Stephanie Jaramillo, Assistant [email protected]

Patrick Garrett, Assistant [email protected]

Lydia Westerhaus, Assistant Designer

[email protected]

MSC Software Corporation4675 MacArthur Court, Suite 900, Newport Beach, CA 92660

714.540.8900 | www.mscsoftware.com

EDITORIAL PREFACE

The World is Nonlinear Srinivas Reddy, MSC Software

CUSTOMER SPOTLIGHT

Simulation Helps Increase Sales by $4M Nonlinear FEA Validates New Cold Roll Forming Process

Hadley Group

Getting to the Root Cause of Cracks Heat Transfer Analysis Helps Solve

Tough Forging ProblemComtes/Pilsen Steel

Designing the Right Tire Nonlinear FEA Accelerates Development of

Non-Pneumatic, Non-Solid Tire for Mining IndustryBig Tyre

Optimizing Engine Performance Simulation Saves Millions per year

by Getting Design Right the First TimeLitens Automotive Group

SPECIAL SPOTLIGHT

What Engineers Can Dowith Marc Nonlinear FEASrinivas Reddy, MSC Software

3 75

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3/16Volume III - Summer 2013 | 1

EDITORIAL PREFACE

Srinivas ReddySr. Product

Marketing Manager,MSC Software

The World is NonlinearA

s engineers can attest, designing better productsrequires understanding of materials, loads and

boundary conditions, environmental conditions, and

component interaction in assemblies. Rise in the use

of engineered materials like composites, elastomers and

plastics, and special alloys, and more stringent market

based or regulation based requirements necessitate

deeper knowledge of product behavior well before being

introduced into the market. Tis means that the inherent

nonlinear response of the structural systems and the

physical processes cannot be ignored during development

phases.

Companies seeking to gain further insights into product

behavior are going beyond virtual product testing

by adopting simulation to understand and improvemanufacturing processes. Since manufacturing processes

are designed to introduce permanent deformation or

change material characteristics, accurate simulations

require robust handling of all the types of nonlinearities,

namely: Geometric, Material, Boundary condition/contact,

and Multiphysics.

Te nonlinear simulation solution of Marc from

MSC Software has been providing the advantage of

accurate nonlinear modeling for four decades through

its broad set of capabilities highlighted at the end of this

document. With its powerful technology, Marc has also

been addressing the manufacturing problems in various

processes, like forming, welding, cutting, extrusion,curing, and more.

Tis supplemental issue highlights engineering ingenuity

of some of our customers and the way they address their

manufacturing challenges using nonlinear simulation. In

the following customer stories, you see how the power of

innovation effectively comes together with the right tools

to solve complex design and manufacturing problems.

Hadley Industries, whose core business is

manufacturing cold roll formed products, used in

building construction industry, developed and patented

a unique cold forming process to significantly improve

mechanical and structural properties of strip steel. By

using Marc to simulate the manufacturing process, they

expect to save on considerable tooling costs (which

could range from $30,000 to $150,000 for each design),

and estimate to increase sales volume estimated to $4million over the next three years offering a superior

product in the market.

Big Tyre, a manufacturer of solid wheels primarily used

in underground mining, is focused on improving safety

by avoiding punctures and related damage and cost and

improving performance. While the mining industry is

moving towards solid tires, it comes with its challenges

in the form of ground rutting, leading to further ride

problems. Big yre has developed a non-pneumatic,

non-solid segmented tire to overcome these problems

by using composite leaf springs that are four times as

flexible as steel. Since creating physical prototypes and

testing multiple designs is a very expensive process, Bigyre has been using Marc to test and perfect their design.

Litens Automotive Groupis a full service design

and manufacturer of engineered power transmission

systems and components. Its patented orqFiltr

crankshaft vibration control system incorporates a series

of components that transmit power through frictional

contacts rather than fixed connections. Te product

must be frequently customized to deliver optimal

performance for a specific automotive engine. o avoid

the high costs and time-consuming trial and error

process, Litens has used Marc to accurately predict the

design behavior, saving millions of dollars per year across

their product line. Pilsen Steel, a leading producer of castings, ingots and

forgings, located in Pilsen, Czech Republic, experienced

difficulties with ingots cracking in a forging operation.

COMES FH, contracted to investigate the problem,

used Marc to analyze the process of heating the ingots

in the furnace, which helped them to identify the

root cause of failure. COMES team also identified a

solution to overcome this problem using Marc, which

was then verified during the actual manufacturing

process. Tis has helped reduce reject rate of the product

and increased confidence in the process parameters.

I have truly enjoyed learning about some unique ways

our customers have been using our products, and Im

sure you will too.

* If you are new to nonlinear analysis, a great introduction to it can be found in the white paper When f=Ku, An Introductory Guide to

Nonlinear Analysis, published by MSC Software, which is available at the following link: www.mscsoftware.com/f_not_equal_ku



CUSTOMER SPOTLIGHT

Hadley Industries PLCs core businessis manufacturing cold roll formed

products, primarily to the building andconstruction industries. Te companydeveloped and patented a unique coldforming process known as UltraSEELwhich significantly improves mechanicaland structural properties of the strip steel byimparting a dimpling pattern prior to the rollforming operation. Te geometry is much toocomplex to determine the structural propertiesof the end product based on analyticalcalculations alone, and it could cost $30,000to $150,000 for tooling to manufacture the

part so its properties could be physicallymeasured.

Hadley addressed this challenge by usingMarc nonlinear finite element analysissoftware to predict the highly nonlinearchanges in geometry and material propertiesthat occur during the UltraSEEL process,cold roll forming and secondary processes.

Marc overcame problems seen with otherfinite element software packages such asnonconvergence and provided reliable andconsistent results that matched experimentalmeasurements, said Dr. Martin English,

Design and Development Manager forHadley. Te ability to accurately simulatethe process and quickly determine itsperformance in customer applications hasbeen responsible for a substantial increasein sales volume estimated to total over$4 million over the next three years.

ChallengeComplex Geometry and ProcessCreates Simulation Challenge

When evaluating any new cold roll formingapplication, the potential customer needsto accurately investigate the performanceof the finished product by estimatingsection properties such as stiffness andload-carrying capacity in order to make abuying decision. Standard cold roll formedproducts have a uniform cross sectionalgeometry, so theoretical calculations can

be relatively easily performed to determinetheir section properties. Te geometryformed by the UltraSEEL process ismuch more complicated and the materialproperties vary over the geometry, sotheoretical calculations cannot be used toaccurately analyze its performance. Inthe past, the only way to fully understandthe behavior of a section produced by theUltraSEEL process was to invest in acomplete set of tooling, produce prototypesand perform physical testing, English said.

Te high cost of this approach was a majorobstacle to trying out the new process.

Hadley has worked for a number of yearsin developing the capability to simulate thedimpling process as well as the subsequentcold rolling forming and secondary operationswith the goal of developing the capabilityto predict the performance of the finished

product. Te company tried one popular

finite element analysis software package only

to discover that the results did not correlate

well with physical test ing. So Hadley assessed

three leading developers of nonlinear finite

element analysis software by using them

to simulate a complex nonlinear problem

involving compression of a thin-walled

column. Marc demonstrated its capabilities tosolve applications involving highly nonlinear

changes in geometry by providing by far

the most accurate results on this difficult

problem, said Bac Nguyen, Research

and Development Engineer for Hadley.

Simulation Helps

Increase Sales by $4MNonlinear FEA Validates New Cold Roll Forming Process

Hadley Group | Based on an interview with Dr. Martin English, Design & Development Manager

Marc overcameproblems seen withother finite elementsoftware packages suchas nonconvergence andprovided reliable andconsistent results thatmatched experimentalmeasurements.



Solution

Transferring Geometry and MaterialData from One Process to Next

Complex and interrelated nonlinear changesin contact, geometry and material propertiesoccur during the UltraSEEL process andsubsequent section forming and secondaryoperations. Te simulation challenge involvesboth accurately simulating these processes as

well as applications under loading, Nguyen

said. Tis requires simulations that connectto previous or subsequent simulations toperform continuous processes while takinginto account the changes in geometry, materialand structural properties of the materials. Animportant advantage of Marc in this regardis its PRE SAE procedure which can beused to transfer the geometry of the dimpledstrip together with its material data includingstress/strain data generated from the dimplingprocess into the subsequent simulationssuch as the cold roll forming process.

Te ideal approach is to simulate the entirechain of processes as a sequence from start tofinish: 1) the dimpling process that deforms aflat steel strip into a dimpled strip, 2) the coldroll forming process that produces the desiredsection, and 3) additional processes such asshear cutting and applications such as productsunder tension, bending, compression loads, etc.Te geometry and material data of the dimpledstrip are transferred from one process to thenext in a closed loop. Tis approach is practicalfor small sections of dimpled productsand optimizing the dimpling process itself.However, the models of the rolls and dimpledstrip can contain tens of millions of elements

for larger models so transferring the stress/

strain data between each of the stages becomesvery complicated and time-consuming,resulting in high computational costs.

Hadley Group addresses this challengeby using a simplified method to computethe properties of large dimpled products.Tis approach begins with simulating thedeformation of a flat steel plate by producinga single dimple. Tis general dimple geometryis used to generate a dimpled strip. 3Delements are used for smaller products and

shell elements are used for larger products. Itsimportant to note that only the geometry ofthe dimple is transferred from the dimplingprocess. Te material properties of thedimple are provided from a separate tensiletest on a dimpled steel sample. Tis test canbe quickly and inexpensively performedwithout tooling. Te next step is simulatingthe cold roll forming process that developsthe dimpled strip into the desired dimpledproduct, other processes and applications.

Results/Benefits

Simulation Results MatchExperimental Data

Both simulation approaches have beenextensively validated by experimentalresults and have demonstrated the abilityto accurately represent the dimpling, coldforming and secondary processes, Nguyensaid. In a typical example, a computer aideddesign (CAD) model of the top and bottomrolls was imported into Marc for preprocessing.

An elastic-plastic material model was usedwith a Youngs modulus of 205 GPa and aPoissons ratio of 0.30. Te top and bottom

rolls were modeled as rigid bodies thatrotated around their central axes.Te plainstrip was generated in Marc and placed in apre-defined position between the two rolls.Five layers of elements were used throughthe strip thickness to model both bendingand stretching phenomena. wo differentmeshes were evaluated, one with 37,980 solidelements and the other with 149,810 solidelements. Te dimpling simulation showedthat the maximum plastic strain and stressdeveloped in the two meshes differed by lessthan 7% and 4% respectively so the coarsermesh was used for the balance of the study.

Te top and bottom rolls had an overlappinggap of 0.40 mm between the mating teeth.Te sheet was fully fixed at one end andinitially fed to the rotating rolls with avelocity equal to the linear velocity at thetip of the roll teeth. When the roll teeth

just grasped the strip, the fixed end wasreleased and the strip was deformed by therotating rolls. Te original plain sheet andthe dimpled sheet were used in tension andbending simulations. Te engineering stressand strain data of the plain steel sheet wereobtained from tensile tests. Te dimpled sheetwas merged into the new model in order tostart the new analysis and the PRE SAEoption was employed to directly transfer resultdata from the previous dimpling process intothe tensile and bending simulations. Te

simulation was validated by comparing the3 dimensional geometry of the predictedshape with scanned data of the physicalsample, Nguyen said. Te geometry of thepredicted dimpled sheet differed from theactual process by less than 1.7%. Te distancesbetween adjacent dimples on the simulatedsheet also matched the actual dimpled sheet.Te predicted plastic strain distributioncorrelated well with experimental resultsobtained with micro-hardness tests. In thetensile test the predicted yield and ultimateforces in the plain sheet were 2% and 4%greater than the experimental results andthe predicted yield and ultimate force in thedimpled sheet were about 1% and 5% lessthan the experimental results. Te predictedand experimental values for ultimate loadin the bending test were also close with amaximum difference of 0.4% and 4% for theplain and the dimpled sheets respectively.

Te reliable and consistent results providedby Marc make it possible to accurately assessthe applicability of UltraSEEL for existingand new products in a short time frame at alow cost, English concluded. Te accuratesimulations have enabled Hadley to make

and substantiate technical claims regardingthe benefits of the process. As a result, thecompany has increased its sales of UltraSEELproducts and also generated additionalrevenue by increasing licensing of the processamounting to an estimated $4 million overthe next three years.u

Results



CUSTOMER SPOTLIGHT

Getting to theRoot Cause of CracksHeat Transfer Analysis Helps Solve Tough Forging Problem

Comtes/Pilsen Steel | Based on an interview with Dr. Filip Tikal, Computer Modeling Specialist

Aleading producer of castings, ingots andforgings, Pilsen Steel, Pilsen, CzechRepublic, recently experienced difficulties with

ingots cracking in a forging operation. Te

company contracted with COMES FH to

investigate and determine the root cause of the

formation of longitudinal cracks on a diverse

load of 34CrNiMo6 steel ingots in a forging

operation. Previously the ingots were cooledafter casting in water to between 500oC and

600oC. Te ingots were then placed in the

forging furnace which is at a temperature of

1100oC to 1200oC. It was unclear whether the

root cause of the cracks was heating the ingots

or the forging operation.

COMES used MSC Softwares Marc

nonlinear finite element analysis (FEA)

software to analyze the process of heating the

ingots in the furnace, which was suspected as

the root cause of the cracks.

Te results showed that increasing thetemperature of the ingots by 100oC prior to

putting them into the furnace reduced thermal

stresses to acceptable levels. Pilsen Steel

implemented this change and it eliminated the

cracking problem.

Challenge

COMES FH was tasked with investigating

the root cause of the formation of longitudinal

cracks on a diverse load of 34CrNiMo6 steel

ingots in a forging operation.

In their current process, Pilsen Steel was

cooling the formed Ingots in water to between

500o

C and 600o

C. Te ingots were thenplaced in the forging furnace which is at a

temperature of 1100oC to 1200oC.

Once cooled, the Ingots longitudinal cracks

contained a series of undesirable longitudinal

cracks. It was unclear whether the root cause of

the cracks was heating the ingots or the forging

operation.

Marc is the only finite element analysis

software I am aware of that is capable of

handling all of the complexities of this analysis

problem, ikal said. Performing thermal

analysis on the complete ingot workload

requires determining the radiant heat transferbetween the furnace and each of the ingots

with shading effects taken into account. Marcexcels at this type of challenging multiphysics

problem which is why it is our finite element

analysis tool of choice. Marc is an implicit

nonlinear FEA software program that

simulates static, dynamic coupled physics

problems.

Marc eliminates the need for the simplifying

assumptions that are required with linear

FEA, making it possible to accurately simulate

complex real-world behavior under realistic

environments and operating conditions.

Solution

Pilsen Steel provided the geometry of the

ingot and furnace in the form of 2D drawings.

Marc is the onlyfinite element analysissoftware I am awareof that is capable ofhandling all of thecomplexities of thisanalysis problem.



COMES FH researchers reproduced theingot geometry in SolidWorks. Ten theycreated a simple 2D axisymmetric model of asingle ingot and the furnace wall. Te materialmodel for the simulations was obtainedthrough experimental testing includingthermal capacity, thermal conductivity, heatexpansion coefficient and phase transformationin the COMES FH mechanical testinglaboratory.

Te researchers ran a transient analysis fora period of 5 minutes starting with whenthe ingot was placed in the furnace. Marccalculated the radiant heat transfer fromthe furnace to the ingot then converted thethermal gradients into mechanical stresseson the ingot. Te results showed very highstresses in the ingot so the 2D axisymmetricmodel was expanded to a full 2D model alsoconsisting of a single ingot.

Te researchers then expanded the 2D modelby adding additional ingots to determine theeffects of the placement of the ingots in the

furnace and of the shading of ingots fromradiation heat transfer by other ingots. Teactual layout and materials of the ingots inthe work load were monitored in the plant forseveral months to ensure accurate modeling ofthe ingot placement.

Next, the 2D model was extruded to a 3Dmodel consisting of the furnace and a typicalload of ingots. Te 3D model providedverification of the 2D analysis as well as amore detailed prediction of the location ofthe cracks, which was used for validation bycomparing the analysis results with

inspection data.

Tese results confirmed that heating the ingotsin the furnace generated thermal stresses thatlater caused cracks to form during forging.Based on the analysis results, researchers wereable to predict which ingots would developcracks and the location of those cracks. In boththe analysis and in production, cracks wereprimarily seen on ingots placed near the wallof the furnace.

It was clear that the problem was caused by

thermal gradients during the heating operation.Te temperature of the furnace could not bereduced so the researchers wondered whetherraising the ingot temperature would eliminatethe cracking problem and, if so, what was thelowest ingot temperature that would eliminatecracks? o answer these questions, COMESFH researchers ran a series of analyses whilevarying the starting temperature of the ingotsin 50oC increments.

A high performance computing (HPC) clusterwith 32 cores was used to provide a fastturnaround on this more complex analysis.

Te simulation showed that the cracksoriginated in areas where high thermal stresseswere generated as the ingots were heated.

COMES researchers next ran a number ofadditional analysis runs that evaluated theimpact of adjusting the temperature of theingots prior to inserting them into the furnace.

Results/Benefits

Te results showed that raising the ingottemperature to 700oC completely eliminatedthe cracking problem. COMES FH

researchers worked with Pilsen Steel engineers

to modify the soaking process used to cool the

ingots after casting to provide assurance that

ingots would be at least this temperature when

they were placed in the furnace.

As predicted by the analysis, when these

changes were implemented they eliminated the

cracking problem.

About Pilsen Steel

Pilsen Steel produces steel, ductile and grey-

iron castings, ingots and finished machined

forgings for a wide range of industries such

as power generation and shipbuilding as

well as for further processing by rolling

mills. Te company performs the complete

production process under one roof including

steel making, casting, forging and round and

finish machining. wo thirds of the companys

production is exported. Pilsen Steel delivered

the wheel shaft and other castings totaling

more than 200 metric tonnes for the LondonEye Ferris wheel. Pilsen Steel is also the worlds

leading producer of wind turbine shafts and

one of the largest suppliers of large crankshafts

for 4-stroke diesel engines.

About COMTES FHT

COMES FH offers a wide range of

services to metal producing and metalworking

companies including physical testing, material

analysis, computer simulation, process

design and development, and prototype

manufacturing. COMES FHs customersinclude steelmakers, rolling mills, forge

shops and nonferrous metal producers. Te

companys capabilities include fracture-

toughness testing, high- and low-cycle fatigue

testing, high temperature testing, strain

measurement, material analysis with electron

microscopes, electron backscatter diffraction

(EBSD) analysis and energy dispersive

X-ray analysis (EDX) analysis of chemical

composition. COMES FH cooperates

with industrial partners, primarily in Europe,

and participates in research and developmentprojects with research institutes and

universities all over the world. COMES FH

employs more than 65 researchers, technicians

and other employees.u



CUSTOMER SPOTLIGHT

D esigning the right tire for large wheeledvehicles used to haul coal and othermaterials in underground mines presentsan enormous design challenge. Pneumatictires present risks because of the dangerof an explosion in a confined space whilesolid tires are associated with relatively largevibrations experienced by the driver. Bigyre, a company that specializes in producing

solid tires for mining vehicles, is developinga unique alternative which uses arrays ofleaf-springs, typically made of compositematerials, to provide performance similar topneumatic tires without the risk of blow-outs.Te company began designing the new tiresin 2002. Tey first designed and built drivetires for a racing go-kart - these prototypes,built in 2006, proved the concept very well.Next they designed full-size prototypes formining vehicles using finite element analysisbut found that the software was incapableof modeling the rubber once it was bulging

under load, causing the analysis of the wheelto always terminate early while carryingmuch less than full load. Tis seriouslyinhibited their ability to design the wheel consequently the first full-size prototype formining, while again confirming the concept,did not meet the design criterion they had set.

Challenge

Underground Tire Challenges

Big yre is a manufacturer of solid wheelsthat are primarily used in undergroundmining vehicles. Many mining companieshave switched from pneumatic tires to solidwheels because of the dangers presented bypneumatic tires underground, Louden said.

Mines underground have bolts sticking outof the walls that can easily cause punctures.ires on heavy vehicles are inflated as high as

170 psi, so when they are torn or punctured aconsiderable amount of force is released. Dueto space constraints underground, workersare often in close proximity to the tires sothe potential for injury when a tire is tornor ruptures is a major concern. Because ofthese concerns, many mining companieshave switched to solid rubber-tired wheelsor solid tires comprising a pneumatic tire

whose interior is filled with foam. Tesetires eliminate the risk of punctures buttheir dampening properties are inferior topneumatic tires so operators experienceconsiderably more vibration. In some mines,operators are restricted to spending no morethan 90 minutes a day on machines withsolid wheels due to the effects of vibrations.

Another problem is that foam-filled solidtires dont provide as even a distribution ofpressure on the ground as pneumatic tires. Tehighest pressure is usually seen in the centerof the tire which can lead to the formationof ruts on the floor of the mine where the

mine is working on soft strata. Big yrehas developed a non-pneumatic, non solidsegmented tire which it hopes will overcomethese problems and potentially revolutionizethe underground mining industry. Te tireuses composite leaf springs that are morethan four times as flexible as steel. Te leafsprings are configured in opposing arrays sothe wheels are completely balanced. Te innerend of each leaf spring is connected to a steelhub, while the outer end is connected to steelor fiber segments that are bonded to a rubbertread. Tis design eliminates the need for the

tires to be inflated so it eliminates the risk ofpunctures, reduces heat entrapment and isalso expected to provide greater load, speed,haulage distance and longer life relative topneumatic tires. Compared to solid wheels,the new design provides reduced vibration,increased ride comfort, lower contact pressure,

more even pressure distribution, and improvedlateral stability on slopes. While prototype

wheels are open so that the springs canbe viewed, the production models will be

sealed on both sides for safety reasons andto prevent the tire from being contaminatedby particles and debris from the mine.

Solution

Introducing SimulationInto The Design Process

Te design concept provides the flexibilityand challenge of defining various designparameters including the number of springsin an array, thickness of springs, curvature ofsprings, length of springs, material properties

of springs, geometry and material propertiesof the segments that the springs attach toon the outer diameter of the wheel, as wellas many others. Te design criterion is toprovide a very efficient vertical loading forthe size of the wheel while providing similarif not equivalent suspension to a pneumatic

Designing the Right TireNonlinear FEA Accelerates Development of Non-Pneumatic,Non-Solid Tire for Mining Industry

Big Tyre | Based on an interview with Bruce Louden

We were pleasantlysurprised that Marc wasable to handle such ademanding analysisproblem in such a short

period of time and deliverresults that closelymatched test resultson the prototype.



tire, with excellent torque capacity andlateral stability. When you are designingsomething that has never been done before itcan be frustrating, Louden said. Using thetraditional build and test method, withoutsuitable FEA software, we would have hadto build prototype after prototype, which

would have been very expensive and time-consuming. It was clear that we needed tosimulate the performance of the tire but this

was a very challenging simulation problem.In order to simulate the performance of thenew tire, Big yre engineers needed to model

the 3D contact between the springs and thesegments and between the rubber and theroad, the glued contacts between the segmentsand the rubber and the self-contact of thesprings. Tey needed to address the hyper-elastic material behavior of the rubber, thelarge deformation and (deliberate)bucklingof the springs, and the elastic plastic materialproperties with failure for the composite leafsprings. Tey also needed to model the pin-

joints between the segments while allowingfor large deformations and driving the wheel.Big yre engineers tried to evaluate theperformance of the new tire using the softwarepackage they had previously successfullyused to analyze structures. Tis softwarepackage is excellent for analyzing structuresor assemblies with small deflections but couldnot cope with the highly nonlinear behaviorfound in the new tire, said John Shaw,Managing Director of Solidtech Engineering

Services, a consulting company that providesengineering services to Big yre. We wereonly able to solve about 40% of what wewanted and we were suspicious of these resultsbecause we were not sure that the nonlinearproperties of the wheel were properly takeninto account. Most important, we were unableto determine the failure point of the wheelwhich is the most critical design specification.

We talked to Compumod because wediscovered an article on the web thatdescribed how MSC FEA software was

capable of re-meshing during an analysis tohandle excessive strain in materials such asrubber, Louden said. When we describedthe problem, they told us that Marc wasthe right simulation tool to address it. Bigyre commissioned Compumod to simulatethe initial prototype. Big yre provided 3Dgeometry of the wheel and Compumodimported the geometry into Patran to createthe finite element model. Hexagonal elementswere used for the springs and rubber andtetrahedral elements were used for the steelsegments. Symmetry in one plane was usedto reduce the size of the model. Te hinges

between the different segments and betweenthe springs and segments were modeled withrigid RBE2 elements that allowed free rotationaround their own axes parallel to the wheelaxis. 3D contact was defined between theground and rubber. Te rubber was glued tothe segments through a special glued contactcondition. Normal contact was defined

Fig. 1: Inventor Bruce Louden with nonpneumatic

non-solid wheel prototype

Fig. 4: Hinges connect leaf springs to segments

Fig. 2: Picture of Underground Mining Machine (Eimco

913) with Big Tyres first full-size prototype wheel

Fig. 5: Simulation results for vertical loading of

symmetry model-b

Fig. 3: Marc model of segmented tire prototype

Fig. 6: Force vs. displacement curve

Fig. 8: Simulation results for moving wheelFig. 7: Picture of prototype wheel advancing over

an obstacle

between the springs and the segments andbetween the springs themselves. Big yreprovided data for the material properties ofthe rubber and springs by conducting forcedeflection experiments in their laboratory.

Results/Benefits

Nonlinear Analysis with Marc

Compumod first conducted a nonlinearstatic analysis on one spring to correlate themodel material properties with experimentaldata. Te material properties were tuned toreplicate the measured reaction force in theexperiment. Ten a nonlinear analysis wasperformed on the entire wheel to assess itsstrength. Te wheel was given an enforceddisplacement of 150 mm which was solvedin 100 nonlinear increments. Te reactionforce was then measured on the groundand graphed against displacement. Te firstnegative slope indicated failure of the wheelat 252 kiloNewtons or 25.7 metric tons,which is well over the target of 16 metrictons. After the first collapse of the wheel, thecontact between the springs and betweenthe springs and segments added stiffness tothe wheel and the reaction force increasedagain for increasing displacements. Wewere pleasantly surprised that Marc wasable to handle such a demanding analysisproblem in such a short period of timeand deliver results that closely matched testresults on the prototype, Louden said.

After seeing the benefits of the software,we decided to purchase Patran and Marc,Louden said. Compumod organized trainingfor us in their Sydney office and handed overthe models they created in the consultingproject. We very quickly began designing the

second full-size version of our design, andhave been able to improve the design at amuch faster pace than in the past. It evenallows us to simulate driving maneuvers of thevehicles, including obstacles on the road.u



L itens Automotive Groups patentedorqFiltr crankshaft vibration controltechnology uses an arc spring isolatormechanism to decouple the accessory drivesystem inertia from the engine torsionalvibrations. Te product is dimensionallyrather small but incorporates a complexmechanism consisting of a series of

components that transmit power to eachother through complicated frictional contactsrather than fixed connections. Te productmust frequently be customized to deliveroptimal performance for a specific automotiveengine. In the past, this involved a time-consuming and expensive trial and errorprocess.

Recently, Litens has developed the abilityto accurately simulate the operation of theorqFiltr, making it possible to accuratelyevaluate performance of design alternativesand iterate to the optimal design before

building the first prototype. MSC SoftwaresMarc nonlinear finite element analysis (FEA)

software has been used to accurately predicthow the design behaves, how componentsmove and react against each other and whathappens under dynamic loading conditions,said Dr. Steve Jia, Chief Engineer, CAEechnologies and Materials Engineering, forLitens. It is difficult to accurately estimatethe cost savings we have obtained through

virtual product development (VPD) but weare certain that it amounts to millions ofdollars per year across our completeproduct line.

Dynamic Tension Control

High static and dynamic accessory belttensions reduce belt life, reduce accessorycomponent bearing life, increase noise, wastefuel and add weight and cost through copingstrategies. Litens specializes in deliveringengineered control of pre-set (static) andrunning (dynamic) belt tension, resultingin accessory drive systems that are efficient,quiet and transmit maximum power under allconditions.

Litens orqFiltr controls the system resonantfrequency by tuning the spring stiffness to thesystem inertia. Because the spring stiffnessis softer than traditional rubber isolators,vibrations from the engine are mostlyabsorbed before being transmitted to theaccessory drive belt. Tis results in isolationof all components in the accessory drive,and any accessory drive system resonancehas very small peak amplitudes since there islittle excitation. orqFiltr springs are madeof steel and do not deteriorate like rubber.

Additionally, the built-in automatic clutchsystem eliminates belt squeal associated withresonance of rubber dampers so no separateone-way clutch is needed.

Te orqFiltr device connects to the enginecrankshaft through four bolts that connect tothe holes in the driver shaft shown in the tophalf of Figure 1. Te driver shaft has two wingtabs that compress the arc springs shown inred on the drawing. Te arc springs connectto two shells shown in black in the drawing.Half of the shells have been removed for

display purposes. Te shells in turn connectto the clutch springs which are shown ingray in the drawing. Te clutch springs havea frictional engagement with the pulley thatdrives the accessory belt.

Very complex engine vibration loading drivesthe device. Te arc springs absorb most of theangular vibration energy of the engine and theclutch transmits power in only one direction,serving to decouple the engine from theaccessory drive system. Its interesting to notethat none of the components in the load pathhave a fixed connection to each other and

torque is transmitted only through frictionalcontacts rather than fixed connections. Inaddition, the contact conditions includingthe magnitude, location and direction of thecontact forces are continually changing astorque varies or the device rotates.

Challenge

Design Challenge

Tis device provides an enormous designchallenge, Dr. Jia said. We need to fullyunderstand the behavior of the design under

dynamic loading conditions in order to ensurethat we will deliver the right products the firsttime. We need to determine the magnitude,location and direction of the action-reactionforces and stress and deformation/deflectionon each component and to investigate thecontact mechanism in order to achieve

Litens Automotive Group | Based on an interview with Steve Jia, Chief Engineer

OptimizingEngine PerformanceSimulation Saves Millions per year by Getting Design Right the First Time

Marc not onlysubstantially reducesdevelopment time andcost, but also is theonly tool that enables

us to investigate howthe proposed designworks.

CUSTOMER SPOTLIGHT



an optimal design. Moreover, the automotiveindustry is very cost-competitive andweight-conscious so we also need to removeunnecessary material in the design in order tominimize the weight.

We can determine the overall dynamicperformance of a crankshaft decouplerthough physical experiments but theinformation that can be gained from physical

Fig. 1: TorqFilter geometry

Fig. 4: Marc highlights contact locations and forces

Fig. 2: TorqFiltr mesh

Fig. 3: Maximum principal stresses

experiments is limited because there are nosensors available at a reasonable cost thatcan tell us what is going on inside that smallassembly, Dr. Jia continued. We are stillleft guessing as to what is happening insidesuch as contact locations and forces andstresses and deflections of the individualcomponents.

Solution

Picking the RightSimulation Technology

Litens has evaluated a number of differentsimulation technologies. Large displacementdynamic simulation systems such as MSCs

Adams software do a great job of simulatingcomplex mechanisms, however, they arenot designed to handle the elastoplasticnonlinearities seen in this application. Tereare a number of finite element analysissoftware programs on the market but most are

limited to solving within the limits of linearmaterial properties and displacements, smallstrains and small rotations. Some softwarepackages claim to have nonlinear capabilitiesbut are not able to consistently and reliablysolve problems involving continuallychanging contact conditions betweencomponents, large rotational sliding frictionalcontacts and elastoplastic material behaviors.

On the other hand, Marc was built from theground up to consistently obtain convergedsolutions for highly nonlinear problemsinvolving nonlinear materials, large strain

and displacement and contacts. Marc alsoprovides multiphysics capabilities, enablingengineers to simulate coupling betweenstructures, thermal, fluid, acoustics, electricaland magnetics.

Litens analysts receive a detailed computeraided design model from the companysdesign engineers. Tey import the geometryinto Patran, the companys pre-processorof choice. Te biggest challenge in pre-processing is to reconcile the detailed meshingrequired in areas such as where the clutchinserts into a slot in the lower spring shell

with fillets of 0.2 mm with the need to keepmesh size as large as possible in areas withsmaller transients to reduce solution times.Patran gives Litens analysts complete controlover the mesh distribution. Analysts typicallymanually create a surface mesh in criticalareas and use the automesher to fill in theless critical areas. Te model is then sent to ahigh performance computing computer with32 CPU/cores and 256 gigabytes of RAM forsolution.

Results/Benefits

Understanding Howthe Design Behaves

Te simulation results enable Litens tounderstand how the design behaves, howthe components affect each other and what

happens as the product rotates through largeangles of displacement. We can see howevery component moves and reacts against

other components as the product rotatesthrough its full range of motion, Dr. Jia said.We can determine contact locations, contactforces, stresses and deflections, many things

we need to know to optimize the design ofthe product. For example, our clutch was

originally designed in an S-shape based onprevious experience, but the FEA results

showed us that a C-shape provided muchbetter performance at no increase in cost.Simulation results with Marc are consistently

within 5% to 10% of physical testing results,

and even less than 5% in some cases, givingus confidence to use simulation to drive thedesign process.

Figure 3 shows the maximum principalstresses at one point in the rotation. Tefigure shows that the highest stress is in thearc springs. Te ability to view stress on

each location of each component makes itpossible to identify hot spots so they can becorrected to avoid premature failures. At thesame time, areas where stresses are low present

the opportunity to remove material to savecosts. By the way, for this plot the scale wasset to 900 Megapascals in order to easily viewstresses in the arc spring in relation to other

components. Litens analysts lower the scalein order to distinguish differences in stressesamong the components with stresses that areso close to each other that they all show up as

green in Figure 3.

Figure 4 highlights the ability of Marc todetermine the contact locations and forces.Te colored areas show the location of the

contact and the magnitude of the contactforces. Analysts can determine these valuesat any point in the rotation or can generatean animation that visually shows the contact

locations and forces changing as the devicerotates. Its not practical to obtain this typeof information using physical testing,Dr. Jia said.

Marc has been widely used in our everyday

VPD to simulate the complete mechanismand to virtually measure everything we need

to optimize the designs. Marc not onlysubstantially reduces development time andcost, but also is the only tool that enables usto investigate how the proposed design works

and how the product behaves when a physicalpart is not available during conceptualdevelopment stage or a physical experimentis not practical or cost-prohibitive, Dr. Jia

said. Over the years, we have developedgreat confidence in both the Marc softwareplatform as well as our own ability to apply

the tools in an accurate and consistentmethod. Obviously this approach savesmoney and time and has become such anembedded part of our engineering processthat I cannot see us developing any new

product without this capability.u



TECHNOLOGY MATTERS

Static Analysis

Perform linear and nonlinear static analysisto virtually test your designs

Include advanced nonlinear material modelsfor metals, composites, elastomers, plastics,

ceramics, powder metals, soils, concrete,

shape memory alloys, glass and more

Incorporate both large deformation and

large strain behavior

Accurately model nonlinear boundary

conditions including follower force effects,foundations, and contact

Perform creep simulations to determine thelong term response of the structure.

Perform post-buckling analysis to performstability studies

Determine the inertia relief force to balancefree structures

Perform steady-state rolling analysis of tires

Perform mechanical wear analysis due to

friction

Export or import DMIG files for

compatibility with MSC Nastran

Perform global-local analysis to better

capture local behavior

Dynamic Analysis

Perform natural mode analysis of structures

to determine structural stability under

dynamic loads

Conduct frequency response analysis

subjected to harmonic loads or randomvibrations to analyze structural performance

Include advanced damping models thatincorporate frequency and deformation

dependent damping observed in rubber andplastics

Obtain insight into dynamic performanceof structures through transient analysis

Gain improved accuracy through accuratemodeling of contact, nonlinear materials,and loading conditions

Create Modal Neutral Files (MNF) that

may be shared with Adams includingnonlinear preload

Heat Transfer

Perform steady-state and transient analysisfor one-, two-, and three-dimensionalbodies

Obtain temperature distributions in a

structure for linear and nonlinear heattransfer problems

Model nonlinearities including temperature-

dependent properties, latent heat (phasechange) effect, heat convection in theflow direction, and nonlinear boundaryconditions (convection and radiation)

Compute radiation view factors faster and

more accurately

Simulate thermal degradation of TermalProtection Systems (PS) with advancedpyrolysis model

Perform ablation analysis for space systems,brakes, and bio-medical applications

Compute heat fluxes across multiplecomponents that come into contact

Thermomechanical Coupling

Analyze structural response due totemperature changes in the environment

and thermal gradients in the structure Model heat generation due to plasticity and

friction between different components foraccurate physics

Incorporate heat generation due to curingin composite manufacturing.

Simulate the influence of annealing

Simulate the effects of changes to thermalboundary conditions due to largedeformations

Electrostatics & Magnetostatics

Evaluate electric fields and magnetic fields

in a body or medium Compute electric potential field, electric

displacement vectors, magnetic induction,magnetic field vector, and more to gaininsight

How DoEngineers UseMarc Nonlinear FEA?The complete nonlinear analysis solution that reducesphysical testing costs through reliable, robust simulation.


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Simulating Manufacturing Processes On-Demand >>

Analysis of Cold Roll Formed Products and Processes On-Demand >>

Simulation of Failure and Crack Propagation

On-Demand >>

Introduction to Simufact.welding On-Demand >>

Improving Safety and Reliability with Simulation of Elastomers On-Demand >>

Advanced Contact Modeling for Accurate Simulations On-Demand >>



Integrated Solutions

Adams

Multibody DynamicsSimulation

Actran

Powerful AcousticSimulation Software

Digimat

The Nonlinear Multi-scale

Material and StructureModeling Platform

Easy5

Advanced ControlsSimulation

Marc

Advanced Nonlinear& Multiphysics

SimXpertMultidiscipline Simulation

Solver Solutions

MSC Nastran

Structural &Multidiscipline

Dytran

Explicit Nonlinear & FluidStructure Interaction

MSC Fatigue

Fatigue Life Prediction

Sinda

Advanced Thermal

Mid-Sized BusinessSolutions

MSC Nastran Desktop

Multidiscipline Simulationfor the Desktop

SimDesigner

CAD-EmbeddedMultidiscipline Simulation

Modeling Solutions

PatranFE Modeling and Pre/PostProcessing

SimXpert

Multidiscipline SimulationEnvironment

Simulation Process& Data Management

SimManager

Simulation Process& Data Management

MaterialCenter

Materials Life CycleManagement

MSCs Solution PortfolioMSC Software makes products that enable engineers to validate and

optimize their designs using virtual prototypes. Customers in almost every

part of manufacturing use our software to complement, and in some cases

even replace the physical prototype build and test process that has

traditionally been used in product design.

MSC ProductsSimulating Reality, Delivering Certainty

SIMU

LATIO

NPROCE

SS&DATAMANAGEMEN

T

MULTIDISCIPLINEENGINEER

ING

MATERIALS

SYSTEMS PA

RTS

STRU

CTURES&MULTI-PHYSICS

DURA

BI

LITY A

COUSTICS

CONTROLS&MULTIBODY

DYNA

MICS


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Documents

2013 SRMv3-2 Supplemental2013