ALSTOM Transport SelectsSIMPACK as Common SolutionAlong with Siemens Mobility and Bombardier Transportation, another global player, ALSTOM Transport, is now using SIMPACK as a standard software tool.

This decision was made after several years of using a wide variety of MBS and dedicated software tools through-out the company. The performance of SIMPACK at the ALSTOM’s Salzgitter site in Germany, proved SIMPACK to be essential for all other sites across Europe.

ALSTOM, A TeChnOLOgy LeAder

INTEC is very proud that this deci-sion was taken at the same time that ALSTOM unveiled its new AGV train and set a new world speed record of 574.8 km/h with the “V150” proto-type. All of this shows the commit-ment of ALSTOM to being a technol-ogy leader.

VehICLe dynAMICS, nVh And COnTrOL In One SOLuTIOn

ALSTOM Transport will use SIMPACK for the development of all products,

from tramways to high-speed trains, and for calculations ranging from safe-ty to NVH analysis and control systems development.

These systems require the use of highly reliable numerical methods for obtain-ing sufficient accuracy. The module SIMPACK Rail has always benefited from the renowned SIMPACK solvers. In addition, the module has now been further strengthened with improved contact methods and the new SODAS-RT 2 solver.

SIMPACK, The wOrLd’S LeAdIng rAILwAy SIMuLATIOn SOfTwAre

SIMPACK has been in the railway simu-lation industry for more than a dec-ade. SIMPACK Rail, released in 1996, was the first SIMPACK add-on module. SIMPACK Rail provides all the neces-sary functionality for creating and working with highly detailed and ac-curate railway dynamics models. These include a powerful rail-wheel contact model, an easy-to-use graphical user interface and many specialised mod-elling elements which are common to the railway industry.

The completely redesigned SIMPACK Rail module, released with SIMPACK 8.901, further simplifies the model set-up and handling and also improves the simulation robustness. In addition, the enhancements ease the way for future developments.

Thanks to all the customers in the rail industry who trust in INTEC’s compe-tence and SIMPACK’s speed, accuracy, robustness and versatility, SIMPACK is now the world-leading MBS tool for modelling railway vehicles.

VOLuMe 12, SeCOnd ISSue nOVeMBer 2008

EditorINTEC GmbH, Argelsrieder Feld 13, 82234 Wessling, Germany

» TITLe STOry ..............................01

François Barral and Christoph Weidemann, INTEC

» APPLICATIOn .............................02

Prashant Khapane, INTECLanding Gear Dynamics

» APPLICATIOn ............................ 04

Valentin Keppler, Biomotions SolutionsBiomechanical Motorcycle Rider

» APPLICATIOn ............................ 06

Stefan Lehner, Oskar WallrappIngenieurbüro Stefan LehnerHuman Head Protection

» newS ........................................ 09

Steven Mulski, INTECNew SIMPACK Website

» SOfTwAre ............................... 10

Steven Mulski, INTECNew Contact Methods

» SOfTwAre ................................11

Wolfgang Trautenberg, INTEC SIMPACK Viewer

Stefan Dietz, INTEC Deformation Contouring

2

SIMPACK»news, november 2008

» APPLICATIOn

Prashant Khapane, INTEC

Simulation of Landing Gear Dynamics using SIMPACK

Fig. 1: SIMPACK as a virtual test-bed

Fig. 2: Slip-optimised braking algorithm

Fig. 3: Landing gear vibration modes

In a variety of mechanical systems fric-tion induced vibrations are a major concern. The aircraft landing gear is by nature a complex multi-degree-of-free-dom dynamic system. It may encounter various vibration modes which can be induced by brake frictional character-istics and design features. These brake induced oscillations can lead to very high loads in the landing gear and brake structure which may result in passenger discomfort and sometimes even component failure.

Along with the serious fore and aft oscillations of a landing gear, often referred to as gear walk, and shimmy, other vibrations in aircraft landing systems are not only annoying and disconcerting but can also affect the stability of the aircraft during take-off, landing, and rolling. Although equa-tions for representing various parts of a landing gear are well established, solving the problems manually with mathematical programs can be slow and laborious. Simplifications made to reduce problem size may introduce in-accuracies such that a design modifica-tion to correct a problem in one area causes unforeseen vibration in other parts of the structure.

InTrOduCTIOn

Originally, Multi-body Simulation (MBS) software was designed for the analysis of purely mechanical rigid

body systems, sometimes added by force laws from other fields such as hy-draulics or electronics, mostly included as source code. Since rigid body MBS is not relying on the exact structure and geometry of its components its main applications were principle dynamic in-vestigations in the early development phase of a project. Today the request for the features of MBS-software is much more demanding. Modern MBS-software packages enable interdiscipli-nary modelling and analysis, either by user enhancements of the MBS func-tionality or via interfaces to other CAE tools or both. As a rule, the individual extensions of MBS programs are well adapted to the needs of MBS compu-tation but limited in their facilities and performance. Interfaces to other CAE software on the other hand not only offer the entire possibilities and func-tionality of proven software tools but widely reduce the modelling effort as most of these models already exist, e.g. for CAD drawings or FEA stress analysis only appropriate conversion is needed. Computer Aided Engineering (CAE) tools such as Flexible Multi-body Meth-ods are an excellent test-bed for mod-elling a landing gear and complete air-craft system, see Fig.1. Since the MBS tools such as SIMPACK are modelled as an open system they can accept inputs from many other standard software tools such as Matlab etc. With the help of these sub-modules one can simulate important ground manoeuvres in the

3 » APPLICATIOn

Prashant Khapane, INTEC

Fig. 5: Effect of mechanical trail

Fig. 6: Shimmy Analysis

Fig 4: Complex ground manouvre

pre-design phase to save high costs of flight-tests. Clearly MBS is the favoured tool for analysis of the dynamics of the landing gear and brake system. It also allows concurrent engineering with other Computer Aided Engineering (CAE) tools such as Nastran which ensures ac-curate modelling for the purpose.

MOdeLLIng LAndIng geAr In SIMPACK

In SIMPACK this multi-body system is represented by rigid body elements such as main-fitting, the shock tube, and two or four wheels, respectively. The shock absorbers (oleo) are located between the shock tube and main fit-ting. All landing gears have one trans-lational degree of freedom for the shock absorber and one rotational de-gree of freedom for each wheel.

The main landing gears may have an additional bogie attached to the shock tube with a rotational degree of free-dom along the y-axis with 4 wheels at-tached to it. To model landing gears of large aircraft such as A380 main land-ing gear which has 6 wheels, a bogie, and a pitch trimmer in addition can be more complex. To model the system successfully one needs to define prop-er force elements to simulate the be-haviour of the system. SIMPACK has a built-in library of many force elements and it is also possible to write so called user-routines which gives additional freedom to model different systems. Force elements apply external or inter-nal forces and torques in the system. They may depend upon the state of the system, e.g. the distance between two points, and upon time. Force elements do not affect the degrees of freedom of the system, but may introduce addi-tional states, or boundary conditions, to the differential equation system of the MBS model. The force elements describing the landing gear characteristics have been modeled in detail for this work by means of so-called user-routines in SIMPACK. While the equations of the physical phenomena as such are valid independently from the exact aircraft type and can be taken from standard textbooks the parameters for the force elements are usually proprietary. It is also possible to model individual body elements in a tool like NASTRAN and then import it in SIMPACK using the

interface FEMBS [3].For transport aircraft the main task of vertical energy dissipation is almost ex-clusively taken over by an oleo-pneu-matic shock-strut. This device combines a gas spring with oil and additional friction damping [1]. Damping force is provided by oil flow forced through an orifice by vertical strut motion. Often the oil flow is “controlled” by means of a metering pin. The gas spring is represented by a law of polytropic expansion as with spring force. The properties of the passive damper are determined by the laws describing the flow of a viscous fluid, e.g. oil, through an orifice. It is possible to program ac-tive, semi-active, and passive elements using either library elements or by means of user-elements in SIMPACK. Tyre elements can also be modelled the same way. One can make use of ‘Con-trol Elements’ in SIMPACK or SIMAT interface to model an ABS algorithm based on slip-optimization principle. It can be further enhanced as shown in Fig. 2. For further details about the force elements please refer to the lit-erature [1, 3].

reSuLTS And AnALySIS

The results presented here are for a two mass model main landing gear of the Embraer regional aircraft and a complete large transport aircraft. It is possible to simulate complex ground manoeuvres using these sub-modules, see Fig. 5. With the help of modelling elements one can study landing gear and brake interaction and the related friction induced vibrations such as gear walk and shimmy, see Fig. 4. One can also perform parameter variation to study and optimize various parameters affecting landing gear shimmy. For the simulation of rolling and braking ma-noeuvres it is safe to assume that the aircraft is in static-equilibrium on the ground. This work was conducted by Dr. Khap-ane during his employment at DLR.

Literature1. W.R. Krüger and M. Spieck, Interdisciplinary

Landing Gear Layout for large Transport Air-

craft. AIAA, 4964, 1998.

2. R. Lernbeiss, Simulation eines Flugzeugfahr-

werks bei elastischer Betrachtung des Feder-

beines. Dipl.Arbeit at DLR, Oberpfaffenhofen.

3. P. Khapane, Gear walk instability studies using

flexible multibody methods in SIMPACK. Jour-

nal of Aerosp.Sci.Technol., 10:19-25, 2006.

4

SIMPACK»news, november 2008

» APPLICATIOn

Valentin Keppler,Biomotions Solutions

Biomechanical Rider for Motorcycle Simulations

Compared with other vehicles like cars, the mechanical interaction between rider and his motorcycle is much clos-er. despite this fact motorcycle models usually do not account for this interac-tion. The reason may be the different challenges of biomechanics and vehi-cle dynamics. To enable the analysis of issues like motorcycle ride comfort, safety and instable ride modes Biomo-tion Solutions has developed a biome-chanical rider model for motorcycle simulations (fig. 1). The model was tested on a motorcycle model that the Technical University Dresden provided us with (Fig. 2-3).

The huMAn BOdy MOdeL

Based on anthropometrical data (NASA publications amongst others) Biomo-tion Solutions has implemented a 17 segment full body model. The model consists of 2 legs (foot, shank and thigh), a 3-parted trunk, neck head and two arms (hand, forearm, upper arm). Furthermore, each of these rigid bod-ies is coupled with a so-called wob-bling mass which takes into account that human body tissue is not a rigid material. Especially for ride comfort simulations the consideration of wob-bling masses is crucial.

enABLIng ACTIVe MOVeMenTS

Contrary to the handling of four-wheeled vehicles, motorcycles and bicycles are a priori unstable. The rid-er has to control the lean angle. If he doesn’t, sooner or later the vehicle will tumble down. To account for this fact we have implemented passive and ac-tive actuators into the model. The lower extremities, the trunk and head-neck are stabilized by passive im-pedances. To enable the rider model to control the handlebars, shoulders and elbows are actuated via muscle moment generators. Their input is provided by our driver model controller, which currently runs as a SIMULINK Model under a Co-Sim-ulation (Fig. 4).

BAnKIng A BIKe ArOund The COrner

Theory of controlling a two-wheeled-vehicle is complex in detail but can be simplified to a control strategy which can be coped with. At first we have to discuss the movements a rider can make to steer his bike. Three different steering modes can be identified. The rider can steer with the handlebars, lean his body to the side and move his bottom laterally to shift the Centre of Mass (COM). All these strategies which in reality are all combined by experienced rid-ers lead to a change in the lean angle which forces the motorcycle to change direction. Theory provides considera-tions that all three control strategies can be superposed. But laterally shift-ing the body weight only influences lightweight vehicles like bicycles. The heavier a motorcycle is, the more dominant the so-called countersteer-ing with the handlebars is. To cope with the different demands we decided to take only the banking via controlling the steering angle into account at first.

COunTer STeerIng wITh hAndLeBAr

A motorcycle can only follow a curved road trajectory when the COM result-ing from the masses of rider and bike leans toward the inside of the turn. The lean angle must be appropriate for the velocity of the bike and the radius of the turn. To initiate a turn, the rider countersteers. That means he pushes the handlebars in the contrary direction until the targeted lean angle (equivalent to the roll angle) is reached. Then the rider pushes the handlebars to target in the desired direction. So the Degree Of Freedom (DOF) which can be used to control the roll angle and thus the motorcycle trajectory is the steering angle. Literature of mo-torcycle control theory describes the option to calculate desired roll angles by PID-controllers. The input of these can at first be the lateral error of the

Fig. 1: Rider model can be used with different motorcycle models

Fig. 2: Steering through a crossover road track

Fig. 3: Jumping over SIN obstacle

5 » APPLICATIOn

Valentin Keppler,Biomotions Solutions

bike’s position (commonly measured by a sensor ahead of the vehicle). This also may be combined with the measurement of the yaw-angle which also describes the difference between the bike’s direction and the curvature of the road trajectory. Both strategies can be superposed; PID-pa-rameters have to be chosen carefully to allow for stable operation.

The MOTOrCyCLe MOdeL

For modelling the motorcycle we used the model kit from the Techni-cal University Dresden, designed to quickly generate a typical, parame-terised motorcycle for the multibody simulation tool SIMPACK. The kit itself was designed at the Chair for Vehicle Modelling and Simulation by M. Beitelschmidt, K. Büttner and V. Quarz (e-mail: Fzgsim@mailbox.tu-dresden.de). Biomotion Solutions Rider Model was used in combina-tion with this motorcycle model to brake, to follow road tracks like the crossover, and to go over obstacles.

AnALySIS Of SAfeTy ISSueS

Motorcycle and rider are a coupled system whose dynamics emerges from their interaction. Experienced riders are reporting possibilities to provoke or to damp out highly dan-gerous instable ride modes like weave or wobble. We used our rider model to analyse the rider-bike-system close to the weave mode. Riding at 50 meters per second a transient distur-bance moment has been applied at the steering. The bike then showed a short latency time in which a nega-tive damped oscillation at about 4 Hz showed up which finally led to expo-nential rising amplitude in yaw angle and to uncontrollable crashes.

Further we have analysed the sensi-tivity of this weave phenomenon to the seat cushion parameters. The re-sults predict strong influence of bio-mechanical factors on ride dynamics. Even just a change of 20 percent in

seat parameters may differentiate be-tween stable and unstable riding (i.e. getting into weave mode (Fig. 5)).

rIde COMfOrT AnALySIS

The use of human body models to an-alyse ride comfort has been realised for cars in the past. We extended this principle to motorcycles by using our driver model. We used a measured road excitation and placed corre-sponding sensors at the frame and at the rider’s pelvis. By processing accel-eration data we were able to identify the MIMO (Multiple In-Multiple Out) transfer function of the motorcycle seat. This function is useful for de-scribing the ride comfort of a sitting human. The curve in Fig. 6 describes the ratio of the measured accelera-tion of the pelvis and the frame. The lower the values and the faster that the curve decreases, the better the ride comfort. In combination with stability tests described above, the model can be used to optimise mo-torcycles’ design parameters, target-ing safety and comfort.

reSuLTS And PrOSPeCTS The usability of our biomechanical Rider Model has been tested success-fully in different tasks ranging from normal riding modes like braking or banking, up to the analysis of issues of comfort or safety. The results are very promising and so we will extend the rider model’s capabilities in the future. Possible improvements may be accounting for steering through weight shifting or gaining a deeper data pool by getting into detailed parameter identification combined with ride measurements.

On The weB

Some animation sequences are acces-sible on our homepage: www.biomo-tion-solutions.de/drivermodel

For further details please contact: keppler@biomotion-solutions.de

Fig. 4: Biomechanical muscle mo-ments calculated by a SIMULINK controller

Fig. 5: Analyse mechanical interac-tion: weave instability influenced by seat parameters

Fig. 6: Ride comfort analysis using measured road excitations

Fig. 1: The anatomical human head neck extremity with definition of the related bodies, the inertial fra-me and the head frame

Fig. 2: Hysteresis function of the torque-angle relation

6

SIMPACK»news, november 2008

» APPLICATIOn

Stefan Lehner, Oskar WallrappHochschule München

MBS Model of the Human Head and Neck for Investigating the Effectiveness of Head Protectors in FootballAlthough about 22% of all injuries in football are injuries of the head, head protectors are nearly irrelevant in prophylaxis. So soccer has approxi-mately the same rate of head injuries as American football and Ice hock-ey. In the last years with increasing number of elbow tackling in heading duels the acceptance of head protec-tors was discussed more and more. furthermore, head injuries are caused by the head hitting a hard surface such as another head, ground, or post. further reason for concussions are unexpected head impacts of the ball with high velocities or from short dis-tances, when no muscle activities can counteract the impact.heading is an essential part of football and in normal controlled heading situ-ations the limits that cause symptoms of concussions are not exceeded. nev-ertheless, the risk of lasting damages of the neuro-physiological system due to a high number of controlled or un-controlled heading situations has not been completely investigated.

In this paper, an anatomical detailed human head-neck model including nonlinear vertebra elasticity and liga-ments and tendons interactions is de-rived using multibody system (MBS) modelling techniques. The head-neck muscles are modelled as a control unit to satisfy an input head motion. The impact with an elastic object such as a soccer ball is described by a body and one-side linear viscoelastic contact force element. The parameters of all models are taken from literature, CT-scans, or from specific physical experi-ments.

gLOBAL defInITIOnS

For the investigation of the head inju-ry a detailed head-neck MBS is derived. As shown in Fig. 1, the model contains the rigid bodies of the – Vertebra T3, T2, T1, C7 until C1, and – the head.

These bodies are attached by joints and force elements as follows:

– Vertebra T3 is inertial fix.– Between vertebra T3 and T2, T2 and

T1 until C3 and C2 a joint of six DOF added by a nonlinear applied force / torque law is used, respectively. The details are given in section 2. 2.

– Between C2 and C1 a revolute joint about the vertical axis (the no-saying axis)

– Between C1 and head a revolute joint about the transversal axis (nod-ding axis – for flexion and extension) are applied.

The latter joints represent the lower and the upper head joints, respectively. In addition to the viscoelasticity of the intervertebral discs, ligaments en-chain the head – here seven ligaments are considered. Moreover, neck mus-cles move the head – here 23 muscles are considered within the model, where nine muscles force the flexion and 14 muscles force the extension of the head.

The individual muscle force is mod-elled as an active control unit distrib-uted from the global net action of the head by the “equal-stress-theorem” using the physiological cross section area (PCSA) and the maximum of the muscle force of each muscle. The mus-cles are attached at the head body and the inertial frame.

MOdeLS Of The VerTeBrAS And LIgAMenTS wITh The deSCrIPTIOn Of The VISCOeLASTIC MATerIAL BehAVIOur

The geometry of the vertebra bodies is taken from CT scans and their mass properties from the literature. The rotations of the vertebras are lim-ited. The data of the range of motion (RoM) are taken from the literature. For the vertebra viscoelasticity a six-

Fig. 3b: MBS of the experimental set-up to validate the developed force elements

Fig. 3a: Experimental set-up for evaluation of the stiffness of inter-vertebral joints

7 » APPLICATIOn

Stefan Lehner, Oskar WallrappHochschule München

dimensional nonlinear force model is applied. The resulting torques are based on a Kelvin model (a spring with a serial damper is in parallel with an additional spring), where the spring with a torque-angle relation is given by a function as shown in Fig. 2 and is scaled for each specific vertebra by the RoM. The damping behaviour is about 50 % of the stiffness value.

In the longitudinal directions and the transversal plane of the special ele-ment, a Kelvin model is also used. The stiffness is obtained as complex func-tion related to the discs parameters. Carrying out experimental cadaver tests validated the proposed force laws. Special attention was focused on testing the biomechanical behaviour of intervertebral discs. The used exper-imental set-up applied moments in the three main anatomical planes (frontal, sagittal, transversal) and evaluated motion with an optical 3D analysis sys-tem (Fig. 3).

Specific ligaments are considered within the simulation. The applied interaction forces are described by a Kelvin model and their parameters are found from preparations similar to the viscoelasticity of a vertebra.

MOdeL Of The neCK MuSCLeS

The head is moved by a complex set of muscles attached at the head and the bones of neck and shoulder. Here-in, 23 muscles are considered where 9 muscles control the flexion and 14 muscles the extension of the head mo-tion. For this rotation about the z-axis, the absolute head angle is observed for a given goal motion

. Therefore, the force of a sin-gular muscle j is found by a cascade control unit and implemented in a special user routine. The goal function of the control unit

can be taken from a motion analysis or other input techniques.

eXPerIMenT And SIMuLATIOn Of heAd IMPACT By A BALL

Referring to this head-neck model, an impact of a soccer ball to the human head is simulated using the general MBS program SIMPACK and validated by an experiment with a test person. From these simulation results a Head Impact Power (HIP) Index developed for evaluation of injury risks when playing American Football is obtained and fur-thermore, the efficiency of head pro-tections (e.g. commercial headgear) can be found from further simulations.

The eXPerIMenT

At first a test person was hit by a soc-cer ball. The person was prepared by markers for a motion analysis using the VICON Motion Capture System. The person could not see the flying ball and thus could not anticipate the impact. The ball velocity was 4 m/s. As shown in Fig. 5, after impact of the ball, first the head moved backwards, followed by a muscle-activated return to initial position.

The SIMPACK SIMuLATIOnS

Since the test person tries to bring back the head to the straight initial position and orientation, the goal function for the neck muscles is chosen

= 0.

Together with the models defined above the MBS simulation leads to the time history of the head angle, which is in good accordance to the experi-mental results (Fig. 4). The motion of the ball and the head for some time steps is shown in Fig. 5. With these results the validation to the MBS neck-head model is success-fully performed.

Fig. 4: Time history of the head angle for an impact by a ball at the test person (Full line shows the experiment, bright line the simulation)

Fig. 5: Simulation of an uncontrolled heading situation: Start of simulation (t = 0 ms), Ball impact (t = 10 ms), max. extension (t = 100 ms), max. flexion (t = 270 ms), end of simulation (t = 300 ms)

8

SIMPACK»news, november 2008

COnCLuSIOn

The developed model is a powerful tool for investigating the effectiveness of football headgear. In the simulated loading situations only a small reduc-tion of the injury risk was investigat-ed. With simple parameter variations of the model of the headgear – and therefore modifications of design and material behaviour – the developed MBS-model could also be used in the optimization and developmental phase of products.

Due to the detailed anatomical setup, the use of validated force elements of the soft tissue structures and the accordance of the simulation results with experimental data the paper has shown in detail that realistic im-pact situations can be analysed with the developed SIMPACK MBS-model of the head and neck. Simulations of automotive rear-end collisions for ex-ample could point out potentials of reduction of whiplash injuries due to modifications of interior equipment.

For references see:Proceedings of MULTIBODY DYNAM-ICS 2007, ECCOMAS Thematic Con-ference, C.L. Bottasso, P. Masarati, L. Trainelli (eds.), Milano, Italy, 25–28 June 2007

» APPLICATIOn

Stefan Lehner, Oskar WallrappHochschule München

Apart from having a completely new look and feel, the SIMPACK web-site’s architecture has been overhauled to offer a simpler overview and easy location of topic specific information.

Within applications, website visitors can choose a distinct engineering sector. From here they are given direct access to relevant information, such as SIMPACK software products, newsletters articles and user meet-ing presentations. A search engine is now also available.

The easiest way to see what the new website offers is by simply visiting us at www.simpack.com. We hope you enjoy it!

Website Highlights:Current newsEasy access to application specific informationTopical organisation of user meeting presentation and newsletter articles“Related links boxes” on the right side of pagesSearch engineModel and film databaseIndividual page addressing (easy to email page location)

new SIMPACK website Online

New website enables easy location of application specific information

Fast • Accurate • Robust • Versatile

INTEC GmbH . Argelsrieder Feld 13 . 82234 Wessling . Germany . Phone: +49 (0)8153 92 88-0 . info@simpack.de . Legal Notice . Sitemap

Home > Applications

9

Fig. 2: Polygonal Contact Method (PCM)

Fig. 3: Components intersection (PCM)

10

SIMPACK»news, november 2008

» SOfTwAre

Steven Mulski, INTEC

SIMPACK 8901 includes the addition of two new contact methods. These are the geometric Primitive Contact (gPC) and Polygonal Contact Models (PCM).

geOMeTrIC PrIMITIVe COnTACT (gPC)

The GPC method is primarily based upon simple primitives. The analyti-cal descriptions of the contact geom-etry enables extremely fast calculation times and is therefore suitable for models with numerous contact bodies and also for some real-time applica-tions. The GPC also supports contact with general meshed surfaces using algorithms similar to the PCM method which is described below.

Supported Geometries: • Cuboid• Cylinder• Sphere• Cone• General Meshed Surfaces (Obj)

A user only needs to define one force element for all possible contact inter-actions. Contact primitives are selected within the force element by simply dou-ble-clicking on the 3D graphical repre-sentation. The force law considers stiff-ness, damping and coulomb friction.

This new feature will be licensed with the current SIMPACK contact module.

POLygOnAL COnTACT MOdeL (PCM)

PCM has been available for several years but up to now only as a user rou-tine, see SIMPACK News “Polygonal Contact Model”, Gerhard Hippmann, August 2003 issue.

PCM enables an efficient, accurate and robust method for simulating contact between general complicated primi-tives. The contact forces are based upon the elastic foundation model, aereal damping and regularised cou-lomb friction. The licensing of the elements is also included within the current contact module.

uSAge

These new features have vastly extend-ed the already wide range of contact functionality within SIMPACK. Sev-eral commercial projects with the GPC method are already in progress.

We hope these elements also increase the level of fun with SIMPACK and we look forward to seeing many new and diverse user applications.

New Contact Methods in SIMPACK

Fig. 1: Geometric Primitive Contact (GPC)

Fig. 1: Absolute deformation of a rocker arm

Fig. 2: Settings in the properties di-alogue of the animation view

Fig. 1: SIMPACK Viewer

11 » SOfTwAre

Wolfgang Trautenberg, Stefan Dietz, INTEC

with the SIMPACK Viewer, InTeC launches a no cost product for viewing SIMPACK results as plots and anima-tions, without a SIMPACK installation. SIMPACK Viewer operates both as a standalone tool as well as a plugin in for office applications such as Power-Point, Internet explorer and excel.

SIMPACK Users can now share their results with peers, customers or man-agers who do not have a SIMPACK installation.

SIMPACK Viewer can visualize SIMPACK results based on SIMPACK binary re-sult files (.sbr) or SIMPACK project files (.spf). From existing .sbr files, 3D ani-mations can be viewed.

Even complete pages of a SIMPACK project file can be viewed. This enables the User to share pages that contains

both animations and plots, e.g. an ani-mation of a car with the tyre forces plotted along with it.

Since the User views a real 3D anima-tion and no pre-recorded movie, view operations like zoom, pan, rotate and making objects transparent can be performed while viewing the results.

In addition to using SIMPACK Viewer as a standalone tool, Users can also em-bed it into standard office applications.

Three-PhASe reLeASe Of VIewer:

1. Viewing animations from .sbr files2. Viewing single pages of projects3. As a plugin for office tools

SIMPACK Viewer, phase 1, will soon be ready for download at www.simpack.com.

Contour plots of flexible body defor-mation have been available in SIM-PACK’s PostProcessor since the release of version 8900. The plots help the user to better understand the simula-tion results, see fig. 1.

An additional input to the PostProc-essor is the mbf file that is created in the last step of FEMBS by clicking on

“Write SID and mbf file”. This mbf file is stored together with the SID file ei-ther in the local working directory or in the flexible body database. To en-able the contour plots edit the proper-ties of the animation view in the tab

“flexible bodies” and check “enable contouring”. First, the deformation to be displayed is selected.

Available options are the x, y and z di-rection as well as the absolute defor-mation. Then, the “deformation/stress probe” may be activated, which ena-

bles the user to move with the cursor over the structure and to obtain the node number and the value for the selected deformation component at the current time step. Finally, the user either selects the range that is to be contoured or the user can accept the default “auto bounds”, see Fig. 2. The deformation in between the master nodes is determined by interpolation. When looking at the results, keep in mind that the deformation is always with respect to the body fixed refer-ence frame.

To obtain the mbf file an FE input deck is considered when generating the fbi file. The mesh data is then stored in the fbi file and automatically transferred to the mbf file. For huge FE-models it is useful to reduce the amount of data. This can be done by generating an FE model file that only contains the inter-esting parts of the mesh.

SIMPACK Viewer

Tips and Tricks - Deformation Contouring

COnTACT

Wind Real-Time

General Machinery Drive Train

other Land Machinery

» gerMAnyheAdQuArTerSINTEC GmbH Argelsrieder Feld 13 82234 WesslingGermany Tel. +49 - 8153 - 9288 - 0 Fax +49 - 8153 - 9288 - 11 intec@simpack.dewww.simpack.com

» ChInAGlobal Engineering Technology Group (GET Group)Tri-Tower, C Building, Room 1802, 1804Zhongguancun East Road 66 Haidian District, Beijing 100190P.R. China Tel. +86 - 10 - 626 708 90tom.fu@get-technologys.comwww.get-technologys.com

» frAnCe INTEC France SAS1, Boulevard Vivier Merle69443 Lyon Cedex 03FranceTel. +33 - 426 29 85 40Mobile +33 - 673 881 965francois.barral@simpack.fr

» greAT BrITAInINTEC Dynamics Ltd.Cambridge Road Industrial EstateWhetstoneLeicester LE8 6LHUKTel. +44 116 275 1313Fax +44 116 275 1333suresh.gupta@intecdynamics.co.ukbjorn.vanuem@intecdynamics.co.uk

» BrAzILVirtualCAE Rua Tiradentes, 160 - Sala 22São Caetano do Sul - São PauloCEP: 09541-220BrasilTel. +55 11 4229-1349Mobile +55 11 9698-6930leandro@virtualcae.com.br www.virtualcae.com.br

» IndIAProSIM R&D Center21/B, 1st Flr, 9th MainShankar NagarMahalaksmi LayoutBangalore 560096, IndiaTel. +91 80 233 - 79686Fax +91 80 235 - 78292shama@pro-sim.comwww.pro-sim.com

PLeASe SIgn Me uP fOr The free deLIVery Of The SIMPACK»newS(fax to +49-8153-9288-11)

SIMPACK»newS1996 – 2008

INTEC GmbHArgelsrieder Feld 1382234 Wesslingwww.simpack.com

Circulation: 5000

SIMPACK Kinematics & DynamicsSIMPACK AutomotiveSIMPACK EngineSIMPACK RailSIMPACK Rail SwitchesSIMPACK ChainSIMPACK GearwheelSIMPACK NVHSIMPACK ControlSIMPACK ContactSIMPACK User RoutinesSIMPACK Code ExportSIMPACK ElastomerSIMPACK SIMBEAMSIMPACK Interfaces FEMBS, Loads, ProSIM, CatSIM, IdeSIM, MATSIM, SIMAT

Leading MBS Technologyfor Technology Leaders

Automotive

Engine

Rail

Name

First Name

Firm

Street

Post Code

Town

Country

Telephone

Fax

E-Mail

I wOuLd Be InTereSTed In The fOLLOwIng APPLICATIOnS

» JAPAn INTEC Japan K.K.5F Okubo Bldg.2-4-12 YotsuyaShinjuku-ku Tokyo 160-0004, JapanTel. +81 - 3 - 5360-6631Fax +81 - 3 - 5360-6632intec@simpack.jpwww.simpack.jp

» uSAINTEC US Inc.5 Research DriveGreenville, SC 29607USATel. +1- 888 - 899 - 8565Fax +1 - 864 - 283 - 7125robertsolomon@simpack-us.com