### Simulation

The choice of calculation method is often a decisive statement about the costs and accuracy of a simulation. Not all tasks can be classified into static or dynamic and fast linear or nonlinear. Our extensive experience helps you make the solution efficient and product-specific and to select the appropriate calculation method.

Our main focus in the technical calculation is in the following areas:

## Services

For many components, it is sufficient to choose this form of computation. Especially with the expected low elastic deformation and permanent joining techniques such as bolts and welds linearization is allowed.

For example, the bending and torsional stiffness of a body is a linear problem. The know-how lies primarily in the choice of metal joining techniques and the support conditions.

For this category, especially recommend the program system MSC / Nastran, ABAQUS, and ANSYS.

Examples:

• Vehicle body under torsion
• Trace-line plot for bending stress

In linear stability analysis, the stresses in the elastic range are considered. With a sufficiently fine grid mapping in areas of high-stress gradients and linearized component connections as well as boundary conditions, good results are expected. In general, the calculation models are used for direct analysis of linear stiffness.

The systems are suitable for this program MSC / Nastran, ABAQUS and ANSYS

Examples

• Stresses of a welded sheet metal warehouse
• Stresses in a cast lever

A structure loaded by external loads acting on the other hand is associated with the ground forces into balance. Through this special case of linear static stress analysis, it is possible to examine without storage components’ influence. This method is used, for example, often used for stress analysis of moving body structures under dynamic loads.

To solve these problems are especially recommend the program system MSC / Nastran, ABAQUS, and ANSYS.

Examples:

• Body stress during cornering
• Body stress at maximum wheel load

The possible buckling load and the associated torsion behavior also bump mode, one claimed to pressure component in the vehicle sector are rarely used.

We offer topologysheet thickness, and shape optimization.

The topology optimization, we often use to optimize the cutting of metal structures and the use of materials with complex cast components. Here, the components can, under the stress of multiple load cases are optimized simultaneously. The leftover from the program structure is then taken into account the manufacturing constraints, as well as created all functional aspects, of the new construction.

The sheet thickness optimization is needed, for example, the wall thickness of a body, taking into account static and dynamic target values ​​to be distributed optimally. The new sheet metal thicknesses are then set together with the requirements of the crash and the strength. Another application is the optimal thickness distribution in a plastic injection molded part dar.

In the shape optimization can be varied geometrical dimensions of a structure. With regard to the existing geometry, for example, radius, diameter, or body size. There are only finite element meshes, the structure can be changed via an appropriate parametrization of node coordinates within their borders.

Examples:

• Topology optimization of a carrier sheet for multiple loads
• Topology optimization of a drive lever
• Sheet thickness optimization

For the estimation of component life previously calculated stresses and a life program are fed. Here, the multiaxial stress be. The stresses can a linear/nonlinear static load calculation unit or a linear/nonlinear transient dynamic calculation are taken.

Through the execution of many life issues, especially in the area of ​​the vehicle body, we draw on a very large return potential in this field experience necessary. In the field of strength and durability, we have performed for a major automobile manufacturer in the German region to integrate into the development process of vehicles.

The survival analysis is performed with the comprehensive program FALANCS LMS or the LMS Virtual.Lab successor.

Examples:

• Damage to a vehicle body after completion of the test program
• Damage to a trailer hitch after completion of a test program
• Damage to an absorber

Temperature calculations are then of particular interest when clamped components are operated in a wide temperature range. Then the body’s natural occurring stresses can lead to component damage or unacceptable deformation.

More and more important to win even components that are made of several different materials. Occurring here bimetallic effects can bring many negative attributes with it.

The natural frequencies of a system are paramount in the interpretation of vibrations. To avoid stress concentration, excessive vibration and acoustic problems can be assigned specific frequency window, which can minimize the effect of the components with each other and that of excitation.

In the calculation of natural frequencies of very complex structures, eg of a complete vehicle, we can have a grown up over many years of experience with ever undertaken to attempt matching results.

Examples:

• Torsion of a convertible structure
• Bending natural frequency of a convertible roof system
• Natural frequency of a built-in RAC

On the basis of the calculated natural frequencies of a system that can help with the modal frequency response analysis of dynamic transmission path from one point to another charge. The transmission paths, the response of a structure be write-in frequency domain.

Similar to the natural frequency analysis are many projects in the past to a considerable know-how have helped. In the field of structure-borne noise, we provide the analysis of Input Impedance and Transfer functions.

As a classic program for this purpose we use MSC / Nastran. Such analysis can of course also be performed with the programs ABAQUS and ANSYS.

Examples:

• Operating deflection shape of a centrifuge
• Input impedances of a rear axle bearing carrier

On the basis of the calculated natural frequencies of a system can be adjusted using modal transient response analysis to calculate the response of the system in time domain. Are stops and contacts in the system is negligible, so tensions, forces and displacements are used to evaluate the design at different excitation types.

Typical applications include all types of shakers simulations. Besides the calculation and solution of structural problems, we offer here at the definition and design of test rigs. Above all suppliers will take advantage of our knowledge and experience in the field of overall vehicle dynamics. Even without bodies, entire assemblies in a dynamic environment can be checked correctly.

As a classic program for this purpose we use MSC / Nastran. Such analysis can of course also be performed with the programs ABAQUS and ANSYS.

A special case of frequency-response analysis, the interior acoustics dar. The transfer functions are determined not only here in the body through the sound field, but up to the microphone at any point in the medium of air. The size and shape of the interior, as well as the quality of interior materials here, have additional implications.

As a classic program for this purpose, we use MSC / Nastran. Such analysis can of course also be performed with the programs ABAQUS and ANSYS.

Another possibility is offered by the program BEAKUS, which is based on the BE method. Thus it is possible for the sound radiation in the disturbed or undisturbed space to calculate.

Examples:

• Typical sound pressure waveform at the driver’s ear
• Rapid distribution on the surface of a gearbox

Contacts in a system are often defined when that may change during exercise by touching of bodies of the load path. An example is found in the compression of a multicellular seal profile which ascends through the internal block formation of a cell, the progressivity of the force-ID.

Another typical application example illustrates the calculation of a flange in which a statement is to be made over the sealing function. Contact is always necessary for a situation where only compressive forces can be transmitted.

A special case of contact, the “Tied-contact”, allows connecting of different networks together. In certain cases this can be time for networking will be saved.

For such tasks are used in our house the programs ABAQUS, ANSYS, and MSC / Marc.

Examples:

• Contact with centrifugal force calculation, steam pressure, and temperature stress
• Contact with self-sealing deformation
• Calculation of a strut tower support bearing with bolt preload

Geometric nonlinearity must be considered when changes due to deformation of the components of the system stiffness. In nearly all non-linear calculations, this option is selected.

An implicit dynamic analysis is static preferable whenever inertial effects or vibrations can affect the overall result and there are non-negligible nonlinearities.

In our house, almost all kinematic calculations, such as linkage of soft or hard tops and tailgate covers can be calculated using this method. The advantages over conventional rigid body kinematics lie in the fact that we use this method to simulate reality, almost without restrictions. We are able to open performance-driven hydraulic system components and the kinematics of all attacks in real-time and to close. In addition to the force required and the joint forces of the elastic analysis also includes statements on the uniformity of movement and provides the voltages of each component of the motion. Contact and nonlinear material properties of any kind may be considered.

After several years of numerical optimization and application of this process, we have been able to make the process for a wide range of tasks inexpensively available.

For such calculations in the first place, the program ABAQUS is used.

Examples:

• Opening and closing a hard-shell roof system
• Opening and closing a tailgate system
• One-sided stall load of a hard-shell roof system

If the load in one component is so high that the lower yield strength of a material is exceeded, a nonlinear material model is used. Most trials originated from the material plastic strain curve that describes the strain behavior up to the allowable upper limit yield.

Another nonlinear material behavior, the group of elastomers dar. The parameters for the coefficients of material models, we determine, according to the “Shore Hardness” or go to your curves try a “curve fitting” by.

Are no material values ​​present in our own database, or you, we’ll take care of the determination of the appropriate material parameters. In addition to clearly defined DIN tests for metallic materials, we also set completely new, problem-oriented test scenarios for alternative composites. We work primarily with institutions of various universities.

For such tasks are used in our house the programs ABAQUS, ANSYS, and MSC / Marc.

Examples:

• Plastically deformed hook closure
• After crossing a threshold bent spring strut
• Test setup of a fiber composite material
• Derived analytical model of a fiber composite material
• Self-development calculation model for folding fabric

In the field of vehicle safety, it is possible to cover us all, with the FE method usually to calculate areas.

These are all for one high-speed load cases for the front, side and rear crashes. Many development projects together with our customers have led to a great experience potential. In the low-speed load cases we often failed the available space for the implementation of new energy concepts deformation optimally exploit.

In importance in recent years has also won the pedestrian protection. Here we have developed under different projects concepts for bumpers and front flap systems.

The three programs calculate PAM-CRASH, LS-DYNA and ABAQUS / explicit are used in our simulation for the different crash scenarios. The choice of program to be used depends on the wishes of our customers.

makross models for grills and control units provide excellent correlation to test results in the FMVSS 201 and ECE R21 load cases

• Rear-end Crash
• Pedestrian safety
• Side crash
•

Using detailed models, we calculate abuse load cases.

• Info Display
• Glove compartment lock

Dummy simulations are nowadays an integral part of most crash load cases. If, in addition to the vehicle parameters, the dummy load values ​​are also required for a crash scenario, we carry out the complete analysis with airbag systems.

When designing the components of seats, for example, we often use rigid body dummies that are available free of charge. The load introduction into the structure can thus be reproduced well.

Front- and rear crash analysis, ECE-R17, intrinsically frequency/shaker/ noise analysis (explicit and implicit)

References:

D4/T99 Audi, BMW 7-Series (F01), Rolls Royce (RR4), VW Golf / Passat / Skoda

• Armrest

• Center console

As part of theses and pre-development topics, we have developed for our customers, a calculation method, whereby the entire contract process, including a door or door lock and seal mechanism, can be simulated. With the results of the calculation, most questions are answered.

Firstly, collisions with other body parts and the Spaltmaßsituationen be discussed. On the other hand, the dynamic decay and the shape of the force-time curve of the hook lock power allow conclusions about the expected closing sound. The transient force profiles can serve the design of locks, hinges, and bump stops.

Another purpose of this calculation method was to make statements about the structural strength of the supporting structure and the connected components. For this, we have joined with the company LMS to develop a way to process the transient element stresses in the life FALANCS LMS program continues. Can be vorrausgesagt until the beginning of a failure with this process, the number of supplements for a particular closing speed. Enables the integration of nonlinear material behavior with strain rate it to simulate abuse load cases.

For the simulation of a door or flap, supplement is why the three programs PAM-CRASH, LS-DYNA, and ABAQUS / explicit

Join a kinematic analysis of nonlinearities which are not implicitly dynamically convergable, can be found with an explicit rigid body simulation of a solution. This occurs especially when parts of the kinematics are defined by slotted guides with distinct regions of contact, or a cloth simulation for a soft-top is to be integrated.

Examples:

• Explosive effect on vehicle structures

Static load cases with very large nonlinearities can often be calculated implicitly requires strong simplifications. In certain cases it is therefore advisable to calculate the page type to give up accuracy and realism for the constraints mapping. As examples, a quasi-static roof blister test or ECE R14 Body belts and blocks are used. For all calculations, the calculation time is shortened as far as that there are no effects due to inertia loads are detectable.

Due to long development work we have been able to establish a calculation method that reflects the material behavior during the opening and closing of a roof system. So it is possible to predict accurately and fabric folds over-stretching to make them visible. possible chafing and are located in the tray jammed material areas.

Already existing before the first prototypes, it is possible to optimize the storage material by selective folding design.

Convertible Modern systems can also be opened and closed while driving, the fluid simulation offers here information about the pressure at the opening roof shells. In addition, the pressure distribution on components such as roof systems, convertible roof shells, side windows, rear spoilers, etc. are determined at high vehicle speeds. The calculated pressures or forces serve both static and transient structure as input for further calculations.

Basis of a high quality and meaningful calculations is the underlying finite element mesh. Here we have our parameters ideas and quality guidelines. If necessary, we will cater to your needs.

Working with a partner company in China and our own branch in Shanghai, we are able to ensure a competitive prices in the future in spite of the high and constantly growing quality requirements . FE models are made by highly qualified engineers according to our or your needs. A streamlined and rehearsed process thus represents capacities, which can be introduced whenever needed.

Our customers can directly benefit of this increased flexibility and reduced costs.

Complicated and very time consuming mid plane-shell models of plastic or cast components are affordable. Our capabilities allow us to create demanding special mesh with high quality standards for the complete satisfaction of our costumers.