CASIMIR/Automotive – CAE Solution for Virtual Seating Comfort Analysis

The CASIMIR/Automotive software tool was developed specifically for the virtual evaluation and optimization of seating comfort. The basis for this is a deep understanding of the interaction between seat and human, which results in special requirements for the modeling of both.

CASIMIR, virtual occupant model for analyzing seating comfort:

"My name is CASIMIR. Thanks to years of ongoing development, I now accurately reproduce humans and their mechanical as well as sensory abilities. So when I sit on a model of a seat, you can see where it can still be improved so that future occupants always drive safely and comfortably. And all of this happens purely digitally."

A model in CASIMIR/Automotive therefore always consists of two central components

Individual model of the unoccupied seat

From the seat structure to the upholstery – with the help of various assistants such as a Material Manager, you can create an exact finite element model of your seat. If required, we will gladly support you with precise modeling or material tests.

Customizable virtual human model

As anatomy-based finite element models, CASIMIR human models describe the static and dynamic properties of typical occupants – expressed by percentiles such as f05, m50 and m95. After selecting the appropriate configuration, the desired postures can be assumed and displayed with the help of the Posture Preview.

The CASIMIR virtual occupant model can be used independently of the CASIMIR/Automotive software tool wherever human models are needed in product development – for example, in aviation or in corridor and cargo vehicles.

Valid seating comfort evaluation through realistic loading

When both models are combined, the so-called occupied seat can be tested virtually. Standard load cases as well as individual scenarios can be efficiently investigated. The simulation is geometrically non-linear and takes into account the frictional contact with the seat cushion and backrest.

This allows you to determine and optimize variables for evaluating seating comfort – such as seat pressure distribution or the seat transfer function – realistically and reproducibly at a very early stage of development.

Comprehensive analysis without expensive and time-consuming prototype tests

CASIMIR/Automotive can be used to digitally determine all key seating comfort parameters:

  • Static seat pressure distribution
  • "Meat-to-Metal"
  • H-point according to SAE J826 (manikin + simulation method)
  • Backset value according to FMVSS 202a
  • Seat transfer function in horizontal (x and y) and vertical direction (z)
  • Dynamic loads on the occupants while driving

In post-processing, various evaluation methods are available, such as the Bodymap or Dimensions of Perception. They make it possible to establish a correlation between physical variables and the subjective perception of the occupant. In addition, alternative design variants can be compared quickly and easily on the basis of the results.

Easy integration into existing workflows

To enable easy integration into existing workflows, CASIMIR/Automotive was integrated into the FE preprocessor HyperMesh® and uses SIMULIA Abaqus as FE solver.

MEMOSIK® – Physical Dummy for the Evaluation of Vibration Comfort

The MEMOSIK active vibration dummy can be used to efficiently evaluate the vibration comfort of vehicle seats – both on test benches and in actual use.

 

Precise analysis thanks to driver-typical dynamic mass

If a seat is only loaded with a rigid mass as part of the seating comfort analysis, the results are often very inaccurate. MEMOSIK is therefore designed to simulate the vibration behavior of the occupant on the seat. Technically, this is done by reproducing a so-called driver-typical dynamic mass.

This process has been tried and tested and continuously improved over many years. With the aid of intelligent control technology, the system can switch quickly between different driver groups, the so-called percentiles:

  • Small woman (f05)
  • Medium-sized man (m50)
  • Large man (m95)

Objective and reproducible test results

With a MEMOSIK measurement, immediately after the test drive you have:

  • the vertical seat transfer function including its characteristics,
  • the evaluation of the coherence as well as
  • the vibrations acting on the driver via the seat surface, including an evaluation thereof.

In contrast to subjective tests, these results are reproducible.

Also available as a virtual model

MEMOSIK is a physical vibration dummy, i.e. it consists of steel and electronics. Its virtual counterpart is CASIMIR, our numerical occupant model. In order to digitally map and compare the measured results, a virtual model of MEMOSIK is also available in CASIMIR/Automotive.

Seat Test Benches for the Objective Evaluation of Seating Comfort

In order to meet the high demands placed on modern seats, the reliable and reproducible determination of the relevant evaluation variables during development and production is crucial. Although test persons reflect the actual application scenario, they also contain a great deal of uncertainty due to their subjectivity and low reproducibility.

These uncertainties can lead to incorrect decisions, and corrections are often extremely time-consuming and costly. Automated seat test benches, on the other hand, provide unambiguous, reproducible and comparable results.

Learn more in the following video.

Seat test benches are primarily used in two areas:

In development

A typical field of application is the determination of seat pressure distribution and seating behavior as well as the hysteresis of the entire seat within the scope of variant evaluations or benchmarks. Based on the objective and reproducible results, different variants can be compared much more reliably.

Another area of application is the automated H-point and backset measurement in accordance with the SAE J826 and FMVSS 202a standards.

In production

Typically, seating comfort, the function/calibration of the seat-belt reminder or seat occupancy detection, adjuster noise or handling forces are monitored. All quality-, comfort- and safety-relevant parameters can be reliably and precisely tested.

Documentation of the results enables consistent quality assurance. If necessary, it is possible to intervene in the production parameters at an early stage.

Customized Development – Complete Solution from a Single Source

Several OEMs have been relying on our individual test systems for vehicle seats for many years. For design, development and construction, we can draw on our many years of experience in the fields of seating comfort and simulation of passenger car seats.

You receive a comprehensive solution consisting of:

  • Measuring and testing technology/sensor technology
  • Software and sequence control
  • Automation technology

The test results can be visualized with a variety of evaluation methods.

We support you in the analysis and interpretation of your data

If you are pressed for time or do not have enough capacity for large and complex analyses, our experienced (simulation) engineers will gladly take on the entire project or partial tasks. Furthermore, we support you in specifying the quantities to be measured as well as in interpreting and evaluating the results. Learn more about our engineering services in the field of seating comfort here.


Please contact us personally

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We will gladly advise you on questions related to (virtual) seat development, seating comfort and virtual human models.

Dipl.-Ing. Jörg Hofmann
Product Manager CASIMIR

+49 931 49708-280
hofmann@woelfel.de
Formular

Aravinda Veeraraghavan
Technical Support

Dr.-Ing. Georg Enß
Sales

+49 40 524715-262
enss@woelfel.de
Formular