• Frontal Impact Dummies
  • Hybrid II (50th percentile) rigid dummy for aeronautics applications
  • Express Hybrid III 50th & 5th percentile dummies
  • Hybrid III 50th, 95th & 5th percentile dummies
• Side Impact Dummies
  • ES2 & ES2-re
  • FTSS SID-IIs SBL C & D
  • US SID
  • SIDHIII
  • WorldSID 50%
  • WorldSID 5%
• Rear Impact Dummy
  • BIORID IIg
• Child Dummies
  • Hybrid III 6 years
  • Hybrid III 10 years
  • P series 18 months, 3, 6, and 10 years
  • Q series 3 years
  • CRABI 12 months
• Pedestrian Impactors
  • Head (EEVC adult & child, FMVSS 201)
  • Pedestrian headforms EEVC
  • Lower leg EEVC impactor
  • Upper leg EEVC impactor
  • Standing HIII 50th rigid dummy
  • Standing HIII child 6 years rigid dummy

Human Models & Barriers

• Human Dummy Models
  • Complete human model: Humos2
  • Human head, leg and foot models
• Frontal Barriers
  • ODB (ECE 94 frontal regulation) solid & shell models
  • PDB V8XT (EEVC WG15 proposal) – shell & solid models
  • TRL full width (NCAP consumer test) – shell & solid models
• Side Barriers
  • NHTSA FMVSS 214 – solid & shell models
  • Progress ECE 95 – solid & shell models (Cellbond)
  • AEMDB V3.9 (EEVC W13 update proposal) – solid & shell models (Cellbond)
  • IIHS SUV barrier – solid & shell models (Cellbond)
• Rear Barriers
  • RCAR IIHS low impact
  • US FMVSS 310 rear impact barrier
  • ECE rear impact barrier

Our engineering team’s finite element simulation expertise allows us to test the softness and hardness of the seat, helping optimize the design and ensure maximum passenger comfort. Our process incorporates international standards, such as SAE J2896 (Motor Vehicle Seat Comfort Performance Measures J2896), to cover all aspects of design and simulation according to global requirements.

Additionally, our numerical simulation procedures ensure prediction accuracy through the consistent chaining of stresses and strains derived from the trim manufacturing and assembly process.

In the proposed FMVSS No. 202a, manufacturers were given the option of meeting either of two sets of requirements. The first set was a comprehensive group of dimension and strength requirements, compliance with which is measured statically. The second set was made of requirements that would have to be met in a dynamic test. NHTSA (National Highway Traffic Safety Administration) in FMVSS 202a, Head Restraints, specifies requirements for head restraints to reduce the frequency and severity of neck injury in rear-end and other collisions.

The standard applies to each front and rear outboard Designated Seating Position with a head restraint, and allows head restraints to be tested either dynamically or statically. Exceptions are made for school buses; refer to the Code of Federal Regulations for the specific exceptions. This test procedure covers the static requirements. Finite element simulation software, such as Ansys LS-DYNA, Simulia Abaqus, ESI Pam-Crash and Altair RADIOSS, is used by our engineers with special-purpose dummies to simulate head restraints based on FMVSS 202a in order to reduce the frequency and severity of neck injury in rear-end and other collisions.

Other related regulations:

• ▶ FMVSS201 Head Impact
• ▶ FMVSS207/210 Seatbelt Anchorage
• ▶ FMVSS208 Frontal Impact
• ▶ FMVSS214 Static & Dynamic Side Impact
• ▶ FMVSS225 Child Restraint Anchorage
• ▶ FMVSS301 Rear Impact & Fuel Integrity
• ▶ Insurance Institute for Highway Safety (IIHS) Offset Frontal Impact
• ▶ IIHS Side Impact
• ▶ IIHS Low Speed Bumper Impact

Although whiplash injuries can occur in any kind of crash, an occupant’s chances of sustaining this type of injury are greatest in rear-end collisions. When a vehicle is struck from behind, typically several things occur in quick succession to an occupant of that vehicle. First, from the occupant’s frame of reference, the back of the seat moves forward into his or her torso, straightening the spine and forcing the head to rise vertically. Second, as the seat pushes the occupant’s body forward, the unrestrained head tends to lag behind.

This causes the neck to change shape, first taking on an S-shape and then bending backward. Third, the forces on the neck accelerate the head, which catches up with — and, depending on the seat back stiffness and whether the occupant is using a shoulder belt, passes — the restrained torso. This motion of the head and neck, which is like the lash of a whip, gives the resulting neck injuries their popular name. Finite Element simulation with advanced FEA software enables us to simulate seat whiplash with the most detailed and accurate procedure to capture real-world behavior.

Euro NCAP’s whiplash testing procedure involves a rear-end collision simulation with a crash test dummy sitting in the driver’s seat. The dummy is equipped with sensors that measure the forces exerted on the neck during the crash. The resulting data is used to calculate a Whiplash Injury Criterion (WIC) score, which is used to assess the seat’s performance. Japan NCAP’s whiplash testing procedure is similar to Euro NCAP’s, but it uses a different crash test dummy and has slightly different test conditions. China NCAP’s whiplash testing procedure is also similar to Euro NCAP’s, but it includes additional test conditions to simulate different crash scenarios.

These regulatory testing procedures aim to ensure that automotive seats provide adequate protection against whiplash injuries in the event of a rear-end collision. Finite Element simulation with Ansys LS-DYNA, Simulia Abaqus, ESI Pam-Crash and Altair RADIOSS, combined with special-purpose dummies, is used by our engineers to improve the accuracy of these tests and help optimize the design of seats for better whiplash protection.

Meat-to-metal simulation is a method that evaluates the contact between the occupant’s body and the seat structure, taking into account the deformation of the foam and the stiffness of the seat structure. This analysis allows engineers to predict the comfort and durability of the seat, and optimize the design to reduce pressure points and improve overall comfort. Meat-to-metal simulation is particularly useful in the design of high-performance seats, such as those used in sports cars or airplanes, where comfort and support are critical for safety and performance.

When seating the human models, finite element simulation can accurately evaluate meat-to-metal behavior, including the physical deformation of the seat. This simulation accounts for foam deformation, foam–metal frame interaction, and foam–occupant body interaction. Our engineers can simulate the seat’s behavior under complex loading conditions and optimize its design for maximum comfort and safety.

The dynamic comfort design of a car seat is crucial in ensuring the comfort of the occupant and reducing driving fatigue. It involves optimizing the seat’s dynamic characteristics to isolate sensitive vibrations that may cause discomfort and fatigue in the occupant.

The primary source of vibration that affects driving fatigue is the random vibration of the vehicle and the mechanical vibration caused by uneven roads during driving. The driver experiences linear vibrations in the longitudinal, lateral, and vertical directions, as well as angular vibrations in these three directions. Vibration is transmitted to the buttocks and back of the human body through the seat, causing systemic vibration.

To improve dynamic comfort design, the following functions can be achieved using finite element simulation tools such as Ansys LS-DYNA, Simulia Abaqus, ESI Pam-Crash and Altair RADIOSS:

• ▶ Reduce the seat resonance frequency to minimize high-frequency areas most influential to the human body.
• ▶ Reduce vibration transmission rate during resonance to lessen impact below the spring.
• ▶ Minimize vibration transmission around the occupant at 10 Hz to reduce resonance influence and seat-back high-frequency vibration.
• ▶ Consider the road surface, tire, suspension, and seat–occupant as a complete dynamic system to reduce fatigue under varying road inputs.
• ▶ Optimize the seat’s dynamic characteristics to minimize energy input into the body, reduce response in sensitive frequency regions, and lower RMS acceleration transmitted.

The use of high-quality materials with excellent shock-absorbing properties, active vibration control technology, ergonomic seat shape design, and consideration of psychological comfort factors can further enhance dynamic comfort.

Seat dynamic comfort design is not only about comfort but also safety. It meets all federal regulations and crash-safety standards for automotive seats, and includes features such as side airbags, pretensioned seat belts with force limiters, and headrests that prevent whiplash injuries. Simulation results are reported according to ISO 2631 (Mechanical vibration and shock — Evaluation of human exposure to whole-body vibration).

Heated and Cooled Seat Thermal Comfort Simulation

Heated and cooled seats are no longer exclusive to luxury cars, as more carmakers offer them for their midrange models. However, designing and optimizing such seats to enhance the occupant’s thermal comfort is a complex process. It involves considering the interactions among the occupant, the seat cover, the cushion foam, and the heating or ventilation systems (air flow), and moisture management, as well as the occupant’s subjective perception of thermal comfort.

One way to address this challenge is to use numerical simulation (Finite Element and/or CFD) to simulate the thermal comfort of a driver sitting in a heated or cooled seat. This approach requires digital human models that can capture the human body’s thermal behavior and objective thermal comfort criteria.

Realistic simulations can be performed taking into account aspects such as blood flow, breathing, evaporation, metabolic responses, sweating, shiver, cardiac output, and the local heat exchange between the manikin and its interaction with both seat and environment.

Our Finite Element tools (Ansys LS-DYNA, Simulia Abaqus, ESI Pam-Crash, Altair RADIOSS) and CFD tools (Siemens Star-ccm+, Ansys Fluent, OpenFoam) for seat design and virtual testing can save time and money in the design and development process, while also improving the thermal comfort and overall quality of the final product.