HORK Enterprises
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Vehicle Restraint Systems Development

Henk Helleman has worked on a great number of vehicles. Some were more memorable than others. Below is an overview of those that stuck. Some, because a new technology was introduced, some because they were a personal first.

Henk trained the Fiat engineers in the use of MADYMO and helped them set up their first models for restraint systems performance evaluation. These models were subsequently used by the restraints system supplier (Breed Technologies) during development and for production quality control, there after.

Henk trained the Hyundai engineers in the use of MADYMO and helped them set up restraint system performance models. During several extended stays in South-Korea, engineering support was provided to develop the restraint systems for the Elantra and Accent models. The vehicles were prepared for European and US certification, which included preparing for the European side impact regulations that were then under development. Both vehicle models ended up being great success stories for Hyundai in all markets. Certifying a vehicle for the US market involves a lot of development and testing. The low volume EB110 program could not afford all the prototypes normally needed during development testing. By using existing airbag systems and making extensive use of simulation analysis, much time and budget was saved. Henk built the accurate simulation models and conducted the performance optimization of the restraint system. Still, two of them ended up being crashed into the concrete barrier... For confirmation.

We worked on this one in 1994, but had to keep it under wraps for almost 10 years as this was Volvo's test bed for possible future safety technology. The vehicle was finally revealed, as a concept, in 2001. The car has a highly adjustable steering column and adjustable pedals to create a comfortable and safe seating position for short and tall drivers. Very little obscures the all-around visibility and there is a cowl airbag to catch the unfortunate pedestrian who gets hit by the car. Only so much has been revealed about this vehicle, so we still won't give out the details as some of the safety technologies researched have yet to be disclosed and implemented on production vehicles. Using simulation analysis allowed for many concepts to be investigated without the need to build and test prototypes. The 3-abreast front seated Falcon had a unique passenger airbag that provided head impact protection for the middle occupant. The resulting large airbag required careful deployment. Simulation analysis was used to gauge the inflator limits that could safety deploy the airbag under hot and cold conditions and assure timely seating.

The integration of the restraint system for the Fiat Tipo/C was managed from the Breed UK office, but the component development and testing was done in the US. The development fell in the period that airbag inflators were switching from Azide based propellants to new generants that were more environmentally friendly. So we got to do the performance engineering twice and simulation analysis helped greatly to shorten the development time. Henk worked in close cooperation with the inflator development engineers to find a matching performance for the new generants. After a rather embarrassing consumer test, the platform also became the test bed for alternative venting methods, using a permeable patch of fabric rather than discrete vent holes. When the project was finished we knew more about fabric venting properties than the supplier. Working off the Hyundai Galloper as the Mule vehicle, detailed simulation models were developed and validated in support of the developent of the total safety system of the Hyundai HP1 Santa-Fe, for which the restraints supplier, Breed Technologies, had taken systems responsibility. The program included technology transfer regarding the integrated development of a total safety system.

"Watch out for the suspension being a little sloppy on these development vehicles", said the Jaguar program manager as he handed over the keys.
Strictly speaking we didn't need to drive the cars for the development of the Occupant Spatial Sensor System, but we found a reason after all. We needed to test the system under driving conditions when the wind would possibly interfere with performance of the system. Road testing was much cheaper and more practical than wind tunnel testing, so off we went. 😄 The driver airbag of the BMW E46 was one of the first to have a dual-stage inflator. It served as an example for many airbags that followed. The bag was modeled in great detail with computational fluid dynamics being used to assess the injury risk to closely seated occupants. This allowed for balancing the output of the first and second stages prior to hardware being available for testing.

For the Ford Freestyle roll-over sensors and side curtains were developed to better protect the occupants in Roll-Over accidents. Simulation analysis was used to provide "gap-closure" timing, which tells how much time there is to get the side curtain between the occupant and the window. Simulation analysis was also used to provide input for the sensor development engineers to tell the difference between sporty driving and a roll-over accident that would require the side curtain to be deployed. Roll-over testing was still in its infancy with various test protocols being evaluated, such as the "curb-trip", the "cork-screw", and the "dolly test" The latter would become the standard test for FMVSS 208. The side curtain of the Ford Galaxy was evaluated against the newly proposed (NPRM 214) Dynamic Oblique Pole Test. How much energy must be absorbed if the pole is aimed straight at the driver's head? How quickly must the curtain deploy. Computational Fluid Dynamics was used to find better ways ways to fill the side curtain in the shortest amount of time. For these applications the composition of the gas that fills the cushion is important, as the speed of sound in Helium is higher than in Argon or Nitrogen, so it can flow faster and fill quicker.

The GM Epsilon is a global platform that formed the basis for (amongst others) the Saab 93 and 95, the Opel Insignia and Vectra, the Saturn Aura, the Cadillac BLS, Chevy Malibu, and Pontiac G6. With such a potentially large volume it was the focus for many innovative, cost saving technologies. One focus was to explore whether the side curtain could be bonded together rather than sewn. Combined fluid/structural analysis determined the strength requirements for the bonds. That allowed various bonding methods to be evaluated for suitability. The Tesla Model S only existed in concept, then known as "Whitestar". Dimensions and weights were largely "to be determined". So, where do you start designing a restraint system for that? The Chief Engineer argued that, despite it's considerable battery weight, it wouldn't be any heavier than a comparable sedan, due to its all-aluminum structure. Henk figured the weight was going to be somewhat like a Towncar. However, with plenty of crush space up front, the crash pulse would look more like a mid-engined sports car. Henk pleaded with Peter to omit the customary engine sub-frame, if at all possible, and set off to conceptualize the gentlest restraint system imaginable. It came out much as planned.

The Ford B562 was designated the “global, low-cost platform”. It formed the basis for both the Ford Ka, designed for developed markets, and the Figo, slated for the rest of the world. That meant, it had to be certified against a diverse set of regulations and meet a variety of customer expectations. It slotted under the sophisticated B299 Fiesta model that sported a 5-star NCAP safety rating. To not compete with its own product, the Ka was given a 4-star EuroNCAP target, with the notion that a customer who wanted and could afford more safety, could opt for the Fiesta, instead. The occupant safety systems were co-developed between Ford Brasil and Dearborn to be able to cover the plurality of model iterations. The occupant crash safety of each model was improved considerably over its immediate predecessor.