gucio1234 pisze:Wyslalem zapytanie do ARB czy robili crash testy swoich zderzakow do Disco i czy mozna gdzies poznac wyniki. Jak dostane jakas odpowiedz podziele sie na forum.
WERSJA DLA NIECIERPLIWYCH
Poniżej zamieszcam moje pytanie i odpowiedz ARB na temat ich zderzakow (oferuja dwa modele: dla aut bez poduszek i z poduszkami).
Niestety nie bardzo mam czas na tlumaczenie - zalaczam wersje oryginalna korespondencji
WERSJA DLA CIERPLIWYCH POLIGLOTÓW
Moje pytanie do ARB
Dear Sirs, You offer two types of Winch Bars for Land Rover Discovery I : 3432080 - Non-Air Bag Winch Bar 3432050 - Air-Bag Compatible Winch Bar Land Rover equipped the Discovery vehicles with two types of Air-Bag systems: 1. Distributed SRS with two crash sensors mounted near the head lamps - before 1997 2. Single Point Sensing (SPS) SRS with the crash sensor built-in the airbag diagnostic control unit (located in the middle of the car, between the front seats) - after 1997 If my vehicle is equipped with SPS system is the 3432080 model right or it is neccessary to select 3432050. My understandig is that if there is one central crash sensor then the non-air bag model is OK, but I would like to hear the expert\'s opinion. Did you perform any crash test with your winch bumpers ? Is there any place I could find the results ?
Odpowiedż od ARB
Thank you for your enquiry regarding air bag compatibility of ARB Bull Bars. The correct bar to fit to a Discovery Series 1 fitted with air bags is the 3432050, as this bar has been designed to work with all Series 1 air bag systems. ARB has undertaken extensive air bag testing, which included frontal collision testing, and in fact we were one of the first Bull Bar manufacturers to do so. This testing allowed us to prove that our engineered air bag mounting system operated correctly, and subsequently we predominantly rely on computer modelling to test bars.
Below I have included an excellent explanation of the engineering involved in designing and manufacturing air bag compatible bull bars that was written by our National Product And Services Manager.
Modern chassis equipped 4x4 vehicles fitted with SRS Airbags present a potential problem when fitted with bull bars. That potential problem is premature deployment of the air bags, ie earlier in the impact cycle than intended, or deploying when the impact is not really severe enough to warrant their use at all.
This is because the bull bar is effectively an extension of the structural mass of the vehicle’s chassis and the risk is that if this is a completely rigid structure, low speed and /or minor impacts will be misread by the air bag sensors as a much more significant impact.
Bear in mind that the forces we are talking about, those that need to be involved before air bags trigger are quite large. Multiple tonnes of impact force (In some cases over 10 tonnes per chassis rail) need to be reached before the bags deploy so we are only talking about big impacts. The airbag sensor's location is irrelevant. They are not sensors that require physical contact or damage to occur to themselves, and typically they are a team of several g force sensing units which must all register extreme deceleration to transmit the signal to fire the airbags.
In modern standard vehicles, the front sheet metal, plastic bumpers, headlights and all sorts of componentry are in place ahead of the chassis rails, and where they are closer to the vehicle surface, they are often softened on their ends with a crumple zone (or crush can) that is sacrificed in minor impacts along with all of that componentry, to avoid triggering the air bags inappropriately. This is the problem for owners of course, in that all of that sacrificed componentry is not only expensive, it disables the vehicle when damaged in say an animal strike.
The crush cans and related parts on the standard vehicle are relatively small and localised ahead of the chassis rails so whilst that small section is comparatively strong, most of the frontal area of the vehicle remains weak and vulnerable.
Impacts on the standard vehicle other than directly in front of the chassis rails or crushable structure will cause considerable damage.
So there are in fact three zones on the front of most of these vehicles. The inner structural chassis (or superstructure in the case of a monococue construction vehicle), the structural crushable area ahead of the chassis, and the outer sheet metal, plastic and glass body parts.
Our engineers replicate the crush performance of the vehicles standard crushable components when they design the bull bar mounts so that in a big impact the bar (and hence the air bag triggering system) behaves the same as the standard vehicle. The benefit of the bull bar lies in the fact that it is a very large strong part and it extends the strength of the frontal parts of the chassis outwards and upwards to protect the softer vulnerable components. Thus, the vehicle can then survive an animal strike without being disabled.
Anecdotal evidence also suggests that in a serious accident the existence of a bull bar also assists in spreading the impact load over a much wider area of the vehicles involved and hence assists in minimising intrusion into the survival space.
One often underestimated value in having a bull bar fitted is the confidence it gives the driver in a potential animal strike situation. Many rural accidents are caused by panicked owners of non bull bar protected vehicles swerving off the road or into the path of oncoming traffic when faced with a sudden appearance of an animal in their path.
Your comment about high speed impacts is largely correct, however each situation, vehicle, impact point and circumstance is unique and somewhat unpredictable. We have seen our bars after 100kmh animal strikes and in some cases they are largely undamaged or may only require a new chassis bracket or the like and yet have saved thousands of dollars of damage to the vehicle.
I trust this explanation has helped your understanding, however please consider me at your service should you require further information.
If I can be of any further assistance, please don’t hesitate to contact me.