Tony Posted March 25, 2007 Report Share Posted March 25, 2007 From this image can you explain how this car crashed... Classic example of many areas covered in wim. Quote Link to comment Share on other sites More sharing options...
Noel Posted March 25, 2007 Report Share Posted March 25, 2007 Muppet behind the wheel.... Quote Link to comment Share on other sites More sharing options...
Tony Posted March 25, 2007 Author Report Share Posted March 25, 2007 Muppet behind the wheel.... Well yes and no! What failed the car or the driver? Quote Link to comment Share on other sites More sharing options...
jammy Posted March 25, 2007 Report Share Posted March 25, 2007 Muppet behind the wheel.... Well yes and no! What failed the car or the driver? driver error?goin to fast and didnt see the corner/post Quote Link to comment Share on other sites More sharing options...
jammy Posted March 25, 2007 Report Share Posted March 25, 2007 Muppet behind the wheel.... Well yes and no! What failed the car or the driver? driver error?goin to fast and didnt see the corner/post mite of been the car that failed??????? well it was a mondeo Quote Link to comment Share on other sites More sharing options...
Tony Posted March 25, 2007 Author Report Share Posted March 25, 2007 Muppet behind the wheel.... Well yes and no! What failed the car or the driver? driver error?goin to fast and didnt see the corner/post mite of been the car that failed??????? well it was a mondeo Well ok... Can i remind you this club is concentrated chassis dynamics, complimented by the power train. This particular accident has some obvious possibilities for us to explain and explore. So i ask again. How do your think this accident happened? Quote Link to comment Share on other sites More sharing options...
scorps Posted March 25, 2007 Report Share Posted March 25, 2007 All is revealed here: Going to fast on a bend coupled with speed humps. http://www.wheels-inmotion.co.uk/forum/ind...ic=1038&hl= Quote Link to comment Share on other sites More sharing options...
jammy Posted March 25, 2007 Report Share Posted March 25, 2007 sorry tony..my bad... wondering if as the mondeo was starting to go roung the bend another car was coming towards him a bit fast and stepped over the white line in order to get around the bend and the mondeo driver swerved to miss it and hit the post. looks like a very hard impact too... Quote Link to comment Share on other sites More sharing options...
Tony Posted March 25, 2007 Author Report Share Posted March 25, 2007 All is revealed here:http://www.wheels-inmotion.co.uk/forum/ind...ic=1038&hl= Adds to the question... We have many common factors here resulting in this accident. I would hope some members could suggest what elements allowed this scene. How did the car fail!...... Or did the car actually do it's job? Quote Link to comment Share on other sites More sharing options...
scorps Posted March 25, 2007 Report Share Posted March 25, 2007 Hit the hump so hard it lifted,by the time it hit the ground he ran out of rd and got personal to the lampost. Quote Link to comment Share on other sites More sharing options...
Tony Posted March 25, 2007 Author Report Share Posted March 25, 2007 Hit the hump so hard it lifted,by the time it hit the ground he ran out of rd and got personal to the lampost. Well i want to concentrate on the visible evidence. What went wrong geometrically, pneumatically and mechanically on that bend? Quote Link to comment Share on other sites More sharing options...
jammy Posted March 25, 2007 Report Share Posted March 25, 2007 Hit the hump so hard it lifted,by the time it hit the ground he ran out of rd and got personal to the lampost. Well i want to concentrate on the visible evidence. What went wrong geometrically, pneumatically and mechanically on that bend? im probabbly way off but all i can think of is its somthing to do with the lower arm or track rod end falling...? Quote Link to comment Share on other sites More sharing options...
scorps Posted March 25, 2007 Report Share Posted March 25, 2007 Understeer. Quote Link to comment Share on other sites More sharing options...
Noel Posted March 25, 2007 Report Share Posted March 25, 2007 OK here's my version.... It was late at night with low visibility and the driver was unfamiliar with the area and travelling too fast... the fact that there is a broken center line gave the driver no warning that there was a sharp bend approaching , in reaction to seeing the bend to late the driver locked up the brakes (mustn't of had ABS) and severely under-steered straight into the lamppost... Quote Link to comment Share on other sites More sharing options...
Rich Posted March 25, 2007 Report Share Posted March 25, 2007 Hit the hump so hard it lifted,by the time it hit the ground he ran out of rd and got personal to the lampost. Can I just point out that the humps have only been put in this week, they weren't there when this accident happened. So you could approach the bend doing well over the 30mph limit. OK here's my version.... It was late at night with low visibility and the driver was unfamiliar with the area and travelling too fast... the fact that there is a broken center line gave the driver no warning that there was a sharp bend approaching , in reaction to seeing the bend to late the driver locked up the brakes (mustn't of had ABS) and severely under-steered straight into the lamppost... It happened around 5pm a couple of days into the new year so was dark. Also the lighting was fairly poor on this stretch, they've improved this though cos of the new humps. There are the warning signs on the side of the road to indicate it's a sharp bend which can be seen quite clearly via the headlights. I agree about the car not having ABS, I think it was an M reg so when they braked they locked. The car hit the post and the back end smashed into the brick wall behind it. Also cos of the time of year the road was damp and possibly frosty. There was an article in the paper about it, I will have to try and find it when I go to work. A week after this happened someone else drive straight into the tree you see in the background next to the lamp post. Looked like they didn't even attempt to steer around the corner! Quote Link to comment Share on other sites More sharing options...
Tony Posted March 26, 2007 Author Report Share Posted March 26, 2007 When i look at this image this is what i see. 1: weight transfer 2: Poor Dynamic index 3: Pneumatic saturation during the moment of Yaw 4: Resultant under-steer A classic example where the commands at the chassis exceeds the cars ability to reply to the conditions like driver ability, speed, weather and indeed the radius of the bend. If you take the calibration topics here in wim you can actually read this accident like a book. Quote Link to comment Share on other sites More sharing options...
scorps Posted March 27, 2007 Report Share Posted March 27, 2007 4: Resultant under-steerIf you take the calibration topics here in wim you can actually read this accident like a book. Understeer. I gave a short version :ph34r_anim: Quote Link to comment Share on other sites More sharing options...
Rich Posted March 27, 2007 Report Share Posted March 27, 2007 What do you mean by number 3, that one has me baffled?!! Quote Link to comment Share on other sites More sharing options...
Tony Posted March 27, 2007 Author Report Share Posted March 27, 2007 What do you mean by number 3, that one has me baffled?!! Perfecting the tyre contact patch is our goal through developments of the suspension and geometric compensation. It is easy to forget this patch has limitations.. This car was traveling with the commands below the saturation limits... As it approached the bend lateral commands, weight transfer and braking forces were all retained within the patch. As the Yaw continued the commands at the patch saturated the ability of the entire calibration, this exceeded then... Under-steered (by design) and the car crashed. Quote Link to comment Share on other sites More sharing options...
Sam@TDi Posted March 28, 2007 Report Share Posted March 28, 2007 What do you mean by number 3, that one has me baffled?!! Perfecting the tyre contact patch is our goal through developments of the suspension and geometric compensation. It is easy to forget this patch has limitations.. This car was traveling with the commands below the saturation limits... As it approached the bend lateral commands, weight transfer and braking forces were all retained within the patch. As the Yaw continued the commands at the patch saturated the ability of the entire calibration, this exceeded then... Under-steered (by design) and the car crashed. This is also a superb example of exactly why normal passenger cars are built to perform a "front first departure" in limit control situation..... look at how the car hit the solid obstacle, smack bang in the middle of the crumple zone, and straight enough for the occupants to get the most benefit from their seat belts and front air bags In a sentence, modern cars are designed to hit things head on.... so the chassis dynamics is tweeked to make this the most likely scenario. This accident happened exactly how the Ford design team would of hoped, and i'd guess that any occupants walked away. Quote Link to comment Share on other sites More sharing options...
Noel Posted March 28, 2007 Report Share Posted March 28, 2007 To put another spin on it...... more thought should have been given to the placement of those streetlights, also is it ok to overtake on that bend? :ph34r_anim: shouldn't it have a continuous white line Quote Link to comment Share on other sites More sharing options...
Rich Posted March 28, 2007 Report Share Posted March 28, 2007 Cheers Tony, made abit of sense! :ph34r_anim: :ph34r_anim: The bloke driving wasn't hurt, don't even think the car had an air bag, if it did it never went off. The police were there for about an hour with the bloke, don't know if he got nicked for anything! I use this stretch of road every day and before the humps were put in the lighting was very poor, if you don't know the road you wouldn't see the bend until you were on top of it, but the signs can be seen clearly if you're paying attention to the road! When I go around it I normally cut across both lanes as you can see if there's any oncoming traffic... Quote Link to comment Share on other sites More sharing options...
Tony Posted March 28, 2007 Author Report Share Posted March 28, 2007 Cheers Tony, made abit of sense! :ph34r_anim: :ph34r_anim: The bloke driving wasn't hurt, don't even think the car had an air bag, if it did it never went off. The police were there for about an hour with the bloke, don't know if he got nicked for anything! I use this stretch of road every day and before the humps were put in the lighting was very poor, if you don't know the road you wouldn't see the bend until you were on top of it, but the signs can be seen clearly if you're paying attention to the road! When I go around it I normally cut across both lanes as you can see if there's any oncoming traffic... As Sam@tdi says this example is a classic "success" by design. Tyre saturation is a difficult topic to explain so i will try another approach. Imagine the human walking step forward has on the shoe The commands are predictable and within the limits of the shoes design. Add to this step a hill and you are walking up it, well the commands are increased but still within the contact patch's design. Now add some rain.... Now your commands on the shoes contact patch are becoming saturated, the commands are at the limit. Now the rain turns into snow.... On the very next step the shoes contact patch and your commands become saturated.. It lets go, you slip and fall on your arse. Basically the commands exceeded the product. Quote Link to comment Share on other sites More sharing options...
Rich Posted March 28, 2007 Report Share Posted March 28, 2007 Good explaination, I understand now. So if you take our trainers, there are different tread patterns for different environments/circumstances; walking/running, dry/wet etc. Assuming this car just had budget tyres on with a symetrical pattern, would different ones have prevented it from happening or changed the way the car crashed? :ph34r_anim: Quote Link to comment Share on other sites More sharing options...
Tony Posted March 28, 2007 Author Report Share Posted March 28, 2007 Good explaination, I understand now. So if you take our trainers, there are different tread patterns for different environments/circumstances; walking/running, dry/wet etc. Assuming this car just had budget tyres on with a symetrical pattern, would different ones have prevented it from happening or changed the way the car crashed? :ph34r_anim: Advanced limitations can be assumed depending on the intention. Understanding the "shoes" limitations is forward thinking. My example suggests how the pent-up commands can exceed the required ability of the patch. If by example you intend to climb a hill in trainers then ski back down, then trainers will be saturated since the commands exceed the ability of the patch, but development requests in advance can assume a solution in advance allowing a more suitable means to control "down hill" saturation. Point of this thread it to understand the commands on the tyre via the chassis positions on a domestic car can be exceeded... The most common expedient to saturation is speed! Quote Link to comment Share on other sites More sharing options...
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