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Old 13th July 2013, 12:56   #76
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Default re: Evasive manoeuvres & Rollovers?

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Originally Posted by SS-Traveller View Post
EXACTLY what YOU have defined! Now would you answer the question?
From my understanding of the term "Destructive testing", no, Elk test does not fall under that category.

I am not the authority on the term. You are free to use your resources and make your own understanding of the term yourself.

What is the relevance of the question to the discussion considering that usage of the term has already led to a few OT posts and more?

Does "Destructive testing" have anything to do with vehicle dynamics?

I do not wish to answer any more questions on "destructive testing" just for argument's sake.

Cheers.
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Old 13th July 2013, 15:52   #77
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Default re: Evasive manoeuvres & Rollovers?

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Originally Posted by SS-Traveller View Post
Is a moose/elk test destructive testing or not?
No, a moose/elk test is certainly not destructive testing.

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Originally Posted by gthang View Post

Does "Destructive testing" have anything to do with vehicle dynamics?
Yes, when it involves destructive testing of the suspension.
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Old 13th July 2013, 16:32   #78
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Default re: Evasive manoeuvres & Rollovers?

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Originally Posted by gthang View Post
From my understanding of the term "Destructive testing", no, Elk test does not fall under that category.
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Originally Posted by VeyronSuperSprt View Post
No, a moose/elk test is certainly not destructive testing.
I consider it to be **POTENTIALLY** destructive testing - and I don't know whether such a term is used technically in other spheres of engineering.

Given that a moose test can overturn a vehicle and destroy it, wouldn't such a test be considered potentially destructive at least? And because there is such a possibility, both manufacturers and testers, at least in India, would be very averse to conducting such a test (especially because conducting such a test is not required for homologation as per ARAI requirements).

Therefore, for a SUV to be considered safe during evasive manoeuvres, unless ARAI (or some other government body) sets some parameters that are compulsory, my guess would be that no one would conduct a moose test to find out whether your SUV can survive such driving. In a country where crash tests are not conducted, do we think a moose test would happen anytime soon?
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Old 13th July 2013, 16:48   #79
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Default re: Evasive manoeuvres & Rollovers?

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Originally Posted by SS-Traveller View Post

Given that a moose test can overturn a vehicle and destroy it, wouldn't such a test be considered potentially destructive at least?
The fact that a particular test destroys a vehicle does not classify the test under "destructive testing". A crash test which totally destroys a car itself is not destructive testing. The term destructive testing does not have a direct connection with the word "destroy". It is the repetitive test sequences which are used to establish reliability of the vehicle only that constitute destructive testing.
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Old 13th July 2013, 20:36   #80
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Default re: Evasive manoeuvres & Rollovers?

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Originally Posted by joybhowmik View Post

Curious to know how you judged that the work is that of a student - the author appears to be a professor emeritus (a very high stature even amongst academicians).
You are right! Just googled.
Went through the paper again. In my mind, my first impression stands. This is not the paper one expects of a professor, let alone an emeritus. Flabbergasted does not come close to explaining what I feel.

Quote:
Or perhaps you wished to dismiss the author's line of reasoning as too simple (like that of a student)- in which case would be good to know if you have a better explanation of the phenomenon?
One does not need an engineer or professor to tell us that tall and narrow = less stable. We need them to explain to us laymen the difficult part of vehicle dynamics as a whole. Of the part played by tyres and suspension.

One cannot disregard/ ignore these by the stroke of a pen. Which is what has been done. To quote
Quote:
It should be emphasized that the effects of suspension movement, tire movement or
electronic/mechanical stability control may be very important in the rollover tendency for a
vehicle. Suspension and tire movements would likely increase the tendency for rollovers,
while electronic/mechanical stability control is designed to make it less likely that a vehiclewould get in a situation where rollovers occur. These analyses do not account for such and,
thus, can only compare vehicles as rigid unintelligent bodies.
The normal course would be to factor these in, work them out, and then show that these are not important in the context of the given situation, and therefore can be ignored.
Alternately, one can give a closely reasoned argument (and backed up by other peoples work in the same area) which supports the premise that things like tyres, suspension, weight distribution (esp. polar moment of inertia) do not really matter.
Factoring all these, and getting an analytic solution is going to be very very hard (make that impossible). Ignoring all these 'unnecessary complications' is normally a deadline staring students response when submitting a term paper!

Incidentally, (IMHO) the title of the paper should not be the Physics of Automobile Rollovers, but 'why my metric is better than the NHTSA metric'.

Regards
Sutripta
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Old 13th July 2013, 22:37   #81
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Default re: Evasive manoeuvres & Rollovers?

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Originally Posted by VeyronSuperSprt View Post
...repetitive test sequences which are used to establish reliability of the vehicle only that constitute destructive testing.
Isn't the moose test all about repetitive test sequences at increasing speeds until a limit is reached (whether resulting in rollover or skid/loss of control), thus establishing reliability in performance?

EDIT: Just wondering: can the test be renamed for India and be called the cow test / stray dog test?

Last edited by SS-Traveller : 13th July 2013 at 22:39.
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Old 13th July 2013, 22:42   #82
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Default re: Evasive manoeuvres & Rollovers?

^^ Dada, we think on similar lines, see this old post from me -

http://www.team-bhp.com/forum/intern...ml#post3038984 (2012 Jeep Grand Cherokee fails the 'Elk Test'!)

Spike
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Old 13th July 2013, 22:52   #83
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Default re: Evasive manoeuvres & Rollovers?

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Originally Posted by Sutripta View Post
One does not need an engineer or professor to tell us that tall and narrow = less stable. We need them to explain to us laymen the difficult part of vehicle dynamics as a whole. Of the part played by tyres and suspension.
Like I said earlier - if you do have your own or someone else's published paper to explain this phenomenon - do be so kind as to provide us with insights.
Until then, please do not belittle someone else's work. That is in bad taste.
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Old 14th July 2013, 07:41   #84
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Default re: Evasive manoeuvres & Rollovers?

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Originally Posted by SS-Traveller View Post
In a country where crash tests are not conducted, do we think a moose test would happen anytime soon?
So, what are you trying to say?

That a DOUBLE correction maneuver test at highway speeds (Elk test) for a road condition that hardly happens in India will not be conducted by ARAI or any testing agency, who does nothing but mileage and emissions tests currently, because it might fall under destructive testing category(which it does not)?

Am I close?

Cheers
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Old 14th July 2013, 08:06   #85
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Default re: Evasive manoeuvres & Rollovers?

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Originally Posted by SS-Traveller View Post
establishing reliability in performance?
Destructive testing is done to establish reliability in terms of component failure / wear and tear / breakdown.

Quote:
Originally Posted by SS-Traveller View Post
EDIT: Just wondering: can the test be renamed for India and be called the cow test / stray dog test?
In India the test can be renamed the cow / stray dog / pet dog / pedestrian / cyclist / motorcyclist / auto / car / van / lorry / bus / test or it could also be shortened to “anything that moves” test.
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Old 14th July 2013, 11:50   #86
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Default re: Evasive manoeuvres & Rollovers?

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Originally Posted by gthang View Post
So, what are you trying to say?
My contention is precisely what I have stated earlier...
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Originally Posted by SS-Traveller View Post
This is one topic perfect for verbal duels and debates, none of which would be applicable to real world driving.
Samurai has already stated very clearly with reasons, that...
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Originally Posted by Samurai View Post
This cannot be tested by magazines.
...and neither will the auto OEMs or ARAI / government agencies test this parameter.

Therefore, the original question of whether one's SUV can survive an evasive manoeuvre, is unanswerable via a forum debate, where we can quote all the physics we please. And as to your question of...
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Originally Posted by gthang View Post
...Elk test......will not be conducted by ARAI or any testing agency...because it might fall under destructive testing category?
...that *because* is equally unanswerable because the workings and decision-making processes of such govt. agencies is beyond the comprehension and control of the general car-owning population.

It is therefore fruitless to persist in trying to outsmart each other and prove who is the greater scientist/physicist/automobile engineer/road test specialist, and unless we have fresh evidence and standardized data with which different SUVs can be compared for their fitness in surviving evasive manoeuvres, this thread may please be closed.

Anyone with any new evidence to present, which allows comparative analysis of stability of various SUVs sold in India, including ones designed in the country during evasive manoeuvres, can report the thread for reopening.
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Old 14th July 2013, 12:06   #87
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Default re: Evasive manoeuvres & Rollovers?

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Originally Posted by nilanjanray View Post
This thread is becoming a bit ridiculous. Refer to the thread starters question. Would first time suv buyers benefit from such an argument or from practical advice on how to modify one's driving style when moving to a suv?
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Originally Posted by chinkara View Post
I don't see where this point of "Many Indian users buy SUVs for the wrong reasons" is coming from. W

I am interested in the technical parameters (especially having experienced a topple once - although aided by a truck pushing me over).

..........
Quote:
Originally Posted by shankar.balan View Post
What a nice eye-opener post just when things were getting cloudy with smoke and volcanic ash!
I totally agree.
Most users of different types of vehicles really do not stop to think before mashing their clod-hopping number tens on the accelerator pedal.
I think that a sound set of tips from experts on how to handle different situations in an SUV or car, would be far more valuable to the users of this forum rather than these involved, esoteric debates which sometimes look like they are beginning to verge on the wannabe quasi-erudite and totally impractical side.
Nilanjan, you might want to lead off with some tips, to which the many experienced SUV users out there can add!
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Originally Posted by Samurai View Post
I drive through a rather infamous Shiradi ghat ...... I have a layman's idea about how SUVs behave in quick turns or evasive maneuvers.

The Jeep experience is very useful because it makes you learn very quickly about SUVs and quick turns.......... If we start worrying angles and g forces, we are really fooling ourselves. We can only observe behavior, and make use of it, and adapt to it. Therefore, I suggest practice, practice, practice... on twisty roads. You will soon know how fast you can turn at every kind of angles, in your SUV.
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Originally Posted by gthang View Post
There are two ways to learn/improve one's driving. One is by using the "seat of the pants" technique, which your suggestions would fall under. The other, is to use your head, and to use the seat of your pants to validate what you should feel.

..........
One thing is common across the board, though. No one likes to hear that their driving can be improved. Seems to be an universal sore spot.

It's ridiculous to think that one can actually calculate "g" forces in your head while driving, and the assumption that the knowledge of "g" force requires you to be an Engineer or mathematician is also preposterous.

Why the aversion towards learning basic physics? ..........

Are we claiming to be auto enthusiasts just to go oooh and aaah about the flowing lines of a car, or how good the back seat feels over rough roads?

Guess the saying "Ignorance is bliss" is not without founding.

Cheers.
Whoa . I never knew a thread I started would be 'smoking' so much. When I started this, it was with a certain intention. The stimulus for that was the recent pictures posted on the forum of the Ecosport turning turtle (well, almost) on a test drive. I have seen owners of the Duster (and other SUVs) boasting about the top speeds they do on our highways. 140-160 kph on our roads is nothing short of suicidal, considering the condition of the roads and the chaotic traffic. When it is combined with excessive speed on a curve where the other end in invisible or hidden behind the butt of the vehicle in front of us, it is a recipe for a fatal disaster.

Therefore, I was thinking that if someone had a simple way to work out the top speed that can be considered for a vehicle it would make us all safer drivers. I agree that the 'seat of the pants' technique mentioned by gthang here is the best bet because it would be ridiculous to think we can get the figures for the radius of the curve on the road, height of center of gravity of the vehicle etc, that can be plugged in to get the ideal speed for that curve in an instant. The idea was, if all of us could work out an average speed for an average curve for the vehicles we own, we could slow down to 'that' safe speed sufficiently early to avoid putting ourselves and other road users in danger.

I've seen on various forums, spawned after the launch of the XUV500 and Duster, many drivers who graduated to a 'large burly' car from their hatchbacks or sedans boasting about their driving prowess. It is either the top speed or the 'off-roading' experience they have had. There is a genuine need to educate such people about safe driving because most of them drive the SUV like a regular car and complain about it 'rolling around' or 'jerking around', and when they end up crashing they blame the car. Apparently, their driving skills are sublime. It is always the car that is to blame!

Instead of the ongoing debate, I was hoping that experiences users could give inputs about how a SUV, compact or otherwise, should be driven in our not so ideal roads & traffic.

There is this sticker in my Duster (pic attached) that tells you what to do & not to do but I wonder how many of us even bother to look at that!
Attached Thumbnails
Evasive manoeuvres & Rollovers?-wp_20130714_003.jpg  

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Old 14th July 2013, 13:29   #88
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Default re: Evasive manoeuvres & Rollovers?

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Originally Posted by Sutripta View Post
^^^
.....
What would happen if one were driving on say an ice lake (using normal tyres)?

Regards
Sutripta
Hi Sutripta, Got
this on YouTube
It is not driving on ice but close to it.

FINALLY, ?
..... In Slow; Out Fast
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Old 14th July 2013, 13:30   #89
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Default re: Evasive manoeuvres & Rollovers?

On the safari, I use a simple rule. If the tires start squealing, I am taking the curves too fast.
That said, you can push a monoque much more than you can push a tall ladder on frame.

Moreover, when driving on mountain roads, passengers start getting uncomfortable far earlier than you hit the limits of the vehicle. So as long as you are not ignoring the motion sick passenger, you are doing fine.
Why go till the limit, its not a rally. Staying well within the safety margin is always good.
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Old 14th July 2013, 13:47   #90
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All car / suv owners can try this experiment:

Drive through a winding road with your seat height at the highest position
and drive back with the lowest position.


You will find a remarkable change in your car's cornering ability.



I find the lower the seat,
the better I can feel the grip available to the car.
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