Crashworthiness of Aluminum Structured Cars

The article says that a properly designed aluminum car can weigh 45-50% less than the equivalent steel car and still have excellent crashworthiness.

It also seems to suggest that the Lotus Elise was not designed to achieve excellent crashworthiness because it lacks front and rear extensions designed to absorb crash energy:

"In both sheet unibody and space frame vehicles, the aluminum structure provides the main safety cage to protect the vehicle occupants and is therefore design to remain essentially intact in a collision while the front and rear extensions of the aluminium structure (except for the Lotus Elise) are designed to collapse by concertina-type folding or controlled deep bending collapse to absorb kinetic energy in the collision." (first paragraph on p.3).

>>>It also seems to suggest that the Lotus Elise was not designed to achieve excellent crashworthiness because it lacks front and rear extensions designed to absorb crash energy: <<<

I heard that the Elise did well in the 30 MPH into a wall test in which the car was driveable afterwards and the occupants faired reasonably well considering. The composite body ahead of the frame absorbs a great deal of energy. But it can't take low MPH crashes with some damage or cosmetic issues.

Stan

The Elise chassis itself should remain outside the deformations in a crash as it's not a unibody design.

At the front there's the specifically designed fibreglass (not CF, although it's black...) crash-box that also houses the radiator which forms the 'crumple zone' and absorbs most of the crash energy with a controlled de-lamination of the fibreglass. (if you look carefully you'll see it has 'tubes' moulded in it's shape to give a very specific crash behaviour and energy dispersal)

At the rear the rear clamshell with it's luggage space, as well as the separate aluminium longerons and steel subframe bolted to the chassis form the crash protection zone.

In all these the chassis itself shoud remain free of damage and repair involves removing the damaged parts and putting on new ones.

Bye, Arno.

tragic accident...don't know the details regarding speed, etc...

http://www.newsandstar.co.uk/news/viewarticle.aspx?id=128011

Arno said:

In all these the chassis itself should remain free of damage and repair involves removing the damaged parts and putting on new ones.

Click to expand...

Yep. I even believe that Lotus has a patent on the crash structure technology used in the front of the Elise. As Arno indicated, the crash structure is a replaceable part in the Elise and does not require the deformation of the chassis. Apparently, it works quite well.

Any info on the side-impact capabilities and the windshield pillar strength of the Elise? I guess the doors do come with the required side impact beams, and the occupants are seated some distance inwards as a result of the chassis tub.

Personally, I think the Elise is a pretty safe vehicle in a single vehicle crash. However, the fact that the car is pretty low => it's presumably weaker upper body would be the part protecting you from a taller vehicle (read: SUV) in a multi-vehicle crash. And that thought scares me. I once heard from a guy who said the scariest moment of his life was when a woman reversed her SUV into his Lamborghini. Thank god she stopped short of his windshield. And then it took them 6 months to get the parts from Italy to repair the vehicle ... and that could be another issue with a low-volume car like the Elise.

There's zero windshield strength- rollover protection comes from the roll bar.

Looks like good news for a single car collision with an immoveable object.

Unfortunately, as already been stated, it is business as usual for the SUV that runs a red light.
I don't reckon any passenger car(in the normal definition) has anti intrusion barriers at SUV bumper height.


I thought it nice that Lotus Engineering are an aluminum tech company in their own right. They were smart in patenting their extrusion/chemweld/divot technology before approaching Hydro.
Now, if Lotus cars could run with that ball.....
m.

thegit said:

Now, if Lotus cars could run with that ball.....

Click to expand...

They have.

Remember, car manufacturing is only a part (and probably the smaller part) of Lotus' business. They act as engineering consultants to many other car manufacturers including, in all probability, the others that are manufacturing "aluminum" cars...

Keep in mind that even though the Elise is small, it weighs relatively little - so, there's less momentum that needs to be absorbed by crash structures.

HermansLotus, How did this accident happen? Driver error, mechanical failure, etc?
Dan Parker

eliseowner2b said:

HermansLotus, How did this accident happen? Driver error, mechanical failure, etc?
Dan Parker

Click to expand...

I wasn't there but from what I have been told it was driver error.

People have been crashing these cars here over in the UK for the last 8 years !...if the design wasnt particularly safe we would know about it.

My father in law works at a Lotus bodyshop - youd be amazed at how well the Elise fares after a crash...it always looks bad as the bodywork disintegrates (as intended) ...but most of the time, replacement of clams, front/rear crash structure and off you go again.

How many tin top road cars have a steel roll hoop? ...not many - a friend of mine has crashed 2 Elises so badly that there were both written off. On one occasion he rolled multiple times, dropped down about 20ft off the road, rolled again...then got out and walked away (he has 4 point harnesses though)

Id sooner be in an Elise than a lot of other cars on the market