My dear #cae engineers,
Something new to discuss today…
One of my trainees asked me, what happens in frontal crash, if a car doesn’t have front hood (bonnet) or it has a very small bonnet?
First, we see that how does a bonnet deforms in front crash and absorb the crash energy?
As shown In image1, the car has enough space in front to deform and absorb the KE. The front of the car (bonnet, front cross member, and side member in chassis) is designed in such a way, that they must deform.

In image2, the car doesn’t have any front hood. Take an example of a typical van. In this situation, there is nothing to protect the occupant cabin. In absence of bonnet, the deformations reach easily to occupant. So, no chance of survival of the occupants.

Then question arises, how to design a safe car without any bonnet or front hood? The answer will surprise you.
To answer this, I take an example of a popular car of #germany named #smart (for two) developed by #daimler . This car has a very small bonnet or almost no bonnet. The car is only 9 feet long and weighing approx. 1124 kg.
A car “without bonnet” is designed in such a way, that the opposite car must absorb the energy and make this “without bonnet car” safe. Interesting!
Now I explain you- The car (without bonnet) is designed like a very hard nutshell with high strength steel, so they do not deform in crash (The structure shown with blue color in image4). That’s the reason this small baby of #daimler is costly.
If they do not deform in crash, then who is going to absorb the energy? Yes, the crash object of other side. The #Smartfortwo, designed by #daimler works on this principle. A really challenging design developed by #daimler . Appreciable!
You can check in image3 if a #smart car (for two) crashes with a big car like S-class of Mercedes-Benz AG, the maximum energy is absorbed by the opposite car, not by this baby. You can observe that the deformation in S-class structure is more in compared to Smart. That’s how it has been designed.
But one can ask, what happens when 2 smart cars crash with each other, or this car crashes with a rigid structure? This we will discuss on next week..
till that…Stay tuned! Enjoy the day!