Hood design-Week 2

Hood:

Hood or generally called as bonnet is a cover provided on the engine compartment. This can be opened to allow access to work on engine compartment. They are at the very frint of a vehicle so, they play an important role in safety, Aerodynamics, Aesthetics of a vehicle.

In design perspective, they should be following some design considerations.

Such as pedestrian safety, Opening angel, force distribution.

Opening angel mainly depends on the height of the persion who is opening the hood. We take average height of the region we are talking about and according to that we decide our opening angel.

A Hood consist of Outer Panel, Inner Panel, Striker, Hinge as well as latch.

1. Outer Panel:

So that is how the outer panel of a hood should look like. It stays at the outer side of the hood facing the front. It decides the aesthetics as well as the strength of the body.

It should be designed in such a way that, It covers all the safety criteria as well as should look good in aesthetics.

It is attached to the inner panel by Hemming process. Threre is a small gap provided between them for mastics to reduce noice and vibration.

2. Inner Panel:

-This is the inner panel of the hood. The backbone of a hood. It provides strengh and support to the outer panel. It has embosses all over itself to provide better stress distribution as well as load distribution.

Latch and hinge assamblies are mounted over this part. The embosses and the cuts are made in such a way that it reduces the load impected on the outer panel. Which provides extrenal safety in case of collision as well as provides safety to padestrians.

3. Striker and Hinge:

Striker is the part which is meant to lock the hood with engine compartment. A hook is provided on the frame body of a vehicle on where the striker rests and locks the hood.

Hinges are meant to make and angel for opening of the hood. As we know that any mounting is made on a flat surface. It should be make sure that the mountings for striker and himge assamblies must made on a flat surface. Which will provide better support and maximum contact surface between them.

4. Trajectory Circle:

It is a circle made with help of hinge axis. This circle is made exactly in between both the hinges. Another line is made on the striker as shown in the image above. To follow the design consideration, it has to be sure that the line on the striker must be tangent to the trajectory circle. Thus, the striker will be fixed on the hook correctly.

5. Emboss Definitions:

As it can be seen in the part that the load impected should be distributed in such a way that it impacts as less as possible on the body. Thus providing safety to padestrian and to the passengers.

Manufacturing precess:

Deep Drawing:

It is a type of forming process, which performs under the conditions of tensile and compressive strength.

Deep drawing is a sheet metal forming process in which a sheet metal blank is radially drawn into a forming die by the mechanical action of a punch. It is thus a shape transformation process with material retention. The process is considered "deep" drawing when the depth of the drawn part exceeds its diameter.

It is much quicker, more efficient and it gives good qulity to the products. That iswhy it is highly used in various industries.

Hemming:

Hemming is a sheet metal forming process in which sheets are joined by bending it to 180°. Automotive body panels and automotive parts such as deck-lids, trunk-lids, doors, hoods and tailgates are formed by hemming process.

In this process, usually a sheet is bent with the help of inner sheet in three different stages.

Purpose:

Hemming is a forming operation in which the edges of the sheet are folded or folded over another part in order to achieve a tight fit. Normally hemming operations are used to connect parts together, to improve the appearance of a part and to reinforce part edges.

Final Assambly: