hood design challenge

DEFINITION OF HOOD : The hood or bonnet (Commonwealth English ) is the hinged cover over the engine of motor vehicles that allows access to the engine compartment (or trunk on rear-engine and some mid-engine vehicles) for maintenance and repair. In many motor vehicles built in the 1930s and 1940s, the resemblance to an actual hood or bonnet is clear when open and viewed head-on; in modern vehicles it continues to serve the same purpose but no longer resembles a head covering.

The hood release system is common on most vehicles and usually consists of an interior hood latch handle, hood release cable and hood latch assembly. The hood latch handle is usually located below the steering wheel, beside the driver\'s seat or set into the door frame. On race cars or cars with aftermarket hoods (that do not use the factory latch system) the hood may be held down by hood pins. Some aftermarket hoods that have latch system are still equipped with hood pins to hold the hood buttoned down if the latch fails^]. A hood may contain a hood ornament, hood scoop, power bulge, and/or wiper jets. Hoods are typically made out of steel, but aluminum is rapidly gaining popularity with auto companies. Aftermarket manufacturers may construct hoods out of fiberglass, carbon fiber, or dry carbon.

Functions:-

1. Acts as a engine unit protector,and protects from environmental issues.
2. Protects passenger from frontal crash and plays a vital role in pedestrian safety.

1. Overall helps to improve the aerodynamic performance of the car.

Given data:

1. Outer panel thickness: 0.75mm.
2. Inner panel thickness: 0.75 mm.
3. Reinforcement thickness: 1.5mm.

Solution:

1. Overall design of the hood.

1. Inner panel design.

Inner panel is the part of the hood which provide its strength and rigidity it also helps in diverting the force acting on it towards the hinges while crashing and keeps the passenger and driver safe by reducing the effect of crash directly on them.

In this part there are embosses are created to provide strength to the sheet metal.

There are metal cut outs to reduce the weight of the inner panel.

While designing we also have to keep in mind that the embosses we creating should in such a shape that it will divert the forces towards the hinges. The design should be in the form of ‘W’.

Side Relief

Here side relief of 3mm is provided.

Hemming

Hemming is the process of joining two metal parts by wrapping around the one metal part to the other.

Hinge & striker placement

Here hinge and striker are placed using a large circle to align them correctly.

Mastic point

These are the points where mastic sealants are provided. Mastic sealants are the rubber paste type sealants which used attach the outer panel of the hood to inner panel of the hood which also reduces the noise due the vibration between the metallic parts.

Moment of inertia

Moment of inertia of the section of the hood is calculated by using the sectional sketch of the hood.

Link for design part ­- https://drive.google.com/drive/folders/1WCBr7_0vsirZ_qtqrZBOpu0aNeiFizvr

Prepared by – Nazrul Islam