HOOD Designing

Design of HOOD

Hood:

It’s is the opening body panel that covers the engine of the front engine vehicle. It is considered as the body door since it has inner panel as well as outer panel.

• INNER PANNEL : It provides strength to the hood
• OUTER PANNEL: It works as the outer covering and gives good asthetics to hood

Its purpose to cover the engine and absorb the energy during impact and dissipate it outside the vehicle.

Design considerations for hood:

• Master section:

It is a predefined sketch adoptable on different situation.

• Embossing on the inner pannel:

Embossing is done on the inner pannel in such a way that the direction of the generated force during collision is towards the hinge points.

• Hinge axis and striker point co-relation:

A circle is to be constructed with center at hinge axis mid point and radius from mid point to the striker point. There are two criteria for hinge and striker.

• The hood must trace the trajectory of the circle
• Striker must be perpendicular to the trajectory on this position locally

Local emboss and reinforcement are given at the hinge point

• Hemming process:

To join inner and outer pannel hemming process is used to avoid welding marks. Ts is done by three rollers placed at different angle and no of passes are given

• Front and end relief:

Reliefs are given on the corner of the inner pannel.

• EURO-NCAP:

EURO-NCAP carries out crash test to decide how much a car is safer for pedestrian.

WAP:

Wrap around distance is the trace of the points received on the front structure ,when one end of the flexible tape of required length is held at round level and other end in contact of hood opening edge.

• Child Impact Zone: 1000 to 1500 mm of WAD.
• Adult Impact Zone: 1500 to 2100 mm of WAD.

• Impact point location:

Manufacturer provides the EURO-NCAP colour data for grid location, this data is supplied before testing of the vehicle and predicted level of protection is verified by EURO-NCAP. The ares for child impact and adult impact is calculated.

• Rating criteria:

HIC RATING	Colour of the zone
HIC <650	GREEN
650 < HIC<1000	YELLOW
1000< HIC <1350	ORANGE
1350<HIC<1700	BROWN
1700<HIC	RED

• Mastic points:

They are used in place of stiffner to increase the stiffness around 80mm diameter area. They are positioned in a way such that almost all the area between the outer and inner panel is covered.