Hood design-Week 2

Hood Design-Challange:

Introduction:

Hood is main component of a car at the front portion,It is used to decorate the car and add luxurious look.The shape of the bonnet is made aerodynamic in order to minimize the air effect.

Hood design consideration:

The hood of a car is considered as the frontal BIW enclosure component.Bonnet are designed to reduce air resistance as the air flow around car.Apart from this,Bonnet are also designed to meet several other requirement ,They serve a great deal of purpose in protecting the passengers inside the car and the pedestrians in the event of an accident,it also acts as the cover for the engine.

1.The European New Car Assesment Programme(Euro NCAP) is a European car safety performance assesment program which has developed test specification and rating system for assessing pedestrian injuries during impacts with the front of vehicle such test include a series of tests using impacts designed to bio-mimic a collision at speed of 40Km/h.

2.They describe a situation in which a pedestrian is situated laterally and a car first hits one of his legs,Test are conducted on the leg,Upper leg and most importantly the head,as head trauma is most commoly responsible for casuality.

3.So to avoide several injury to the head the high impact area for adult and children are subjected to less thickness,Also no reinforcement should be provided in that area as during head collision,the hood will absorb the head impact energy leading to collapse of the hood and thus protecting severe head injury.

4.Another importent criteria for the hood design is the protection of the occupants inside the car during front collision ,The design of the hood should be in such a way that the during the collision,The force should travel in the upward direction through the embosses and directed towards the body of car.

Following parts are using the hood assembly for this report.

1.Hood outer panel

2.Hood inner panel

3.Hinge Assembly

4.Striker Assembly

Hood thickness:

Outer panel- 0.75mm

inner panel-0.75

Reinforcement thickness-1.5mm

Inner panel:

• The inner panel only we can research and implement the safety of pedestrians and as well as the driver,In this panel only we attch the reinforcement,embossed,mastic point etc.
• It is an object of the present invention to provide a hood inner panel capable of reduction of a reaction force of the hood inner panel even if a level of deformation of a hood of a vehicle increase and ensure a sufficient energy absorption capacity.

Outer panel:

We can also call it as cover of inner panel,It is the part,Which gives luxurious look to the hood or bonnet,Outer and inner panel can not join by any welding process like spot welding or rivet,which spoil the outer look of the car,The outer panel is generally extract model from the the prototype design.

Hinge Assembly:

Hinge is a component that fixes the hood to the fenders of the car,the latch must be fixed perpendicular to the hinge axis so that the hood opens or close properly.

Striker Assembly:

Latch and striker is used for locking the hood with the car,It is usually placed on the space provided on the inner panel.

The process involving in design hood as a sheet metal operations is

• Blanking
• Hemming
• Punch cutting or piercing
• Deep drawing
• Embossing

Hemming:

1.The hemming is a sheet metal forming process in which sheets are jointed by bending it usually to 180 degree,Automotive body panels and parts such as deck lids,trunk lids,door,hood and tailgates are formed by hemming process.

2.Roll hemming is carried out incrementally with a hemming roller,An industrial robot guides the hemming roller and forms the flange,Roll hemming operation can also be divided into several pre hemming and final hemming proess steps.

While doing the hemming process a relief angle is formed as a product of hemming when attaining at the corner of the sheet.

Deep Drawing:

• Deep drawing is a manufacturing process that is used extensively in the forming of sheet metal into a cup or box like structures,pots and pans for cooking containers,sinks,automobile parts,such as panel and gas tanks,are among a few of the items manufactured by sheet metal deep drawing.
• A deep drawing of sheet metal is performed with a punch and die.The punch is the desired shape of the base of the part,once drawn,The die cavity matches the punch and is a little winder to allow for its passage,a well as clearance.for many calculation the sheet metal thinkness is assumed to remain constant.

Embossing:

• The sheet metal embossing operation is commonly accomplished with a combination of heat and pressure on the sheet metal depending on what type of embossing is required.
• A sheet metal is drawn through the male and female roller dies,producing a pattern or design on the sheet metal,depending on the roller dies used,different patterns can be produced on the sheet metal.

Latch trajectory:

While openging or closing the hood the latch must be perfectly aligned to the fixing or striker point for that,the latches trajectory must be perpendicular to the hinges axis.

Final Hood assembly:

Conclusion:

We have designed a hood that falls under the rules and regulation of the manufacturer's standards.