Hood design-Week 2

OBJECTIVE

TO BUILT THE INNER PANEL & REINFORCEMENT ACCORDING TO THE STANDARDS, HEM THE OUTER PANEL WITH THE INNER PANEL AND PROVIDE MASTIC DATA.

HOOD

A CAR HOOD IS ALSO REFERRED TO AS A BONNET IN SOME OTHER COUNTRIES. GENERALLY, IT IS USED TO COVER THE ENGINE AND ITS ACCESSORIES. THE HOOD IS ALSO CONSIDERED AS ANOTHER DOOR THAT IS USED TO REPAIR AND HELPED TO MAINTAIN THE ENGINE.

HOOD PARTS

• OUTER PANEL
• INNER PANEL
• STRIKER
• HINGE ASSEMBLY

DESIGN METHODOLOGY

THE METHOD USED IN THIS PROJECT IS START TOP DOWN WITH THE REFERENCE OF THE MASTER SECTION

DESIGN CONSIDERATIONS

• PEDESTRIAN RATING
• FORCE DISTRIBUTION
• ENSURING DFM (SHEET METAL PROCESS)
• HOOD STANDARDS
• DEFORM SHAPE
• EURO NCAP
• NOISE VIBRATION HARSHNESS

PEDESTRIAN RATING

1. THE MOST IMPORTANT THING IS A SAFETY REGARDLESS OF ANYTHING. SO THERE ARE TIMES THAT PEDESTRIANS WILL BE HIT BY THE HOOD OF A CAR. WHILE THE HEAD IS LAID ON THE HOOD THAT SPECIFIC PORTION SHOULD ABSORB THE ENERGY INSTEAD OF RESISTING. TO PREVENT CAUSES.
2. THE HITTING ZONE WILL BE DIFFERENT BECAUSE OF SO MANY FACTORS LIKE AGES, COUNTRY, ETC.

WRAP AROUND DISTANCE

• WHEN A CAR CRASHES ON A PEDESTRIAN THE WHOLE BODY WRAPS AROUND THE FRONT SHAPE OF THE CAR. AND THE HEAD IMPACT ON THE WINDSCREEN.
• THE DISTANCE ON WHICH THE HEAD IMPACTS THE CAR FROM THE GROUND IS CALLED (WAD).
• CHILD'S HEAD IMPACT ZONE=1000MM TO 1700 MM (3.5 KG)
• ADULT HEAD IMPACT ZONE = 1700MM TO 2100MM (4.5 KG)

FORCE DISTRIBUTION

WHEN THE FORCE IS ACTING ON THE CENTER OF THE HOOD THE FORCE SHOULD BE SPREAD LIKE A WAVE INSTEAD OF A SINGLE DIRECTION, IT WILL DRASTICALLY REDUCE THE IMPACT ON THE PASSENGERS BY ADDING EMBOSS WE CAN ACHIEVE THIS SHOWN IN THE FIGURE.

EMBOSS

SHEET METAL EMBOSSING IS A STAMPING PROCESS FOR PRODUCING RAISED OR SUNKEN DESIGNS OR RELIEF IN THE SHEET METAL. THIS PROCESS CAN BE MADE BY MEANS OF MATCHED MALE AND FEMALE ROLLER DIES OR BY PASSING SHEET OR A STRIP OF METAL BETWEEN ROLLS OF THE DESIRED PATTERN. IT IS OFTEN COMBINED WITH FOIL STAMPING TO CREATE A SHINY, 3D EFFECT. TO PROVIDE STRENGTH TO THE INNER PANEL AND TO DISTRIBUTE THE FORCES PRODUCED DURING THE IMPACT WITH PEDESTRIAN OR OTHER OBSTACLES TO ENSURE THE SAFETY OF THE PASSENGERS. THE FORCES ARE DIRECTED OUTWARDS THROUGH THE EMBOSSING PATH.

MASTIC DATA

MASTIC SEALS ARE USED AS A BOND BETWEEN THE INNER AND OUTER PANELS.IT IS ALSO USED TO IMPROVE THE STIFFNESS OF THE AREA. IT PLAYS A VITAL ROLE WHICH IS REDUCING THE NVH, THE GAP BETWEEN THE INNER AND OUTER PANEL IS 5 MM. MASTIC SEAL WILL OCCUPY THE 5 MM GAP.

HINGE & STRIKER

THE HINGE IS ACT AS A MECHANISM TO OPEN AND CLOSE THE HOOD AND THE STRIKER IS USED AS A LOCK BY CREATING A REFERENCE CIRCLE BY USING THE HINGE AXIS WE CAN FIND THE STRIKER TRAJECTORY AND PLACE IT THERE

HEMMING

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 REINFORCE PART EDGES.

HEM RELIEF

THE RELIEF IS GIVEN TO EDGE DUE TO MANUFACTURING PURPOSE TO EASE THE PROCESS OF HEMMING IF THE RELIEF IS NOT THERE IT WILL DEFORM OR CRAMBLE

FINAL ASSEMBLY

CONCLUSION

THE HOOD/BONNET OF THE CAR HAS BEEN DESIGNED AND ASSEMBLED ACCORDING TO STANDARDS