HOOD DESIGN

OBJECTIVE:

Design Hood Outer Panel, Inner Panel and the necessary reinforcements by following the Master Section mentioned with the Design parameters which includes hood and its components, Latch Trajectory, Mastic Data, Emboss Definitions, Manufacturing process like Deep-Drawing and Hemming

AIM:

To create and assemble hood outer panel and inner panel along with their reinforcements by following the master section and design rules.

SOFTWARE USED:

Siemens NX cad

CAR HOOD:

Hood of the car is used to cover the engine compartment. Hood of car consists of outer and inner panel along with latch and Stricker and hinge. Outer panel is a sheet metal which is used to cover the inner panel. The reinforcements for the latch and Stricker is created in the inner panel.

A hood gives access to maintain and repair the engine components. Hood also consists of support rod and wiper jets.

Safety for Pedestrians:

The hood of car is usually fabricated from sheet metal, which is an energy absorbing structure. Most serious head injuries occur when there is insufficient clearance between the hood and the stiff underlying engine components. Crash mitigation tests that measure the potential for head and leg injuries resulting from pedestrian-motor vehicle crashes have been in place for many years in Europe and Japan.

Euro NCAP began head and leg testing in 1997 and Japan began pedestrian head protection testing in 2003 and pedestrian leg protection testing in 2011. In general, these tests launch projectiles designed to simulate a person’s legs or head into various locations on a vehicle’s hood and bumper to assess the effectiveness in limiting pedestrian injury

The head form test area is defined as the outer structure that includes the upper surface of all outer structures. It includes, but is not limited to, the bonnet, wings, windscreen scuttle, wiper arms/spindles, windscreen frame, A-pillars and roof. It is bounded by the geometric trace of the 1000mm wrap around line in the front, the Bonnet Side Reference Lines and the 2100mm wrap around distance (WAD)

COMPONENTS OF HOOD:

SUPPORT ROD:

Hood prop rods are stable rods intended to safely hold up vehicle hoods during inspection and repairs.

LATCH TRAJECTORY:

This is the part of the hood that has a trajectory or hook type design used to lock or unlock from the vehicle engine compartment

HINGE ASSEMBLY:

This hinge was placed on the hood to give rollover action to tilt up or tilt down the hood.

HOOD OUTER PANNEL:

The outer panel is actually a sheet metal which is designed to get a good look for a vehicle by covering the inner panel and engine parts of the car.

HOOD INNER PANNEL:

The main part of the hood which gives support to the outer panel of the car and with its embossing shapes dissipates the force in different directions when the vehicle takes crashes to not to injure the men in the car.

MASTIC SEALANTS:

A mastic sealant is elastic compound that behaves like the rubber. It is placed between the outer and inner panel. It is in paste form which after the hot furnace bath gets hardened thus joining the outer and inner panel. Mastic sealant has the tendency to increase the strength of the panel and has influence of 80mm diameter.

EMBOSSING:

Sheet metal embossing is a stamping process for producing raised designs or relief in sheet metal. Depending on the roller dies used, different patterns can be produced on the metal sheet.

MANUFACTURING PROCESS:

DEEP DRAWING:

The deep drawing process is a forming process which occurs under a combination of tensile and compressive conditions. A flat sheet metal blank is formed into a hollow body open on one side or a hollow body is formed into a hollow body with a smaller cross-section.

STEP 1:

Place the sheet metal blank inside the die

STEP 2:

In the next step, the shank holder grips the sheet metal blank in between the die and shank holder with the required pressure

STEP 3:

After gripping the sheet metal blank with the required pressure deep drawing punch stretches the sheet metal blank inside the die. During this operation, reduce the shank holder pressure continuously to ensure the free movement of the material. High shank holder pressure can cause wrinkles in sheet metal parts. Thinning is a common problem during stretching operations.

STEP 5

After sheet metal drawing operation, remove the finished parts from the die and send it for final finish operations.

HEMMING PROCESS:

Hemming is a process used to join inner and outer panels together. It is the process of bending/folding the flange of the outer panel over the inner panel. The accuracy of the operation significantly affects the appearance of the car’s outer surfaces.

VIEWS:

FEATURE TREE:

CONCLUSION:

Thus the hood is designed and assembled using Siemens NX cad.