Hood design-Week 2

AIM:

To the Design car hood outer and inner panel and these reinforcements.

• Design the outer panel with the Hem
• Design the inner panel
• Design all the necessary reinforcements
• Mirror and position the Hinge & Striker
• Provide Mastic Data
• Emboss Define
• Provide the Detailed Report

Data to be used:

Hood Thickness Information

• Outer Panel Thickness = 0.75mm
• Inner Panel Thickness = 0.75mm
• Reinforcement Thickness = 1.5mm

HOOD :-

Introduction:

• The hood may be hinged at either the front or the rear edge, or in earlier models. It may be split into two sections, one each side, each hinged along the centerline. A further variant combines the bonnet and wheel arches into one section and allows the entire front bodywork to tilt forwards around a pivot near the front of the vehicle.
• Hood is used to covering car engines, radiators, and many other parts, therefore, the hood must be designed in such a way that all the maintenance on the engine. When cars come across any accident from the front portion most of the time the hood system gets damaged and absorbs some part of the impact energy resulting from the crash.
• The hood is exquisitely designed to enhance the graceful look of the car.

PARTS OF AN HOOD:-

The hood has the inner pannel, outer panel and reinforcement, it will provide the strength and emboss.

Latch and striker mechanism is used to open and close the hood whenever is needed. Latch and hinge is needed some reinforcement for strength.

TYPES OF HOOD SUPPORTS:-

• Gas Stay
• Support Rod

Gas stay

spring stays are designed to be used on upward lifting doors, once you have opened the door slightly the spring will push the door to the fully open position, Euro fit stock various size springs depending on the door size requirements. This is mostly used for where the car bonnet weight is heavy.

Support Rod

This is widely used in many car, because this very easy and cheap. In this type we have to lift the hood by ourselves and place the support rod in the space provided either in the hood or engine component. This is mostly used for where the car bonnet weight is small.

Material Selection of Hood Design Assembly:-

Hood is typically made out of steel or aluminum, although aftermarket manufacturers may manufacture hoods out of fiberglass, carbon fiber, or dry carbon.

Grade 304 stainless steel and Grade 302 mild steel for the outer and inner panel.Flex fiber or reinforcement vinyl ester composite for Latch.Elastomer /silicon Polymer and Silicon copper paste for mastic seal.

Inner panel:-

Inner panel supports outer panel. It consists of different embosses and hole at different places. Embosses provide stiffness as well as dissipate energy towards hinges. To determine the most effective position of hole, the method of modal stiffness is employed.Inner pannel is offset of the parent work surface.inner pannel thickness is 0.75mm.

Outer Panel:-

Outer panel is nothing but a outer skin of inner panel. Otherwise called as a cover of inner panel. It is the part, which gives luxurious look to the hood or bonnet. Outer pannel and inner pannel cannot join by any welding process like spot welding or rivet, which spoil the outer look of a car.The outer pannel is generally extracted model from the prototype design.

EMBOSS:-

The geometry is created based on the master section that was designed above. After performing the initial stages of design, we will provide local embosses to strengthen the component. The component will be strengthened based on the master section. When a force impacts the hood from the front, it travels in an upward direction. The component is designed to divert the force away from the passengers into the hinges, as shown in the image belowThe embosses in the inner panel are made according to the diversion of the load path. The emboss depth is kept at a maximum of 5mm to be on the safer side so that the part is manufacturable.To provide strenth to the inner pannel and to distribute the force produced during the impact with pedstrian or other obstacles to ensure the saftey of the passengers.The forces are directed outwards through the embossing path.

Mastic Sealant:-

The Mastic sealant or the Mastic point is an elastic compound that behaves like a rubber. The mastic points are defined on the hood inner panel where the hood can easily deform. They help the hood outer panel to come back to its original shape after it gets deformed. The mastic has an influence area of 80mm.

Hemming:-

Hemming is the process of joining both the outer and inner panel together. The hemming process roles and wraps the hood outer panel around the inner panel and holds it tightly together. The following are the dimensions followed for hemming.

Position of Hinge and Striker:-

For postioning hinge and striker,we have to place hinge tantatively and take hine axis point and place position from data taken from the parent car or our own.The other major functional of the hood is the opening and closing of the hood. This is done with the help of the latch and striker. To position the latch and striker effectively, we position the hinge and draw the hinge axis. Now, using the hinge axis as the center we draw a big circle to the position where we need the latch to be placed. Then, we draw a tangent line to the circle at that point and place the latch in that region.

Latch And Hinge Reinforcement:-

To furthermore reduce the impact to the occupants inside the car, additional latch and hinge reinforcement to the hood. When latch and striker are placed, there is a drop in strength at that position thus reinforcement is required. Also, stiffness pads are placed to reduce NVH. Hinge and latch reinforcement thickness is kept at 1.2 mm but it may vary.

Conclusion:-

Thus I have designed the hood of the car that satisfies the industry’s manufacturing requirements, functional requirements.