Hood design-Week 2

*HOOD-

-Hood is a cover that is situated in the front area of the vehicle which is to access the engine and other components.

-Generally, the hood is hinged to the front edge of the vehicle. There are two parts in a Hood i.e. Inner Panel of the Hood and the Outer Panel of the Hood. The Inner panel consists of various embossed dimensional shapes which are as per the components situated in the front area. The Outer Panel is generally made of the same material as the material used for the outer frame of the car. The outer panel is made so that the Hood looks aesthetically pleasing and in line with the design of the whole vehicle. The material used to make the hood is generally metal such as steel, aluminum, etc. Sometimes, the hood is also made up of Fiberglass or carbon fiber to reduce the weight of the vehicle and reduce the chances of getting hurt by the impact of the hood.

*HOOD DESIGN-

*The angle of the hood depends from region to region on the average height of a person in the particular region.

*It depends on the length of the supporter. There should be enough clearance between the tip of the hood and the striker

*We release the primary latch to open the hood and there should be a clearance of 10-15mm to release the secondary latch.

*We need to consider the opening angle situation. Less the angle more the chances of hitting the hood and causing an injury.

‎*All support rods have a structure that is not straight.

*Maximum curvature cannot be more than 35mm for the supporting rod. More curvature might lead to the supporting rod bending due to the weight of the hood.

*The support rod needs to be situated on the opposite side of the battery component to avoid a collision. Also, it will be difficult for the operator to mount the battery if the rod is in the same position as that of the battery position.

*Grommets are predefined parts that are present in the engine compartment as well as the hood compartment to mount the support rod.

*Other than the supporting rod a "Gas stay" can also be used. Gas stay is generally used in the back door of a car.

*In GAS STAY one end is mounted on the hood and the other end on the engine compartment. STUD BALL is used to mount the Gas stay. Also, we add a bracket to improve the strength and additional weight. The main advantage of a Gas Stay over the support rod is that there is no man force required to open the hood.

*Weight of bracket may vary around 150-200gms and the weight of the Gas stay may vary from 500-800gms since it needs to hold the hood whose weight might be around 8.5-9kg.

*Gas stay is used when hood weight and length are more since a human might not be able to lift the hood as we just need to apply the initial thrust while opening or closing the hood.

*REINFORCEMENT:-

*Whenever there is some cavity created in the hood to add the hinge or other screw parts then the strength of the material decreases and to compensate for that we add reinforcement.

*The HOOD INNER PANEL is a big reinforcement to the HOOD OUTER PANEL. Also., there is LATCH AND STRIKER REINFORCEMENT and HINGE REINFORCEMENT. Also, a STIFFENER PAD is added which is a harder sponge material with no predefined shape and is introduced between the INNER HOOD PANEL and OUTER HOOD PANEL to give reinforcement and reduce the NOISE, VIBRATION, and HARDNESS.

*The thickness of INNER AND OUTERHOOD is around 0.65-0.75mm. The thickness of REINFORCEMENT is more and might depend on the budget and requirement. It is around 1.5mm for HINGE REINFORCEMENT and 1mm for LATCH AND STRIKER REINFORCEMENT as per the CAE team's advice as per the parent car reinforcement dimensions.

*MASTIC SEAL REINFORCEMENT is used between INNER & OUTER HOOD PANEL. It provides local reinforcement up to 80mm in diameter. Position it in such a way that it covers most of the hood area. It is made up of HARD RUBBER MATERIAL. First is introduced as a paste material and when it is introduced to the hot bath inside the furnace the paste will harden enough to join the inner & outer hood panels.

*The Gap between the Inner and Outer Hood Panel will be around 5mm and will be filled with Mastic seal reinforcement.