Challenge

Fender Design

SShivaprabhu Ashok Belageri27 Sept 2022

OBJECTIVE

To design the mounting areas of front fender of BIW using the fender skin data and as per master section given using NX CAD.

FENDER

Fender is the part of an automobile vehicle body that frames a wheel well. Its primary function is to prevent sand, mud, rocks, liquids, and other road spray from being thrown into the air by the rotating tire.

When vehicle is moving, tyres pick up stones and others and hurl them in all directions. Fenders are basically present to prevent any injuries to pedestrians and contain the motion of these particles. Most passenger automobiles have four fenders, one over each wheel. For vehicles with a narrow car body that exposes the tire, the fender is an exposed curve over the top of the tire. For wide body vehicles that cover the tire, the fender forms the wheel well surrounding the tire, and is not directly visible from above the car body.

TYPES OF FENDERS

Full Bumper Type

This type of fender is not commonly used because of more scrap producing while manufacturing. The blank of steel or aluminium used to produce this type has more wastages in wheel area portion. So this type is not economically good to manufacture.

2.Half Bumper Type

This type of fenders most commonly used. The cons of full bumper type is satisfied in this design, and the blank area of wastage while producing the part is drastically reduced by scrap management. Here we use the lots of plastic on the bumper which in term decreases the cars weight and increases the performance.

FENDER WHEEL ARCH

Wheel arch is the semi-circular part of the fender positioned above the wheel of the vehicle. The design of the wheel arch of fender should be such that it must shield wheels and protect both passengers’ compartment and pedestrians from the projection of water, mud, rocks, sand.

Different countries have different wheel arch regulations in place, and the wheel arch design has to comply with them to be deemed usable in that country. This wheel arch regulations will defer from each country based on their standards and customs.

MASTER SECTION

DESIGNED FENDER

MOUNTING REGIONS ON FENDER

The front fender is manufactured as a separate part, this is then mounted to the body of car. For front fender basically, it has 5 mounting points / regions

Drip area
Bumper mount
Sill mount
Body mount
A-pillar mount

DRIP MOUNT AREA

It is the most important mounting unit of a fender. Its connected with the engine compartment and therefore a lot of design constraints are to be followed while designing the drip area. It should have sufficient clearance from the front and rear end of the fender to accommodate the cowl mounting region and headlamp housing unit respectively. A minimum of 150mm distance is kept from the front side and a distance of 300mm or less can be kept on the rear side.

The total length of drip area from the top of fender should be less than 40 mm. This is to avoid the spring back effect during manufacturing. The edge of the mounting should be atleast 10mm away from any nearby component in the engine compartment. Two darts are added on the longer side of the drip area in order to provide the stiffness and adds strength to the part. Embossing is provided on the mounting to strengthen them during fastening. Bead is provided at the outer edge to increase the rigidity of the part.

BUMPER MOUNT AREA

Bumper mounting area is used to fix the plastic bumper to the fender with the help of the fasteners.

SILL MOUNT AREA

Sill is the panel directly below the bottom of the door supporting the floor and may be used to combine the floor and the body. Sill mount area is also an important mounting part. This mounting point is basically on the bottom of the fender. The mounting part should be created such that the fender is firmly attached to the sill.

BODY MOUNT AREA

It is another mounting area created for the body side on the fender. This mounting is created such that it can be mounted on the body of the car. It may consist of one or two bolting holes.

A-PILLAR MOUNT

The A-pillar is the structural pillar that combines the body to the roof. This makes the sides of the windshield rest. A-pillar mounting area depends upon the A-pillar of the car. This mounting is critical in design as it has to be mounted on A-pillar properly.

BAFFLE MOUNT

Baffle mounting are clip fit type of mounting on the inner side of the fender arch over the tyre. It protects the car engine compartment and pedestrian’s from causing injuries from chip out debris on the road when the car in motion. They are mounted on the fender using a special type of locking clips which are made up of plastics.