Automotive Fender - Wheel arch design check: European Standard

Objective:

To check the given fender wheel arch design against the European standards and to suggest necessary modifications.

Wheel arch:

It is the semi-circular edge of the fender which houses wheel-well. The wheel arch gives access to the wheel and other components attached to it. Also it allows the tilting of wheels while steering to both sides without causing any interference between wheel and body. The wheel arch is designed in such a way that it allows any possible kind of motion that the wheel can have and to prevent any materials that could fly out from the wheel during the motion. Thus it has a crucial role in pedestrian safety and the safety of other vehicles.

Need of Regulations:

In order to ensure the safety, the designs of the passenger car fenders are constrained by implementing regulations that control the wheel arch area.

There are many regulatory norms all around the world as they change with the road conditions in different regions. Now we are considering the European standards for this model.

European Standard:

There are 5 checkpoints on the sections SA, SB, SC, SD & SE as shown.

In all these checkpoints the clearance “L” should be greater than 10 mm.

Given Model:

Wheel guard should meet the above-mentioned requirement when the vehicle is in running condition and the wheels are in dead ahead position.

Section SA:

Here the measured clearance value is = 9.9490 mm

Since the clearance is less than the required 10 mm, The part fails here. The fender should be redesigned to achieve at least 0.051 mm more clearance at section SA.

Section SB:

Here the measured clearance value is = 10.00 mm

At section SB which is 30 degrees forward from the vertical, the clearance value "L" is sufficient to meet the European standard.

Section SC:

Here the measured clearance value is = -0.1139 mm

The negative value shows that the wheel's outer face is not within the outer edge of the fender.ie, The wheel is projecting out from the wheel arch.

To meet the European standards the fender should be redesigned to get at least 10.1139 mm more clearance at section SC.

Section SD

Here the measured clearance value is = -1.7926 mm

Here also we got negative clearance. So we need 11.7926 mm more clearance at section SD.

Section SE:

Here the measured clearance value is = -3.6017 mm

This much negative clearance results in a big safety issue. To meet the European requirements there must be 13.6017 mm more clearance at section SE.

Result:

The given model is analyzed according to the European standards. Since it does not meet the requirements at all sections other than SB, the deign fails and needs to be modified to have a minimum positive clearance of 10 mm at all sections.