Fender Design - Wheel Arch Challenge

Objective: Performing Wheel arch calculation with an European Standards and prove whether the car is passed for standard or not.

Introduction

Wheel Arch: 

               The wheel arch is an arch-shaped cavity in the body of a vehicle, which houses a wheel. It has two important functions. It serves for the safety of pedestrians and other cars because the wheel is situated in the body of a vehicle. The second function is to protect the car from the sticky materials, such as mud, may adhere to the smooth outer tire surface, while smooth loose objects, such as stones, can become temporarily embedded in the tread grooves as the tire rolls over the ground. These materials can be ejected from the surface of the tire at high velocity as the tire imparts kinetic energy to the attached objects. For a vehicle moving forward, the top of the tire is rotating upward and forward and can throw objects into the air at other vehicles or pedestrians in front of the vehicle.

Types of Fender Wheel arch Regulations and standards:

JAPAN REGULATIONS:

• Measure clearance L of tire ,hub, cap & fender in three different positions within area K and produce clearance check chart to validate.
• Clearance must be greater than 5 mm in all the three positions.
• Wheel guard reqmt: The value of a shall be more than 5 mim at a line 30" forward and 50 rearward from the central vertical axis of axis of wheel.

EUROPEAN REGULATIONS:

• Measure CL L at sections SA-SA SB-SB SC-SC SD-SD SE-SE and produce CL check chart to validate.
• At all five sections the CL L value should be greater than 10 mm to satisfy the European regulations.
• Wheel guard regmt: The value of 'a shall be more than 5 mm at a line 30* forward and 50* rearward from the central vertical axis of axis of wheel.

US REGULATIONS:

• Make clearance check details on all positions from -100* to 100* & make the clearance check table.
• All values should be greater than 5 mm to satisfy the regulations. The value of 'a' shall be more than 5 mm at a line 30* forward and 50*.
• rearward from the central vertical axis of axis of wheel.

Our Analysis:

There are several regulations for Fender wheel arch design, but this analysis is according to European standards.

Analysis is done by opening part file in NX CAD and marking required lines from center of wheel to the wheel arch. Points were plotted as per European standards and then measurements were made for wheel arch from referenced points SA-SA, SB-SB, SC-SC, SD-SD, SE-SE.

The given wheel arch measurements are tabulated as below

Section	Required Clearance (L) mm	Measured clearance (L) mm	Remarks
SB	10	10	PASS
SA	10	9.94	FAIL
SC	10	0.11	FAIL
SD	10	2.87	FAIL
SE	10	5.97	FAIL

PROOF:

OBSERVATIONS: 

From above results; since, SA, SC, SD & SE distances are less than 10mm which is necessary to pass the European Standards, the design front fender wheel arch not passed the standard. 

CONCLUSION:  The styling team is required to modify the styling surface of the fender such that the clearance "L" at sections SA, SC, SD and SE is equal to ar greater than 10 mm by increasing the curvature at those sections towards outside.