Fender Design - Wheel Arch Challenge

Fender

Fender is a part of an automobile, motorcycle or other vehicle body that frames a wheel well (the fender underside). Its primary purpose is to prevent sand, mud, rocks, liquids, and other road spray from being thrown into the air by the rotating tire. Fenders are typically rigid and can be damaged by contact with the road surface.

The main purpose of fenders on cars is that they shield the wheels and they protect the passengers, the pedestrians, and the other vehicles from stones, mud, liquid, and other debris that can fly in the air because of the speeding rotating wheels while the car is running.

Fender mainly is of two types

• Full bumper type
  • It covers more area and consumes material compared to half bumper.
  • Scrap material is more compared to the half bumper.

• Half bumper type
  • It covers less area and consumes less material
  • A single sheet can be used to produce more than one bumper.

Wheel Arch

• It is a curved part of the Fender positioned right above the Wheel.
• The Wheel Arch is designed such that it protects both the pedestrian and car cabin from mud, water rocks and other road spray
• 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.
• For avoiding design alterations of the same vehicle to meet the different regulations in different countries, the maximum values of the concerned regulation parameters are taken into consideration for design purpose.

Fender Wheel Arch Regulations

Japan Regulations

> Measure cleareance L of the hub, cap & fender in 3 different locations whicth in are K and produce clearance check chart to validate.

> Clearance must be greater than 5mm in all the three positions.

> Wheel guard requirement : The values of a shall be more than 5mm at a line 30˚ forward and 50˚ reward from the central vertical axis of axis wheel.

European Regulations:

> The Clearance ‘L’ should be measured at sections SA-SA, SB-SB, SC-SC, SD-SD and SE-SE and create clearance check chart to validate

> At all the five sections the value of L should be greater than 10mm to satisfy the European Regulations

> Wheel guard requirement: The value of ‘a’ should be more than 5mm at line 30° forward and 50° rearwards from the central vertical axis of the wheel

US Regulations

> Clearance ‘L’ is to be checked at all positions from -100° to 100° and create clearance check chart to validate.

> The value of L should be greater than 5mm to satisfy the regulations.

> Wheel guard requirement: The value of ‘a’ should be more than 5mm at line 30° forward and 50° rearwards from the central vertical axis of the wheel.

Calculation of wheel arch area according to European Regulations

For calculation of clearance between Wheel Arch and Wheel we have to create a sketch on the outer most face of the wheel.

A Datum Plane is created at the outermost face of the wheel. The sketch is created on the created Datum Plane. Horizontal line is drawn across the centre of the wheel & perpendicular line SA is dropped at the centre of the wheel. Than 2 lines SB and SC are created at 30° forward of SA and 50° rearward of SA respectively. A line is created 150mm from center parallel to the center line. Fender edge curve and 150mm offset intersection point is taken as reference for creation of SE and using SE & SC by derived line command SD is created.

Obtaining the clearance L at the designated 5 points

The clearance distance 'L' is calculated at points SA-SA, SB-SB, SC-SC, SD-SD and SE-SE, which should be greater than or equal to 10mm
i) Clearance 'L' at SA-SA, L =9.9489mm

ii) Clearance 'L' at SB-SB, L=10 mm

iii) Clearance 'L' at SC-SC, L = 0.113667mm

iv) Clearance 'L' at SD-SD, L = -3.3957mm

v) Clearance ‘L’ at SE-SE, L = -7.1327mm

Measuring the clearance value 'a' for Wheel Guard Requirement

i) Clearance 'a' at 30°line SB a = 47.3026mm

ii) Clearance 'a' at 50°line SC a = 38.7192mm

Conclusion:

Section	L(>10mm)	Result	a(>5mm)	Result
SA-SA	9.95mm	Pass	47.3026mm	Pass
SB-SB	10.00mm	Pass
SC-SC	0.114mm	Fail	38.7192mm	Pass
SD-SD	-3.396mm	Fail
SE-SE	-7.133mm	Fail

From the above results we can conclude that the Fender does not pass the European Regulations, as the minimum clearance L between the Fender Wheel Arch and Wheel for vehicle and pedestrian safety is 10mm & this design does not meet the requirement.