Fender Design - Wheel Arch Challenge

FENDER DESIGN - WHEEL ARCH CALCULATION:

• AIM: To calculate the wheel arc area and decide whether the car will pass the European standards or not
• INTRODUCTION:

FENDER:

• Fender is the US English term for the part of an automobile (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.
• 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.
• Wheel wells tend to be much larger than the diameter of the tire, because they do not move with the tire suspension and consequently must be large enough to allow the full range of tire motion on the suspension without touching the interior of the wheel well.
• More elaborate designs include fender skirts for enclosing the outside edge of the wheel well, and stylized pontoon fenders for exposed fenders.
• 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:
• Wheel Arch is the semi-circular curve on the fender just above the wheels of the car
• It has some standard specifications
• For a vehicle to has its use permit in different countries, the wheel arch of the fender must compliant with the standards set by the respective countries

• TYPES OF WHEEL ARCH REGULATIONS:
  • 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.

• ANALYSIS:
  • There are different regulations in this regard based on different regions. This analysis has been done according to European Regulations.
  • The part file was opened using NX CAD and the points were plotted on the wheel arch after taking the required measurements from the wheel centre.
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• The clearance value 'L' was measured and found to be as follows

• Section	Required Clearance (mm)	Measured Clearance ‘L’ (mm)	Remarks
  B	10	10	Pass
  A	10	9.9467	Fail
  C	10	0.0486	Fail
  D	10	2.7746	Fail
  E	10	5.8277	Fail

• From the above observations the positions SA SC SD SE are less than 10mm which is necessary to pass the European standards. Hence, the front fender wheel arch does not pass the European standard.
• ‘A’ values for sections

Sl no	Section	‘a’ value
1	B	44.5774
2	A	27.8075
3	C	38.2593
4	D	47.7065
5	E	42.5761

• SUGGESTIONS TO STYLING TEAM:

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