Fender Design - Wheel Arch Challenge

Fender- Wheel Arch Calculation

• Fender is the part of an automobile, motorcycle or another vehicle body that frames a wheel well (the fender underside).
• Its primary purpose is to prevent sand, mud, rocks, liquids, and other roads 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.

Fender mainly are 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.

Fender wheel arch area

• The wheel arch is the semicircular part positioned above the wheel of a vehicle.
• The main factors to be considered while designing the wheel arch area are
  • The wheel should be placed inside the fender or in other words, there should be a minimum distance between the outer surface of the fender and outer surface of the wheel.
    
    • The distance ‘L’ as mentioned in the above figure should be a minimum value, which varies as per standards followed by different countries.
    • This helps to reduce the chance of chipping of the wheel with outer particles.
    • It helps in increasing pedestrian safety.
• Some of the different standards followed are
  • Japanese standards
  • European standards
  • American standards.
• Japanese standards
  • The clearance ‘L’ between the outer surface of the tire & fender in three different positions within area K as mentioned in the figure below must be greater than 5 mm
  • The value of ‘L’ shall be more than 5 mm at line 30 forward and 50 rearwards from the central vertical axis to the axis of the wheel.

• European standards
  • The clearance ‘L’ at sections at SA, SB, SC SD AND SE should be greater than 10 mm to satisfy European regulations.

• US standards
  • The clearance ‘L’ at all positions (every 10^o) from -20^o to 180^o should be greater than 5 mm to satisfy US regulations.

Fender wheel arch area calculation

• Aim: to calculate wheel arch area for the given fender as per European standards.

HOW TO CREATE LINES

• A Datum Plane is created at the outermost face of the wheel.
• A sketch is created on the new datum plane which is created.
• Horizontal line is drawn across the centre of the wheel axis.
• A perpendicular line in 90 degree is drawn from the centre of the wheel axis which is known as SA.
• Two lines of SB and SC are drawn at 30° forward from the SA and 50° rearward of SA respectively.
• A point is created at 150mm vertically above the horizontal line which coincides with the fender edge.
• A line SE is created from the centre axis of the wheel through the point which is created at 150mm.
• A midpoint is created between the SC and SE lines. Then a line SD from centre axis of the wheel is drawn through the midpoint which is created between the SC and SE.

Obtaining clearance value ‘L’ at the required sections:

A clearance distance value of ‘L’ is calculated at the required sections according to the European regulations such as SA, SB, SC, SD, SE which should be greater than or equal to 10mm.

Clearance value ‘L’ at section SA

Clearance value ‘L’ at section SB

Clearance value ‘L’ at section SC

Clearance value ‘L’ at section SD

Clearance value ‘L’ at section SE

MEASURING THE CLEARANCE VALUE ‘a’ FOR THE WHEEL GUARD REQUIREMENT:

The wheel guard requirement value ‘a’ should be greater than 5mm at a line of 30 degree forward and 50-degree rearward line from the central vertical axis of axis of wheel.

Clearance value ‘a’ at 30°-line SB:

• Clearance value ‘a’ at 30°-line SB is 44.757

Clearance value ‘a’ at 30°-line SC:

• Clearance value ‘a’ at 50°-line SC is 38.3mm.

  SECTION	L≥10M	RESULT	A≥5MM	RESULT
  SA	10	PASS	44.7	FAIL
  SB	9.9	FAIL
  SC	0.113	FAIL
  SD	2.9	FAIL	38.5	FAIL
  SE	5.8	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 should be 10mm and this design does not meet the European Regulation requirements.