Fender Design - Wheel Arch Challenge

Fender Design - Wheel Arch Challenge

Aim :

To calculate the wheel arch gap at required points and check whether the car passes the European standard.

Objective :

• Study about the different wheel arch gap standards.
• Draw the lines at the required angle and points for the European standard.
• Measure the distance at each angles and mention given model is passes or fails European Standards.

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 passenger the pedestrains 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.

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 parameters are taken into consideration for design purpose."

Fender Wheel Arch Regulations in Different Countries -

Japan Regulations -

• The clearance "L" for tire, hub, cap and fender is to be measured within area K and create clearance check chart to validate.
• The value of L should be greater than 5mm at all positions.
• Wheel guard requirement : The value of "a" should be more than 5mm at line 30degree forward and 50degree rearwards from the central vertical axis of the 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 30degree forward and 50degree rearwards from the central vertical axis of the wheel.

US Regulations -

• Clearance "L" is to be checked at all positions from -100degree to 100degree 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 30degree forward and 50degree rearwards from the central vertical axis of the wheel.

Calculation for the given Wheel Arch gap at required points and to check whether the car passes the European standard or not -

Given -

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

From the given part file we need to open in the NX cad and from the part file they give the fender and the wheel. So, now we need to check for the European regulations standard. Now we need to create the Datum plane at the outer most face of the wheel as shown in figure.

Now Create a Sketch on the Datum Plane to check whether it Satisfies the European standards as per the european regulations as shown in the fig below -

Now for calculating the Clearance value at different sections of wheel and the fender we created intersection points in sketch b/w them & then projected it on the fender surface.

So the difference b/w the two points is Clearance as shown in the fig below-

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

As we can see in the above fig -

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

1. Clearance 'L' at point SA-SA is (L) = 9.9490mm
2. Clearance 'L' at point SB-SB is (L) = 10mm
3. Clearance 'L' at point SC-SC is (L) = - 0.1126 mm
4. Clearance 'L' at point SD-SD is (L) = - 2.4176mm
5. Clearance 'L' at point SE-SE is (L) = - 4.9589mm

Note: - The negative sign is used because the curvature of the fender-wheel arch is going down from the wheel surface.

Observation Table:

Sections	Clearance Measured (mm)	Test Result
SA	9.9490	Fail
SB	10.0000	Pass
SC	-0.1126	Fail
SD	-2.4176	Fail
SE	-49589	Fail

And For Calculating for Wheel guard requirement :

The value of "a" should be more than 5mm at line 30degree forward and 50degree rearwards from the central vertical axis of the wheel.

The Clearance Value for 'a' at 30deg and 50deg is more then 5mm

At SB = 43.1330mm > 5mm

At Sc = 38.6897mm > 5mm

Therefore it clears for Wheel Guard Requirements

All Clearance Dimensions -

Conclusion:

The given model is analysed according to the European Standards and from the above table it is clear that the fender does not pass the European standards at all sections except at section SB.

And I suggest that the model should be sent to the styling team and they should modify the curvature of the fender in such a way that there should have a minimum clearance of 10 mm.