Fender Design - Wheel Arch Challenge
Aim:
Calculate the Wheel Arch gap at required points and check whether the car passes the European standard.
Introduction:
Wheel Arch is the semi-circular part of the fender positioned above the wheel of the vehicle. The design of Wheel arch of a fender should be such that it must shield wheels and protect both passengers' compartment and pedestrians from projection of water, mud and stones. The wheel Arch area of the fender is usually designed as a cover or sheild over the tyre along its perimeter to stop any debris or stones, dirt, sand, snow etc. from getting thrown into the vehicle/ BIW area as well as outside the vehicle and onto other vehicles or pedestrians on the road. For the vehicle to has its use permit in different countries, the wheel arch of fenders must be compliant with the standards and regulations set by the respective countries.
Sectional modulus optimization of hood:
Sectional Modulus is the ratio of moment of inertia and distance between the neutral axis and extreme end.It gives the idea of how much the material is resistant to bend/ deformation. As the moment of inertia increases the sectional modulus increases and hence more is the resistant to the bend. Change is made in the design to improve the sectional modulus by varying the Y. For this emboss were given to reduce the distance between the inner and outer panel, as the distance decreases the sectional modulus increases.
Below are the images of initial and final moment of inertia.
IJISET - International Journal of Innovative Science, Engineering & Technology, Vol. 7 Issue 3, March 2020
ISSN (Online) 2348 – 7968 | Impact Factor (2019) – 6.248. The inertia is increased, which increases the sectional modulus of the hood panel. This makes the hood more resistive towards the bend. Main purpose of this analysis was to get the inertia of the hood and study of sectional modulus and improve it to withstand more loads.
Wheel Arc Verification Using European Standards:
Wheel Arc is the part of fender and semicircular part positioned above the wheel. It protects the wheel from unwanted particles and entering of those particles into the engine compartment and even provides safety for pedestrian. Requirements have been proposed by vehicle and road safety community to the minimum requirement of wheel arc distance
from the wheel for safety.
Rules –
Measure of CL L is done on sections SA, SB , SC, SD, SE.
At all sections the value of CL L should be greater that 10mm.
Wheel guard requirement : The value of a shall be more that 5mm at 300 forward and 500 rearward from the central axis of wheel.
European Standards
Wheel Arc
All the necessary distances are measured and tabulated below for analysis.
Section Clearance Measured(mm) Comments
SA- 10 Pass & SB- 10 Pass are
SC- 2.965 Fail
SD- 0.225 Fail
SE- 3.152 Fail
Negative sign indicates that the wheel arc is behind the wheel.
All the section don\'t have the CL L value at least 10mm, only SA and SB is seen to have value 10mm.
Therefore the wheel arch does not satisfy the requirements as per the European standards. So the styling team needs to work at the section of SC, SD, and SE. For safety purpose the wheel arc should be outside the wheel and the value greater that 10mm and the SD, SE part should come outside the wheel.
Japan Regulations Requirement:
- Measure clearance L of tire, hub, cap and 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 requirement: The value of ‘a’ shall be more than 5 mm at a line 30deg forward and 50deg rearward from the central vertical axis of axis of wheel.
Japan Regulation on Wheel arch
For the Japan requirement, we take 50deg on the right of the wheel and 30 deg on the left of the wheel and on this region, when we project the we will have to have a gap of minimum 5mm.
Why this requirement changing from region to region is, this regulation is fixed with respect to the region’s road condition. Japan’s government fixes this 5 mm value. Like ARAI (in India), there is a regulation team in Japan and they will be fixing this value. So, once we get our fender from the wheel data, we define the wheel center and we create a perpendicular line and that point is A, from top view and from the side view. WE project the side view line on top view. We take a 50 deg line and we project the value and we mark it. Then we take a 30deg line towards front. All these points should have minimum clearance of 5 mm and this is the region or regulation for Japan. We will have to do this study and see whether our fender is matching this requirement. If it is not matching, we will have to again go t our styling colleagues and ask them to change the curvature of the fender.
European Regulations Requirement:
Measure CL L at sections SA-SA SB-SB SC-SC SD-SD SE-SE and produce CK 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 requirement: the value of ‘a’ shall be more than 5mm at a line 30deg forward and 50 rearward from the central vertical axis of axis of wheel.
Europe Regulation on Wheel Arch
When it comes to European regulations, we will have to again take the wheel center and mark the 30 deg line and 50 deg line like what we did for Japan. We have got two pints now additionally we will have to take a 150mm intersection point from the wheel center which touches the fender edge (i.e. wheel arc) and draw a line which intersects through that point and that line will be SE. and in between 50deg line and 150mm line we will take a midpoint and draw a line from the wheel center. And on all these regions the length should 10 mm and this study we will be doing for European regulations. If our car is addressed to various market, say for Japan, Europe, and US also then we will have to take one major requirement and see the maximum value what the clearance have to be. So that we don’t prepare variations in fender. We cannot have two different fenders for one model car. so we take the maximum deviation value and use the same for all the cars.
US Regulations Requirement:
- Make clearance check details on all positions from – 100deg to 100deg and make the clearance check table.
- All values should be greater than 5mm to satisfy the regulations.
- The value of ‘a’ shall be more than 5mm at a line 30deg forward and 50deg rearward from the central vertical axis of axis of wheel.
US Regulation on Wheel Arch
In United States, we have to do the same check for every 10degfrom -20deg to 0. When we do this, we should have 5mm clearance from the length. So, if our car is prepared to three different markets, say Japan, US and Europe, we basically keep 10mm for all regions so that we satisfy all the requirements. And for Europe also checking on all the regions. So as a styling feedback, we will be giving drip area and wheel arch area. These two are important feedbacks what a fender engineer gives to styling team.
Conclusion:
From the above results, we can conclude that the given fender does not pass the European standards for wheel arch area. In this work, the major BIW components were designed using necessary design standards and consideration with CATIA software. Design of Hood involved design of inner panel with necessary reinforcements and embosses and hemmed with outer panel. Hemming involves joining of two surfaces and hemming adhesives are widely used to give improved strength, part stiffness, crash performance and corrosion protection. Mounting points of fender were designed. Roof design involved design of bow roofs and embosses on outer roof panel, heat distortion test was performed to check the design optimization. Tail gate design involved design of inner panel and hemming with outer panel. Optimization is carried out to get a safe design and to produce the part with optimal cost. It provides a unique design solution and requires less space with with compact dimension. To further reduce the cost of production and to get optimal design there is a scope for further study in optimization of design.