Fender Design Challenge
Fender Design
OBJECTIVE:
To design car front fender with A-Pillar, Bumper, Cowl, Drip area, and Sill Mountings with the help of Master section and data provided using the SIEMENS NX-CAD
INTRODUCTION:
FENDER:
Fender is the American English term for the 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 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.
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.
Fender mainly consists of two types,
FULL BUMPER TYPE:
- It covers more area and consumes more material compared to half bumper
- Scrap material is more compared to half bumper
HALF BUMPER TYPE:
- It covers less area and consumes less material
- In this, a single sheet can be used to produce more than one bumper
DESIGN CONSIDERATIONS:
- Embosses are provided to increase the strength
- The corner flanges are smoothened to ease the productivity of the part
- Fillet of 2-3mm is provided to avoid sharp corners and edges.
- Uniform wall thickness of 0.75 mm is maintained.
- The wheels that are outside the fender are more prone to Chipping than the wheels that are located inside the fender. Hence the wheels that are inside the fender are mostly preferred.
- Darts are provided in some areas to improve the stiffness of the mountings to avoid NVH issues.
STYLING PART:
It is the part given to design the fender with the A-Pillar, sill, cowl, bumper, and drip area mountings by the styling team.
MASTER SECTION:
- This gives complete information about designing the drip area.
- Then A-pillar, Sill, Cowl, and Bumper mountings are designed on basis of Engineering standards.
DESIGN METHODOLOGY:
The design methodology of the fender is explained with the help of a flow chart for easy and better understanding
DESIGN OF A-PILLAR/BODY MOUNTING:
Initially, the skin data provided by the styling team is to be extracted. Then the outer edge of the fender was offset inwards to a required length. By using a Trim sheet unwanted portions were trimmed out easily at required places. By using the law extension, the A-Pillar was extended and trimmed on sides to get a flat edge. Then flat Emboss is created by creating a plane and using it as a reference for Emboss creation. Sketches are drawn on the Datum plane and project to the surface. Then for creating a fastener hole that needs around a 5mm gap to stiffen it, the trim command was used. Required blends are added to all edges using a face blend.
DESIGN OF DRIP AREA MOUNTING: 
On basis of the Master section as reference drip mounting was created. The drip area must be 150mm apart from the front edge so that drip mounting won’t disturb the headlamp mounting. In the same way from backward, the drip area must be 200mm apart from the back edge to avoid the coincidence with engine cables. For creating this drip area at the required distance two planes were created and then an intersection curve was used to create the curve on the surface as required. Then remaining unwanted portions are trimmed out. The drip area was created at the required angle as provided in the master section. After creating the law extension as required by the master section the required emboss were created. Then datum plane is created for creating the flat emboss as per dimensions. Then holes are created by using a trim sheet for creating the fasteners. Required blends are created for improving the aesthetics of the fender.
DESIGN OF SILL MOUNTING:
For creating the Sill Mounting the extra portions were trimmed off. Then datum plane was created and a required sketch was drawn and projected. Some holes for placing fasteners are created and edges were blended. Embosses are created on basis of the plane for creating a flat.
DESIGN OF BUMPER MOUNTING:
Firstly, unwanted portions were trimmed off using a curve on the surface and trim surface command. Then datum plane is created for getting Flat Emboss. Sketches are drawn on a plane and projected to the surface for creating the required Emboss. Embosses for a draft are given in a way that satisfies the requirements of manufacturability. Finally required blends were applied.
DESIGN OF COWL MOUNTING:
The main requirement of Cowl mounting is to fit the splash mounting on it which protects the Engine compartment from debris that enters during driving. For placing splash their mounting areas were created with required holes for placing fasteners. Then datum plane is created for drawing sketches and projecting them onto the required surface. Using trim sheet holes are created on basis of sketches.
Views of Model:
Front View:
Side View:
Top View:
Isometric View:
CONCLUSION:
The front fender of a car is designed with A-Pillar, Bumper, Cowl, Drip, and Sill mountings with the help of the master section and data provided using the SIEMENS NX CAD.