Hood design-Week 2
Aim: - The main objective of this project is to learn the essential tools, commands, and surface modelling of Hood designing using Siemens NX Cad. This project is to develop a design idea for hood BIW that satisfies the manufacturing requirements, functional requirements, and EURO NCAP standards.
Introduction: - The hood is the engine cover that is hinged to the body of the car (front-engine automobile). It allows you access to the vehicle's engine and is also necessary for safety against a frontal collision.
The hood (North American English) or bonnet (Commonwealth English) is the hinged cover that covers the engine of a motor vehicle. Hoods on rear-engine and certain mid-engine cars can be opened to gain access to the engine compartment or trunk for maintenance and repair. Generally, the passenger car hood can be kept down by a hidden Latch. However, in a race car or aftermarket vehicle, the hoods may be kept down by a hood pin. Hoods may also have a hood scoop, wiper jets, a power bulge, and/or a hood ornament. Car hoods are normally made of steel and, on occasion, aluminium. Other materials, like carbon fibre, fibreglass, or dry carbon, can be used to create aftermarket automobile hoods. The hood design may differ from one SUV to the next. The hood is also built to meet a variety of needs. A car hood is designed to protect your vehicle's performance components, especially the engine, while also allowing for simple access for repairs and maintenance. They are quite useful in protecting both the passenger inside the automobile and the pedestrian in the case of an accident. The hood may also sustain damage.
Types of hoods support
There are two types of support available for the hood support
- Gas Stay
- Support Rod
Gas Stay
Staying with Gas A gas stay is a device that uses a gas actuator to maintain the engine hood of a car in its open position. This is mostly employed when the automobile hood is hefty. No men's might is necessary for this. Spring stays are intended for use on upward-lifting doors; once the door is slightly open, the spring will force the entry to the completely open position. Depending on the door size, Euro Fit has a variety of spring sizes.
Support Rod
A support rod is a device that employs a rod to support an automobile's open engine hood. This is often used when the weight of the car bonnet is light. We must lift the hood and install the provided support into either the hood or an engine component.
Design constraints to be followed: -
- Passenger safety
- Pedestrian safety
- Manufacturing feasibility
- Position the striker along the Trajectory of the centre of the hinge axis.
- Joining techniques of the inner and outer panels.
Passenger Safety cc
Pedestrian Safety According to the NCAP Euro evaluation, pedestrian safety must be addressed during the design process. The hood is classified into two categories based on the side reference line. The side reference line is a 45-degree angle drawn from the ground. If this line falls on the fender, the hood is inlaid; if it falls on the hood, the hood is wrapped around the hood.
Wrap-around distance defines the impact zones on the hood for children and adults. The adult head impact zone is defined as the space between the wrap-around lengths of 1000- 1500mm in the child head impact zone and 1500-2100 WAD. We know where the pedestrian would be hit; as a design engineer, we must ensure that they are exerting the least amount of force possible so that they do not sustain any injury while not jeopardising the strength of the hood, ensuring passenger safety.
The side reference line and wrap-around distance are used to establish the Head impact area. Using the head injury criterion derived using the expression, this zone will receive a red, yellow, and green grade. As a result, the inner panel was retained 25mm from the outer panel and embosses were constructed to increase the hood's strength.
Components of Hood
1. Outer Panel
2. Inner Panel
3. Hinge
4. Latch
5. Reinforcement
Conclusion
Thus, the hood is designed considering passenger and pedestrian safety as per the master section is successfully complete.