Mechanical Designs

Roller Bearing assembly

Rear wing mounting assembly

Connecting Rod

Spur gear

Three-arm flange

FEA Simulation

Design of a impact attenuator

Introduction

This study focuses on evaluating the design of an attenuator intended to protect a chassis that encloses a battery, fuel cell, and hydrogen pressure vessels. The chassis is engineered to limit deflection to a maximum of 5 mm under frontal and lateral impacts from a 1300 kg body moving at 4 m/s. Accordingly, the attenuator must significantly reduce the velocity—and therefore the kinetic energy—of the impactor, particularly under more severe conditions where speeds may reach 13.86 m/s.

Design strategy

  • Chassis: sandwich laminate using IGF-31 Blatz-Ko Foam, the skin are made of IM6/Epoxy unidirectional composite.
  • Reinforcements: AS4/PEEK unidirectional, modeled with the Enhanced Composite Damage method and a thickness of 0.0002 [m].
  • Attenuator: material must be expandable, lightweight, cost-effective, and have favourable buckling properties to enhance energy absorption during collisions. Therefore, Aluminium 7020 was selected. 
  • Impact structure: defined as a Rigid Material, this material does not deform, which is ideal for reducing computational cost and simulation time.

Challenges:

  • Contacts: follows the contact diagram order. 
  • Bolts: represented as 42 CBUSH-type springs with a stiffness of 45e+6 N/m. This method is an approximation to simulate the effect of bolts.

Results:

During the results, the chassis enveloppe presented a design flaw which needed reinforcements. Combined with the aluminium impact attenuator, the impact structure presented a rebound while the chassis maximum deflection reached a maximum of 5mm.

CFD Simulation

Development of a GT3 aero package

Introduction:

A CFD analysis is performed to understand the impact of aerodynamic components on vehicle performance. To this manner, a aero-package was developed for the DrivAer model that included a rear wing, a diffuser and  a splitter. 

With the objective of achieving a drag-area product of CDA = 1.02 and maximizing aerodynamic efficiency (CL/CD).

Design and mesh study:

  • Aero-package: the design was dispatch between 3 designers. My contribution relied on the development of the floor section with the installation of a diffuser and the floor edges.
  • Mesh: making sure that the total blockage is under 1%, the mesh is refined in the high gradient regions. Using a structured mesh widely used in automotive simulation and a 6 layers of the 0.016m Prism Layer.

Results:

The iteration process shows tremendous aerodynamic performance compared to the reference model. the better flow and vortex management in the wake structure allowed to drastically reduce the drag contribution of the car. Downforce on the other hand was importandly increase with the floor producing 613N being the major contributor to the total 407N. this important contribution is due to the development of a vortex all along the floor generated by the front splitter and helping flow attachment on the diffuser. 

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