Experimental and Finite Element Nonlinear Dynamics Analysis of Formula SAE Impact Attenuator

Abstract

Energy absorption and weight are major concerns in the design of an impact attenuator. To reduce the costs involved in the design and development of a new attenuator, it is important to minimise the time spent in the development and testing phase. The aim of this paper is to report on a study that used computer dynamic simulation to analyse the energy absorption and damage in a new impact attenuator. All initial requirements of the new attenuator were set in accordance with the 2011 Formula SAE rules. In this study, a nonlinear dynamic finite element was used to simulate an FSAE impact attenuator crash against a rigid barrier. Geometrical and material nonlinearities were performed using ABAQUS/Explicit commercial code. The numerical model was verified by experimental tests. Agreement between the numerical simulations and the test results showed that finite element analysis could be used effectively to predict the energy absorption and damage performance of an impact attenuator.

List of Symbols

τ ₁, τ ₂

Time instant

δEα

Virtual kinetic force

δTα

Internal force

δWα

External forces

V

Volume occupied by a part of the body in the current configuration

S

The surface bounding in the volume

ρ

Material density

${f^{{({V_{\alpha }})}}}$

Externally applied forces per unit volume

${f^{{(S_{\sigma}^{{(\alpha )}})}}}$

Externally applied surface traction per unit surface area

σ

Cauchy stress tensor field

ε

Conjugate strain tensor

u

Displacement

ü

Accelerations

$\bar{u}$

Velocities

$\delta \prod_{\alpha}^{cont }$

Virtual contact work

δ

Arbitrary, virtual and compatible variation

$\delta {{\bar{g}}_N}$

Variation in gap

$\delta {g_T}$

Variation in tangential displacement

${g_N}$

Gap

${g_T}$

Relative displacement in a tangential direction

${{\bar{g}}_T}$

Relative sliding velocity

${t_T}$

Tangential stress vector

${t_N}$

Contact force

τ _crit

Threshold of tangential contact traction for tangential slip

${\upvarepsilon_N}$

Penalty parameter

${{\bar{n}}^1}$

Normal vector

${{\bar{x}}^1}$

Deformation of the master surface

x ²

Deformation of the slave surface

${\rm S}_c^{(1) }$

Master surface

$S_c^{(2) }$

Slave surface