PSI - Issue 17

Available online at www.sciencedirect.com Structural Int grity Procedia 00 (2019) 000 – 000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2019) 000 – 000 Available online at www.sciencedirect.com ScienceDirect

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ScienceDirect

Procedia Structural Integrity 17 (2019) 886–893

ICSI 2019 The 3rd International Conference on Structural Integrity Numerical and Experimental Analysis of the Suspension Connection Zone of a Formula Student Monocoque Chassis Formiga J. a , Sousa L. a , Infante V. a ICSI 2019 The 3rd International Conference on Structural Integrity Numerical and Experimental Analysis of the Suspension Connection Zone of a Formula Student Monocoque Chassis Formiga J. a , Sousa L. a , Infante V. a Abstract This work focuses on the suspension attachment area f FST Lisboa’s formula stud nt monocoqu chassis, analysing two types of reinforcements, inserts and ch mfers, changi g some of their parameters for g ome ry improvement. A finite lement mod l was b ilt in order to set the comparison between the different geom tries, first separately nd then when i cluded in a suspensi n quarter-car assembly. The geometries with best results were selected and a laminate layup optimization was made. Lastly, for validation of the numerical m d l, four specimens of each one of the two approaches were built and a pull-out test was performed on them, with a custom develo ed apparatus. Failure modes, similar to those previ wed by theory, were achieved and a finest correlation between the experimental and n merical results was found for inserts, b tter than for chamfers, mostly due to manufacturing difficulties. The obtained results and conclusions were applied in the design and construction of the team’s new prototype monocoque. a LAETA, IDMEC, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal a LAETA, IDMEC, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal Abstract This work focuses on the suspension attachment area of FST Lisboa’s formula student monocoque chassis, analysing two types of reinforcements, inserts and chamfers, changing some of their parameters for geometry improvement. A finite element model was built in order to set the comparison between the different geometries, first separately and then when included in a suspension quarter-car assembly. The geometries with best results were selected and a laminate layup optimization was made. Lastly, for validation of the numerical model, four specimens of each one of the two approaches were built and a pull-out test was performed on them, with a custom developed apparatus. Failure modes, similar to those previewed by theory, were achieved and a finest correlation between the experimental and numerical results was found for inserts, better than for chamfers, mostly due to manufacturing difficulties. The obtained results and conclusions were applied in the design and construction of the team’s new prototype monocoque.

© 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ICSI 2019 organizers. © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ICSI 2019 organizers. © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ICSI 2019 organizers.

Keywords: sandwich structures, suspension attachment to monocoque chassis, inserts, finite element model, pull out test Keywords: sandwich structures, suspension attachment to monocoque chassis, inserts, finite element model, pull out test

1. Introduction 1. Introduction

The pursuit a target of lightest structures without despise to their safety and strength started in motorsport and easily spread into the automotive industry that is trying to include more composite materials instead of metal in their vehicles, to reduce the overall weight and, consequently, the fuel or electricity consumption, Gebhardt et al. (2014). FST Lisboa is Instituto Superior Técnico's formula student team and have been applying this type of structures in their 8 prototypes, 3 combustion and 5 electric cars. The team is heading towards a new electric one, the FST09e, their fifth car with a full carbon fibre monocoque. Despite those advantages, sandwich structures are very weak under localized loads since the honeycomb core compresses easily. Considering this, reinforcements are introduced to spread the force into a larger area. This work will explore two different reinforcements configurations that are possible to use on the suspension connection zone of a monocoque chassis. A through the thickness insert will be compared with a chamfer, The pursuit a target of lightest structures without despise to their safety and strength started in motorsport and easily spread into the automotive industry that is trying to include more composite materials instead of metal in their vehicles, to reduce the overall weight and, consequently, the fuel or electricity consumption, Gebhardt et al. (2014). FST Lisboa is Instituto Superior Técnico's formula student team and have been applying this type of structures in their 8 prototypes, 3 combustion and 5 electric cars. The team is heading towards a new electric one, the FST09e, their fifth car with a full carbon fibre monocoque. Despite those advantages, sandwich structures are very weak under localized loads since the honeycomb core compresses easily. Considering this, reinforcements are introduced to spread the force into a larger area. This work will explore two different reinforcements configurations that are possible to use on the suspension connection zone of a monocoque chassis. A through the thickness insert will be compared with a chamfer,

2452-3216 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ICSI 2019 organizers. 2452-3216 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ICSI 2019 organizers.

2452-3216  2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ICSI 2019 organizers. 10.1016/j.prostr.2019.08.118