PSI - Issue 17

Available online at www.sciencedirect.com Structural Integrity 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

www.elsevier.com/locate/procedia www.elsevier.com/locate/procedia

ScienceDirect

Procedia Structural Integrity 17 (2019) 596–601

ICSI 2019 The 3rd International Conference on Structural Integrity Dynamic response and fatigue life of Vacuum cast Polyurethane polymer material C P Okeke a,b *, S J Brown b , M T Greenrod b , R C Lane b , A N Thite a and J F Durodola a a School of Engineering, Computing and Mathematics, Oxford Brookes University, Oxford – OX33 1HX, UK b Wipac Ltd, London Road, Buckingham, MK18 1BH, UK The objective of this paper is to measure the dynamic response transmissibility and fatigue life of vacuum cast Polyurethane (PU) polymer material used in the construction of automotive lamps. Polymers used in automotive lamps, if mass produced, are injection moulded. For ultra-low volume production, however, the cost of tooling for these traditional manufacturing methods is often very high. Hence, alternative approaches such as Silicone Tool – Vacuum (STV) casting are used. The parts produced using alternative approaches may have inferior dynamic performance. The specimens for dynamic response and fatigue testing were cut-out from a vacuum cast polyurethane plate. An instrumented beam was mounted on a shaker table and using sine sweep base excitation the dynamic response was measured. Using measured acceleration, response transmissibility was calculated. The bending fatigue properties were measured on a vibration shaker using a 4-point bending based resonance test apparatus. A series of tests were carried out to obtain average performance parameters. The dynamic response shows nonlinearity, as expected of polymers, and a large variation in dynamic properties is observed. The obtained fatigue life curve shows significant scatter at 40% fatigue load level. The assessed fracture surface micrograph of the fatigued specimens at three load levels shows surface tear at 80% and 60% load levels. Overall, the Vacuum cast polyurethane shows less fatigue performance than the conventional polymers of automotive lamps. ICSI 2019 The 3rd International Conference on Structural Integrity Dynamic response and fatigue life of Vacuum cast Polyurethane polymer material C P Okeke a,b *, S J Brown b , M T Greenrod b , R C Lane b , A N Thite a and J F Durodola a a School of Engineering, Computing and Mathematics, Oxford Brookes University, Oxford – OX33 1HX, UK b Wipac Ltd, London Road, Buckingham, MK18 1BH, UK Abstract The objective of this paper is to measure the dynamic response transmissibility and fatigue life of vacuu cast Polyurethane (PU) polymer material used in the construction of automotive lamps. Polymers used in automotive lamps, if mass produced, are injection moulded. For ultra-low volume production, however, the cost of tooling for these traditional manufacturing methods is often very high. Henc , alternative approaches such as Silicone Tool – Vacuu (STV) casting are used. The parts produced using alternative approaches may have inferior dynamic performance. The specimens for dynamic response and fatigue testing were cut-out from a vacuum cast polyurethane plate. An instrumented beam was mounted on a shaker table and using sine sweep base excitation t e dynamic response was measured. Using measured acceleration, response transmissibility was calculated. The bending fatigue properties were measured on a vibration shaker using a 4-point bending based resonance test apparatus. A series of tests were carried out to obtain average perfor ance parameters. The dynamic response shows nonlinearity, as expected of polymers, and a large variation in dynamic properties is observed. The obtained fatigue life curve shows significant scatter at 40% fatigue load level. The assessed fracture surface micrograph of the fatig ed specimens at three load levels shows surface tear at 80% and 60% load levels. Overall, the Vacuum cast polyurethane shows less fatigue performance than the conventional polymers of automotive lamps. Abstract

© 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: Fatigue life; Polyurethane; Polymer; Dynamic; Acceleration; Transmissibility; Fractograph; Response; Vacuum cast Keywords: Fatigue life; Polyurethane; Polymer; Dynamic; Acceleration; Transmissibility; Fractograph; Response; Vacuum cast

* Corresponding author. Tel.: +44-(0)1865-423011 E-mail address: 14101309@brookes.ac.uk * Correspon ing author. Tel.: +44-(0)1865-423011 E-mail address: 14101309@brookes.ac.uk

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.2019.08.080