IMPACT PROPERTIES OF THERMOPLASTIC LAMINATES FOR AUTOMOTIVE APPLICATIONS C. Santulli, R. Brooks, A.C. Long, C.D. Rudd, M.J. Wilson, N.A. Warrior School of Mechanical, Materials, Manufacturing Engineering & Management University of Nottingham University Park Nottingham NG7 2RD Abstract - This work has been developed in the University of Nottingham under the framework of the CRACTAC (Crashworthy Automotive Structures Using Thermoplastic Composites) DTI/EPSRC/Industrial Foresight Vehicle project. The impact properties of different thermoplastic laminates reinforced with commingled glass and polypropylene fibres have been investigated. The materials studied are a two-dimensional woven commingled material (Twintex), a three-dimensional commingled material (3-D Parkhill) and, for comparative purposes, a glass mat thermoplastic laminate (GMT). The laminates were selected for their interest as automotive composites. The study of impact properties has been divided into two parts. Firstly, flat plaques of the three materials were compression moulded under various moulding conditions and then subjected to a number of different impact tests (instrumented falling weight, Dart penetration and Charpy impact tests). The results of these tests are discussed in the light of the moulding conditions and quality, e.g. consolidation and voidage, and conclusions have been drawn regarding optimum moulding conditions for impact performance. Secondly, a demonstrator automotive component (side intrusion beam) has been manufactured and moulded using different laminate configurations with the three materials under investigation. The manufactured beams were impacted in a drop- weight tower. The results obtained indicate optimum beam material, lay-up configuration and moulding conditions. Conclusions are presented regarding beam design and production conditions for improved performance. INTRODUCTION Thermoplastic laminates, comprising commingled glass and polypropylene fibres, are finding increasing use in automotive applications [1, 2]. It is widely known that the energy absorption capabilities under impact loading conditions of thermoplastic composites, are, in general, superior to metallic materials and thermosetting composites [3, 4}. For this reason these materials are being considered seriously for automotive crash management applications, e.g., crash cores, frontal side impact structures. Commingled materials are usually converted into high volume automotive components using non-isothermal compression moulding. During this process, parameters such as moulding pressure, time at pressure preheat and tooling temperatures all affect the material consolidation. Previous studies, using Twintex® commingled glass/PP fabrics, have identified optimum moulding conditions for maximising static mechanical properties e.g., flexural stiffness and strength [5]. In this study, the focus is on the relationship between processing conditions and impact properties. For comparative purposes, a number of glass reinforced polypropylene composites are investigated including 2-D woven commingled fabric (Twintex®), a 3-D woven laminate and glass mat thermoplastic (GMT). Some preliminary results of the impact performance of automotive side intrusion beam demonstrator component are also presented.