DEVELOPMENT OF EXPERIMENTAL TECHNIQUE FOR MEASURING STRAIN AND DEFORMATION IN MANUFACTURING OF THERMOPLASTIC COMPOSITES USING AUTOMATED FIBER PLACEMENT (AFP)

摘要

Advanced thermoplastic composites have attracted the interest of aerospace industry because ofrntheir superior properties such as no shelf life, high fracture toughness, high temperaturernresistance, high fatigue performance etc. However, manufacturing methods for thermoplasticrncomposites are limited due to high viscosity of the resin which in turn requires high processrntemperatures and pressure. Automated Fiber Placement (AFP) technique has shown a greatrnpotential in manufacturing of thermoplastic composites due to the flexibility of the process inrnmanufacturing large and complex structures. Furthermore, since the heating and pressure can bernapplied simultaneously and on the go, in-situ consolidation of the part can be achieved to avoidrnautoclave process.rnHigh process temperature, high pressure and fast process rate involved in manufacturing ofrnthermoplastic composite using AFP result in a transient strain development. This strain in turnrncauses residual stress in the manufactured part. There are several experimental techniques forrnmeasuring the residual stress in thermoplastic composites, reviewed in [1]. In this paper, a newrnexperimental technique is introduced to measure transient strain during manufacturing processrnusing Digital Image Correlation (DIC) technique. This technique can provide full-field strain andrndeformation measurement of the thermoplastic composite tape as a function of time during thernheating and pressing.