This experimental study probes the dynamic behaviour of a 3mm ABS sheet during positive mould vacuum-assisted thermoforming. In this process, the sheet undergoes large and fast deformations, caused by the applied vacuum and mechanical stretching by the mould. The objective is to elucidate the complexities of these large, rapid and non-isothermal deformations. The non-isothermal conditions are caused by the radiative heating of the sheet, convective heat loss to the surrounding air and conductive heat transfer from the sheet to the mould. Utilizing stereo Digital Image Correlation (DIC) in tandem with thermal imaging, the present study accurately maps the occurring displacement, strain and strain rate field in relation to real-time temperature variation of the material. The study progresses to observe the ABS material from the moment it contacts the mould until it conforms to a positive 250mm diameter semi-sphere cast aluminium mould. The DIC methods are validated by comparing thickness values derived from DIC’s principal strain directions to ultrasonic thickness gauge readings. This knowledge not only broadens the understanding of the thermo-mechanical behaviour of the material but also aids in optimizing process parameters for improved thickness uniformity in thermoformed products.

One of the drawbacks of natural fibers and their composites is their inherent hydrophilic nature. The effect of moisture on mechanical properties of a composite is irrefutable. This study deals with hygroscopic characteristics of Enset-PLA composites and its effect on the mechanical properties of the composite. To do this, injection molded composite specimens of different fiber volume fraction; plasticizer ratio, fiber length, and fiber age have been considered. The specimens are exposed to distilled water and the moisture absorption was monitored on a daily base. Subsequently, the specimens are subjected to mechanical loading to determine the effect of moisture on their Strength, Stiffness and strain at break strength. Lastly, individual and joint effects of considered factors have been scrutinized using optimal design of experiment. The result from the study shows that maximum and minimum moisture uptake is noticed for 25% and 10% fiber ratio respectively. Due to moisture effect, tensile and bending strength is decreased by 11% and 5% respectively for 15% fiber volume fraction; while 16% and 13% for 25% fiber volume fraction respectively. Increasing amount of plasticizer increases moisture resistance. The result indicate that Enset-PLA composite have competitive properties and stability when exposed to moisture.