Percorrer por autor "Amaro, Ana M."
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- Comparative Analysis of Pressure Platform and Insole Devices for Plantar Pressure AssessmentPublication . Amaro, Catarina M.; Paulino, Maria F.; Valvez, Sara; Roseiro, Luis; Castro, Maria António; Amaro, Ana M.Foot plantar pressure refers to the pressure or force that the foot generates in contact with the ground, varying across different regions of the foot. This parameter is essential in static and dynamic analyses to access accurate diagnoses, study the human body biomechanics, create functional footwear designs, aid in rehabilitation and physiotherapy, and prevent injuries in athletes during sports practice. This study presents an experimental comparison between two different plantar pressure measurement devices, Pedar® (sensorized insoles) and Physiosensing® (pressure platform). The devices were selected based on their capacity to measure contact area and peak pressure points. Results showed that Physiosensing® provided a more uniform measurement of the contact area, proving its efficiency for weight distribution and stability analysis applications, particularly in posture assessment and balance studies. The Pedar® system showed higher capacity in peak pressure point detection. Therefore, the insole system is more suitable for applications requiring precise high-pressure zone localization. Comparative analysis highlights the strengths and limitations of each device and offers insights regarding its optimal usage in clinical, sports, and research settings.
- Joining of Fibre-Reinforced Thermoplastic Polymer Composites by Friction StirWelding—A ReviewPublication . Pereira, Miguel A. R.; Galvão, Ivan; Costa, José Domingos; Amaro, Ana M.; Leal, Rui M.The objective of the current work is to show the potential of the friction stir welding (FSW) and its variants to join fibre-reinforced thermoplastic polymer (FRTP) composites. To accomplish that, the FSW technique and two other important variants, the friction stir spot welding (FSSW) and the refill friction stir spot welding (RFSSW), are presented and explained in a brief but complete way. Since the joining of FRTP composites by FSSW has not yet been demonstrated, the literature review will be focused on the FSW and RFSSW techniques. In each review, the welding conditions and parameters studied by the different authors are presented and discussed, as well as the most important conclusions taken from them. About FSW, it can be concluded that the rotational speed and the welding speed have great influence on heat generation, mixture quality, and fibre fragmentation degree, while the tilt angle only has residual influence on the process. The reduction of internal and external defects can be achieved by adjusting axial force and plunge depth. Threaded or grooved conical pins achieved better results than other geometries. Stationary shoulder tools showed better performance than conventional tools. Regarding the RFSSW, it has not yet been possible to deepen conclusions about most of the welding parameters, but its feasibility is demonstrated.
- Joining of Polyethylene Using a Non-Conventional Friction Stir Welding ToolPublication . Pereira, Miguel A. R.; Galvão, Ivan; Costa, José Domingos; Leal, Rui M.; Amaro, Ana M.The objective of the current study was to butt-weld 6 mm-thick polyethylene (PE) plates by friction stir welding (FSW) using a non-conventional stationary shoulder tool. The welds were performed with an unheated shoulder and with a shoulder temperature of 85 C. Additionally, rotational speeds of 870, 1140 and 1500 rpm; welding speeds of 60 and 120 mm/min; and plunge depths of 5.5 and 5.7 mm were used. The influence of these parameters on morphology, hardness, ultimate tensile strength, elongation at break and fracture modes was evaluated. Shoulder heating proved to be crucial for the optimization of PE joints by FSW, as it clearly improved joint efficiency. Furthermore, shoulder heating promoted the reduction in internal and external defects, such as porosity and surface burning. Defect-free weld seams were obtained with higher rotational speeds and a lower welding speed. A maximum joint efficiency of about 97% was achieved with a shoulder temperature of 85 C, a rotational speed of 1500 rpm, a welding speed of 60 mm/min and a plunge depth of 5.7 mm. A weld with the average joint efficiency of 92% was produced at 120 mm/min, which based on the literature found is the highest welding speed reported that achieved a joint efficiency above 90%.