Browsing by Author "Ramalho, Armando"
Now showing 1 - 2 of 2
Results Per Page
Sort Options
- Development of a preliminary finite element model to assess the effects of friction on the residual limb of a transfemoral amputeePublication . Ramalho, Armando; Ferraz, Miguel; Gaspar, Marcelo; Capela, CarlosThe use of numerical modelling tools allows optimizing the development of complex anatomical artefacts, such as customized prostheses for lower limb amputees. These numerical tools make it possible to characterize the interfacial interactions taking place between different parts of the prosthesis and the residual limb. This allows for understanding which rectifications and fittings having to be made on the custom design of the artificial body part without the need for manufacturing and donning prostheses. To such end, current research focused on the development of a preliminary Finite Element Model to assess the effects of friction on the residual limb of a transfemoral amputee, as the friction on the contact between the soft tissues, the liner and the prosthesis of the amputee is of major importance for his/her health and comfort.
- Evaluation of the structural strength of anisotropic PLA components manufactured by 3D printingPublication . Ramalho, Armando; Freitas, Dino; Amorim Almeida, HenriquePredicting the mechanical strength of components manufactured by additive processes is a challenging task that is difficulted by the complexity of the geometries fabricated by these processes, along with the anisotropy enhanced by the layer-by-layer manufacturing method and the difficulty in quickly obtaining the elastic and strength properties of the materials, which are strongly influenced by the manufacturing parameters. The use of 3D CAD models in the design phase of components manufactured by 3D printing facilitates the use of the finite element method in assessing their strength and simulating their in-service behavior. However, the finite element analysis of 3D printed parts using anisotropic material behaviour are rare and restricted to simple geometries. To deal with the anisotropy of materials, intense research has been carried out for the last decades in the field of evaluating the mechanical strength of composite materials, introducing several specific failure criteria. In this article, the in-service behaviour of PLA components manufactured by 3D printing is simulated, applying criteria usually used in the study of composite materials to evaluate their mechanical strength. The simulation through the finite element method was developed on the Hexagon Marc/Mentat software, using the Maximum Stress and Hoffman failure criteria.