9 research outputs found
Biomechanical importance of proximal human femur morphology and mechanics in orthopaedic purposes
Bone morphology is essential in orthopedic surgery to perform precise preoperative planning and surgery as well as to appropriately design optimal medical implants. In this study we provided a database of surgically important morphological parameters of proximal human femur for orthopedic and biomedical research purposes (study 1), indicated accuracy of the 3D reconstructed images in comparison with the optical 3D scan of real human femur (study 2), and reported the accuracy and reliability of the developed image-based finite element model in comparison with the experimental results (study 3)
Fibre-reinforced additive manufacturing: from design guidelines to advanced lattice structures
In pursuit of achieving ultimate lightweight designs with additive manufacturing (AM), engineers across industries are increasingly gravitating towards composites and architected cellular solids; more precisely, fibre-reinforced polymers and functionally graded lattices (FGLs). Control over material anisotropy and the cell topology in design for AM (DfAM) offer immense scope for customising a part’s properties and for the efficient use of material. This research expands the knowledge on the design with fibre-reinforced AM (FRAM) and the elastic-plastic performance of FGLs.
Novel toolpath strategies, design guidelines and assessment criteria for FRAM were developed. For this purpose, an open-source solution was proposed, successfully overcoming the limitations of commercial printers. The effect of infill patterns on structural performance, economy, and manufacturability was examined. It was demonstrated how print paths informed by stress trajectories and key geometric features can outperform conventional patterns, laying the groundwork for more sophisticated process planning.
A compilation of the first comprehensive database on fibre-reinforced FGLs provided insights into the effect of grading on the elastic performance and energy absorption capability, subject to strut-and surface-based lattices, build direction and fibre volume fraction. It was elucidated how grading the unit cell density within a lattice offers the possibility of tailoring the stiffness and achieving higher energy absorption than ungraded lattices. Vice versa, grading the unit cell size of lattices yielded no effect on the performance and is thus exclusively governed by the density. These findings help exploit the lightweight potential of FGLs through better informed DfAM.
A new and efficient methodology for predicting the elastic-plastic characteristics of FGLs under large strain deformation, assuming homogenised material properties, was presented. A phenomenological constitutive model that was calibrated based upon interpolated material data of uniform density lattices facilitated a computationally inexpensive simulation approach and thus helps streamline the design workflow with architected lattices.Open Acces
PRELIMINARY FINDINGS OF A POTENZIATED PIEZOSURGERGICAL DEVICE AT THE RABBIT SKULL
The number of available ultrasonic osteotomes has remarkably increased. In vitro and in vivo studies
have revealed differences between conventional osteotomes, such as rotating or sawing devices, and
ultrasound-supported osteotomes (Piezosurgery®) regarding the micromorphology and roughness
values of osteotomized bone surfaces.
Objective: the present study compares the micro-morphologies and roughness values of
osteotomized bone surfaces after the application of rotating and sawing devices, Piezosurgery
Medical® and Piezosurgery Medical New Generation Powerful Handpiece.
Methods: Fresh, standard-sized bony samples were taken from a rabbit skull using the following
osteotomes: rotating and sawing devices, Piezosurgery Medical® and a Piezosurgery Medical New
Generation Powerful Handpiece. The required duration of time for each osteotomy was recorded.
Micromorphologies and roughness values to characterize the bone surfaces following the different
osteotomy methods were described. The prepared surfaces were examined via light microscopy,
environmental surface electron microscopy (ESEM), transmission electron microscopy (TEM), confocal
laser scanning microscopy (CLSM) and atomic force microscopy. The selective cutting of mineralized
tissues while preserving adjacent soft tissue (dura mater and nervous tissue) was studied. Bone
necrosis of the osteotomy sites and the vitality of the osteocytes near the sectional plane were
investigated, as well as the proportion of apoptosis or cell degeneration.
Results and Conclusions: The potential positive effects on bone healing and reossification
associated with different devices were evaluated and the comparative analysis among the different
devices used was performed, in order to determine the best osteotomes to be employed during
cranio-facial surgery
Memorias XII Congeso Colombiano de MorfologĂa Pontificia Universidad Javeriana Cali (Colombia)
Memorias XII Congeso Colombiano de MorfologĂa Pontificia Universidad Javeriana Cali (Colombia), del 29 de septiembre al 01 de octubre de 201