13 research outputs found

    Design, manufacturing & analysis of an ABS differential gear system model

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    Com o apoio RAADRI.This work presents the assessment of Von Mises stresses in straight-tooth bevel differential gear system of a pedagogical model. This model was designed and the straight-tooth gears were formed using a 3D printing rapid prototyping. Two different percentages of densities (60% and 100%) of printed gears with ABS (Acrylonitrile butadiene styrene) were analysed and compared. Von Mises stresses in the teeth of the gears were obtained using finite element analysis (FEA) with PTC Creo Parametric 2.0. Results showed that the manufactured gears by the method of 60% of ABS density are capable to withstand the applied forces, i.e. the allowable stress of the material is not achieved

    Experimental and Numerical Characterization of Stress-Strain Fields on Sandwich Beams Subjected to 3PB and 4PB

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    Trabalho apresentado em 18th International Conference on New Trends in Fatigue and Fracture, 17-20 julho, Lisboa, PortugalThis work aims to evaluate and characterize the stress-strain fields in sandwich beams subjected to 3PB and 4PB. The correlation between the experimental and the finite element analysis are presented and allows to a better knowledge and understanding of the complex stress-strain fields in sandwich beams when subjected to bending loading. 3D finite element models were carried out using Siemens NX10 for assessing at three- and four-point-bending tests of sandwich beams with different conditions: two lengths of span (short- and long-beam); two core thicknesses (20 and 30 mm); and two different face materials (aluminum and basalt fiber reinforced polymer). The results obtained in the 3D finite element analyses were compared with the experimental results obtained by the digital image correlation and strain gauges so that the entire stress-strain-fields through thickness is analyzed and validated. Strain results obtained via digital image correlation, strain gauges and finite element analysis are in good agreement and the strain gauges analysis are complementary to digital image correlation in order to obtain the full-field strains in the sandwich composites.N/

    Effect of Fused Filament Fabrication Processing Parameters on The Mechanical Properties of PLA Components

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    Trabalho apresentado em XVI Portuguese Conference on Fracture, 23-24 abril 2018, Covilhã, Portugalinfo:eu-repo/semantics/publishedVersio

    Flexural testing and analysis of full-strain-fields in sandwich composites

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    The objective of this work was to characterize the full-field flexural behavior of composite sandwich beams. Finite element analysis was used to estimate the behavior of sandwich beams under three- and four-point-bending tests and were compared with experimental results obtained via digital image correlation and strain-gages. Two different core thicknesses and two different sandwich lengths were used to simulate short- and long-beam. Two distinct sandwich beams were fabricated by bonding basalt fiber reinforced polymer composite face sheets (laminates) to polyurethane core and aluminum face sheets glued to polyurethane core with an adhesive film. Full-strain-fields and flexural displacements were obtained by means of strain-gages and digital image correlation technique. Experimental results were in good agreement with predictions and digital image technique attested to be a complementary method to strain-gages in experimental full-strain-fields analysis

    Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

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    Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat
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