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Experimental and numerical analysis of the response of a carbon fiber composite material to an explosion.
No full textThe aeronautical industry, in its search for more weight-efficient solutions, increasingly uses composite materials due to their specific properties. However, these are vulnerable to loads perpendicular to their lamination plane. Due to these vulnerabilities, numerous studies have tried to evaluate the threat of different states of perpendicular loading, there are numerous studies of high and low velocity impacts of rigid projectiles, the impact of non-rigid projectiles such as birds, ice, etc. have also been studied. or rubber like that of a tire. However, the study of impulsive loads on composite materials is very scarce.
In this work, a combined experimental/numerical study is presented to evaluate the response of a fabric-type CFRP to shock waves, representative of impulsive loads due to explosions. The experimental tests were carried out at the so-called 'SIMLab Shock Tube Facility (SSTF)', at the Norwegian University of Science and Technology (NTNU). Laminates were tested at different pressures to investigate their behavior from an elastic response to total failure. In addition, two high-speed cameras were used to obtain, with the 3D-DIC methodology, the displacement fields. In order to study the internal damage produced in the laminates, non-destructive ultrasonic inspection techniques were used.
To reproduce the behavior of the laminates, a continuous damage model was used, which takes into account the intralaminar damages of the composite material such as fiber breakage. Interlaminar damage was modeled using cohesive surfaces
Analysis of composite beams using reduced order modeling
No full textBeam-like components help to provide structural integrity in a wide range of applications. Initially made of alloys or natural materials such as wood, today’s technologies like pultrusion make possible the manufacturing of such components with composite materials providing good quality products with high performance to weight ratio. The anisotropic nature of composite materials, though, poses a challenging framework when numerically simulating them. This work presents the integration in standard Finite Element (FE) packages of a machine learning methodology that naturally captures the behaviour of composite materials: the multiscale method for periodic structures using domain decomposition and ECM-hyper reduction. The method provides a special type of finite element that can be assembled using FE libraries. However, the kinematics of this element may be described by more Degrees of Freedom (DoF) per node than most standard FE packages consider, hence implementing it is a non-trivial task. The strategy presented here tries to tackle the limitation by means of static condensation followed by a regression procedure. Periodic boundary conditions are employed for the extra DoFs while the regression consists in a polynomial on the logarithmic space. This paper focuses on the performance of the integrated beam element through the analysis of a pultruded omega profile whose anisotropy requires the use of complex models to accurately capture its mechanical behaviour. The agreement between the results obtained with the proposed model and those given by more complex formulations validates the methodology and enables its use in regular FE codes to characterize complex composite beam structures
DOENÇA POLICÍSTICA DO FÍGADO ASSOCIADA A DOENÇA POLICÍSTICA RENAL: RELATO DE CASO NA ATENÇÃO BÁSICA E REVISÃO DA LITERATURA
No full textA Doença Policística do Fígado (DPF) é caracterizada pela formação de múltiplos cistos hepáticos e pode se apresentar de forma isolada ou associada à Doença Renal Policística Autossômica Dominante (DRPAD). A maioria dos casos é assintomática, mas alguns pacientes desenvolvem sintomas compressivos e complicações. Este trabalho descreve um caso clínico de DPF diagnosticado incidentalmente em paciente sintomática e realiza uma revisão crítica da literatura recente, enfatizando aspectos etiológicos, fisiopatológicos e terapêuticos da doença
Machine learning-driven synthesis of multi-hazard fragility surfaces for seismic and tsunami resilience
Get PDFSeismic energy dissipation and system fragility analysis of continuous reinforced concrete highway bridges
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