Non-Intrusive model coupling: A flexible way to handle local geometric and mechanical details in FEA

Computer Aided Engineering (CAE) often involves structural mechanics analysis (most of the time using the finite element method). When dealing with nonlinear complex models on large 3D structures, the computational cost becomes prohibitive. In this paper, we present the recent developments linked to an innovative computing method: non-intrusive coupling. Such a method allows to efficiently taking into account local modifications on an initial existing model in a non-intrusive way: the previously computed analysis is left unchanged. Large scale linear models can thus be easily computed, then localised nonlinear complex models can be used to pinpoint the analysis where required on the structure. After a presentation of the scientific context and a description of non-intrusive coupling methods, we will present its application to crack growth simulation and parallel structure analysis

Local/global non-intrusive parallel coupling for large scale mechanical analysis

The permanent increase in available computing resources can achieve more and more ambitious numerical simulations (most of the time using the finite element method). When dealing with non-linear complex models on large 3D structures, the computational cost becomes prohibitive. In this paper, we present the recent developments linked to an innovative computing method: non-intrusive coupling. Such a method allows to efficiently take into account local modifiations on an initial existing model in a non-intrusive way: the previously computed analysis is left unchanged. Large scale linear models can thus be easily computed, then localised non-linear complex models can be used to pinpoint the analysis where required on the structure. After a presentation of the scientific context and a description of non-intrusive coupling methods, we will present its application to crack growth simulation and parallel structure analysis

Non-intrusive Coupling: Recent Advances and Scalable Nonlinear Domain Decomposition

This paper provides a detailed review of the global/local non-intrusive coupling algorithm. Such method allows to alter a global finite element model, without actually modifying its corresponding numerical operator. We also look into improvements of the initial algorithm (Quasi- Newton and dynamic relaxation), and provide comparisons based on several relevant test cases. Innovative examples and advanced applications of the non-intrusive coupling algorithm are provided, granting a handy framework for both researchers and engineers willing to make use of such process. Finally, a novel nonlinear domain decomposition method is derived from the global/local non-intrusive cou- pling strategy, without the need to use a parallel code or software. Such method being intended to large scale analysis, we show its scalability. Jointly, an efficient high level Message Passing Interface coupling framework is also proposed, granting an universal and flexible way for easy software coupling. A sample code is also given

Surgical Stabilization for Multiple Rib Fractures: Whom the Benefit? -A Prospective Observational Study

Background: Surgical repair has demonstrated a beneficial effect on outcome for patients presenting with flail chest or with multiple rib fractures. We hypothesized that benefit on outcome parameters concerns predominantly patients being extubated within 24 hours post-operatively. Methods: We prospectively recorded all patients presenting with chest traumatism eligible for surgical repair with anticipated early extubation according to our institutional consensus (flail chest, major deformity, poor pain control, associated lesions requiring thoracotomy). We compared outcomes of patients extubated within 24 hours post-operatively to those who required prolonged ventilator support. We tested predictive factors for prolonged intubation with univariate and multivariate analysis. Results: From 2010 to 2014, 132 patients required surgical repair. Two thirds were extubated within 24 hours following surgical repair. Pneumonia was the main complication and occurred in 30.3% of all patients. Patients extubated within 24 hours following surgical repair had significantly shorter ICU stay and shorter in-hospital stay (P<0.0001 both). Pneumonia occurred significantly more often in patients with longer mechanical ventilation (over 24 hours) (P<0.0001) and the overall post-operative complications rate was higher (P=0.0001). Main independent risk factors for delayed extubation were bilateral chest rib fractures and initially associated pneumothorax. Conclusions: We conclude that patients extubated within 24 hours after repair have an improved outcome with reduced complication rate and shorter hospital stay. The initial extent of the trauma is an important risk factor for delayed extubation and high complication rate despite surgical stabilization

A method to replace lightning strike tests by ball impacts in the design process of lightweight composite aircraft panels

Composite material aircrafts are protected against lightning on the basis of complex and expansive lightning strike experimental plans aiming at designing optimal protections. The paper aims at reducing the number of lightning strike tests on protected and painted composite panels. An analytical calculation is presented that gives the characteristics of an equivalent mechanical impact configuration based on an assessment of the typical time scale of energy deposit and kinematic behaviour during a lightning strike test. The paper presents our analytical hypotheses and calculations, as well as experimental lighting strikes and mechanical impact settings and results. The method is shown to give an acceptable approximation of both the kinematics and the delamination surface

Biomarker-Based HIV Incidence in a Community Sample of Men Who Have Sex with Men in Paris, France

BACKGROUND: Population-based estimates of HIV incidence in France have revealed that men who have sex with men (MSM) are the most affected population and contribute to nearly half of new infections each year. We sought to estimate HIV incidence among sexually active MSM in Paris gay community social venues. METHODOLOGY/ PRINCIPAL FINDINGS: A cross-sectional survey was conducted in 2009 in a sample of commercial venues such as bars, saunas and backrooms. We collected a behavioural questionnaire and blood sample. Specimens were tested for HIV infection and positive specimens then tested for recent infection by the enzyme immunoassay for recent HIV-1 infection (EIA-RI). We assessed the presence of antiretroviral therapy among infected individuals to rule out treated patients in the algorithm that determined recent infection. Biomarker-based cross-sectional incidence estimates were calculated. We enrolled 886 MSM participants among which 157 (18%) tested HIV positive. In positive individuals who knew they were infected, 75% of EIA-RI positive results were due to ART. Of 157 HIV positive specimens, 15 were deemed to be recently infected. The overall HIV incidence was estimated at 3.8% person-years (py) [95%CI: 1.5-6.2]. Although differences were not significant, incidence was estimated to be 3.5% py [0.1-6.1] in men having had a negative HIV test in previous year and 4.8% py [0.1-10.6] in men having had their last HIV test more than one year before the survey, or never tested. Incidence was estimated at 4.1% py [0-8.3] in men under 35 years and 2.5% py [0-5.4] in older men. CONCLUSIONS/ SIGNIFICANCE: This is the first community-based survey to estimate HIV incidence among MSM in France. It includes ART detection and reveals a high level of HIV transmission in sexually active individuals, despite a high uptake of HIV testing. These data call for effective prevention programs targeting MSM engaged in high-risk behaviours

Vers une nouvelle érudition : numérisation et recherche en histoire du livre

En décembre 1999, à l\u27Enssib, s’est déroulé le colloque "Vers une nouvelle érudition : numérisation et recherche en histoire du livre", organisé dans le cadre des 12e Entretiens du Centre Jacques Cartier sous la responsabilité de Dominique Varry (enssib), Annie Charon (école nationale des chartes) et Guylaine Baudry (Université de Montréal)

Tests & Documentation - Les bonnes pratiques de la programmation avec Python

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Introduction à la programmation orientée objet - Comment créer ses propres structures en Python ?

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