Pinball-based Contact-Impact Model with Parabolic Elements in EUROPLEXUS

Contact-impact algorithms are an important component of numerical simulation software in fast transient dynamics. Traditionally, contact algorithms have been based on so-called sliding lines and sliding surfaces. However, sliding-based algorithms may present some difficulties in detecting contact in complex geometrical situations, especially in 3D. The pinball contact-impact method as an alternative formulation has been implemented in EUROPLEXUS, initially based upon a strong Lagrange-multiplier based solution strategy of the contact constraints. Recently, at Onera Lille (F) some crash calculations involving many contacts were attempted, initially with linear displacement continuum elements (CAR4 in 2D). However, to improve accuracy and to help mitigate spurious locking phenomena, it was desired to perform the same calculations with parabolic elements, namely by the 9-node Lagrange element Q93. The present work considers two different approaches to modeling contact with parabolic elements. The first approach uses a phantom mesh of linear-displacement elements, used only for contact detection, and superposed to the structural mesh made of parabolic elements. Such a technique is fully general and could be useful also in other special contact situations, not only with parabolic elements. The second approach is based on a (new) ‘native’ pinball formulation for the parabolic elements, which has now been developed and implemented in EUROPLEXUS.JRC.G.5-European laboratory for structural assessmen

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Editorial pour MCD 7:

Productive leisure activity among women living with breast and ovary cancer: an alternative intervention strategy to improve their subjective well-being (SWB)

This study explored the relationship between leisure engagement and the subjective well-being of women with breast and/or ovary cancer diagnosis in Portugal, Honduras and Nicaragua. A mixed methods approach was designed where 7 participants were involved in a leisure activity (assembling post-surgical bras) in a peer-based group. Furthermore, 128 participants were surveyed through a questionnaire including 7 life domains mentioned as indicators of SWB. This study gathered data regarding the social support sources of participants and their experiences with illness. In addition, the quantitative portion of the research indicated the main benefits of being engaged in a leisure activity: developing new talents, building a support network, increasing self-esteem and avoid overthinking about illness. Crucial to the preliminary data needed to implement an intervention strategy to foster SWB for women affected by BC/OC, valuable results were obtained regarding the interest of participants in textile art leisure activities. The sample from Honduras reported that 84% of its participants were interested in this activity, 74% of women from Portugal and 47% of Nicaraguans. The study confirmed there is a positive association between SWB and participating in a leisure activity. Statistically significant data was reported when correlating SWB and leisure engagement, SWB and country, and SWB and organizations in charge of supporting cancer patients. This presents empirical evidence for the usefulness of leisure activity engagement as an indicator of SWB. Future studies should consider testing the correlation between leisure domain and SWB

Productive leisure activity among women living with breast and ovary cancer: an alternative intervention strategy to improve their subjective well-being (SWB)

This study explored the relationship between leisure engagement and the subjective well-being of women with breast and/or ovary cancer diagnosis in Portugal, Honduras and Nicaragua. A mixed methods approach was designed where 7 participants were involved in a leisure activity (assembling post-surgical bras) in a peer-based group. Furthermore, 128 participants were surveyed through a questionnaire including 7 life domains mentioned as indicators of SWB. This study gathered data regarding the social support sources of participants and their experiences with illness. In addition, the quantitative portion of the research indicated the main benefits of being engaged in a leisure activity: developing new talents, building a support network, increasing self-esteem and avoid overthinking about illness. Crucial to the preliminary data needed to implement an intervention strategy to foster SWB for women affected by BC/OC, valuable results were obtained regarding the interest of participants in textile art leisure activities. The sample from Honduras reported that 84% of its participants were interested in this activity, 74% of women from Portugal and 47% of Nicaraguans. The study confirmed there is a positive association between SWB and participating in a leisure activity. Statistically significant data was reported when correlating SWB and leisure engagement, SWB and country, and SWB and organizations in charge of supporting cancer patients. This presents empirical evidence for the usefulness of leisure activity engagement as an indicator of SWB. Future studies should consider testing the correlation between leisure domain and SWB

Optimisation study of large-scale enzymatic synthesis of oleyl oleate, a liquid wax ester, by response surface methodology

An optimisation study of the large-scale enzymatic synthesis of a liquid wax ester from oleic acid and oleyl alcohol using Novozym 435 was carried out. Investigations were performed in batch mode with a stirred tank reactor (STR) with one multi-bladed impeller. Response surface methodology (RSM) based on a five-level, three-variable central composite rotatable design (CCRD) was used to evaluate the interactive effects of various parameters. The parameters are amount of enzyme (A) (90–120 g), impeller speed (B) (100–400 rpm) and temperature (C) (40–60 °C). The optimum conditions derived via RSM at a fixed reaction time of 1 h were successfully optimised as A = 104 g, B = 388.0 rpm and C = 49.7 °C. The actual experimental yield was 96.7% under the optimum conditions, which compared well with the maximum predicted value of 97.6%

Full aircraft ditching simulation by advanced fluid-structure interaction computational methods: a comparative analysis

International audienceMost of air traffic operates over water, airports are mostly located around water, and near-airport operations (such takeoff, final approach, and landing) take place above water. Fortunately emergency landings on water, comprising ditching and crash on water, do not occur frequently. However, as passenger safety under dynamic loads is of key importance in modern aerospace vehicle design, ditching analysis is an important part of the aircraft design. The landing of an airplane on water is an emergency situation that an aircraft faces only once. Loss of the aircraft is acceptable, provided the crew and passengers can safely escape and be rescued. For a water contact to qualify as a ditching, it is necessary that the touchdown follows a prudent approach and acceptable procedures. The design must provide structural integrity to protect all occupants, ensure that no excessive decelerations will be experienced by the occupants, and provide sufficient time for safe egress from a damaged aircraft (FAR 25.801 on Ditching)

Influence de l'agro-industrie sur la production de cacao au Cameroun

Le cacaoyer (Theobroma cacao) est un arbre forestier cultivé dans des systèmes agroforestier. La cacaoculture au Cameroun représente un grand intérêt commercial. Il s'agit d'un produit d'exportation fort. La filière englobe de nombreux acteurs qui ont des objectifs et des rôles différents. De nombreux événements ont forgé une histoire évolutive de cette filière, qui est aujourd'hui en pleine mutation. Cette étude propose un descriptif et une analyse de la filière en s'intéressant plus particulièrement au jeu d'acteurs entre les producteurs de fèves de cacao et les acheteurs de ces fèves, à savoir les agro-industriels et les exportateurs. Les résultats obtenus ont mis en évidence l'impact de la demande du consommateur, dernier maillon de la filière. L'intérêt que le consommateur accorde à un produit certifié a un impact direct sur les acheteurs de fèves de cacao. Ces derniers incitent ainsi les producteurs à s'orienter vers les productions certifiées. Cette certification a un impact positif sur les systèmes agro-forestiers et sur l'organisation paysanne, dessein poursuivi par le dernier maillon pour favoriser le premier maillon de la filière. (Résumé d'auteur

Full aircraft ditching simulation: a comparative analysis of advanced coupled fluid-structure computational methods

The communication concerns advanced numerical simulations of the transient fluid structure interaction occurring during aircraft ditching. While the structural model used the Finite Element method, either the Arbitrary Lagrangian-Eulerian or the hybrid Smoothed Particle Hydrodynamics Finite Element approaches were considered for the fluid model. Both computational methods were comprehensively compared using data of guided ditching experiments. The numerical results were satisfactory in terms of local pressures, local strains, and global force to consider further applications to full-scale structures. In this communication, these computational methods are applied to full spacecraft and aircraft (full-scale) ditching problems