A comparison of the modelling methodologies to capture the damage onset and delamination initiation in Abaqus and LS-Dyna is presented. A quasi-isotropic carbon fibre reinforced polymer laminate is modelled under a low-energy impact scenario. Hashin, Puck and Cuntze criteria are implemented for assessing intra-laminar damage in Abaqus in the linear elastic regime without damage evolution, with Virtual Crack Closure Technique being used for inter-laminar failure. In LS-Dyna, the Chang-Chang criterion is used for the intra-lamina failure with damage evolution, whereas delamination is captured using cohesive zone model and the tiebreak contact algorithm. The implementations carried out by both finite element software result in a modelling work well set to analyse and predict the impact response at the initial stages of delamination and damage within the plies. The composite damage criteria used in both finite element codes overall predict stiffer results when compared with the experimental data, however, remain in close agreement with each other.

There has been considerable interest in stratospheric airships as a cost-effective alternative to earth orbit satellites for sightseeing, aerial photography, communication and carrying weapons, etc. Many countries have plans to develop the airship owing to its greatly expected usage. The suspended curtain plays a vital role in force transmission in stratospheric airships but lacks attention. In this paper, the relationship between the optimal shape of suspended curtain and load conditions was studied through CAE Abaqus and Isight. Firstly, by using secondary development function of Abaqus, parametric FEA models of suspended curtains and envelopes have been established, several parameters were used to describe the shape of suspended curtains. Secondly, parameters of the suspended curtain shape were optimized under different loading conditions by means of the genetic algorithm. Lastly, through the analysis of the results, some conclusions are summarized: The relationship between n1(n2) and nb was found to be linear when the suspended curtain is subjected to vertical load. The stress transfer law of suspended curtain and inflatable membrane structure under the inclined load were also obtained, which are valuable for the structural engineering design of stratospheric airships..

Cet article présente un élément de coque bilinéaire enrichi, adapté à la modélisation des tôles soudées par points de soudure électrique, et implémenté sous Abaqus. L'élément de base est un élément de Simo-Rifaï en petits déplacements et en élasticité linéaire. La modélisation proposée des points de soudure s'inspire des méthodes de modélisation d'inclusion dans un milieu infini par éléments-finis étendus. Le point de soudure est considéré comme quasi ponctuel dans le milieu continu 2D de la tôle ; les fonctions d'enrichissement de l'espace d'approximation des déplacements représentent les modes de déformation locaux des tôles autour des points de soudure, et permettent de représenter correctement les déformées de tôles assemblées sans avoir à mailler les points de soudure. Des exemples démontrent la possibilité de calculer des assemblages de tôles maillées indépendamment.

Ce travail est consacré à la présentation d'une nouvelle méthodologie de prévision de l'usinage par enlèvement de copeau. Cette méthodologie est basée sur le couplage fort entre le comportement thermo-mécanique et l'endommagement ductile. Elle utilise également une adaptation de la taille des éléments en fonction de critères physiques (endommagement, plasticité, ...) et géométriques (courbures locales, ...). Cette approche est étudiée et comparée à l'approche classique basée sur le simple écoulement visco-plastique.