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02.09.2022

Assemblages soudés dans RFEM 6

Dans RFEM 6, il est possible de définir des soudures linéiques sur les lignes entre les surfaces et de calculer les contraintes de soudure à l'aide du module complémentaire Analyse contrainte-déformation. Dans cet article, nous vous expliquons comment procéder.

Les assemblages soudés peuvent être définis via la boîte de dialogue « Nouvel assemblage soudé », comme le montre la Figure 1. Le choix du type d'assemblage est important pour la définition d'un assemblage soudé. Plusieurs types sont disponibles dans le programme : assemblage bout à bout, assemblage en équerre, assemblage à recouvrement et assemblage en T. Veuillez noter qu'il est également nécessaire de définir un type de soudure. The list offers different options for performing weld design checks depending on the joint type.

Les assemblages soudés peuvent être disposés « en continu » sur toute la longueur de la ligne. Ainsi, lorsque vous entrez les paramètres de soudure, vous devez assigner la « Taille de soudure » pour définir l'épaisseur de la soudure, tandis que la « Longueur de la soudure » est prise à partir de la longueur de ligne. For asymmetrical weld configurations, the position of the weld seam can be defined in relation to the connected surface (red part in the dialogue graphic). If the "Surface Normal (+z)" option is selected, the weld seam is defined on the bottom of the connected surface, whereas the "Reverse Surface Normal (-z)" option allows a definition on the top without having to reverse the surface orientation.

A line welded joint can be assigned to a line that belongs to or is integrated into the subsequently selected surfaces. The line and surface numbers may be assigned in the upper right corner of the dialog box, or by graphical selection in the working window. Please note, that the order in which the surfaces are selected is not arbitrary. By definition, the first surface is always considered to be the "connected surface" and is used for determining the stress in the weld seam.

The orientation of the weld seam is defined by the following rules:

  • w corresponds to the weld seam axis and is always identical to the x-axis of the line on which the line weld seam is defined.
  • s is orientated parallel to the z-axis of the first surface from the line weld definition (simplified method) or is parallel to the effective weld throat (directional method).
  • j is orientated orthogonally to the w-s plane.

The coordinate system of the weld seam can be activated/deactivated using the display navigator.

Une fois les assemblages soudés créés et assignés, vous pouvez définir des spécifications de base concernant l'analyse des assemblages soudés. This can be done via the Stress-Strain Analysis – Configuration tab of the same dialog box (Image 4), or via the Stress-Strain Analysis entry in the navigator (Image 5).

First, you can select the stress components relevant for your calculation. You can analyse normal stresses in the j-direction σj (corresponds to σ in EN 1993-1-8 [1]), as well as the transverse shear stresses τs (equal to τ in [1]) and longitudinal shear stresses τw (corresponds to τ according to [1]) at the critical verification points of the weld seam (for more details, please refer to ), deux nœuds. Various equivalent stresses are also available.

For stress components with defined limit stress, utilisation values are calculated in addition to the stress values. This means that stress verification checks in accordance with national codes, such as the EN 1993-1-8 [1], can be carried out with little effort.

Des options spéciales sont également disponibles dans cette boîte de dialogue. For instance, you can control the smoothing of the stresses (that is, the distribution of the local stress peaks over the weld seam length) and the stress analysis method. For weld configurations with fillet welds, the stresses can be determined with reference to the connected surface orientation (simplified method according to EN 1993-1-8 [1]) or the inclined effective weld throat (directional method according to [1]).

Weld eccentricities can be considered if relevant. This way, additional moments may occur, for example, in the case of one-sided fillet weld structures.

Une fois le calcul terminé, les contraintes dans les assemblages soudés linéiques sont disponibles sous forme graphique et sous forme de tableau. The navigator allows you to control which stresses will be graphically displayed, whereas the table provides an overview of the stresses by design situations, loading, line, and location.

The result details provide additional intermediate results such as the opening angle between the connected surfaces, the inclination angle of the effective weld throat or line weld forces per unit length M, W, V and P that provide the basis for stress calculation.


Auteur

Elle est responsable de la création d'articles techniques et fournit un support technique aux clients de Dlubal Software.

Liens
Références
  1. EN 1993-1-8 calcul des structures en acier - Partie 1-8 : Calcul des assemblages. (2010) Berlin : Beth Verlag GmbH


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