In the present paper we are trying to establish a 3D simulation framework for Resin Transfer Molding for a laminated preform using the already developed porous media theory for composite materials process simulation purposes. The aim here is to implement the process phenomena, such as coupling of sub-processes that are happening simultaneously, in a full 3D description of the problem. For this purpose, an 8-node solid shell element is employed to be able to handle complex 3D stress-strain states. The development is exemplified considering RTM process where the main focus of the modeling will be on the flow advancement into fiber preform and flow front capturing. To this end, the theory of two-phase porous media is used along with assuming hyper-elastic material response for the fiber bed to formulate the problem. A finite element formulation and implementation of the two-phase problem is developed, and the results are presented accordingly. 

Aim of this research was determination of effects of shielding and backing gas pureness on quality of welded joints produced from austenitic stainless-steel grade X5CrNi18-10 (1.4301) pipes Ø 50.8 x 1.5 mm by orbital TIG welding without use of additional material. In the case of stainless steel, it is of importance not only to prepare shielding of the molten metal pool but as well protection of welded joint root from oxygen, which causes formation of colorful oxide layers. Presence of oxidized layer primarily decreases corrosion resistance of stainless-steel. Performed examination included: chemical composition of welded join material, delta ferrite testing, non-destructive joint testing, visual testing with discoloration assessment from face and root side (acc. to Danish Force Technology Institute report 93.34 and American ASME BPE-2012 norm), radiographic testing, destructive welded joint testing. Metallurgical shielding of the welded joint face was produced with Argon 5.0 pure, with a flow rate of 8 dm3/min. Root of welded joint was at first protected with Argon 5.0 pure, then argon-atmospheric air mixtures were used. Backing gas flow rate was set to achieve a relative pressure of 300 Pa. Quantity of residual oxygen in gas mixture was selected based on Danish Force Technology Institute report 93.34.