Search results for "stringer"

Effect of the mutual position between weld seam and reinforcement on the residual stress distribution in Friction Stir Welding of AA6082 skin and str…

2016

Abstract In the paper, a numerical and experimental study was carried out to highlight the effect of the distance d between the weld seam and the reinforcement on the residual stress distribution in Friction Stir Welded AA6082-T6 structures. An L-shaped profile was welded to a sheet metal with varying tool rotation and distance d from the weld seam. The Cut Compliance method was used to determine the resulting longitudinal residual stress. A dedicated FE model for FSW was set up, validated and utilized to predict the longitudinal residual stress in the assembled part. The analysis allowed the identification of a few design guidelines in order to reduce the detrimental effects of the residua…

Influence of Centerline Intermetallic Stringers on Pitting Corrosion Resistance of Superduplex Stainless Steel

2021

Superduplex stainless steel UNS S32750 / EN 1.4410 is commonly used in marine environment, petrochemical, oil and gas, chemical and desalination industries, requiring materials with superior corrosion and mechanical properties. Very few residual intermetallic particles may be present under the form of centerline stringers whose effects on corrosion properties are not well documented. A previous study demonstrated the negligible influence of the intermetallic phases in centerline stringers (typically < 0.1% over thickness) on the hydrogen embrittlement susceptibility of superduplex stainless steel [1]. The present study aims at highlighting the impact of centerline intermetallic stringers on…

Caratterizzazione microstrutturale e meccanica di giunti friction skin-stringer (2024/t4-7075/t6) saldati a basso e alto apporto termico

2011

On the FSW of AA2024-T4 and AA7075-T6 T-joints: an industrial case study

2009

In this paper, the authors present the results of a wide experimental campaign on aeronautical T-shaped parts of industrial interest characterized by dissimilar materials for the skin and stringer. The friction stir welding process engineering was developed with the aim to determine the specific process parameters determining the soundness on the obtained T-parts both from the metallurgical and mechanical point of view. Furthermore, the performance of the obtained T-joints was investigated.

Material Flow in FSW of T-joints: Experimental and Numerical Analysis

2008

In the paper the authors present the results of both an experimental and a numerical campaign focused on the analysis of the occurring material flow in the FSW of T joints of aluminum alloys. In particular to investigate the metal flow experimental tests and observations has been developed utilizing a thin foil of copper as marker placed between the skin and the stringer. In this way, the actual metal flow occurring during the FSW of T-joints has been highlighted together with the real bonding surface. The acquired information is definitively useful in order to choose effective set of process parameters, improving the process mechanics and avoiding the insurgence of defects.

Improved global-local model to predict guided-wave scattering patterns from discontinuities in complex parts

2019

Ultrasonic guided-wave testing can greatly benefit from (1) an ability to provide quantitative information on the damage that is being detected, and (2) an ability to select the best mode-frequency combination for maximum sensitivity to a given type of damage. Achieving these capabilities in complex structures (e.g. nonprismatic structures such as a stiffened panel in aerospace fuselages) is a nontrivial task. This paper will discuss an improved Global-Local (GL) method where the geometrical “local” discontinuity (e.g. the stiffener) is modelled by traditional FE discretization and the rest of the structure (“global” part) is modelled by Semi-Analytical Finite Element (SAFE) cross-sectional…

Mechanical and microstructural characterization of friction stir welded skin and stringer joints

2013

A microstructural and mechanical investigation on lap joints welded by friction stir welding and made out of a 7075-T6 stringer and a 2024-T4 skin is presented. In particular, the metallurgical and mechanical properties of joints have been studied at different tool feed rates (V = 35, 50, 100 mm/min) and constant rotation speed (R = 500 r/min). Temperature distributions have been monitored during the process. It is found that in the welded area, the recrystallized zone (nugget) has an average grain size of about 3 µm and exhibits coarsened MgZn2 particles on grain boundaries. The maximum values of microhardness in the welded skin increase with the process temperature, while they just sligh…

Improved FE model for simulation of friction stir welding of different materials

2010

Abstract One of the most relevant aspects of friction stir welding is the possibility to weld different materials. In the present paper, the authors present an improved continuum finite element model for the simulation of friction stir welding processes aimed to obtain T joints, made of a stringer in AA7175-T73511 and of a skin in AA2024-T4. The model, taking into account the thermomechanical behaviours of the two different materials, is utilised to study the occurring material flow and residual stress state. Numerical results are compared with experimental observations: the model is able to predict the material flow, obtaining important information on the joint failure mode.

Theoretical elastoplastic buckling of stringer stiffened cylindrical shells

1985

Abstract A linear analysis method is offered to predict the theoretical elastoplastic buckling of stringer stiffened cylindrical shells subjected to longitudinal loading. Welding residual stresses are taken into account in the calculation, but effects of geometrical imperfections and pre-buckling displacements are ignored. The examples analysed show a good correlation between the analytical results and those obtained experimentally with stocky models of moderate geometrical imperfections.

Dissimilar titanium-aluminum skin-stringer joints by FSW: process mechanics and performance

2022

Ever since its inception, friction stir welding (FSW) is being validated by scientific investigations as an effective substitution for fusion-based conventional joining technologies. One of the main strengths of FSW is the possibility to produce dissimilar joints, even using materials extremely different in terms of thermal and mechanical properties. The goal of the present research is to investigate the feasibility of both Al-Ti skin-stringer and reversed Ti-Al skin-stringer joints, highlighting the effect of joint configuration and main process parameters on material flow and joint mechanical properties. During the investigation, the essentiality of the proper heat input through balancing