scholarly journals Performance of Friction Stir Welded Tailor Welded Blanks in AA5059 and AA6082 Alloys for Marine Applications

2016 ◽  
Vol 710 ◽  
pp. 91-96
Author(s):  
Eduardo E. Feistauer ◽  
Luciano Bergmann ◽  
Jorge Fernandez Dos Santos
Keyword(s):  
Rotational Speed ◽  
Mechanical Performance ◽  
Local Strain ◽  
Tensile Tests ◽  
Image Correlation ◽  
Friction Stir ◽  
Tailor Welded Blanks ◽  
Weld Properties ◽  
Static Tensile ◽  
Marine Applications

Tailor welded blank (TWB) concepts in aluminum alloys, welded by friction stir welding (FSW), are an attractive solution to reduce structural weight of structures applied on the transportation sector. In the present work the mechanical performance and microstructural features of dissimilar friction stir welded TWBs were assessed. Welds were produced with alloys of particular interest to the shipbuilding sector (AA6082 and AA5083, with a thickness combination of 6 and 8 mm respectively) and the effect of rotational speed on the weld properties was investigated. A digital image correlation system (DIC) was used to characterize the local strain fields during the quasi-static tensile tests. Microstructure analysis revealed the presence of a remnant oxide line (ROL) at the stir zone. Moreover, the rotational speed directly affected the ROL distribution and consequently the mechanical properties of the welds. The TWB produced with low rotation speed and high force (600 rpm and 20kN) has shown the highest mechanical performance and failed at the thermo-mechanical affected zone of the AA6082 plate. The micromechanisms of fracture were assessed by SEM and revealed a ductile fracture with large amounts of dimples spread out on the fracture surface.

scholarly journals Improvement on Mechanical Properties of Submerged Friction Stir Joining of Dissimilar Tailor Welded Aluminum Blanks

2021 ◽  
Vol 2021 ◽  
pp. 1-6
Author(s):  
R. Suryanarayanan ◽  
V. G. Sridhar ◽  
L. Natrayan ◽  
S. Kaliappan ◽  
Anjibabu Merneedi ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Friction Stir Welding ◽  
Mechanical Performance ◽  
Weld Zone ◽  
Tensile Tests ◽  
Welding Parameters ◽  
Negative Effects ◽  
Friction Stir ◽  
Tailor Welded Blanks ◽  
Secondary Precipitates

Friction stir welding is a solid-state welding method that produces joints with superior mechanical and metallurgical properties. However, the negative effects of the thermal cycle during welding dent the mechanical performance of the weld joint. Hence, in this research study, the joining of aluminum tailor welded blanks by friction stir welding is carried out in underwater conditions by varying the welding parameters. The tensile tests revealed that the underwater welded samples showed better results when compared to the air welded samples. Maximum tensile strength of 229.83 MPa was obtained at 1000 rpm, 36 mm/min. The improved tensile strength of the underwater welded samples was credited to the suppression of the precipitation of the secondary precipitates due to the cooling action provided by the water. The lowest hardness of 72 HV was obtained at the edge of the stir zone which indicated the weakest region in the weld zone.

Performance of All-Polypropylene Composites at LNG Temperatures

2017 ◽  
Author(s):  
Bilim Atli-Veltin
Keyword(s):  
Composite Materials ◽  
Mechanical Performance ◽  
Cost Effective ◽  
Tensile Tests ◽  
Small Scale ◽  
Failure Behavior ◽  
Polypropylene Composites ◽  
Design Flexibility ◽  
Static Tensile ◽  
Interlaminar Shear

In the small scale LNG infrastructure, composite materials are scarcely employed. Potentially, cost effective solutions for LNG applications could be developed thanks to the advantages of composite materials over metals such as weight savings, design flexibility and recyclability. The research presented in this paper focuses on the mechanical performance of fully recyclable, thermoplastic Polypropylene (PP) composite tapes at cryogenic LNG temperatures. Quasi-static tensile tests performed on [±45] laminates made of plain woven plies of PURE® show that at −196°C the behavior is bilinear with the failure strain of 6.5% and failure stress of 37 MPa. Such non-brittle failure behavior of PP is desirable for cryogenic applications. The other results presented in the paper contains [0/90] laminate results and the interlaminar shear strength characteristics at room and cryogenic temperatures.

scholarly journals Development of High-Fidelity Imaging Procedures to Establish the Local Material Behavior in Friction Stir Welded Stainless Steel Joints

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 592
Author(s):  
S. Ramachandran ◽  
A. Lakshminarayanan ◽  
P. Reed ◽  
J. Dulieu-Barton
Keyword(s):  
Stainless Steel ◽  
High Resolution ◽  
Microstructural Characterization ◽  
Local Strain ◽  
Material Behavior ◽  
Image Correlation ◽  
Full Field ◽  
Friction Stir ◽  
2D Digital Image Correlation ◽  
304 Austenitic Stainless Steel

Friction stir welded (FSW) 304 austenitic stainless steel (SS) joints are studied using a range of microstructural characterization techniques to identify various sub-regions across the weld. A high-resolution (HR) 2D-digital image correlation (DIC) methodology is developed to assess the local strain response across the weld surface and cross-section in the elastic regime. The HR-DIC methodology includes the stitching of multiple images, as it is only possible to partially cover the FSW region using a single camera with the high-resolution optical set-up. An image processing procedure is described to stitch the strain maps as well as strain data sets that allow full-field strain to be visualized and interrogated over the entire FSW region. It is demonstrated that the strains derived from the DIC can be associated with the local weld geometry and the material microstructure in the region of the FSW. The procedure is validated in the material elastic range and provides an important first step in enabling detailed mechanical assessments of the local effects in the FSW process.

scholarly journals Deformation and damage evolution of a full-scale adhesive joint between a steel bracket and a sandwich panel for naval application

2020 ◽  
pp. 095440622094712
Author(s):  
Pankaj R Jaiswal ◽  
R Iyer Kumar ◽  
M Saeedifar ◽  
MN Saleh ◽  
Geert Luyckx ◽  
...  
Keyword(s):  
Damage Evolution ◽  
Sandwich Panel ◽  
Deformation Behaviour ◽  
Local Strain ◽  
Tensile Tests ◽  
Full Scale ◽  
Image Correlation ◽  
Cohesive Failure ◽  
Local Strains ◽  
Damage Initiation

The increasing interest for the application of adhesive joints in naval superstructures motivates researchers to gain an in-depth understanding of the mechanical behaviour and failure mechanisms of these joints. This work reports on an experimental study of the deformation behaviour and damage evolution of a full-scale multi-material joint using different instrumentation techniques. Adhesively bonded joints of steel to sandwich panel components have been subjected to quasi-static tensile tests during which the global deformation of the joint and local strain distributions were monitored using digital image correlation (DIC). During one particular tensile test, fibre optic Bragg sensors (FBG) were also applied to the specimen’s surface at different locations in order to quantify the evolution of local strains. Additionally, acoustic emission (AE) sensors were installed in order to monitor damage initiation and evolution with increasing levels of imposed deformation. This test showcased adhesive failure at the interface of the steel adherend and the adhesive, while cohesive failure was observed within the adhesive and skin failure at the interface between adhesive and the composite skin of the sandwich panel. The post-mortem observed failures modes were compared to the acoustic events that originated during the test due to damage initiation and propagation within the joint. The evolution of the different sensor signals, i.e. the damage expressed as cumulative AE energy and local strains measured with Bragg sensors and DIC, are mutually compared and acceptable correlation is found.

Modelling Microstructural Effects on the Mechanical Behaviour of a Friction Stirred Channel Aluminium Alloy

2013 ◽  
Vol 577-578 ◽  
pp. 37-40
Author(s):  
Catarina Vidal ◽  
Virgínia Infante ◽  
Yoann Lage ◽  
Pedro Vilaça
Keyword(s):  
Aluminium Alloy ◽  
Mechanical Behaviour ◽  
Bending Strength ◽  
Mechanical Performance ◽  
Tensile Tests ◽  
Single Step ◽  
Workpiece Material ◽  
Element Analysis ◽  
Friction Stir ◽  
Microstructural Effects

Friction stir channelling (FSC) is a relatively new solid-state manufacturing technology able to produce conformal channels in a monolithic plate in a single step. During the FSC process the metal workpiece material is softened by the heat energy generated from dissipation during: plastic deformation, internal material flow and frictional work between the tool and the metal workpiece. The mechanical performance of a friction stirred channel aluminium alloy is affected by microstructure surrounding the channel. A new methodology that simulates a realistic 2D microstructure from experimental metallographic characterization and tensile tests was developed using the commercial software ABAQUS to study the mechanical behaviour of the friction stirred channel 5083-H111 aluminium alloy. Fourpoint bending tests were simulated and compared with experimental results. The RambergOsgood model was also adopted in the finite element analysis. It is seen from this investigation that microstructure can significantly affect the bending strength of friction stirred channel plates.

Crystal Plasticity Simulations of Haynes 230, an Analysis of Single Crystal and Polycrystalline Experiments

2016 ◽  
Vol 258 ◽  
pp. 294-297
Author(s):  
Pietro Giovanni Luccarelli ◽  
Stefano Foletti ◽  
Garrett Pataky ◽  
Huseyin Sehitoglu
Keyword(s):  
Single Crystal ◽  
Crystal Plasticity ◽  
Local Strain ◽  
Tensile Tests ◽  
Electron Back Scatter Diffraction ◽  
Image Correlation ◽  
Model Parameters ◽  
Haynes 230 ◽  
Scale Levels ◽  
Polycrystalline Model

The behavior of a Ni-based superalloy, Haynes 230, was investigated at macro and micro scale level by means of a Crystal Plasticity (CP) model implemented in an open source Finite Element code, Warp3D. Single Crystal and polycrystalline specimens have been experimentally characterized with Digital Image Correlation (DIC) to identify the local strain field evolution. The results of single crystal’s tensile tests were used to obtain an estimation of the constitutive model parameters. Then a polycrystalline model, reproducing a tensile test with loading/unloading steps, was created starting from the microstructural data obtained with EBSD (electron back-scatter diffraction), which allowed the identification of grains geometry and orientations. The polycrystalline simulations were used to verify the prediction of the CP model over the experiment. The results of this study show that the comparison between experiments and numerical analysis is in good agreement on both global and local scale levels.

Effect of Root Flaw on Tensile Behavior of Friction Stir Welded A6061-T6 Aluminum Alloy

2012 ◽  
Vol 482-484 ◽  
pp. 1343-1349
Author(s):  
Ben Yuan Lin ◽  
Ju Jen Liu ◽  
Lee Der Lu ◽  
Hsien Lung J Tsai
Keyword(s):  
Early Stage ◽  
Testing Machine ◽  
Ccd Camera ◽  
Local Strain ◽  
Tensile Tests ◽  
Tensile Behavior ◽  
Tensile Fracture ◽  
Tensile Fracture Surface ◽  
Friction Stir ◽  
Tensile Experiment

The tensile behavior of friction stir joints containing root flaw in A6061-T6 aluminum alloys was investigated. First, plates of this material were butt-jointed by friction stir welding, and the metallographic observation and micro-hardness analysis were made on the cross-section of the weld. Then, tensile tests were performed in MTS 810 testing machine, and a digital CCD camera was used to monitor the process during testing.. Finally, the tensile fracture surface analysis was examined by scanning electron microscopy (SEM). The results show that the root flaw has no apparent effect on the tensile properties. However, it was observed that a crack about 0.3 mm in length occurred in the root part of the weld center in the early stage of tensile test, and the crack did not further propagate during the sequent tensile experiment. The tensile specimens were all fractured in the heat-affected zone (HAZ) of the retreating side, which is the area coincident with the region of maximum local strain and lowest hardness.

The effect of microfibrils cellulose modified epoxy on the quasi-static and fatigue behaviour of open hole carbon textile composites

2018 ◽  
Vol 52 (24) ◽  
pp. 3365-3380 ◽  
Author(s):  
Valter Carvelli ◽  
Toru Fujii ◽  
Kazuya Okubo
Keyword(s):  
Mechanical Performance ◽  
Fatigue Behaviour ◽  
Textile Composites ◽  
Image Correlation ◽  
Cellulose Microfibrils ◽  
Micro Computed Tomography ◽  
The Matrix ◽  
Open Hole ◽  
Static Tensile ◽  
Modified Epoxy

The extensive experimental investigation aimed to assess the effects of hybrid epoxy resin with micro-fibrillated cellulose on tensile quasi-static and fatigue behaviour of open hole carbon plain weave composites. The hybridization of the matrix allowed an improved damage tolerance of the composite leading to increase of the quasi-static tensile strength and extension of the fatigue life. The enhanced mechanical performance of the notched composites was connected to the bridging effect of cellulose microfibrils preventing or delaying the cracks propagation in the matrix and along the fibres interface. The better distribution of the stress state was assessed by digital image correlation strain maps around the hole and the imparted fatigue damage was analysed by scanning electron microscope and X-ray micro-computed tomography visualizations.

Effect of Tool Parameters on Mechanical Properties of Friction Stir Welded Aluminum Alloy

2015 ◽  
Vol 786 ◽  
pp. 111-115 ◽  
Author(s):  
Srinivasa Rao Pedapati ◽  
G. Vimalan ◽  
Mokhtar Awang ◽  
A.M.A. Rani
Keyword(s):  
Mechanical Properties ◽  
Rotational Speed ◽  
Base Material ◽  
Hardness Test ◽  
Tensile Tests ◽  
Tool Geometry ◽  
Welding Parameters ◽  
Material Strength ◽  
Friction Stir ◽  
Tool Profiles

The mechanical properties of weld joints in Friction Stir Welding (FSW) are influenced by the welding parameters such as rotational speed, tool geometry and welding speed. In the present study, three different tool profiles have been used to weld the joints with three different rotational speed and two welding speeds. Full factorial experiments have been conducted using DoE. The mechanical properties of weld joint were evaluated by means of tensile tests and hardness test at room temperature. The experiment result shows that the average highest number of hardness was 40.06 HRB with square tool at a rotational speed of 2000rpm while lowest hardness was 30.84 HRB with cylindrical threaded tool at rotational speed of 1800rpm. The maximum tensile strength of the joint obtained is 265 M Pa which is close to base material strength. It is observed from experimental results that joints made by square tool yield more strength compared to other tool profiles.

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