scholarly journals Some aspects of modelling and simulation of spot welding

2018 ◽  
Vol 178 ◽  
pp. 03006
Author(s):  
Viorel Cohal
Keyword(s):  
Welded Joints ◽  
Spot Welding ◽  
Thermal Field ◽  
Base Material ◽  
Heat Losses ◽  
Thermal Source ◽  
Thermal Processes ◽  
Element Analysis ◽  
Material Density ◽  
Composition And Structure

Mathematical modelling and finite element analysis of thermal processes, much more complex in welding different metals in terms of chemical composition and structure, have allowed investigation and deepening of heat transfer phenomena and the establishment of a new technological spot welding variant for these joints. The distribution of temperatures in welded joints is influenced by the linear energy of the thermal source, the thermal properties of the base material (heat specific heat conductivity, material density and thermal diffusivity) and heat losses to the environment. Thermal field viewing, longitudinal and transverse variations of temperature in heterogeneous welded joints, as well as temperature values recorded at different nodes (points) located in the welding area and adjacent areas, lead to conclusions that will result in specific spot welding technologies.

Assessment of Fatigue Life by FEMFAT on the Weld Configuration of Spot Welding

2008 ◽  
Vol 580-582 ◽  
pp. 625-628
Author(s):  
Bok Kyu Lim ◽  
Min Gun Kim ◽  
Ku Hyun Chung ◽  
Dong Youl Kim ◽  
Young Woo Choi
Keyword(s):  
Welded Joints ◽  
Spot Welding ◽  
Fatigue Behavior ◽  
Tensile Load ◽  
Design Criterion ◽  
Element Analysis ◽  
Single Spot ◽  
Welding Joints ◽  
The Stability ◽  
Spot Welded

The stability of plate structure is a very critical problem. The spot welding is practically designed by experiential decisions; so, it is inefficient and risks fatigue fracture. In real structure, multi-spot welded joints are more frequently used than single-spot welded joint. The fatigue behavior of multi-spot welded joints is different from that of single-spot welded joints. The fatigue lives of spot-welding specimen and multi points spot-welding structure are predicted using a FEMFAT 4.4e based on the linear finite element analysis. It is necessary to establish a reasonable and systematic design criterion for the long life design of the spot-welding body structure. In this study, relative location of spot welding was chosen as parameter and the stress distribution around the spot-welding joints’ subjected tensile load was numerically analyzed.

Fast and accurate multi-material model for the prediction of laser welded structural response

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Waseem Arif ◽  
Hakim Naceur ◽  
Sajjad Miran ◽  
Nicolas Leconte ◽  
Eric Markiewicz
Keyword(s):  
Shell Model ◽  
Welded Joints ◽  
Equivalent Plastic Strain ◽  
Base Material ◽  
Structural Response ◽  
Material Model ◽  
Von Mises Stress ◽  
Computational Time ◽  
Element Analysis ◽  
Content Type

Purpose The purpose of this study is to develop an elasto-plastic multi-material shell model by which finite element analysis of laser welded joints is carried out at the interface of the heat-affected zone and base material. Design/methodology/approach The multi-material shell model is implemented on the simple cantilever and double cantilever welded plates to examine the efficiency of the developed model. Findings By reducing the computational time approximately 20 times with the developed model, the results obtained in the form of von Mises stress and equivalent plastic strain are found in good agreement as compared with the reference solid model. Originality/value The accurate and fast prediction of the stresses and strains in the laser welded joints, and the developed multi-material model is helpful to simulate complex industrial welded structures.

Microstructure of resistance spot welding of maraging steels

1990 ◽  
Vol 48 (4) ◽  
pp. 900-901
Author(s):  
I. Neuman ◽  
S.F. Dirnfeld ◽  
I. Minkoff
Keyword(s):  
Maraging Steel ◽  
Spot Welding ◽  
Lath Martensite ◽  
Base Material ◽  
Aging Treatment ◽  
High Strength ◽  
Maraging Steels ◽  
Heat Treated ◽  
Current Cycle ◽  
Welding Processes

Experimental work on the spot welding of Maraging Steels revealed a surprisingly low level of strength - both in the as welded and in aged conditions. This appeared unusual since in the welding of these materials by other welding processes (TIG,MIG) the strength level is almost that of the base material. The maraging steel C250 investigated had the composition: 18wt%Ni, 8wt%Co, 5wt%Mo and additions of Al and Ti. It has a nominal tensile strength of 250 KSI. The heat treated structure of maraging steel is lath martensite the final high strength is reached by aging treatment at 485°C for 3-4 hours. During the aging process precipitation takes place of Ni3Mo and Ni3Ti and an ordered solid solution containing Co is formed.Three types of spot welding cycles were investigated: multi-pulse current cycle, bi-pulse cycle and single pulsle cycle. TIG welded samples were also tested for comparison.The microstructure investigations were carried out by SEM and EDS as well as by fractography. For multicycle spot welded maraging C250 (without aging), the dendrites start from the fusion line towards the nugget centre with an epitaxial growth region of various widths, as seen in Figure 1.

scholarly journals Shoulder Related Temperature Thresholds in FSSW of Aluminium Alloys

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4375
Author(s):  
David G. Andrade ◽  
Sree Sabari ◽  
Carlos Leitão ◽  
Dulce M. Rodrigues
Keyword(s):  
Heat Generation ◽  
Process Parameters ◽  
Rotational Speed ◽  
Aluminium Alloys ◽  
Spot Welding ◽  
Base Material ◽  
Main Process ◽  
Welding Temperature ◽  
Friction Stir ◽  
Tool Diameter

Friction Stir Spot Welding (FSSW) is assumed as an environment-friendly technique, suitable for the spot welding of several materials. Nevertheless, it is consensual that the temperature control during the process is not feasible, since the exact heat generation mechanisms are still unknown. In current work, the heat generation in FSSW of aluminium alloys, was assessed by producing bead-on-plate spot welds using pinless tools. Coated and uncoated tools, with varied diameters and rotational speeds, were tested. Heat treatable (AA2017, AA6082 and AA7075) and non-heat treatable (AA5083) aluminium alloys were welded to assess any possible influence of the base material properties on heat generation. A parametric analysis enabled to establish a relationship between the process parameters and the heat generation. It was found that for rotational speeds higher than 600 rpm, the main process parameter governing the heat generation is the tool diameter. For each tool diameter, a threshold in the welding temperature was identified, which is independent of the rotational speed and of the aluminium alloy being welded. It is demonstrated that, for aluminium alloys, the temperature in FSSW may be controlled using a suitable combination of rotational speed and tool dimensions. The temperature evolution with process parameters was modelled and the model predictions were found to fit satisfactorily the experimental results.

Creep Modeling of Welded Joints Using the Theta Projection Concept and Finite Element Analysis

1999 ◽  
Vol 122 (1) ◽  
pp. 22-26 ◽  
Author(s):  
M. Law ◽  
W. Payten ◽  
K. Snowden
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
High Temperature ◽  
Welded Joints ◽  
Creep Model ◽  
Projection Data ◽  
Predictive Capability ◽  
Element Analysis ◽  
High Temperature And Pressure ◽  
Temperature And Pressure

Modeling of welded joints under creep conditions with finite element analysis was undertaken using the theta projection method. The results were compared to modeling based on a simple Norton law. Theta projection data extends the accuracy and predictive capability of finite element modeling of critical structures operating at high temperature and pressure. In some cases analyzed, it was found that the results diverged from those gained using a Norton law creep model. [S0094-9930(00)00601-6]

Sheet Material Property Effects upon Dynamic Behavior in Self-Pierce Riveted Joints

2011 ◽  
Vol 675-677 ◽  
pp. 999-1002 ◽  
Author(s):  
Xiao Cong He
Keyword(s):  
Natural Frequency ◽  
Transverse Vibration ◽  
Spot Welding ◽  
Sheet Material ◽  
Vibration Characteristics ◽  
Efficient Design ◽  
Material Density ◽  
Sheet Materials ◽  
Riveted Joints ◽  
Free Transverse Vibration

Self-pierce riveting (SPR) technology offers an alternative to resistance spot welding (RSW) for joining sheet materials. It has been found that the SPR technology produced a much stronger joint than the RSW in fatigue test. For efficient design of SPR structures, the knowledge of dynamic characteristics of the SPR beams is essential. In this paper, the free transverse vibration characteristics of single lap-jointed cantilevered SPR beams are investigated in detail. The focus of the analysis is to reveal the influence on the natural frequency and natural frequency ratio of these beams caused by variations in the material properties of sheet materials to be jointed. It is shown that the transverse natural frequencies of single lap jointed cantilevered SPR beams increase significantly as the Young’s modulus of the sheet materials increases, but change slightly corresponding to the change in Poisson’s ratio. It is also found that the material density of the sheets have significant effects on the free transverse vibration characteristics of the beams.

scholarly journals Microstructure and Mechanical Properties of Modern 11%Cr Heat-Resistant Steel Weld Joints

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3430
Author(s):  
Grzegorz Golański ◽  
Jacek Słania ◽  
Marek Sroka ◽  
Paweł Wieczorek ◽  
Michał Urzynicok ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Welded Joints ◽  
Martensitic Steel ◽  
Base Material ◽  
Hardness Measurement ◽  
Power Industry ◽  
Strength Properties ◽  
Typical Structure ◽  
Δ Ferrite ◽  
The Impact

In addition to good high-temperature creep resistance and adequate heat resistance, steels for the power industry must have, among other things, good weldability. Weldability of such steels is one of the criteria determining whether or not the material is suitable for applications in the power industry. Therefore, when materials such as martensitic steel Thor 115 (T115) are introduced into the modern power industry, the quality and properties of welded joints must be assessed. The paper presents the results of metallographic and mechanical investigations of T115 martensitic steel welded joints. The analysis was carried out on joints welded with two filler metals: WCrMo91 (No. 1) and EPRI P87 (No. 2). The scope of the investigations included: microstructural investigations carried out using optical, scanning and transmission electron microscopy and mechanical testing, i.e., Vickers microhardness and hardness measurement, static tensile test and impact test. The macro- and microstructural investigations revealed correct structure of the weld, without welding imperfections. The microstructural investigations of joint No. 1 revealed a typical structure of this type of joint, i.e., the martensitic structure with numerous precipitates, while in joint No. 2, the so-called Nernst’s layers and δ-ferrite patches were observed in the weld fusion zone as well as the heat affected zone (HAZ). The mechanical properties of the test joints met the requirements for the base material. A slight influence of the δ-ferrite patch on the strength properties of joint No. 2 was observed, and its negative effect on the impact energy of HAZ was visible.

Fabrication of Magnesium-Silicon Nanocomplexes by the Interaction of Polyphenylsiloxane with Magnesium Carbonate

2021 ◽  
Vol 1045 ◽  
pp. 32-39
Author(s):  
Nikolai Shapkin ◽  
Natalia Maslova ◽  
Evgeniy Papynov ◽  
Vladimir Kaminskii ◽  
Alevtina Kapustina ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Mechanochemical Activation ◽  
Magnesium Carbonate ◽  
Polymer Yield ◽  
Element Analysis ◽  
Exchange Method ◽  
Composition And Structure ◽  
Ion Exchange Method ◽  
Heating Up ◽  
Repeated Precipitation

The interaction of magnesium carbonate with polyphenylsiloxane under the conditions of mechanochemical activation with subsequent heating has been investigated. Based on the TGA and DTA data, it has been shown that, upon heating up to 420°C, the reaction proceeded completely with the release of carbon dioxide. The polymer was dissolved in DMFA and purified by repeated precipitation with water. The polymer yield was 64%. The residue insoluble in organic solvents has been obtained by evaporation of an aqueous solution. The composition and structure of the synthesis products have been analyzed by means of element analysis, IR spectroscopy, and diffractometry. It has been demonstrated that the fraction soluble in DMFA had a silicon-to-magnesium ratio equal to 4.2, while the fraction isolated from water had this ratio equal to 1.0. The IR and XRD data enabled one to conclude that, regardless of the different compositions, the structures of all fractions were similar and corresponded to mesomorphic layered polymers produced by the ion exchange method.

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