scholarly journals Finite Element Modelling of Laser Stitch Welding Joints for Structural Dynamic Predictions

2019 ◽  
Vol 16 (2) ◽  
pp. 6556-6567
Author(s):  
M. A. S. Aziz Shah ◽  
M. A. Yunus ◽  
M. N. Abdul Rani ◽  
M. S. Mohd Zin ◽  
W. I. I. Wan Iskandar Mirza
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Dynamic Behaviour ◽  
Welding Process ◽  
Shell Element ◽  
High Strength ◽  
Mode Shapes ◽  
Finite Element Models ◽  
Structural Dynamic ◽  
Welded Structure

Laser stitch welding is a joining technique that has been increasingly popular in automotive industries, such as in the manufacturing and assembling of the car’s body-in-white (BiW) due to its advantages over the resistance spot weld, such as low heat application and high strength weld. The dynamic behaviour of a laser stitch welded structure is relatively difficult to predict accurately due to local parameters being induced during the laser welding process, such as heat affected zone (HAZ) and residual stress in the welded structure. This paper presents the idea of modelling the laser stitch weld by investigating different types of element connectors that can be used to represent laser stitch weld, such as rigid body element (RBE2), shell element (CQUAD4), bar element (CBAR) and area contact model (ACM2) format of element connectors. The accuracy of finite element models of laser stitch welded joints is compared in terms of natural frequencies and mode shapes with the experiment counterparts. The dynamic behaviour of the measured structure is obtained by using an impact hammer with free-free boundary conditions. It is found that the accuracy of the finite element models of the laser stitch welded structure highly depends on the involvement of residual stress and the heat affected zones that are generated from the welding process.

scholarly journals The effect of laser stitch welding residual stress on the dynamic behaviour of thin steel structure

2019 ◽  
Vol 13 (4) ◽  
pp. 5780-5790
Author(s):  
M. A. S. Aziz Shah ◽  
M. A. Yunus ◽  
M. N. Abdul Rani ◽  
A. M. Saman ◽  
M. S. M. Sani ◽  
...  
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Welding Process ◽  
Steel Structure ◽  
Welding Residual Stress ◽  
Mode Shapes ◽  
Finite Element Models ◽  
Welded Structures ◽  
Welded Structure ◽  
Thin Steel

Laser stitch welding is one of the most reliable and efficient permanent metal joining processes in the automotive industry, particularly in the manufacturing of a car body-in-white (BIW). It is widely known that this welding process induces the generation of residual stresses that can influence the dynamic behaviours of welded structures. In order to accurately predict the dynamic behaviours of these welded structures, it is important to experimentally understand the influence of residual stress. Therefore, this study addresses the finite element modelling method of thin steel welded structures with and without the influences of residual stress in order to identify its effect towards dynamic behaviours. The finite element models of thin steel welded structures are developed by employing the area contact model (ACM2) format element connector.  The accuracy of the finite element models is then compared in terms of natural frequencies and mode shapes with the experimental counterparts. The dynamic behaviours of the measured structure are obtained using an impact hammer with free-free boundary conditions. The results demonstrate the importance of considering the influence of laser stitch welding residual stress in predicting the dynamic behaviours of thin steel welded structure.    

Contrastive Study on Finite Element Models of High-Strength Pipelines Crossing Active Faults

2016 ◽  
Vol 850 ◽  
pp. 957-964
Author(s):  
Wei Zheng ◽  
Hong Zhang ◽  
Xiao Ben Liu ◽  
Le Cai Liang ◽  
Yin Shan Han
Keyword(s):  
Finite Element ◽  
Design Method ◽  
Active Faults ◽  
Shell Element ◽  
High Strength ◽  
Element Model ◽  
Beam Element ◽  
Finite Element Models ◽  
Fixed Boundary ◽  
Equivalent Boundary

There is a potential for major damage to the pipelines crossing faults, therefore the strain-based design method is essential for the design of buried pipelines. Finite element models based on soil springs which are able to accurately predict pipelines’ responses to such faulting are recommended by some international guidelines. In this paper, a comparative analysis was carried out among four widely used models (beam element model; shell element model with fixed boundary; shell element model with beam coupled; shell element model with equivalent boundary) in two aspects: differences of results and the efficiency of calculation. The results show that the maximum and minimum strains of models coincided with each other under allowable strain and the calculation efficiency of beam element model was the highest. Besides, the shell element model with beam coupled or equivalent boundary provided the reasonable results and the calculation efficiency of them were higher than the one with fixed boundary. In addition, shell element model with beam coupled had a broader applicability.

scholarly journals Effect of applied load on welding stress at different time periods

2018 ◽  
Vol 224 ◽  
pp. 01069
Author(s):  
Yanhu Wang ◽  
Sergey Konovalov ◽  
Xizhang Chen ◽  
Irina Komissarova
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Applied Load ◽  
Welding Process ◽  
High Strength ◽  
Specific Pressure ◽  
Welding Stress ◽  
Time Periods ◽  
Simulation Results

In this study, pressure finite element welding simulations has been carried out. The welding model is a butt filled weld. The objective is to study the effect of pressure on welding stress of high strength steel at different time periods. From the study we can find that no matter at the first half of welding or and the last half welding or at the cooling time apply the load have little effect to improve the stress. Only under the entire welding process that the distribution of residual stress can be greatly improved. The results show that the residual stresses of the welding workpiece under specific pressure throughout the welding process decreased by 16.2% when compared with weld group without load applied. The maximum residual stresses of weld group without load applied are more than with the specific pressure load plates 120 MPa. But under other times putting the load cannot be improved. This paper just presents a simulation results that have a certain guiding significance.

scholarly journals Microstructure and residual stress analysis of Strenx 700 MC welded joint

2020 ◽  
Vol 26 (2) ◽  
pp. 41-44
Author(s):  
Libor Trško ◽  
Ján Lago ◽  
Michal Jambor ◽  
František Nový ◽  
Otakar Bokůvka ◽  
...  
Keyword(s):  
Residual Stress ◽  
Heat Affected Zone ◽  
Microstructural Analysis ◽  
Fatigue Crack Initiation ◽  
Welding Process ◽  
High Strength ◽  
Carbon Steels ◽  
Fatigue Properties ◽  
Residual Stress Field ◽  
Welded Structure

AbstractHigh strength low alloy (HSLA) steels are a new generation of plain carbon steels with significantly improved mechanical properties while maintaining good weldability with common commercial techniques. Residual stress and microstructural analysis of welded HSLA Strenx 700 MC was carried out in this research. Results have shown that the welding process causes significant grain coarsening in the heat affected zone. The microstructural changes are also accompanied with creation of tensile residual stress field in the weld metal and heat affected zone, reaching up-to depth of 4 mm. Tensile residual stresses are well known for acceleration of fatigue crack initiation and together with coarse grains can lead to significant decrease of the fatigue properties of the welded structure.

Influence Analysis of Welding Residual Stress for Seismic Behavior to Side-Plate Reinforced Section

2012 ◽  
Vol 256-259 ◽  
pp. 2074-2078
Author(s):  
Yun Liu ◽  
Cheng Chao Mao ◽  
Yong Jie Song ◽  
Xue Jing Song
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Seismic Behavior ◽  
Welding Process ◽  
Welding Residual Stress ◽  
Finite Element Models ◽  
Side Plate ◽  
Research Objects ◽  
Seismic Index ◽  
Element Method

Taking side-plate reinforced section as research objects, this paper establishes the models by Ansys non-linear finite element method and simulates welding process of with birth-death element method. Comparing the different seismic index among test specimen and finite element models that based on whether or not considering welding residual stress, based on which, this research draws a conclusion that the influence of welding residual stress for seismic behavior to side-plate reinforced section is not obvious.

Study on Welding Deformation and Residual Stress of H-Section Beam Based on Finite Element Method

2017 ◽  
Vol 753 ◽  
pp. 305-309 ◽  
Author(s):  
Xu Lu
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Finite Element ◽  
Source Parameters ◽  
Welding Process ◽  
Steel Structure ◽  
Bottom Plate ◽  
Welding Deformation ◽  
Element Simulation ◽  
Main Components

The welding H-section beam has good mechanical properties with its superior structure. So they become the main components of steel structure and have been widely used. In this paper, the welded H-section beam is used as the research object. The finite element simulation model is established. The heat source parameters are determined. The deformation of the steel due to the welding process is studied. The results show that the bottom plate and the bottom plate inward bending is about 2.32mm cause by welding process. The residual stress can reach 400MPa.

Dynamic Impact Measurements on Crossings, in Free Floating and In-Situ Conditions

2014 ◽  
Author(s):  
M. A. Boogaard ◽  
A. L. Schwab ◽  
Z. Li
Keyword(s):  
Finite Element ◽  
Condition Monitoring ◽  
Impact Loading ◽  
Dynamic Behaviour ◽  
Element Model ◽  
Mode Shapes ◽  
Dynamic Impact ◽  
In Situ Test ◽  
In Situ Conditions

As vibration based condition monitoring requires a good understanding of the dynamic behaviour of the structure, a good model is needed. At the TU Delft a train borne monitoring system is being developed which currently focusses on crossings. Crossings are prone to very fast degradation due to impact loading. In this paper a finite element model of a free floating frog is presented and validated up to a 100 Hz using dynamic impact measurements. The mode shapes of the free floating frog are then also compared to some preliminary results from an in-situ test. This comparison shows that the in-situ frequencies can be up to twice the free floating frequency.

scholarly journals High-Fidelity Sensitivity Analysis of Modal Properties of Mistuned Bladed Disks Regarding Material Anisotropy

2018 ◽  
Author(s):  
Adam Koscso ◽  
Guido Dhondt ◽  
E. P. Petrov
Keyword(s):  
Sensitivity Analysis ◽  
Finite Element ◽  
Natural Frequencies ◽  
Mode Shapes ◽  
Finite Element Models ◽  
Coordinate Systems ◽  
Bladed Disks ◽  
Bladed Disk ◽  
Material Orientation

A new method has been developed for sensitivity calculations of modal characteristics of bladed disks made of anisotropic materials. The method allows the determination of the sensitivity of the natural frequencies and mode shapes of mistuned bladed disks with respect to anisotropy angles that define the crystal orientation of the monocrystalline blades using full-scale finite element models. An enhanced method is proposed to provide high accuracy for the sensitivity analysis of mode shapes. An approach has also been developed for transforming the modal sensitivities to coordinate systems used in industry for description of the blade anisotropy orientations. The capabilities of the developed methods are demonstrated on examples of a single blade and a mistuned realistic bladed disk finite element models. The modal sensitivity of mistuned bladed disks to anisotropic material orientation is thoroughly studied.

Numerical Investigation on Weld-Induced Imperfections in Aluminum Ship Plates

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Bai-Qiao Chen ◽  
C. Guedes Soares
Keyword(s):  
Finite Element ◽  
Aluminum Alloy ◽  
Material Properties ◽  
Welding Process ◽  
Finite Element Models ◽  
Finite Element Analyses ◽  
Temperature Dependent ◽  
Military Applications ◽  
Structural Responses ◽  
Or In Military

The present work aims at better understanding and predicting the thermal and structural responses of aluminum components subjected to welding, contributing to the design and fabrication of aluminum ships such as catamarans, lifesaving boats, tourist ships, and fast ships used in transportation or in military applications. Taken into consideration the moving heat source in metal inert gas (MIG) welding, finite element models of plates made of aluminum alloy are established and validated against published experimental results. Considering the temperature-dependent thermal and mechanical properties of the aluminum alloy, thermo-elasto-plastic finite element analyses are performed to determine the size of the heat-affected zone (HAZ), the temperature histories, the distortions, and the distributions of residual stresses induced by the welding process. The effects of the material properties on the finite element analyses are discussed, and a simplified model is proposed to represent the material properties based on their values at room temperature.

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