Experimental and 3D Finite Element Studies of CW Laser Forming of Thin Stainless Steel Sheets

2000 ◽  
Vol 123 (1) ◽  
pp. 66-73 ◽  
Author(s):  
Guofei Chen ◽  
Xianfan Xu
Keyword(s):  
Finite Element ◽  
Stainless Steel ◽  
Laser Scanning ◽  
Continuous Wave ◽  
Laser Forming ◽  
Beam Diameter ◽  
Element Analysis ◽  
Scanning Velocity ◽  
3D Finite Element ◽  
Steel Sheets

Laser forming as a springback-free and noncontact forming technique has been under active investigation over the last decade. Previous investigations are mainly focused on forming of large and thick workpieces using high power lasers, with less work on precision, micro-scale bending of small and thin sheets. In this work, a 4 W continuous wave argon ion laser is used as the energy source, and the laser beam is focused to a beam diameter of tens of micrometers to induce bending of thin stainless steel sheets. When the laser scanning velocity is above 8 mm/s, bending can be explained by the temperature gradient mechanism, while decreasing the scanning velocity leads to the buckling mechanism of bending. The bending angle is measured at various processing conditions. A fully 3D finite element analysis is performed to simulate the thermo-elasto-plastic deformation process during laser forming. Experimental measurements and computational results agree in trend, and reasons for the deviation are discussed.

Process Optimization of Laser Micro-Bending Using iSIGHT

2008 ◽  
Vol 575-578 ◽  
pp. 408-415
Author(s):  
Jie Liu ◽  
Yan Jin Guan ◽  
Sheng Sun ◽  
Guang Chun Wang
Keyword(s):  
Finite Element ◽  
Stainless Steel ◽  
Laser Power ◽  
Geometrical Parameters ◽  
Beam Diameter ◽  
Forming Process ◽  
Bending Angle ◽  
Scanning Velocity ◽  
Stainless Steel Foil ◽  
Bending Process

There are many factors, such as the laser and geometrical parameters, which influence greatly on the laser bending process. So it is of great importance to determine these variables properly. Considering the relationship of material properties and temperature, a 3-D thermal-mechanical finite element analysis model for laser micro-bending of stainless steel foil is developed based on the software MSC.Marc, and the laser micro-bending process of 0.1mm thick stainless steel foil is implemented. The finite element method simulation process is integrated with the optimization software package iSIGHT through secondary development. The objective function is to realize the maximum bending angle after single laser scan, and laser power, beam diameter and scanning velocity are regarded as the design variables. The forming process is optimized by using genetic algorithm. The optimal result shows the bending angle can be got to the maximum 1.0332°when the laser power, beam diameter and scanning velocity are 32W, 0.17mm and 132mm/s respectively. The experiment results are in good agreement with optimal results.

scholarly journals Thermo-Mechanical Analysis on Thermal Deformation of Thin Stainless Steel in Laser Micro-Welding

2016 ◽  
Vol 6 (2) ◽  
pp. 51-66 ◽  
Author(s):  
Mohd Idris Shah Ismail ◽  
Yasuhiro Okamoto ◽  
Akira Okada
Keyword(s):  
Finite Element ◽  
Stainless Steel ◽  
Finite Element Model ◽  
High Speed ◽  
Continuous Wave ◽  
Element Model ◽  
Scanning System ◽  
Welding Deformation ◽  
Scanning Velocity ◽  
Stress And Deformation

In the present study, a three-dimensional finite element model has been developed to simulate the temperature, stress and deformation fields in continuous wave (CW) laser micro-welding of thin stainless steel sheet. The welding deformation was experimentally evaluated using a single-mode fiber laser with a high-speed scanning system. Application of developed thermal model demonstrated that the laser parameters, such as laser power, scanning velocity and spot diameter have a significant effect on temperature field and the weld pool. In the case of welding deformation, numerical simulation was carried out by an uncoupled thermo-mechanical model. The welding stress and deformation are generated by plastic deformation during the heating and cooling periods. It was confirmed that the residual stress is higher than yield strength and has strongest effect upon the welding deformation. The numerical simulated results have proved that the developed finite element model is effective to predict thermal histories, thermally induced stresses and welding deformations in the thin material.

The Effect of Nonconventional Laser Beam Geometries on Stress Distribution and Distortions in Laser Bending of Tubes

2006 ◽  
Vol 129 (3) ◽  
pp. 592-600 ◽  
Author(s):  
Shakeel Safdar ◽  
Lin Li ◽  
M. A. Sheikh ◽  
Zhu Liu
Keyword(s):  
Laser Beam ◽  
Laser Scanning ◽  
Thermal Stresses ◽  
Laser Forming ◽  
Beam Diameter ◽  
Hydraulic Systems ◽  
Tube Bending ◽  
Laser Bending ◽  
Scanning Velocity ◽  
Laser Tube

Laser forming is a spring-back-free noncontact forming method that has received considerable attention in recent years. Compared to mechanical bending, no hard tooling, dies, or external force is used. Within laser forming, tube bending is an important industrial activity with applications in critical engineering systems such as heat exchangers, hydraulic systems, boilers, etc. Laser tube bending utilizes the thermal stresses generated during laser scanning to achieve the desired bends. The parameters varied to control the process are usually laser power, beam diameter, scanning velocity, and the number of scans. The thermal stresses generated during laser scanning are strongly dependent upon laser beam geometry. The existing laser bending methods use either circular or rectangular beams. These beam geometries sometimes lead to undesirable effects such as buckling and distortion in tube bending. This paper investigates the effects for various laser beam geometries on laser tube bending. Finite element modeling has been used for the study of the process with some results also validated by experiments.

scholarly journals Pediatric Stainless-Steel Crown Cementation Finite Element Study

2020 ◽  
Author(s):  
Ahmed S. Waly ◽  
Yasser R. Souror ◽  
Salah A. Yousief ◽  
Waleed M.S. Alqahtani ◽  
Mohamed I. El-Anwar
Keyword(s):  
Finite Element ◽  
Stainless Steel ◽  
Laser Scanning ◽  
Second Primary ◽  
Glass Ionomer ◽  
Cement Type ◽  
Primary Molar ◽  
3D Finite Element ◽  
Mandibular Molar ◽  
Zinc Phosphate Glass

Abstract Objective To study the effect of using different cement types under pediatric stainless-steel crown (SSC) around mandibular second primary molar using three-dimensional (3D) finite element analysis. Materials and Methods A 3D finite element model was built for pediatric mandibular molar by laser scanning of natural extracted tooth. Four types of cement (zinc phosphate, glass ionomer, resin-modified glass ionomer, and resin) of 200 μm layers thickness were tested under a stainless-steel crown of 130-μm thickness. Twelve case studies were reported within this research, as the applied load of 330 N was tested with three angulations: vertical, oblique at 45°, and laterally. Results Linear static stress analysis was performed. The resultant stresses and deformations' distribution patterns did not change with cement type, while the values were altered. All deformations and stresses were found within the normal range. Conclusions Analysis results indicated that using stiffer cement material increases tooth structure stresses and reduces crown body stresses and deformations, while bone was nearly insensitive to cement type.

A Finite Element Study of Buckling and Upsetting Mechanisms in Laser Forming of Plates and Tubes

2011 ◽  
Vol 1 (1) ◽  
pp. 1-17
Author(s):  
M. S. Che Jamil ◽  
M. A. Sheikh ◽  
L. Li
Keyword(s):  
Stainless Steel ◽  
Plate Thickness ◽  
Processing Parameters ◽  
Steel Tube ◽  
Laser Forming ◽  
Stainless Steel Tube ◽  
Beam Diameter ◽  
Steel Sheets ◽  
Thermal Residual Stresses ◽  
Underlying Mechanisms

Laser beam forming has emerged as a viable technique to form sheet metal by thermal residual stresses. Although it has been a subject of many studies, its full industrial application is not yet established. This article aims to complement the existing research in the area of laser forming in order to gain a better understanding of the process. A numerical investigation of laser forming of stainless steel sheets has been carried out and validated experimentally using a High Power Diode Laser (HPDL). Three processing parameters are tested; laser power, beam diameter and plate thickness. Also, laser bending of stainless steel tube is simulated and compared against the published experimental data. The main underlying mechanisms of laser forming are demonstrated through the simulations.

Behaviour of Axially Loaded Composite Wall Panel by Using Finite Element Analysis

2015 ◽  
Vol 815 ◽  
pp. 49-53
Author(s):  
Nur Fitriah Isa ◽  
Mohd Zulham Affandi Mohd Zahid ◽  
Liyana Ahmad Sofri ◽  
Norrazman Zaiha Zainol ◽  
Muhammad Azizi Azizan ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Composite Structures ◽  
Element Analysis ◽  
Steel Sheets ◽  
Linear Behavior ◽  
Non Linear ◽  
Composite Wall ◽  
Experimental Values ◽  
Civil Engineering Infrastructure

In order to promote the efficient use of composite materials in civil engineering infrastructure, effort is being directed at the development of design criteria for composite structures. Insofar as design with regard to behavior is concerned, it is well known that a key step is to investigate the influence of geometric differences on the non-linear behavior of the panels. One possible approach is to use the validated numerical model based on the non-linear finite element analysis (FEA). The validation of the composite panel’s element using Trim-deck and Span-deck steel sheets under axial load shows that the present results have very good agreement with experimental references. The developed finite element (FE) models are found to reasonably simulate load-displacement response, stress condition, giving percentage of differences below than 15% compared to the experimental values. Trim-deck design provides better axial resistance than Span-deck. More concrete in between due to larger area of contact is the factor that contributes to its resistance.

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