Experimental and Numerical Studies on Microscale Bending of Stainless Steel With Pulsed Laser

1999 ◽  
Vol 66 (3) ◽  
pp. 772-779 ◽  
Author(s):  
G. Chen ◽  
X. Xu ◽  
C. C. Poon ◽  
A. C. Tam
Keyword(s):  
Stainless Steel ◽  
High Temperature ◽  
Material Properties ◽  
Steel Specimen ◽  
Laser Forming ◽  
Element Analysis ◽  
Bending Angle ◽  
Thermal Residual Stresses ◽  
Property Data ◽  
External Forces

Laser forming or laser bending is a newly developed, flexible technique which modifies the curvature of sheet metal by thermal residual stresses instead of external forces. The process is influenced by many parameters such as laser parameters, material properties, and target dimensions. In this work, a pulsed Nd:YLF laser was used as the energy source. The laser beam was focused into a line shape irradiating on the stainless steel specimen to induce bending. The bending angle was measured at various processing conditions. A finite element analysis was performed with the use of a two-dimensional plane strain model to calculate the thermoelastoplastic deformation process. Experimental measurements and computational results were in good agreement. Numerical sensitivity studies were performed to evaluate the effects of the unavailable material property data at high temperature. It was found that both optical reflectivity and thermal expansion coefficient influenced the bending angle significantly, while other extrapolated material properties at high temperature yielded acceptable results.

Influence of high temperature sodium exposure on microstructure and material properties of AISI 440C Stainless Steel

2022 ◽  
Vol 13 (1) ◽  
pp. 1
Author(s):  
Nashine B.K. ◽  
Jose Varghese ◽  
Sreedhar B. K ◽  
Mariappan K ◽  
Chandramouli S ◽  
...  
Keyword(s):  
Stainless Steel ◽  
High Temperature ◽  
Material Properties

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

2012 ◽  
pp. 140-156
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 ◽  
Thermal Residual Stresses ◽  
Underlying Mechanisms ◽  
Power Diode

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.

scholarly journals Probability Study on the Thermal Stress Distribution in Thick HK40 Stainless Steel Pipe Using Finite Element Method

Designs ◽  
2019 ◽  
Vol 3 (1) ◽  
pp. 9
Author(s):  
Sujith Bobba ◽  
Shaik Abrar ◽  
Shaik Mujeebur Rehman
Keyword(s):  
Finite Element ◽  
Stainless Steel ◽  
High Temperature ◽  
Material Properties ◽  
Thermal Stresses ◽  
Steel Pipe ◽  
Stress Distributions ◽  
Stainless Steel Pipe ◽  
Deterministic Solution ◽  
Analytical Expressions

The present work deals with the development of a finite element methodology for obtaining the stress distributions in thick cylindrical HK40 stainless steel pipe that carries high-temperature fluids. The material properties and loading were assumed to be random variables. Thermal stresses that are generated along radial, axial, and tangential directions are generally computed using very complex analytical expressions. To circumvent such an issue, probability theory and mathematical statistics have been applied to many engineering problems, which allows determination of the safety both quantitatively and objectively based on the concepts of reliability. Monte Carlo simulation methodology is used to study the probabilistic characteristics of thermal stresses, and was implemented to estimate the probabilistic distributions of stresses against the variations arising due to material properties and load. A 2-D probabilistic finite element code was developed in MATLAB, and the deterministic solution was compared with ABAQUS solutions. The values of stresses obtained from the variation of elastic modulus were found to be low compared to the case where the load alone was varying. The probability of failure of the pipe structure was predicted against the variations in internal pressure and thermal gradient. These finite element framework developments are useful for the life estimation of piping structures in high-temperature applications and for the subsequent quantification of the uncertainties in loading and material properties.

Finite Element Analysis of Fibre Reinforce Concrete Beam Subject to High Temperature by Using EURO-Code Models

2011 ◽  
Vol 471-472 ◽  
pp. 343-348
Author(s):  
Ziad K. Awad ◽  
Talal F. Yusaf
Keyword(s):  
Finite Element ◽  
High Temperature ◽  
Material Properties ◽  
Concrete Beam ◽  
Mechanical Load ◽  
Fibre Composite ◽  
Research Work ◽  
Steel Corrosion ◽  
Element Analysis ◽  
Material Response

Glass fibre composite reinforcement bars have been used in the reinforced concrete structures as a powerful solution of the steel corrosion problem. This research work aims to use a 3D finite element method and EURO – code models to simulate a concrete beam reinforced with fibre composite bars under the effects of high temperature. The behaviour of the structure is very complex due to load combination and different material response. The applied load was an external mechanical load and a thermal load. The material response was considered as thermal expansion, cracking, crushing, yielding and changing of material properties with the temperature increase. The FE element was modified to allow temperature distribution and material properties changing to throw thickness of the concrete beam. In addition, the geometrical non – linearity is considered in the analysis due to the large deflection of the structure. The prediction results were compared with the available experimental results, and it gives a well correspond.

An analytical formula for estimating the bending angle by laser forming

2006 ◽  
Vol 220 (2) ◽  
pp. 243-247 ◽  
Author(s):  
H Shen ◽  
Z Yao ◽  
Y Shi ◽  
J Hu
Keyword(s):  
Experimental Data ◽  
Solid Mechanics ◽  
Present Model ◽  
Analytical Formula ◽  
Laser Forming ◽  
Compatibility Conditions ◽  
Bending Angle ◽  
Metal Plates ◽  
External Forces ◽  
Simple Analytical Formula

Laser forming of metal plates offers the advantages of requiring no external forces and thus reduced cost and increased flexibility. It also enables forming of some materials and shapes that are impossible by using the traditional methods. Based on the conventional equilibrium and compatibility conditions used in solid mechanics, a simple analytical formula for predicting the bending angle is derived. The present model is compared with other models and available experimental data, from which the superiority of the present model is demonstrated.

Experimental and Numerical Investigation of Laser Forming of Closed-Cell Aluminum Foam

2015 ◽  
Vol 138 (2) ◽  
Author(s):  
Min Zhang ◽  
Chang Jun Chen ◽  
Grant Brandal ◽  
Dakai Bian ◽  
Y. Lawrence Yao
Keyword(s):  
Effective Property ◽  
Von Mises Stress ◽  
Laser Forming ◽  
Aluminum Foams ◽  
Element Analysis ◽  
Bending Angle ◽  
Cellular Models ◽  
Closed Cell ◽  
Small Pore ◽  
Cell Foam

Aluminum foams are generally very attractive because of their ability of combining different properties such as strength, light weight, thermal, and acoustic insulation. These materials, however, are typically brittle under mechanical forming, and this severely limits their use. Recent studies have shown that laser forming is an effective way for foam panel forming. In this paper, the laser formability of Al–Si closed-cell foam through experiments and numerical simulations was investigated. The bending angle as a function of the number of passes at different laser power and scan velocity values was investigated for large- and small-pore foams. In the finite element analysis, both effective-property and cellular models were considered for the closed-cell foam. Multiscan laser forming was also carried out and simulated to study the accumulative effect on the final bending angle and stress states. The maximum von Mises stress in the scanning section was on the order of 0.8 MPa, which was lower than the yield strength of the closed-cell foam material. This paper further discussed the reasonableness and applicability of the two models.

scholarly journals Probability Study on the Thermal Stress Distribution in the Thick HK40 Stainless Steel Pipe Using Finite Element Method

2018 ◽  
Author(s):  
Shaik Abrar ◽  
Sujith Bobba ◽  
Shaik Mujeebur Rehman
Keyword(s):  
Finite Element ◽  
Stainless Steel ◽  
High Temperature ◽  
Material Properties ◽  
Thermal Stresses ◽  
Steel Pipe ◽  
Stress Distributions ◽  
Stainless Steel Pipe ◽  
Deterministic Solution ◽  
Analytical Expressions

The present work deals with the development of finite element methodology for obtaining the stress distributions in thick cylindrical HK40 stainless steel pipe that carry high temperature fluids. The material properties and loading are assumed to be random variables. Thermal stresses that are generated along radial, axial and tangential directions are computed generally using analytical expressions which are very complex. To circumvent such an issue, the probability theory and mathematical statistics have been applied to many engineering problems which allows to determine the safety both quantitatively and objectively based on the concepts of reliability. Monte Carlo simulation methodology is used to study the probabilistic characteristics of thermal stresses which is used for estimating the probabilistic distributions of stresses against the variations arising due to material properties and load. A 2-D Probabilistic finite element code is developed in MATLAB and the deterministic solution is compared with ABAQUS solutions.  The values of stresses that are obtained from the variation of elastic modulus are found to be low as compared to the case where the load alone is varying. The probability of failure of the pipe structure is predicted against the variations in internal pressure and thermal gradient. These finite element framework developments are useful for the life estimation of piping structures in high temperature applications and subsequently quantifying the uncertainties in loading and material properties.

Light element analysis of irradiation-induced precipitates in Ti-modified 316 stainless steel

1983 ◽  
Vol 41 ◽  
pp. 384-385
Author(s):  
L. E. Thomas
Keyword(s):  
Stainless Steel ◽  
Light Element ◽  
Steel Specimen ◽  
Scanning Transmission Electron Microscope ◽  
Nominal Composition ◽  
Element Analysis ◽  
316 Stainless Steel ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Test Reactor

G and n phases are complex nickel silicides which commonly form in Fe-Ni-Cr based stainless steels and superalloys during neutron irradiation at 400-600°C. Both phases are cubic and are structurally similar to the common carbides M2 3C6 and M6C which form in many of the same alloys during thermal aging. Although G and n have been analyzed previously by energy-dispersive x-ray spectrometry (EDXS), little is known about their carbon contents.To further determine the compositional relationships between the G/n silicides and the M 23C 6/M6C carbides, an irradiated Ti-modified 316 stainless steel specimen containing 0.05 to 0.5μm particles of G and n was analyzed by means of electron energy loss spectroscopy (ELS) and EDXS in a field emission gun scanning transmission electron microscope (STEM). The alloy, LSI, has the nominal composition of Fe-16.8Cr-13.5Ni-l.9Mo-0.87Si-2.0Mn-.15Ti-.045C and was irradiated to 2 x 1022n/cm2, E >0.1 MeV, at 510°C in the EBR-II breeder test reactor.

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.

Investigation of High Temperature Mechanical Properties for Improved Finite Element Analysis Simulations of Forged Railroad Wheels

2005 ◽  
Author(s):  
Steven Dedmon ◽  
James Pilch ◽  
Cameron Lonsdale
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Finite Element Analysis ◽  
Finite Element ◽  
High Temperature ◽  
Element Analysis ◽  
Property Data ◽  
High Temperature Mechanical Property ◽  
Class C ◽  
Mechanical Property Data

Finite element analysis (FEA) programs depend on accurate evaluation of mechanical and physical properties for determination of thermo-mechanical characteristics of wheel designs. For wheel residual stress analyses, both property types are equally important. Also important is knowledge of the anisotropy of properties in a design. For this paper, the authors tested AAR M107/M208 Class “C” steel ingot material and an as-forged (but untreated) wheel. The information presented includes elevated temperature mechanical properties of ingot material taken in circumferential, radial and axial orientations at two depth positions. High temperature mechanical property data (not currently found in the literature beyond 1800F) is also included for the ingot steel. Untreated as-forged AAR Class “C” material mechanical properties were evaluated at temperatures up to 2000F, and at the rim, plate and hub locations. High temperature mechanical property data for heat treated micro-alloy AAR Class “C” wheels are also presented.

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