Numerical Simulation of Laser Bending of Thin Plate Stress Analysis and Prediction

2011 ◽  
Vol 227 ◽  
pp. 27-30
Author(s):  
Toufik Tamsaout ◽  
El Hachemi Amara

Laser forming is a technique consisting in the design and the construction of complex metallic work pieces with special shapes difficult to achieve with the conventional techniques. By using lasers, the main advantage of the process is that it is contactless and does not require any external force. It offers also more flexibility for a lower price. This kind of processing interests the industries that use the stamping or other costly ways for prototypes such as in the aero-spatial, automotive, naval and microelectronics industries. The analytical modeling of laser forming process is often complex or impossible to achieve, since the dimensions and the mechanical properties change with the time and in the space. Therefore, the numerical approach is more suitable for laser forming modeling. Our numerical study is divided into two models, the first one is a purely thermal treatment which allows the determination of the temperature field produced by a laser pass, and the second one consists in the thermo-mechanical coupling treatment. The temperature field resulting from the first stage is used to calculate the stress field, the deformations and the bending angle of the plate.

2014 ◽  
Vol 1003 ◽  
pp. 113-116
Author(s):  
Su Qin Jiang ◽  
Ai Hui Liu ◽  
Xue Ting Wang ◽  
Jian Hua Wu ◽  
Bo Kui Li

To study the bending characteristics of copper alloy thin plate by single pulse laser, the thermal mechanical coupling model of pulsed laser forming (PLF) was established; the dynamic change and steady distribution for the fields of temperature, stress& strain and displacement were analyzed. The results show n that during the pulse laser heating stage, the temperature gradient along the thickness direction is far less than that of the heat affected zone; due to the constraints of materials around the heating field, the compressive stress and negative strain are appeared, the cantilever end of sample produces warping deformations; in the cooling stage, the temperature of top and bottom surface material drops rapidly, the sample is with a negative bending and reduced deformation. This is related to the transferring of the stress change and the recovery of part of the elastic deformation in heating area.


2004 ◽  
Vol 120 ◽  
pp. 507-512
Author(s):  
Zhang Liwen ◽  
Zhong Qi ◽  
Pei Jibin ◽  
Zhang Guoliang ◽  
Xia Yuanliang

Laser forming has become a promising technique to form sheet metal in recent years. This new forming process can produce plastic deformation by thermal stresses resulted from the irradiation of laser beam scanning. In this paper, a 3-D thermo-mechanical FEM model was developed to simulate the laser forming process of shipbuilding steel plate. The finite-element software MSC.Marc was used to calculate the temperature field, stress field and strain field during laser forming process. The transient temperature field and the final bending angle were predicted. Then the effect of laser forming process technical parameters was studied. To evaluate the accuracy of the simulation, a laser forming experiment was performed. It is demonstrated that the finite element simulation results are in good agreement with experimental results.


2018 ◽  
Vol 281 ◽  
pp. 946-951
Author(s):  
Nan Li ◽  
Lei Gao ◽  
Zhong Zhou Yi ◽  
Feng Rui Zhai ◽  
Ke Shan

Laser forming, an advanced technology widely used for the shaping and adjustment of metallic and non-metallic materials, can also be used to process metal/ceramic materials. Laser forming technique is based on the temperature gradient mechanism (TGM) and temperature distribution is the main factor that affects the laser forming process. In this study, the finite element method (FEM) has been applied to predict the temperature field of TC4/SiC metal/ceramic bilayer during the laser forming process. Temperature of different points in the upper surface of the metal material, interface with the two layers and the lower surface of the ceramic material has been calculated. Parameters like laser input power and laser scan-speed have been investigated. This study is aimed at providing data for the precise control of laser forming in the process of shaping and adjusting TC4/SiC bilayers.


2010 ◽  
Vol 148-149 ◽  
pp. 590-594
Author(s):  
Yan Jin Guan ◽  
Hong Mei Zhang ◽  
Sheng Sun ◽  
Guo Qun Zhao

Laser bending process of tubes is a new flexible forming process without rigid tools and external forces. The tube is formed by internal thermal stress induced by laser irradiation. The process simulation of laser bending of tubes is realized numerically. When the other parameters remain invariable, the laser bending angle augments with the increase of the laser power. The laser bending angle decreases with the increase of the scanning velocity. Meanwhile, the bending angle varies with the diameter of the laser spot. The angle begins to decrease when the laser spot diameter get to an optimum value. The bending angle enlarges if the scanning wrap angle augments. The bending angle is largest when the scanning wrap angle is 180°. When the scanning wrap angle is over 180°, the bending angle decreases with the increase of the scanning wrap angle. The relationship between the number of scans and the bending angle is about in direct ratio. The bending angle induced by the first irradiated time is the largest.


Author(s):  
Paramasivan Kalvettukaran ◽  
Sandip Das ◽  
Sundar Marimuthu ◽  
Dipten Misra

The laser bending process, also called the laser forming process, consists of irradiating the surface of a sheet or a plate by means of a moving laser beam with a predefined scanning strategy to generate the desired shape through thermally induced residual stress. This chapter presents the mechanisms of a laser bending process and the technological aspects concerning laser v-bending of rectangular AISI 304 plates for full plates and plates with a central cutout at its middle to highlight the process fundamentals and how processing affects the final bending angle of the workpieces. Laser bending involving plates with a cutout will have numerous applications for car bodies, such as front and rear panels where bending is required to be performed on panels with cutout geometries. To investigate the effects of shape and size of the cutout on temperature distribution, stress distribution, and final bending angle, different shapes such as circular, ellipse, rectangular, and square, as well as different dimensions of cutouts have been chosen.


2008 ◽  
Vol 575-578 ◽  
pp. 1145-1150
Author(s):  
Ying Jin ◽  
Jian Hua Wu ◽  
Yong Jun Shi ◽  
Hong Shen ◽  
Zheng Qiang Yao

Laser forming of a micro-structural element involves a complex thermoplastic process. Numerous efforts had been made on the mechanisms of laser forming for macro-size elements, such as temperature gradient mechanism, buckling mechanism and upsetting mechanism, etc. It is found that the three mechanisms cannot depict fully the process of deformation in the macro-size element forming, let alone meet the needs of the micro-size one. Considering the laser inducing thermal stresses with size factors differing from the conventional analysis, it is essential to reveal the mechanisms dominating the forming process to accurately control the bending angle of a tiny plate. By studying the thermal transfer and elastic-plastic deformation of micro-structural element laser forming, the forming mechanism is explained within the micro size. The finite element model for laser bending is constructed for simulation. The stimulation results are agreement with the experimental data.


2010 ◽  
Vol 132 (1) ◽  
Author(s):  
Dongjiang Wu ◽  
Guangyi Ma ◽  
Fangyong Niu ◽  
Dongming Guo

The present work is a research on the laser forming process of borosilicate glass sheet. The laser forming mechanism was analyzed, and the temperature gradient mechanism was considered as the main forming mechanism of glass bending. According to the experimental results, a thermomechanical finite element (FE)-simulation was applied for investigating the temperature distribution and thermal stress in the thickness direction of the specimen. Cracks, as the primary defect, were summarized to three kinds: “Y” cracks, straight cracks, and arc cracks, while their forming mechanisms were proposed.


Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1472
Author(s):  
Mehdi Safari ◽  
Ricardo Alves de Sousa ◽  
Jalal Joudaki

Laser forming is an emerging manufacturing process capable of producing either uncomplicated and complicated shapes by employing a concentrated heating source. The heat source movement creates local softening, and a plastic strain will be induced during the rise of temperature and the subsequent cooling. This contactless forming process may be used for the simple bending of sheets and tubes or fabrication of doubly-curved parts. Different studies have been carried out over recent years to understand the mechanism of forming and predicting the bending angle. The analysis of process parameters and search for optimized manufacturing conditions are among the most discussed topics. This review describes the main recent findings in the laser forming of single and multilayer sheets, composite and fiber-metal laminate plates, force assisted laser bending, tube bending by laser beam, the optimization technique implemented for process parameters selection and control, doubly-curved parts, and the analytical solutions in laser bending. The main focus is set to the researches published since 2015.


Author(s):  
Vicente Stevens ◽  
Diego Celentano ◽  
Jorge Ramos-Grez ◽  
Magdalena Walczak

This work presents an experimental and numerical analysis of a low output power single-pass laser forming process applied to thin stainless steel sheets. To this end, the proposed methodology consists in four stages respectively devoted to material characterization via tensile testing, estimation of thermal boundary conditions present in laser forming, realization of laser bending tests for two sets of operating variables, and finally, numerical simulation of this process carried out with a coupled thermomechanical finite element formulation accounting for large plastic strains, temperature-dependent material properties and convection–radiation phenomena. The numerical analysis, focused on the description of the evolution of the thermomechanical material response, is found to provide a satisfactory experimental validation of the final bending angle for two laser forming cases with different operating variables. In both cases, the predicted high temperature gradients occurring across the sample thickness show that the deformation process is mainly governed by the thermal gradient mechanism.


Author(s):  
B.A. Lapshinov ◽  
◽  
N.I. Timchenko ◽  

Spectral pyrometry was used to determine the surface temperature distribution of Si, Nb, Cu, and graphite samples when they were locally heated by continuous radiation of an Nd:YAG laser (λ = 1.064 μm). With prolonged exposure to radiation, a stationary temperature field was established in the samples. The thermal spectra were recorded with a small spectrometer in the visible range in the temperature range above 850 K. The optical fiber used to transmit the radiation spectrum to the spectrometer had an additional diaphragm with a diameter of 1 mm located at a certain distance from the fiber end, which ensured the locality of the recorded spectra. The optical fiber moved continuously along the sample, and the spectrometer recorded up to 100 spectra with a frequency of 5-10 Hz. The temperature profile of the samples was calculated based on the results of processing the spectra using the Spectral Pyrometry program.


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