Three-Dimensional Numerical Simulation and Experimental Study of Sheet Metal Bending by Laser Peen Forming

2010 ◽  
Vol 132 (6) ◽  
Author(s):  
Yongxiang Hu ◽  
Yefei Han ◽  
Zhenqiang Yao ◽  
Jun Hu
Keyword(s):  
Numerical Model ◽  
Sheet Metal ◽  
Laser Energy ◽  
Three Dimensional ◽  
Target Surface ◽  
Thick Sheet ◽  
Specimen Thickness ◽  
Forming Process ◽  
Form Complex ◽  
Peen Forming

Laser peen forming (LPF) is a purely mechanical forming method achieved through the use of laser energy to form complex shapes or to modify curvatures. It is flexible and independent of tool inaccuracies that result from wear and deflection. Its nonthermal process makes it possible to form without material degradation or even improve them by inducing compressive stress over the target surface. In the present study, a fully three-dimensional numerical model is developed to simulate the forming process of laser peen forming. The simulation procedure is composed of several steps mainly including the shock pressure prediction, the modal analysis, and the forming process calculation. System critical damping is introduced to prevent unnecessary long post-shock residual oscillations and to greatly decrease the solution time for simulation. The bending profiles and angles with different thicknesses are experimentally measured at different scanning lines and scanning velocities to understand the process and validate the numerical model. The calculated bending profiles and angles agree well with the trend of the measured results. But it is found that simulations with the Johnson–Cook model are more consistent, matching the experimental results for the thick sheet metal with a convex bending, while the elastic-perfectly-plastic model produces a better agreement even though with underestimated values for the thinner sheet metal with a concave bending. The reason for this phenomenon is discussed, combining the effects of strain rate and feature size. Both the simulation and the experiments show that a continuous decrease in bending angle from concave to convex is observed with increasing specimen thickness in general. Large bending distortion is easier to induce by generating a concave curvature with LPF, and the angle of bending distortion depends on the number of laser shocks.

A New Stretch-Forming Process Based on Loading at Discrete Points and its Numerical Investigation

2013 ◽  
Vol 423-426 ◽  
pp. 737-740
Author(s):  
Zhong Yi Cai ◽  
Mi Wang ◽  
Chao Jie Che
Keyword(s):  
Sheet Metal ◽  
Three Dimensional ◽  
Discrete Point ◽  
Stretch Forming ◽  
Sheet Metal Part ◽  
Metal Part ◽  
Forming Process ◽  
Loading Trajectory ◽  
New Process ◽  
Forming Defects

A new stretch-forming process based on discretely loading for three-dimensional sheet metal part is proposed and numerically investigated. The gripping jaw in traditional stretch-forming process is replaced by the discrete array of loading units, and the stretching load is applied at discrete points on the two ends of sheet metal. By controlling the loading trajectory at the each discrete point, an optimal stretch-forming process can be realized. The numerical results on the new stretch-forming process of a saddle-shaped sheet metal part show that the distribution of the deformation on the formed surface of new process is more uniform than that of traditional stretch-forming, and the forming defects can be avoided and better forming quality will be obtained.

Comparison between an Advanced Numerical Simulation of Sheet Incremental Forming Using Adaptive Remeshing and Experimental Results

2013 ◽  
Vol 554-557 ◽  
pp. 1375-1381 ◽  
Author(s):  
Laurence Giraud-Moreau ◽  
Abel Cherouat ◽  
Jie Zhang ◽  
Houman Borouchaki
Keyword(s):  
Numerical Simulation ◽  
Numerical Model ◽  
Sheet Metal ◽  
Metal Forming ◽  
Tool Path ◽  
Incremental Forming ◽  
Computation Time ◽  
Experimental Results ◽  
Forming Process ◽  
Adaptive Remeshing

Recently, new sheet metal forming technique, incremental forming has been introduced. It is based on using a single spherical tool, which is moved along CNC controlled tool path. During the incremental forming process, the sheet blank is fixed in sheet holder. The tool follows a certain tool path and progressively deforms the sheet. Nowadays, numerical simulations of metal forming are widely used by industry to predict the geometry of the part, stresses and strain during the forming process. Because incremental forming is a dieless process, it is perfectly suited for prototyping and small volume production [1, 2]. On the other hand, this process is very slow and therefore it can only be used when a slow series production is required. As the sheet incremental forming process is an emerging process which has a high industrial interest, scientific efforts are required in order to optimize the process and to increase the knowledge of this process through experimental studies and the development of accurate simulation models. In this paper, a comparison between numerical simulation and experimental results is realized in order to assess the suitability of the numerical model. The experimental investigation is realized using a three-axis CNC milling machine. The forming tool consists in a cylindrical rotating punch with a hemispherical head. A subroutine has been developed to describe the tool path from CAM procedure. A numerical model has been developed to simulate the sheet incremental forming process. The finite element code Abaqus explicit has been used. The simulation of the incremental forming process stays a complex task and the computation time is often prohibitive for many reasons. During this simulation, the blank is deformed by a sequence of small increments that requires many numerical increments to be performed. Moreover, the size of the tool diameter is generally very small compared to the size of the metal sheet and thus the contact zone between the tool and the sheet is limited. As the tool deforms almost every part of the sheet, small elements are required everywhere in the sheet resulting in a very high computation time. In this paper, an adaptive remeshing method has been used to simulate the incremental forming process. This strategy, based on adaptive refinement and coarsening procedures avoids having an initially fine mesh, resulting in an enormous computing time. Experiments have been carried out using aluminum alloy sheets. The final geometrical shape and the thickness profile have been measured and compared with the numerical results. These measurements have allowed validating the proposed numerical model. References [1] M. Yamashita, M. Grotoh, S.-Y. Atsumi, Numerical simulation of incremental forming of sheet metal, J. Processing Technology, No. 199 (2008), p. 163 172. [2] C. Henrard, A.M. Hbraken, A. Szekeres, J.R. Duflou, S. He, P. Van Houtte, Comparison of FEM Simulations for the Incremental Forming Process, Advanced Materials Research, 6-8 (2005), p. 533-542.

Research on the Finite Element Simulation of the Laser Shock Forming of TC4 Titanium Alloy

2016 ◽  
Vol 693 ◽  
pp. 1121-1128 ◽  
Author(s):  
Guo He Li ◽  
David Mbukwa ◽  
Wei Zhao
Keyword(s):  
Finite Element ◽  
Sheet Metal ◽  
Laser Energy ◽  
Sheet Thickness ◽  
High Amplitude ◽  
Laser Spot ◽  
Laser Shock ◽  
Forming Process ◽  
Element Analysis ◽  
Laser Shock Forming

laser shock forming, which combines the metal forming and material modification, is a non-mode, flexible forming new technology using laser-induced force effect of high amplitude shock waves to obtain the plastic deformation of sheet metal. in this paper, the simulation of laser shock forming process of tc4 sheet metal was carried out through the commercial finite element analysis software abaqus. the influence of the sheet thickness, laser energy, constraints aperture and laser spot spacing on the sheet metal deformation are investigated. the results show that: with the increase of sheet thickness, the deformation range of sheet decreases, and the amplitude of deformation decreases firstly and then increases. the deformation increases linearly with the increase of laser energy. the larger boundary constraint aperture leads to the larger deformation of sheet metal. there are no obvious influence on the forming accuracy when an opposite laser spot spacing is adopted. therefore, under the condition of meeting the accuracy requirement, for improving the efficiency, adopting a certain laser spot spacing to finish the forming should be considered.

scholarly journals Development on a Prediction Model for Experimental Condition of Flexibly Reconfigurable Roll Forming Process

Metals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 896
Author(s):  
Ji-Woo Park ◽  
Jeong Kim ◽  
Beom-Soo Kang
Keyword(s):  
Regression Analysis ◽  
Regression Model ◽  
Sheet Metal ◽  
Quadratic Function ◽  
Target Surface ◽  
Total Sample ◽  
Roll Forming ◽  
Radius Of Curvature ◽  
Forming Process ◽  
Mean Square Errors

Flexibly-reconfigurable roll forming (FRRF) is a novel sheet metal forming technology by which sheet metal is shaped into a desired curvature using reconfigurable rollers and gaps. FRRF is conducive to producing multi-curvature surfaces by controlling the longitudinal strain distribution. However, it is difficult to predict the forming results since FRRF technology forms a secondary surface from the primary curvature. This study investigates the use of regression analysis as a basis for a model that can predict the longitudinal curvature of sheet metal. The following variables were considered as input parameters: Maximum compression value, radius of curvature in the transverse direction, and initial blank width. Regression model samples are obtained by performing experiments using FRRF equipment whilst the experimental design was generated by a three-level, three-factor full factorial design. The experimental surfaces are of a convex and of a saddle-type shape, with a total sample size of 54. Through regression analysis it has been shown that the longitudinal curvature can be expressed by means of a quadratic equation. The matching quadratic function was verified with R-squared values and root-mean-square errors, whilst the normality of the sample data was also verified. To apply the model to the actual forming process, the regression model was converted to deduce the compression characteristics for forming the target surface. Throughout the study, the proposed analytical procedure was validated, and a statistical formula for estimating the longitudinal curvature produced by the FRRF apparatus established.

Modeling and Simulation of Continuous Flexible Roll Forming Process

2013 ◽  
Vol 365-366 ◽  
pp. 549-552
Author(s):  
Zhou Sui ◽  
Zhong Yi Cai ◽  
Ming Zhe Li
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Three Dimensional ◽  
Rigid Bodies ◽  
Roll Forming ◽  
Forming Process ◽  
Flexible Roll Forming ◽  
Flexible Roll ◽  
Roll Forming Process

The continuous flexible roll forming process is a novel sheet metal forming technique for effectively manufacture of three-dimensional surface parts. In this study, two types of finite element (FE) models were developed under the ABAQUS/Explicit environment. The difference of the two models is that the rolls are defined as discrete rigid bodies in model No.1 and are deformable in model No.2. An experiment was carried out using the continuous sheet metal forming setup. The comparison of the numerical computation results with the experimental results shows that the model No.2 can be used for the shape prediction of continuous flexible roll forming process well.

Forming Stability Analysis of Surface Flexible Rolling

2013 ◽  
Vol 798-799 ◽  
pp. 267-271
Author(s):  
Ren Jun Li ◽  
Ming Zhe Li ◽  
Zhong Yi Cai
Keyword(s):  
Numerical Simulation ◽  
Stability Analysis ◽  
Sheet Metal ◽  
Three Dimensional ◽  
Continuous Manufacturing ◽  
Forming Process ◽  
Metal Parts ◽  
Sheet Metal Parts ◽  
Flexible Rolling ◽  
Simulation Results

Surface flexible rolling method, using two integral working rolls as the forming tool, can achieve fast, flexible and continuous manufacturing of three-dimensional sheet metal parts. This paper introduces the basic principle of surface flexible rolling and discusses the numerical simulation results when the working rolls are bended as circular arcs. The stability indicates the forming effect to some extent and the flow type of the metal can be deduced from stability analysis. To integrate and analyze the simulation results by means of reverse engineering. The analysis results show that the forming process is stable and the effect of surface flexible rolling is fine. It also indicates that inhomogeneous deformation and accumulation occurs during the process. The numerical simulation and experimental results demonstrate that the surface flexible rolling is a feasible and effective way to form three-dimensional sheet metal parts.

Compensations for Tool Path to Enhance Accuracy During Double Sided Incremental Forming

2015 ◽  
Author(s):  
Rakesh Lingam ◽  
Anirban Bhattacharya ◽  
Javed Asghar ◽  
N. Venkata Reddy
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Tool Path ◽  
Incremental Forming ◽  
Single Point ◽  
Three Dimensional ◽  
Geometric Accuracy ◽  
Forming Process ◽  
Incremental Sheet Metal Forming

Incremental Sheet Metal Forming (ISMF) is a flexible sheet metal forming process that enables forming of complex three dimensional components by successive local deformations without using component specific tooling. ISMF is also regarded as die-less manufacturing process and in the absence of part-specific dies, geometric accuracy of formed components is inferior to that of their conventional counterparts. In Single Point Incremental Forming (SPIF), the simplest variant of ISMF, bending near component opening region is unavoidable due to lack of support. The bending in the component opening region can be reduced to a larger extent by another variant of ISMF namely Double Sided Incremental Forming (DSIF) in which a moving tool is used to support the sheet locally at the deformation zone. However the overall geometry of formed components still has unacceptable deviation from the desired geometry. Experimental observation and literature indicates that the supporting tool loses contact with the sheet after forming certain depth. Present work demonstrates a methodology to enhance geometric accuracy of formed components by compensating for tool and sheet deflection due to forming forces. Forming forces necessary to predict compensations are obtained using force equilibrium method along with thickness calculation methodology developed using overlap that occurs during forming (instead of using sine law). Results indicate that there is significant improvement in accuracy of the components produced using compensated tool paths.

Effect of Shot Strip Interval and Shot Times on Laser Shot Peen-Forming with Repetition Laser Pulse

2007 ◽  
Vol 353-358 ◽  
pp. 199-202
Author(s):  
Chao Jun Yang ◽  
Yong Kang Zhang ◽  
Jian Zhong Zhou ◽  
Ming Yong Ni ◽  
Jian Jun Du ◽  
...  
Keyword(s):  
Laser Pulse ◽  
Residual Stresses ◽  
Sheet Metal ◽  
Laser Energy ◽  
Pulse Repetition Frequency ◽  
Laser Shot ◽  
Beam Diameter ◽  
Narrow Strip ◽  
Peen Forming ◽  
Surface Residual Stresses

Laser shot peen-forming of sheet metal(or LasershotSM Peening) is a new plastic forming technique for metallic materials, which uses high-power pulsed laser replacing the tiny balls to peen the surface of sheet metal. When the pressure of shock waves induced by laser impresses an inhomogeneous residual stresses distribution in a given depth on the surface of sheet, it responds to the stress by elongating at the peened surface and effectively bending the sheet. In order to investigate the mechanism of laser shot peen-forming, the narrow strip peen-forming experimental of aluminum alloy 6061-T6 was carried out by using a pulsed Nd:glass laser with 0.5Hz repetition-rate. Here, under some given laser energy, laser pulse width, laser beam diameter and pulse repetition frequency and so on, the influence of shot strip interval and shot times on surface residual stresses and the deformation of the sheet is analyzed. The results show that the bending forming of the sheet metal can be found, and the peened surface of sheet metal becomes convex. That the bending increases with shot strip interval increase is not obvious, but it increases with the shot times increase in a proper range of shot times. Besides, because laser shot peen-forming generates compressive residual stresses on the surface, it offers many desirable characteristics in shaped metals and is a valuable technique for producing components for a range of industries.

FEM Analysis of Sheet Incremental Forming Process

2014 ◽  
Vol 571-572 ◽  
pp. 1079-1082
Author(s):  
Jie Liu
Keyword(s):  
Sheet Metal ◽  
Incremental Forming ◽  
Metal Layer ◽  
Three Dimensional ◽  
Rapid Prototype ◽  
Fem Analysis ◽  
Layer By Layer ◽  
Forming Process ◽  
Rapid Prototype Technology ◽  
Forming Technology

Sheet incremental forming is a new sheet metal dieless forming technology. This paper introduced the fundamentals of the sheet incremental forming process. Based on the principle of “layered manufacture” in rapid prototype technology, this process resolves the intricate three-dimensional geometry information of the workpiece into a series of two-dimensional data, which can be used by an NC system to control a forming tool to make a curvilinear movement over the raw sheet metal layer by layer until the component wanted is formed. This paper introduced the sheet incremental forming system and metal digital forming technology. An FEM model of the incremental forming process is established, and a typical process is analyzed to instruct the parameters selection and the optimization of the forming tracks.

Investigation on Wrinkling Deformation in Multi-Pass Incremental Sheet Forming Process

2016 ◽  
Vol 725 ◽  
pp. 578-585 ◽  
Author(s):  
Zhao Bing Liu ◽  
Paul Anthony Meehan
Keyword(s):  
Thickness Distribution ◽  
Three Dimensional ◽  
Experimental Tests ◽  
Sheet Forming ◽  
Incremental Sheet Forming ◽  
Final Part ◽  
Optimized Design ◽  
Forming Process ◽  
Element Analysis ◽  
Form Complex

Incremental Sheet Forming (ISF) is a promising rapid prototyping technology used to form complex three-dimensional shapes. For forming a part with severely sloped regions, design of multi-stage deformation passes (intermediate shapes or preforms) before the final part, is widely adopted as a desirable and practical way to control the material flow in order to obtain a more uniform thickness distribution and avoid forming failure. However, a problem sometimes encountered in multi-pass forming is wrinkling deformation between two adjacent deformation passes. This may lead to forming process instability and even fracture. The overall quality of the final part may also deteriorate even if the part is formed successfully. In this paper, the wrinkling phenomenon in multi-pass incremental sheet forming is investigated by means of finite element analysis (FEA) and experimental tests to analyse the wrinkling formation mechanism. This research gives an insight into the optimized design of deformation passes in order to eliminate the unwanted wrinkling deformation in multi-pass incremental forming process.

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