Numerical Analysis for the Multi-Point Stretch Forming Process of Aircraft Skin Panel

2011 ◽  
Vol 109 ◽  
pp. 504-508 ◽  
Author(s):  
Yu Shan Deng ◽  
Yuan Yao ◽  
Shao Hui Wang
Keyword(s):  
Numerical Analysis ◽  
Numerical Simulations ◽  
Equivalent Strain ◽  
Stretch Forming ◽  
Forming Process ◽  
Outer Skin ◽  
Free Length ◽  
Aircraft Skin ◽  
A New Technique ◽  
Elastic Cushion

Multi-point stretch forming (MPSF) is a new technique to form aircraft outer skin panel. Since multi-point die is composed by the discrete punches, the result of the MPSF aircraft outer skin panel need to study in depth. The thickness of elastic cushion and free length are two important factors to affect the accuracy, and they must be chosen reasonably. A series of numerical simulations on typical MPSF processes were carried out to an aircraft outer skin panel part. The results show that the thicker the elastic cushion is, the more valid the dimple will be suppressed .The longer free length is, the smaller the equivalent strain and thinning and more uniform the distribution of thickness will be. When the free length is shorter, the degree of effect is relatively obvious on the equivalent strain and thinning and the distribution of thickness; when the free length is longer than a certain value, the degree of effect is small.

Numerical Analysis of the Multi-Point Stretch Forming Process of Aircraft Outer Skin Part

2010 ◽  
Vol 154-155 ◽  
pp. 1068-1072
Author(s):  
Shao Hui Wang ◽  
Zhong Yi Cai ◽  
Ming Zhe Li ◽  
Ying Wu Lan
Keyword(s):  
Numerical Simulation ◽  
Numerical Analysis ◽  
Flexible Manufacturing ◽  
Stretch Forming ◽  
Forming Process ◽  
Outer Skin ◽  
Free Length ◽  
Simulation Results ◽  
The Cost ◽  
Elastic Cushion

As a flexible manufacturing technique, Multi-point stretch forming (MPSF) is a suitable method for forming aircraft outer skin part. The traditional solid stretching die is replaced by the discrete multi-point die (MPSD), and the sheet metal is stretch-formed over the MPSD generated by serial adjusting mode or parallel adjusting mode. The MPSF can be used to form the parts of different shape and reduce the cost and leading time of stretching die fabrication for aircraft outer skin part. A series of numerical simulations on typical MPSF processes of aircraft outer skin part were carried out. The thickness of elastic cushion and free length are important factors to influence on the stretch forming results of stretch-formed parts. The numerical simulation results show that the thicker the elastic cushion is, the more valid the dimple will be suppressed .The longer the free length is, the easier the wrinkle will be brought.

Numerical Analysis for Multi-Point Forming of Aluminum Alloy Profile

2014 ◽  
Vol 1035 ◽  
pp. 128-133 ◽  
Author(s):  
Xue Zhi Liu ◽  
Chun Guo Liu ◽  
Yuan Yao ◽  
Xue Guang Zhang
Keyword(s):  
Numerical Simulation ◽  
Aluminum Alloy ◽  
Numerical Analysis ◽  
Sheet Metal ◽  
Cross Section ◽  
Metal Parts ◽  
Sheet Metal Parts ◽  
Bending Process ◽  
A New Technique ◽  
Elastic Cushion

As a new technique to form sheet metal parts, Multi-point forming (MPF) also can be used on bending aluminum alloy profile. Since the Multi-Point Die (MPD) which replaces the traditional solid bending die is composed of many discrete punch elements, dimples always occur on the plate of profiles. To eliminate the dimpling defects, numerical simulation of the bending process with A6N01S-T5 aluminum alloy hollow profile using MPD were conducted. By comparing the bending effects on MPD with different size of punch elements and with different kind of elastic cushion, reasonable forming parameters were obtained. Pressing of Aluminum alloy profile with different radii on the MPD and solid die were simulated. The cross-section distortion indicated that the aluminum alloy profile can be formed with MPF technique while it has the advantage of flexibility. For the profile with large deformation, multi-step MPF method is a better choice due to its rapid reconfigurable characteristic.

Numerical Investigation on the Process of Stretch-Forming Based on Discretely Loading for Spherical Sheet Metal Parts

2013 ◽  
Vol 816-817 ◽  
pp. 682-685 ◽  
Author(s):  
Zhong Yi Cai ◽  
Mi Wang ◽  
Zhen Yang ◽  
Kun Peng
Keyword(s):  
Sheet Metal ◽  
Equivalent Stress ◽  
Three Dimensional ◽  
Equivalent Strain ◽  
Stretch Forming ◽  
Sheet Metal Part ◽  
Metal Part ◽  
Forming Process ◽  
Sheet Metal Parts ◽  
New Process

Stretch-forming based on discretely loading is a new process for manufacturing three-dimensional sheet metal part, the stretching load is applied at discrete points on the two ends of sheet metal, by controlling the loading trajectory at each discrete point, an optimal stretch-forming process can be realized, and the formed surface with the strains and stresses more uniformly distributed are obtained so that the forming defect can be avoided. The numerically investigated results on the stretch-forming process of spherical sheet metal part show that, comparing with the traditional stretch-forming, the equivalent strain in the new process is reduced by approximately 30% and equivalent stress reduced by 10%, the range of the strain and stress distributions are reduced by approximately 30%.

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.

Dynamics of a Supported Cylinder in Axial Flow

2011 ◽  
Vol 99-100 ◽  
pp. 1059-1062
Author(s):  
Ji Duo Jin ◽  
Ning Li ◽  
Zhao Hong Qin
Keyword(s):  
Nonlinear Dynamics ◽  
Numerical Analysis ◽  
Numerical Simulations ◽  
Nonlinear Model ◽  
Dynamical Behavior ◽  
Axial Flow ◽  
Viscous Force ◽  
Friction Drag ◽  
Flutter Instability ◽  
Nonlinear Force

The nonlinear dynamics are studied for a supported cylinder subjected to axial flow. A nonlinear model is presented for dynamics of the cylinder supported at both ends. The nonlinear terms considered here are the quadratic viscous force and the structural nonlinear force induced by the lateral motions of the cylinder. Using two-mode discretized equation, numerical simulations are carried out for the dynamical behavior of the cylinder to explain the flutter instability found in the experiment. The results of numerical analysis show that at certain value of flow velocity the system loses stability by divergence, and the new equilibrium (the buckled configuration) becomes unstable at higher flow leading to post-divergence flutter. The effect of the friction drag coefficients on the behavior of the system is investigated.

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