Prediction of Burst Pressure in Multistage Tube Hydroforming of Aerospace Alloys

Author(s):  
M. Saboori ◽  
J. Gholipour ◽  
H. Champliaud ◽  
P. Wanjara ◽  
A. Gakwaya ◽  
...  

Bursting, an irreversible failure in tube hydroforming (THF), results mainly from the local plastic instabilities that occur when the biaxial stresses imparted during the process exceed the forming limit strains of the material. To predict the burst pressure, Oyan's and Brozzo's decoupled ductile fracture criteria (DFC) were implemented as user material models in a dynamic nonlinear commercial 3D finite-element (FE) software, ls-dyna. THF of a round to V-shape was selected as a generic representative of an aerospace component for the FE simulations and experimental trials. To validate the simulation results, THF experiments up to bursting were carried out using Inconel 718 (IN 718) tubes with a thickness of 0.9 mm to measure the internal pressures during the process. When comparing the experimental and simulation results, the burst pressure predicated based on Oyane's decoupled damage criterion was found to agree better with the measured data for IN 718 than Brozzo's fracture criterion.

Author(s):  
M. Saboori ◽  
J. Gholipour ◽  
H. Champliaud ◽  
A. Gakwaya ◽  
J. Savoie ◽  
...  

Bursting, an irreversible failure in tube hydroforming (THF), results mainly from the local plastic instabilities that occur when the biaxial stresses imparted during the process exceed the forming limit strains of the material. To predict the burst pressure, Oyane’s and Brozzo’s decoupled ductile fracture criteria were implemented as user material models in a dynamic nonlinear commercial 3D finite element (FE) software, Ls-Dyna. THF of a round to V-shape was selected as a generic representative of an aerospace component for the FE simulations and experimental trials. To validate the simulation results, THF experiments up to bursting were carried out using Inconel 718 (IN 718) tubes with a thickness of 0.9 mm to measure the internal pressures during the process. When comparing the experimental and simulation results, the burst pressure predicated based on Oyane’s decoupled damage criterion was found to agree better with the measured data for IN 718 than Brozzo’s fracture criterion.


Author(s):  
Sergei Alexandrov ◽  
Lihui Lang

This paper deals with some general properties of a ductile fracture criterion, which generalizes two ductile fracture criteria conventionally adopted for metal forming analysis and design. The results are valid for a wide class of material models applicable to both cold and hot metal formings. It is expected that the theoretical features of the fracture criterion emphasized in the present paper can be useful for its experimental verification or for determining its parameters from the experiment.


2011 ◽  
Vol 62 ◽  
pp. 21-35 ◽  
Author(s):  
Anis Ben Abdessalem ◽  
A. El Hami

In metal forming processes, different parameters (Material constants, geometric dimensions, loads …) exhibits unavoidable scatter that lead the process unreliable and unstable. In this paper, we interest particularly in tube hydroforming process (THP). This process consists to apply an inner pressure combined to an axial displacement to manufacture the part. During the manufacturing phase, inappropriate choice of the loading paths can lead to failure. Deterministic approaches are unable to optimize the process with taking into account to the uncertainty. In this work, we introduce the Reliability-Based Design Optimization (RBDO) to optimize the process under probabilistic considerations to ensure a high reliability level and stability during the manufacturing phase and avoid the occurrence of such plastic instability. Taking account of the uncertainty offer to the process a high stability associated with a low probability of failure. The definition of the objective function and the probabilistic constraints takes advantages from the Forming Limit Diagram (FLD) and the Forming Limit Stress Diagram (FLSD) used as a failure criterion to detect the occurrence of wrinkling, severe thinning, and necking. A THP is then introduced as an example to illustrate the proposed approach. The results show the robustness and efficiency of RBDO to improve thickness distribution and minimize the risk of potential failure modes.


1969 ◽  
Vol 91 (4) ◽  
pp. 841-849 ◽  
Author(s):  
R. H. Wynn ◽  
C. W. Smith

Experiments were performed on cracked plates loaded in combined extension and approximately cylindrical bending. A fracture criterion was developed from the Sih-Hartranft bending theory, which, when modified to account for precatastrophic crack extension, agreed well with the experiments in regions where the crack remained open at fracture and appeared to provide a lower bound in the region where crack closure occurred.


2019 ◽  
Vol 55 (16) ◽  
pp. 47 ◽  
Author(s):  
YANG Zhuoyun ◽  
ZHAO Changcai ◽  
DONG Guojiang ◽  
CHEN Guang ◽  
ZHU Liangjin ◽  
...  

2014 ◽  
Vol 622-623 ◽  
pp. 3-14 ◽  
Author(s):  
Kenichi Manabe

A sophisticated servo press with the digital control has been developed and attracted attention in recent years. By utilizing its high function in-process, servo presses have a potential to enhance the forming limit and to improve quality and accuracy of product not only in sheet stamping but also in tube hydroforming processes. On the other hand, in-process control and adaptive process control technologies in metal forming processes using intelligent technique and soft computing have been investigated and developed previously. Nowadays we are in a good environment to realize further advanced adaptive in-process control in metal forming process. To further advance this technology, sensing system is essential element and it should be applied to feedback control optimally in their forming operation. This paper describes the current situation on advanced intelligent process control technology for sheet stamping and tube hydroforming processes on the basis of the research results by the author.


2016 ◽  
Vol 96 ◽  
pp. 401-408 ◽  
Author(s):  
Bolin Ma ◽  
Z.G. Liu ◽  
Zheng Jiang ◽  
Xiangdong Wu ◽  
Keshan Diao ◽  
...  

2020 ◽  
Vol 846 ◽  
pp. 139-145
Author(s):  
Shinichi Nishida ◽  
Daichi Uematsu ◽  
Naoki Ikeda ◽  
Kyohei Ogawa ◽  
Makoto Hagiwara ◽  
...  

This paper describes finite element method analysis (FEM analysis), results of burring processing of large diameter steel pipe and fracture criterion in burring process of large diameter steel pipe. In this study, the pipe is the 150A SGP pipe with a diameter of 165.2 mm and a wall thickness of 5 mm. The pipe is used for a plant as a flow channel of gas and liquid. A burring process of pipe is generally for forming the branch. The burring process is achieved by drawing of die from prepared hole. And the branch pipe is welded to the formed pipe. This process has some problem. One is the forming limit of pipe, and the other is needed to machining the end surface to be welded. Therefore, in this study, the forming limit of SGP pipe was estimated by FEM analysis of burring process. The parameters used for criteria for forming limit are the maximum shear stress and the equivalent strain. As a result of comparing the analysis result and the experimental result, the forming limit of the 150A SGP pipe was estimated that the maximum shear stress is 350 MPa and the equivalent strain is around 0.8.


Sign in / Sign up

Export Citation Format

Share Document