Tube Hydroforming (THF): Process Optimization of an Automotive Component

2013 ◽  
Vol 549 ◽  
pp. 141-148
Author(s):  
Aldo Attanasio ◽  
Elisabetta Ceretti ◽  
Giancarlo Maccarini
Keyword(s):  
Fluid Pressure ◽  
Tube Hydroforming ◽  
Experimental Tests ◽  
Side Impact ◽  
Pressure Curve ◽  
Part Geometry ◽  
Italian Government ◽  
Working Solution ◽  
Hydroforming Process ◽  
Good Agreement

This paper reports the results obtained during a research project funded by the Italian Government and involving several Italian Universities (PRIN INTEMA). The activities have been focused on side impact bar manufacturing by means of Tube Hydroforming process (THF). Punch movement paths and fluid pressure curve were optimized by means of FEM software (LS-DYNA) to guarantee tube sealing and material feeding during the tube deformation. The side impact bar geometry was optimized till reaching the shape guaranteeing the obtainment of safe parts with the best compromise in terms of final part geometry and thickness reduction. Different fluid pressure and punch movement paths were investigated. Once accomplished all the simulations and identified the best working solution, experimental tests were performed setting the process parameters according to the values defined during the simulation phase. Good agreement between FEM and experimental results were highlighted.

Numerical – Experimental Correlation of Sheet Hydroformed Component

2015 ◽  
Vol 651-653 ◽  
pp. 1140-1145
Author(s):  
Alessandro Spagnolo ◽  
Teresa Primo ◽  
Gabriele Papadia ◽  
Antonio del Prete
Keyword(s):  
Finite Element ◽  
Process Parameters ◽  
Complex Geometry ◽  
Thickness Distribution ◽  
Fluid Pressure ◽  
Experimental Tests ◽  
Element Analysis ◽  
Influence Of Process Parameters ◽  
Experimental Correlation ◽  
Hydroforming Process

Sheet hydroforming has gained increasing interest in the automotive and aerospace industries because of its many advantages such as higher forming potentiality, good quality of the formed parts which may have complex geometry. The main advantage is that the uniform pressure can be transferred to any part of the formed blank at the same time. This paper reports numerical and experimental correlation for symmetrical hydroformed component. Experimental tests have been carried out through the hydroforming cell tooling, designed by the authors thanks to a research project, characterized by a variable upper blankholder load of eight different hydraulic actuators. The experimental tests have been carried out following a factorial plane of two factors, with two different levels for each factor and three replicates for each test with a total of 12 tests. In particular two process parameters have been considered: blank holder force, die fluid pressure. Each factor has been varied between an High (H) and Low level (L). The order in which have been conducted the tests has been established through the use of the Minitab software, in order to ensure the data normality and the absence of auto-correlation between the tests. An ANOVA analysis has been performed, in addition, with the aim of evaluating the influence of process parameters on the thickness distribution of the component, its formability and feasibility. Finally, finite element analysis (FEA) was used to understand the formability of a material during the hydroforming process. In this paper, the commercial finite element code LS-Dyna was used to run the simulations. A good numerical – experimental correlation has been obtained.

Investigation on the Effect of Pulsating Pressure on Tube-Hydroforming Process

2011 ◽  
Vol 473 ◽  
pp. 618-623
Author(s):  
Khalil Khalili ◽  
Seyed Yousef Ahmadi-Brooghani ◽  
Amir Ashrafi
Keyword(s):  
Finite Element ◽  
Internal Pressure ◽  
Thickness Distribution ◽  
Tube Hydroforming ◽  
Element Model ◽  
Fe Model ◽  
Axial Feeding ◽  
Hydroforming Process ◽  
The Finite Element Model ◽  
Good Agreement

Tube hydroforming process is one of the metal forming processes which uses internal pressure and axial feeding simultaneously to form a tube into the die cavity shape. This process has some advantages such as weight reduction, more strength and better integration of produced parts. In this study, T-shape tube hydroforming was analyzed by experimental and finite element methods. In Experimental method the pulsating pressure technique without counterpunch was used; so that the internal pressure was increased up to a maximum, the axial feeding was then stopped. Consequently, the pressure decreased to a minimum. The sequence was repeated until the part formed to its final shape. The finite element model was also established to compare the experimental results with the FE model. It is shown that the pulsating pressure improves the process in terms of maximum protrusion height obtained. Counterpunch was eliminated as being unnecessary. The results of simulation including thickness distribution and protrusion height were compared to the part produced experimentally. The result of modeling is in good agreement with the experiment. The paper describes the methodology and gives the results of both experiment and modeling.

Buckling of Tube for Tube Hydroforging

2019 ◽  
Author(s):  
Chetan P. Nikhare
Keyword(s):  
Axial Force ◽  
Thickness Distribution ◽  
Fluid Pressure ◽  
Tube Hydroforming ◽  
Expansion Ratio ◽  
Rigid Bodies ◽  
Maximum Expansion ◽  
Tube Forming ◽  
Strain Pattern ◽  
Hydroforming Process

Abstract Tube forming is one of the most common manufacturing processes to shape the tubes. Within tube forming operations the general practice is to expand and reduce the tube end cross-section and bend the tube by means of a solid mandrel. Mostly the mandrel is rigid bodies. To reduce the friction between the tube and the tool, tube hydroforming process was evolved in which the fluid was highly pressurized to expand the tube shape to the desired shape. By reducing the friction more uniform thickness could be achieved and thus increase in formability. In this paper, the tube was formed in two steps with low fluid pressure and axial force. The tube will be allowed to a useful maximum buckle by applying the axial force and/or a ramp internal pressure which then hydroforged with constant pressure for the maximum expansion ratio. The buckling mechanics of tube with respect to the fluid pressure and the axial force was studied. Further, the pressure requirement for hydroforging was investigated with respect to the length of the tube. The strain pattern and thickness distribution were studied in the buckling/bulging and hydroforging step.

Die Design and Axial Feeding in the Tube-Hydroforming Process

2010 ◽  
Author(s):  
Sin-Liang Lin ◽  
Fuh-Kuo Chen
Keyword(s):  
Finite Element ◽  
Fluid Pressure ◽  
Tube Hydroforming ◽  
Expansion Ratio ◽  
Loading Path ◽  
Structural Part ◽  
Axial Feeding ◽  
Internal Fluid ◽  
Hydroforming Process ◽  
Production Part

In the present study, the loading path with constant internal fluid pressure during axial feeding to hydroform an automotive structural part with higher expansion ratio was investigated. The axial feedings employed at various internal fluid pressures were simulated by the finite element method. It is found that the axial feeding applied at a favorable internal fluid pressure, the production part with higher expansion ratio still could be made. Compared with other loading paths published in literature, which are mainly linear paths, the proposed loading path provides a simple approach to achieve better performance in the hydroforming process. The factors causing wrinkling fin the hydroforming process were also studied by analyzing the relationship between the die face shape and the material flow in the die cavity. An optimum die face design that avoided pinching at the die closing process was then proposed. The actual hydroforming process for manufacturing the automotive structural part was conducted as well in the present study to validate the proposed loading path and the optimum die face design. The consistent agreement between the production part and the finite element simulation results confirms not only the proposed loading path and die face design, but also the effectiveness of the finite element analysis employed in the tube-hydroforming process.

scholarly journals Numerical Optimization of the Blank Dimensions in Tube Hydroforming Using Line-Search and Bisection Methods

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 945
Author(s):  
Antonio Fiorentino ◽  
Paola Serena Ginestra ◽  
Aldo Attanasio ◽  
Elisabetta Ceretti
Keyword(s):  
Numerical Optimization ◽  
Line Search ◽  
Tube Hydroforming ◽  
Minimum Cost ◽  
Experimental Tests ◽  
Complex Problem ◽  
Optimum Process ◽  
Line Search Method ◽  
New Process ◽  
Hydroforming Process

The change from a consolidated manufacturing practice to a new solution is often a complex problem because of the operative limits of technologies and the strict constraints of industrial parts. Moreover, the new process must reflect or enhance the characteristics of the product and, overall, it must be more competitive in performances and costs. Accordingly, the development of a new process is a multilevel and multivariate problem that requires a systematic and hierarchical approach. The present paper focuses on the development of a Tube Hydroforming process capable to replace the current practice for production of T-Joint parts made of AISI 316L for the water pipes market. In particular, the problem must withstand many process and product constraints. Therefore, it was split in three steps focused on specific aspects of the process: identification of process parameters and configuration, numerical optimization of the blank tube dimensions (length and thickness), experimental tests and final improvements. In particular, two numerical methods were implemented in the optimization step: the line–search method to approach to the optimum point and Bisection method to refine the search. These approaches allowed us to identify the optimum process configuration and, in particular, the optimal dimensions of the blank tube that allows one to achieve the product requirements with the minimum cost of material.

Research on Friction Behavior in Tube Hydroforming Process

2012 ◽  
Vol 217-219 ◽  
pp. 1774-1778
Author(s):  
Zai Xiang Zheng ◽  
Jing Xu ◽  
Guo Xian Liu
Keyword(s):  
Material Flow ◽  
Tube Wall ◽  
Thickness Distribution ◽  
Tube Hydroforming ◽  
Experimental Tests ◽  
Friction Model ◽  
Friction Behavior ◽  
Hydroforming Process ◽  
Tooling Design ◽  
Selection Of

In the tube hydroforming process, the friction behavior between the tube blank and the die is very complex. As a result, it is very difficult to build a precise friction model in accordance with the actual working conditions by fully taking into account the various factors. In this paper, the friction behaviors between the tube blank and the die in the guided, transition and expansion zones have been studied with the help of numerical simulation and experimental tests. The influences of the different friction conditions in the three zones as well as the uneven friction behavior in the expansion zone on the thickness distribution of tube wall and the characteristics of material flow have been analyzed and experimental tests have been carried out for the verification. The conclusions have provided theoretical references for the process planning, selection of lubrication and tooling design in the actual production process of tube hydroforming.

scholarly journals Experimental Methods for Measuring the Viscous Friction Coefficient in Hydraulic Spool Valves

2021 ◽  
Vol 13 (13) ◽  
pp. 7174
Author(s):  
Massimo Rundo ◽  
Paolo Casoli ◽  
Antonio Lettini
Keyword(s):  
Friction Coefficient ◽  
Viscous Friction ◽  
Experimental Tests ◽  
Experimental Methods ◽  
Displacement Transducer ◽  
A Posteriori ◽  
Displacement Control ◽  
Spool Valves ◽  
The University ◽  
Good Agreement

In hydraulic components, nonlinearities are responsible for critical behaviors that make it difficult to realize a reliable mathematical model for numerical simulation. With particular reference to hydraulic spool valves, the viscous friction coefficient between the sliding and the fixed body is an unknown parameter that is normally set a posteriori in order to obtain a good agreement with the experimental data. In this paper, two different methodologies to characterize experimentally the viscous friction coefficient in a hydraulic component with spool are presented. The two approaches are significantly different and are both based on experimental tests; they were developed in two distinct laboratories in different periods of time and applied to the same flow compensator of a pump displacement control. One of the procedures was carried out at the Fluid Power Research Laboratory of the Politecnico di Torino, while the other approach was developed at the University of Parma. Both the proposed methods reached similar outcomes; moreover, neither method requires the installation of a spool displacement transducer that can significantly affect the results.

Optimization of Tube Hydroforming Process Using Probabilistic Constraints on Failure Modes

2011 ◽  
Vol 62 ◽  
pp. 21-35 ◽  
Author(s):  
Anis Ben Abdessalem ◽  
A. El Hami
Keyword(s):  
Failure Modes ◽  
High Reliability ◽  
Thickness Distribution ◽  
Tube Hydroforming ◽  
Forming Limit Diagram ◽  
Plastic Instability ◽  
Probabilistic Constraints ◽  
Forming Limit ◽  
Reliability Based Design ◽  
Hydroforming Process

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.

Fluid Added Mass Effect in the Modal Response of a Pump-Turbine Impeller

2009 ◽  
Author(s):  
Eduard Egusquiza ◽  
Carme Valero ◽  
Quanwei Liang ◽  
Miguel Coussirat ◽  
Ulrich Seidel
Keyword(s):  
Natural Frequencies ◽  
Experimental Tests ◽  
Mass Effect ◽  
Added Mass ◽  
Mode Shapes ◽  
Pump Turbine ◽  
Modal Response ◽  
Surrounding Fluid ◽  
Turbine Impeller ◽  
Good Agreement

In this paper, the reduction in the natural frequencies of a pump-turbine impeller prototype when submerged in water has been investigated. The impeller, with a diameter of 2.870m belongs to a pump-turbine unit with a power of around 100MW. To analyze the influence of the added mass, both experimental tests and numerical simulations have been carried out. The experiment has been performed in air and in water. From the frequency response functions the modal characteristics such as natural frequencies and mode shapes have been obtained. A numerical simulation using FEM (Finite Elements Model) was done using the same boundary conditions as in the experiment (impeller in air and surrounded by a mass of water). The modal behaviour has also been calculated. The numerical results were compared with the available experimental results. The comparison shows a good agreement in the natural frequency values both in air and in water. The reduction in frequency due to the added mass effect of surrounding fluid has been calculated. The physics of this phenomenon due to the fluid structure interaction has been investigated from the analysis of the mode-shapes.

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