Computer aided design and optimization of bi-layered tube hydroforming process

Tube hydroforming is one of the unconventional metal forming processes in which high fluid pressure and axial feed are used to deform a tube blank in the desired shape. However, production of bi-layered tubular components using this process has not been investigated in detail in spite of the large number of research studies conducted in this area. Bi-layered tubing can be useful in complex working environments as it offers dual properties that a single layer structure doesn’t have. Consequently, for wider implementation of this technology, a detailed investigation on bi-layered tube hydroforming is required. In this research, both single and bi-layered tube hydroforming processes were numerically modelled using the finite element method (ANSYS LS-DYNA). Experiments were conducted to check the numerical models validation. In addition, Response Surface Methodology (RSM) using the Design-Expert statistical software has been employed along with the finite element modelling to attain a detailed investigation of bi-layered tube hydroforming in the X-type and T-type dies. The process outputs were modelled as functions of both the geometrical factors (tube length, tube diameter, die corner radius, and thicknesses of both layers.) and the process parameters (internal pressure coordinates, axial feed, and coefficient of friction.). Furthermore, the desirability approach was used in conjunction with the RSM models to identify the optimal combinations of each the geometrical factors and process parameters that achieve different objectives simultaneously. In addition, a different optimization approach that applies the iterative optimization algorithm in the ANSYS software was implemented in the process optimization. The finite element models of single and bi-layered tube hydroforming processes were experimentally validated. A comparison of both processes was carried out under different loading paths. Also, response surface modelling of the bi-layered tube hydroforming process outputs was successfully achieved, and the main effects and interaction effects of the input parameters on the responses were discussed. Based on the RSM models, the process was optimized by finding the inputs levels at which the desired objectives are satisfied. Finally, a comparison of the RSM based optimization approach and the iterative optimization algorithm was performed based on the optimum results of each technique

Effect of Annealing Temperatures on Formability of SS 304 tubes during Tube Hydroforming Process: A Numerical study

Tube hydroforming is an advanced manufacturing process which utilizes a liquid medium to deform the tube with required shape. This method has an advantage of attaining uniform pressure throughout the tube at any time during the process. The main aim of the present study was to know the effect of different annealing temperatures on the tube hydroforming of SS 304 steel. Specimens were annealed with four different temperatures, viz., 100oC, 150oC, 200oC and 250oC. Annealed samples were tested to find the tensile properties in terms of yield strength, strength coefficient, strain hardening exponent, elongation and ultimate tensile strength. The evaluated mechanical properties were utilized to run the tube hydroforming simulations using finite element code. Effects of annealing temperatures on bulge height and thickness distribution of the bulged area of the tube were studied using FEM. Numerical simulations confirmed that the annealing temperatures had an effect on the bulge height and thickness distribution in the bulged zone of the tube

Effect of loading paths on hydroforming ability of stepped hollow shaft components from double layer pipes

The step hollow shaft components are composed of two layers of different materials, they are formed using tube hydroforming process due to its high strength and rigidity, low weight and flexible profiles, compared to traditional casting, welding, and forming methods. These products are effectively used in industries such as the automotive, shipbuilding, aerospace and defense, and oil and gas sectors. The success of various double layer pipe hydroforming process depends on several factors, with the most important being the internal pressure path and axial loading path. This paper presents research on the effect of input loading paths on the hydroforming ability of a different two-layer metal structure - an outer layer of SUS304 stainless steel and an inner layer of CDA110 copper - using 3D numerical simulations on Abaqus/CAE software. Output criteria were used to evaluate the forming ability of the formed components, including Von Mises stress, Plastic strain component (PEmax), wall thinning, and pipe profile, based on which the input loading paths were combined during the forming process. These output criteria allow for more accurate predictions of material behavior during the hydroforming process, as well as deformation and stress distribution. This can support the design process, improve product quality, reduce errors, and increase production efficiency. The research results can be applied as a basis for optimizing load paths for the next experimental step in the near future, for undergraduate and graduate training, as well as allowing designers and engineers to optimize the process of hydroforming of different 2-layer tubes, reducing costs, improving accuracy, flexible design, minimizing risks, and increasing efficienc

Experimental process development and aerospace alloy formability studies for hydroforming

Dans le procédé d’hydroformage, la pression d’un fluide est utilisée pour déformer plastiquement un tube paroi mince à l’intérieur d’une matrice fermée afin de remplir la cavité de la matrice. L’hydroformage des tubes possède de nombreux avantages qui rendent ce procédé très intéressant pour plusieurs industries telles que l’automobile et l’aérospatiale. Mais, à cause de différents facteurs tels que la formabilité des matériaux, l’ordre et les séquences du chargement (force de compression axiale et pression interne pendant le procédé), la géométrie de l’outil et la friction, c’est un procédé de mise en forme assez complexe. Ainsi, la simulation par éléments finis combinée à des méthodes d’optimisation peuvent réduire significativement le coût de l’approche “Essai – Erreur” utilisée dans les méthodes conventionnelles de mise en forme. Dans ce mémoire, pour étudier les effets de différent paramètres tels que les conditions de friction, l’épaisseur du tube et la compression axiale sur la pièce finale, des essais d’hydroformage de tube ont été menés en utilisant une matrice de forme ronde à carrée. Les expériences ont été effectuées sur des tubes d’acier inoxydable 321 de 50.8 mm (2 in) de diamètre et deux différentes épaisseurs ; 0.9 mm et 1.2 mm. L’historique du chargement a été enregistré avec le système d’acquisition de la presse. Un système de mesure de déformation automatique, Argus, a été utilisé pour mesurer les déformations sur les tubes hydroformés. Les données collectées à partir des essais initiaux ont été utilisées pour comparer avec les simulations. Le procédé a été simulé et optimisé à partir des logiciels Ls-Dyna et Ls-Opt, respectivement. Les variations de déformations et d’épaisseurs mesurées à partir des expériences ont été comparées aux résultats de la simulation par éléments finis dans les zones critiques. La comparaison des résultats de la simulation et des expériences sont en bon accord indiquant que l’approche peut être utilisée pour prédire la forme finale et les variations d’épaisseurs de pièces hydroformées pour des applications aérospatiales

Latest Hydroforming Technology of Metallic Tubes and Sheets

This Special Issue and Book, ‘Latest Hydroforming Technology of Metallic Tubes and Sheets’, includes 16 papers, which cover the state of the art of forming technologies in the relevant topics in the field. The technologies and methodologies presented in these papers will be very helpful for scientists, engineers, and technicians in product development or forming technology innovation related to tube hydroforming processes

Tube and Sheet Metal Forming Processes and Applications

At present, the manufacturing industry is focused on the production of lighter weight components with better mechanical properties and always fulfilling all the environmental requirements. These challenges have caused a need for developing manufacturing processes in general, including obviously those devoted in particular to the development of thin-walled metallic shapes, as is the case with tubular and sheet metal parts and devices.This Special Issue is thus devoted to research in the fields of sheet metal forming and tube forming, and their applications, including both experimental and numerical approaches and using a variety of scientific and technological tools, such as forming limit diagrams (FLDs), analysis on formability and failure, strain analysis based on circle grids or digital image correlation (DIC), and finite element analysis (FEA), among others.In this context, we are pleased to present this Special Issue dealing with recent studies in the field of tube and sheet metal forming processes and their main applications within different high-tech industries, such as the aerospace, automotive, or medical sectors, among others

Non linear finite element simulation of complex bulge forming processes

Bulge forming is a manufacturing process that is becoming increasingly important as a technology that can be used to produce seamless, lightweight and near-net-shape industrial components. The process is being increasingly applied in the automotive and aerospace industries where the demands for increased structural strength and decreased vehicle weight make it a very attractive manufacturing method. This work is concerned with increasing knowledge of the deformation mechanisms during bulge forming processes using numerical simulation. A number of complex bulge forming operations which have not been satisfactorily analysed in published research were identified and subsequently analysed using commercial finite element software. A non-linear explicit solution method was used in each case. The processes chosen for simulation were: hydraulic bulge forming of cross joints, bulge forming using a solid bulging medium, bulge forming of bimetallic tubes and the behaviour of the die during these bulge forming processes. In each case a number of process parameters were varied and their effect on the process identified. Where possible the finite element results were validated against results from experimental trials. It was found that the simulations predicted the experimental results with accuracy, thus indicating that the models developed here can be used with confidence to predict the behaviour of bulge forming operations. From the results of the finite element simulations it was concluded that when designing processes to bulge form cross joint components that compressive axial loading should be used in conjunction with pressure loading where possible, friction between the die and workpiece should be kept to a minimum where maximum branch height is required and greater tube thickness should be used when seeking to reduce stress and thinning behaviour in the formed component. The results also indicate that, where possible a solid bulging medium should be used as it results in much more favorable forming conditions, which can allow the realisation of greater branch heights. The simulations of bulge forming of bimetallic tubes showed that the relative thickness of the two metal layers has a significant effect on the shape of the final component. It was also found that varying the relative strength of the two metallic layers had a significant effect on the branch height obtained. The development of stress in the die during various bulge forming process was detailed at various stages during the process. It was found that generally a stress concentration moves towards the die bend as the process progresses. The effect of using different die materials was examined and it was concluded that certain materials are unsuitable for use as die materials due to the fact that their yield stress is exceeded during the forming process

Optimization of Operation Sequencing in CAPP Using Hybrid Genetic Algorithm and Simulated Annealing Approach

In any CAPP system, one of the most important process planning functions is selection of the operations and corresponding machines in order to generate the optimal operation sequence. In this paper, the hybrid GA-SA algorithm is used to solve this combinatorial optimization NP (Non-deterministic Polynomial) problem. The network representation is adopted to describe operation and sequencing flexibility in process planning and the mathematical model for process planning is described with the objective of minimizing the production time. Experimental results show effectiveness of the hybrid algorithm that, in comparison with the GA and SA standalone algorithms, gives optimal operation sequence with lesser computational time and lesser number of iterations