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

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

Simulation of Pipe Hydroforming

The importance of investigating the formation of a torsion beam and understanding how it can be manipulated to perform at an optimum condition is crucial to car manufacturers. Developing and remodelling the torsion beam can allow both a simpler structure and quicker assembly while reducing the space required for a car suspension’s system, thus saving time and costs for manufacturers. Nowadays, the use of hydroforming technology has become widespread because it is able to obtain complex hollow parts more easily and has been continually developed to become a globally applied technology in the formation of a torsion beam of a vehicle. With regards to the current issues in academic research and real-world production, this research uses a finite element analysis (FEA) method-based software tool DYNAFORM, to simulate the pipe hydroforming process in order to show the overall manufacturing process, thus providing a precise FEA simulation model of a torsion beam suspension for the automotive manufacturing. This will also provide a math model (a regression equation) for further research and the further application of this technology in the future

Metal Micro-forming

The miniaturization of industrial products is a global trend. Metal forming technology is not only suitable for mass production and excellent in productivity and cost reduction, but it is also a key processing method that is essential for products that utilize advantage of the mechanical and functional properties of metals. However, it is not easy to realize the processing even if the conventional metal forming technology is directly scaled down. This is because the characteristics of materials, processing methods, die and tools, etc., vary greatly with miniaturization. In metal micro forming technology, the size effect of major issues for micro forming have also been clarified academically. New processing methods for metal micro forming have also been developed by introducing new special processing techniques, and it is a new wave of innovation toward high precision, high degree of processing, and high flexibility. To date, several special issues and books have been published on micro-forming technology. This book contains 11 of the latest research results on metal micro forming technology. The editor believes that it will be very useful for understanding the state-of-the-art of metal micro forming technology and for understanding future trends

ANALYSIS OF PART CONSOLIDATION TECHNIQUES FOR AUTOMOTIVE BODY IN WHITE PANELS BASED ON ADVANCED SHEET METAL FORMING TECHNOLOGIES

The automotive industry is looking to move from mass production to mass customization in order to manufacture and sell a variety of products in different markets on a global scale. This requires a robust and cost effective manufacturing system which would help design new products in the shortest possible lead time. This thesis tries to investigate the current sheet metal forming process for body in white, identify the limitations and propose an alternative which would help the industry cut down product lead time and costs. Decision making tools are used to identify the technical requirements of a BIW manufacturing system and optimize the same. Part consolidation techniques are studied in detail and the various means to achieve them are investigated. Industrial origami¨ is proposed as an alternative to automotive stamping and a means to achieve part consolidation. Origami joints and their design features were modeled using cad tools and their load bearing and strength characteristics are compared to that of stamped joints using finite element analysis simulations. A bill of materials of a small sedan is constructed to identify the opportunities for part consolidation and process substitution of stamping using origami

Computer aided optimization of tube hydroforming processes

Tube hydroforming is a process of forming closed-section, hollow parts with different cross sections by applying combined internal hydraulic forming pressure and end axial compressive loads or feeds to force a tubular blank to conform to the shape of a given die cavity. It is one of the most advanced metal forming processes and is ideal for producing seamless, lightweight, near net shape components.. This innovative manufacturing process offers several advantages over conventional manufacturing processes such as part consolidation, weight reduction and lower tooling and process cost. To increase the implementation of this technology in different manufacturing industries, dramatic improvements for hydroformed part design and process development are imperative. The current design and development of tube hydroforming processes is plagued with long design and prototyping lead times of the component. The formability of hydroformed tubular parts is affected by various physical parameters such as material properties, tube and die geometry, boundary conditions and process loading paths. Finite element simulation is perceived by the industry to be a cost-effective process analysis tool and has the capability to provide a greater insight into the deformation mechanisms of the process and hence allow for greater product and process optimization. Recent advances in the non-linear metal forming simulation capabilities of finite element software have made simulation of many complex hydroforming processes much easier. Although finite element based simulation provides a better understanding of the process, trial-and-error based simulation and optimization becomes very costly for complex processes. Thus, powerful intelligent optimization methods are required for better design and understanding of the process. This work develops a better understanding of the forming process and its control parameters. An experimental study of ‘X ’ and ‘T’-branch type tube hydroforming was undertaken and finite element models of these forming processes were built and subsequently validated against the experimental results. Furthermore these forming processes were optimized using finite element simulations enhanced with numerical optimization algorithms and with an adaptive process control algorithm. These new tools enable fast and effective determination of loading paths optimized for successful hydroforming of complex tubular parts and replace trial-and-error approaches by a more efficient customized finite element analysis approach

EXPERIMENTS AND ANALYSIS OF ALUMINUM TUBE HYDROFORMING

This is a thesis on the development of an experimental table-top sized tube hydroforming machine at the University of New Hampshire. This thesis documents the design of the machine and the exploration of the forming envelope of the device via finite element modeling of the forming process. Several experiments on Al-6061-T4 tubes were used to evaluate the plastic behavior and strain limits of the tube in the axial and circumferential (hoop) directions. Two of these material tests, the uniaxial tension test and the ring hoop tension tests, were simulated with finite element models to refine the Al-6061-T4 plasticity curve, including the extrapolation of the hardening curve beyond the point of ultimate tensile stress. 2D and 3D finite element models of the hydroforming process were also used to evaluate potential tube materials, outer diameters, and wall-thickness for future experiments and research efforts

Formability and hydroforming of anisotropic aluminum tubes

textThe automotive industry is required to meet improved fuel efficiency standards and stricter emission controls. Aluminum tube hydroforming is particularly well suited in meeting the goals of lighter, more fuel-efficient and less polluting cars. Its wider use in industry is hindered however by the reduced ductility and more complex constitutive behavior of aluminum in comparison to the steels that it is meant to replace. This study aims to address these issues by improving the understanding of the limitations of the process as applied to aluminum alloys. A series of hydroforming experiments were conducted in a custom testing facility, designed and constructed for the purposes of this project. At the same time, several levels of modeling of the process, of increasing complexity, were developed. A comparison of these models to the experiments revealed a serious deficiency in predicting burst, which was found experimentally to be one of the main limiting factors of the process. This discrepancy between theory and experiment was linked to the adoption of the von Mises yield function for the material at hand. This prompted a separate study, combining experiments and analysis, to calibrate alternative, non-quadratic anisotropic yield functions and assess their performance in predicting burst. The experiments involved testing tubes under combined internal pressure and axial load to failure using various proportional and non-proportional loading paths (free inflation). A number of state of the art yield functions were then implemented in numerical models of these experiments and calibrated to reproduce the induced strain paths and failure strains. The constitutive models were subsequently employed in the finite element models of the hydroforming experiments. The results demonstrate that localized wall thinning in the presence of contact, as it occurs in hydroforming as well as other sheet metal forming problems, is a fully 3D process requiring appropriate modeling with solid elements. This success also required the use of non-quadratic yield functions in the constitutive modeling, although the anisotropy present did not play as profound a role as it did in the simulation of the free inflation experiments. In addition, corresponding shell element calculations were deficient in capturing this type of localization that precipitates failure, irrespective of the sophistication of the constitutive model adopted. This finding contradicts current practice in modeling of sheet metal forming, where the thin-walled assumption is customarily adopted.Aerospace Engineering and Engineering Mechanic

Tube hydroforming of steel for automotive applications.

Tube hydroforming has the potential to produce large structural automotive components which may be utilised for weight reduction in future generation vehicles, by replacing stamped and spot-welded steel assemblies. However, limited implementation of this technology has taken place for Body-In-White (B-I-W) components, due to the complexity of the process and low levels of confidence and knowledge of the technology. This is coupled with assembly issues that this technology presents for B-I-W construction. In contrast the application of this technology for sub-frame and chassis component applications has been successful, principally due to the less stringent assembly requirements and proven cost and performance related benefits. The tube hydroforming process utilises forming fluid, under high pressure, to stretch a tube blank into the shape of a die cavity. The application of the internal pressure may be accompanied by axial feeding of the tube ends to push additional tube material into the die cavity. Close control of process parameters and the die design are essential to produce successful, defect-free components. However, the behaviour and response of steel and the influence of friction under these forming conditions are unknown entities. On the basis of a critical review of literature, a research programme was initiated to engage some of the key forming issues inhibiting wide-scale implementation of steel tube hydroforming for BIW automotive applications. The principal aims of the project were to identify the fundamental influences of steel properties on the tube hydroforming process and to develop a mathematical model of the process for steel tube. The research programme entailed small-scale formability tests and large-scale experimental trials, accompanied by the development of analytical and finite element (FE) models of the tube hydroforming process for various steel grades. The analytical and FE models could be used as design aids in the development of automotive BIW hydroformed components. The research project identified significant changes in both mechanical properties and surface characteristics as a result of the Electric Resistance Welding (ERW) tube manufacturing process. This in turn had a significant impact upon the hydroforming behaviour of the steel tubes. An analytical forming limit curve (FLC) model evaluated in this thesis was deemed to provided a robust means of predicting splitting or excessive thinning of a tube hydroformed component as a result of die geometry, tube material or processing conditions. The FE models developed, which incorporated the analytical FLCs, illustrated that the tube hydroforming process could be predicted with a high level of confidence for simple components