In this paper, the effects of several parameters on the deep drawing process of laminated sheets are comprehensively studied. The main reason to carry out such a process is taking the advantages of different materials, such as high strength, low density and corrosion resistibility, at the same time and in a single component. With this regard, it is possible to take the benefits of the forming processes, such as low waste of material and high directional strength of the components. This research work is concerned with the experimental and finite element studies of the deep drawing process of steel/brass laminated sheets. Several tests were conducted to investigate the influences of some variables, such as the stacking sequence of the layers, lubrication, blank-holder force and the diameter of the composite blank on the load–displacement curve and the final shape of the produced components. Investigation of stress and strain distributions in the deep drawn cup were also done and the FE results showed that the numerical method can predict the same place of tearing for bimetal cup as occurred in experimental tests. The main issues studied in this work are the material flow (occurrence of defects such as wrinkling and fracture) of the layers of the specimen and the required drawing force.

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Deep drawing process of steel/brass laminated sheets

Integration of finite element analysis and design of experiments to analyse the geometrical factors in bi-layered tube hydroforming

Employment of finite element analysis and Response Surface Methodology to investigate the geometrical factors in T-type bi-layered tube hydroforming

To produce highly functional tubular parts with locally different properties, tailor welded tubes (TWTs), which are made by tube-to-tube welding of tubes having different thicknesses or mechanical properties, are hydroformed. Notwithstanding the numerous applications of TWT hydroforming processes, TWT presents some disadvantages and considerable risk owing to the presence of a weld seam. This study proposes and characterizes the tailor layered tube (TLT) hydroforming process, which can fabricate hollow tubular parts with dissimilar thicknesses by using TLTs without welding. The proposed TLT hydroforming process was implemented and characterized both numerically and experimentally to validate its feasibility. The optimal loading path to prevent defects including insufficient bulging and wrinkle were analytically determined and verified by experiments. The deformation behaviors of TLT were also characterized at various processing parameters. The results demonstrate that the proposed TLT hydroforming process can be a feasible alternative for achieving tailored properties even with dissimilar thicknesses, with high reliability.

Tailor layered tube hydroforming for fabricating tubular parts with dissimilar thickness

Discrete layer forming proposed in this study is a hydroforming process which can selectively deform the outer tube to a desired shape without any deformation of the inner tube by piercing small holes in the inner tube. A three-layered tube is assembled from inner, middle, and outer tubes, from either similar or dissimilar materials, and deforms simultaneously when internal pressure and axial feed are applied to the tube. In special working environments, multi-layered tubes with combined material properties, high strength, and corrosion resistance are required to satisfy conflicting performance requirements. The feasibility of proposed discrete layer forming process of three-layered tube was evaluated by a tube hydroforming experiment and process analysis was performed. An optimal loading path to prevent wrinkling around holes was developed by an analytical model and was experimentally verified. The results show that the proposed discrete layer forming process can be successfully applicable to hollow forming of non-axisymmetric multilayered tubes for structural purposes.

Discrete layer hydroforming of three-layered tubes

Feasibility of multi-layered tubular components forming by hydroforming and finite element simulation

Purpose: Optimization of the operating conditions is one of the most significant studies in the hydroforming process, which affect the forming of successful components. Design/methodology/approach: Finite Element simulations have been carried out using the commercial finite element package ANSYS in order to predict the most efficient and acceptable operating condition for certain material properties of multilayered blank and initial blank geometry. Findings: This paper studies the hydroforming process involving combined (axial feed and internal pressure) and multi stage non-linear loading action theoretically and experimentally for a multi layered tubular blank placed in a pre-shaped die block. Research limitations/implications: Finite Element simulation of a multi layered tube hydroforming and optimisation of the best forming conditions based on a number of simulations were carried out to avoid wrinkling or bursting of the tubular blanks. Originality/value:

Experimental and finite element simulation of formability and failures in multilayered tubular components

In the manufacturing process, materials are deformed plastically at a level or lower than the ultimate stress of the materials. In the hydroforming process, the deformation of the material occurs non-linearly and this introduces mechanical stresses which are developed into the final products. This paper describes different kind of mechanical stresses which result from the hydroforming process in a multilayered T-branch simulation. Simulations have been carried out for the multilayered tubes comprising an outer layer of commercial brass and an internal layer of annealed copper. Currently, no classical solution exists for this type of problem. For that reason a numerical analysis has been presented in this paper. Analyses have been carried out under different loading conditions and the allowable stress that is developed in the final products is presented for the top central node and in addition to the overall model.

M. D. Islam

Papers

Feasibility of multi-layered tubular components forming by hydroforming and finite element simulation

Experimental and finite element simulation of formability and failures in multilayered tubular components

Mechanical stresses in the multilayered T-branch hydroforming: numerical simulation