Finite element comparison of single, bi-layered and three-layered tube hydroforming processes
In this paper, single, bi-layered and three-layered tube hydroforming processes were numerically simulated using the finite element method. It was found that the final bulges heights resulted from the models were in good agreement with the experimental results. Three types of modeling were kept with the same geometry, tube material and process parameters to be compared between the obtained hydroformed products (branch height, thickness reduction and wrinkling) using different loading path types. The results were also discussed.
Tailor layered tube hydroforming for fabricating tubular parts with dissimilar thickness
Abstract 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.
Flexural behavior of steel beams strengthened by carbon fiber reinforced polymer plates – Three dimensional finite element simulation
Abstract Debonding, as a mode of failure, is one of the major limitations when using externally bonded carbon fiber reinforced polymer (CFRP) plates in strengthening of steel beams. In this work, mode of failure and flexural behavior of both steel and steel–concrete composite beams strengthened by different lengths of CFRP plates were numerically investigated. The effect of both splicing position (at mid-span and near supports) and CFRP plate ends configuration were studied. Three dimensional finite element analysis (3D FEA) was adopted to simulate the nonlinear behavior of these beams loaded under four point bending configuration. The present numerical analysis assisted by previously valuable experimental results found in the literature succeeded to predict the critical CFRP plate length at which, full efficiency of the adhesively bonded plate is achieved.