Papers by Keyword: FEM Simulation

Abstract: Roll forming pipes for hydrogen infrastructure poses particular challenges for process design, especially with regard to geometric accuracy and the avoidance of forming defects that could compromise the integrity of the pipelines. Geometric accuracy is crucial to ensure uniform pressure distribution within the pipe. Conventional trial-and-error approaches to developing roll flower designs are time-consuming and cost-intensive, especially when working with high-strength steel grades. This work presents an integrated methodology for roll forming of monolithic sheet by incorporating real-world machine stiffness and experimental anisotropy. A finite element model was developed for S235 and S355 steels, validated through three-point bending and Digital Image Correlation (DIC). While database-derived models (JMatPro) underestimated yield stress by up to 30%, the experimental model precisely predicted strain distributions (error < 2%). A central novelty is the integration of in-situ 3D laser scans of the roll forming mill under load, allowing the simulation to account for elastic machine deflection. This enables the prediction of process-induced residual stresses, which are critical for the long-term integrity of pipelines against hydrogen-induced cracking.

Abstract: In fine blanking, a mass production process for safety-critical components, a discrepancy exists between deterministic modeling approaches and the stochastic nature of real-world measurements, often termed process noise. This work combines Finite Element Method simulations with data from industrial-scale fine blanking experiments, featuring long stroke series across multiple coils with systematically varied die clearances. The analysis shows a strong correlation between force curve characteristics and the formation of tears, a relationship that holds across all tested geometries. In contrast, only weak and inconsistent correlations were found between the force signal and the resulting die roll. This weakness is explained by the finding that multiple physical effects, such as material strength and friction, have competing influences on die roll that are not separable in the single force signal. These results demonstrate that the utility of the force signal for quality prediction is highly dependent on the tool geometry, providing a basis for more reliable tool design strategies in fine blanking.

Abstract: The aim of this study is predict tool wear in the fine-blanking process using a tribometer tester with ASTM G99-17 standard. Then, the result of wear volume and tool life were confirmed with finite element simulation and experiment. The punch material used in fine blanking process was selected to be hight speed steel JIS.SKH51 with surface coating thickness 4 µm of TiCN, the work piece material was used as hot-rolled steel JIS.SPHD P/O, with a thickness of 8 mm. The experimented and simulated results were found that the pressure, and sliding velocity were increase in term of linear curve with slope K = 2.09x10^-6 and K = 2.07x10^-6 ,respectively, and the hardness of material was increase in term of power at 1.983 and slope of K = 2.14 x10^-6. These three factors were effect to the wear volume and tool life, simultaneously, the summation of three factors will average as K = 2.10 x10^-6. From comparison of the applied wear equation model with tribology tester the simulated and experimented results were similarly equal with 0.05 by significance at 95% reliability confident. The resulted were precisely confirmed according to the previous research.

Abstract: The FEM (finite element method) simulation was used to study the diffusion bonding deformation of high purity tungsten target. The influence of different welding structure, bonding temperature on the deformation of the final high-purity tungsten target was systematically studied. Meanwhile, some microscopic properties of tungsten target were developed, such as internal stress size and distributions, strain size and distributions. Finally, physical experiments are used to verify numerical simulation results. The results show that the method of adding an intermediate layer can release the residual stress between the high-purity target and back plate. The bonding stress of high-purity tungsten target is mainly concentrated with the tungsten target and the intermediate layer in between, which is easy to fail during the later leveling process. Small deformation of bonding tungsten target can be obtained by low diffusion bonding temperature.

Abstract: This study focused on investigation of the effect of process parameter to the tensile strength of a spot welded S235 low carbon steel through simulation and experiment. Resistance spot welding (RSW) is commonly used in joining metal sheets due to its key capabilities, which is time and cost effective as well as high adaptability for automation. However, strength and reliability of a spot welded joint especially in an auto vehicle can be unpredictable. Premature failure of a spot welded joint can be difficult to be predicted but common factors that had been discussed in many research is related with fatigue and residual stress. Process parameter is recognized as one of critical factors affecting the reliability and quality of a spot welded joint. Different type of material and thickness may require different set of parameter to achieve an optimum result. Experimental procedure alone to demonstrate and investigate the effect could be too costly and time inefficient. Therefore, design of experiment and non-linear FEM simulation analysis were used to analyze and validate the result. This study shows the significance of process parameters such as weld current and electrode pressure to the strength of a spot welded joint and accurate setting is needed prior to the welding process to achieve an optimum result.

Abstract: In this research, the bullet-collision test was done in the different velocity. The influence of its velocity on the deformation shape after collision was discussed by comparison with experiment and simulation. The velocity of the bullet was chosen in several kinds of speed ranges at 80m/s-250m/s. The angle of incidence with the collision object is 90 degree (head-on collision). The deformation shape was measured by 3D measurement instrument and reconstructed with 3D-CAD based on the 3D digital data. The deformation mark of the polycarbonate plate and the penetration shape of acrylic plastic plate caused by the bullet's collision with the object were examined. In addition, the collision simulation of the bullet was done by using FE analysis code “LS-DYNA”, and these analytical results were compared with the 3D digital data which is the experimental results.

Abstract: The technology of cold die drawing of tubes is used for processing of metals and alloys with good or worse formability, while the tube production itself is affected by various process parameters, i. e. mostly die geometry, strain degree and strain rate, force conditions, conditions of friction, method of lubrication and type of used lubricant. The paper is concerned with an evaluation of influence of the selected process parameters, i. e. drawing tool geometry and strain rate on plastic flow and energy intensity of the process of cold die drawing of tubes. The FEM analysis of the drawing process was an important aid for this research. The computer simulation resulted in interesting graphs illustrating the influence of the shape of the drawing tool reduction cone on the size of the drawing force at various strain rates.

Abstract: The hardness of alloys after phase coarsening is analyzed through the linkage between the multiparticle diffusion simulation and the finite element method simulation. Our analysis demonstrates that considerable degradation of the hardness of alloys occurs due to phase coarsening, which is related to the precipitate sizes and their distribution within the alloy. The microstructural evolution alters the manners of the nucleation, multiplication and movement of dislocations within the material, and further leads to different degradation of macroscopic hardness of alloys.

Abstract: Simulation using the DEFORM-3D package of the steady-state pressing mode of a copper busbar on the continuous extrusion line "Conform" was carried out. The nature of the metal flow in the deformation zone was studied. An analysis of the velocities of the metal flow in the prechamber was performed. It was shown that in the channel of the wheel there is pressing out, which negatively affects the quality of the finished busbars and can lead to such defects as "lamination".

Abstract: The paper presents the results of the study of residual stresses in stainless cold-drawn pipes obtained during FEM simulation of the process of sink drawing. The relation of the value of reduction, the taper angle of the working area of the drawing zone, the drawing speed and the friction coefficient to the pattern of distribution and the value of residual stresses in the pipe walls was established.