Papers by Keyword: Finite Element (FE) Simulation

Abstract: There are many models and failure criteria have been developed to predict the ductile fracture (DF) in metal plastic deformation. But usually, it is difficult to select a suitable model and the corresponding criterion from them. So, finding a way to identity their applicability and reliability is useful for selecting these DF criteria. In this paper, ductile fracture of aluminum alloy A5052P-H34 is studied by experiments and finite element simulations. In experiments, the mode I crack was obtained by uniaxial tension of plate with a circular hole in the center. The von Mises yield model and continuum damage mechanics based Rousselier model and modified Rousselier model are chosen to describe the material behavior. Three failure criteria, including the Cockcroft-Latham integral, maximum shear stress theory and critical void volume fraction criterion are investigated to determine their reliability in ductile failure prediction. These constitutive models and DF criteria are implemented by user material subroutine in ABAQUS/Explicit to predict the crack. And the crack initiation and propagation is implemented by element erosion method. By comparing the experiments and simulations, the modified Rousselier’s model with the corresponding criterion shows agreement with the experiments.

Abstract: Ring parts of duplicate gear, double-side flange, high pressure value body, are widely used in engineering machinery, have the common geometrical characteristic of thick-wall, small-hole and deep-groove on the surface. High energy consumption, low material utilization, low productivity and poor quality exist in the current forging technology of this type of rings. In this paper, a new forming method for this type of rings named combined ring rolling (CRR) is proposed. The forming principle of CRR is introduced at first, then, a 3-D coupled thermo-mechanical FE model for the CRR process of a double-side flange ring is developed. By simulation and analysis, the feasibility of CRR technology is testified, and the evolution and distribution rules of stain, temperature, force and power in the rolling process are revealed. The results provide the guideline for the research and development of CRR technology.

Abstract: In this paper, the turning process of 45# steel was simulated and analyzed based on the metal cutting finite element analysis software DEFORM-3D. The analysis result of cutting force was gained. However, due to some reasons of the software itself, there is noise data in analysis results. Thus, it’s needed to filter the data to extract useful information. The selected short-duration and steady-state cutting force data was processed with the use of six-sigma rule through mathematical statistics analysis. As a result, some bad data were rejected. Noise data was filtered out via wavelet analysis and the processed function curve of cutting force that changes with time during the whole cutting course was gained.

Abstract: A simulation and modeling method for micro turn-milling cutting process was investigated to predict the impacts of cutting speed and cutting depth on cutting force. Based on material Johnson-Cook constitutive model and chip separation criteria, the finite element model was established in ABAQUS simulation application, then the model analysis and experiment verification was conducted. The results indicate that the simulation model can predict the value and regularity of cutting force, which can provide guidance on process optimization and machining accuracy control.

Abstract: The cooling process of heavy rail is the important step to the output, that the preflexed rail is cooled on the stepping-type cold bed which has been carried by the chain transmission device. We employed the finite element method to analyze the bending deformation of the U75V rail through natural cooling process, the effected factors including the rail side-laying on the cold bed, the latent heat of phase change, and the thermal radiation are considered in the analysis. In the paper, we discussed the establishment of the heavy rail cooling model, the cooling parameters and the boundary condition, and emphatically analyzed the rail bending deformation changes and its principles through the cooling process. The study of the hundred-meter high speed heavy rail can provide the theoretical foundation and reference value to the formulation of cooling technical parameters and preflex technical schedule.

Abstract: DEFORM-3D is a finite element method(FEM) system which is based on a process simulation system, especially analyzing 3D flow of all kinds of steels forming process. The simulation analysis of metal forming and heat treatment process have been widely used. 16MnR is a common pressure vessel material. However, the material database in DEFORM-3D is lack of 16MnR, so it is urgent to improve the database. In the basis of the DEFORM-3D original material database，16MnR material database was increated by the second development. 16MnR material database and DEFORM-3D finite element simulation software is integrated seamlessly. The improved material database has great significance to numerical simulation in all aspects of the practical application in pressure vessel.

Abstract: The plastic strain finite element mesomechanics simulation of polycrystal martensitic transformation bring up non-linear model of influence microscopic phase transition rate and stress. Further developement and application of Marc and on the base of microscopic chemical energy distribution, evenly. As the simulation showed: 1) Early into the plasticity than that of single crystal.2) Microplastic strain distribution is not uniform, microplastic strain maximum, minimum value ratio in different incremental step fluctuate greatly. 3) Meso martensitic transformation is not uniformly distributed, and uneven degree decreases with increment step. 4) The macro transformation rate simulation curves are exponential trend, and into the fully plastic state reached the point.

Abstract: The concrete-filled steel tubular structure is widely used in practices, as it shows perfect seismic performances such as ductility, and has strong ability of collapse under seismic loading. In this paper, firstly, the stiffness damage and stiffness recovery parameters of concrete constitute model under cyclic loading was calibrated and verified by examples. Then the finite element model was verified by numerical examples of reinforce concrete members and concrete-filled steel tubular members. At last, on the base of the result of analysis and verification, the hysteresis curves on beam-column connection of concrete-filled steel tubular structure under cyclic loading were simulated and compared with experimental results, and the hysteresis characters was analyzed in the end.

Abstract: 6063 aluminum alloys are used as the luggage rack’s material on high-speed trains recently. The study on the AZ31B magnesium alloy is aimed to demonstrate the feasibility of the magnesium alloy’s application as the material of the luggage rack on high-speed trains. First, the mechanical properties of the AZ31B magnesium was obtained after a series of experimental tests on basic mechanical properties of the AZ31B magnesium alloy. The results show that the strength of the magnesium alloy is 1.25 times of the 6063 aluminum alloy and the impact toughness of the AZ31B magnesium alloy is twice as much as the 6063 aluminum alloy. Second, the stress distribution and the maximum value of the equivalent stress in given loading conditions was obtained by finite element strength analysis on the structure of the aluminum alloy luggage rack on high-speed trains. And the FE analysis results indicate that if the AZ31B magnesium alloy is used as the material of the luggage rack instead of the 6063 aluminum alloy, it will have a weight loss of the luggage rack for approximately 33%. In addition, the application of AZ31B magnesium alloy has more advantages in energy-saving, environmental protection and safety control.

Abstract: Braking deceleration of passenger-car has great influence on the pedestrian motion process after collision of human-vehicle accident, but it is considered not enough in current accident reconstruction and vehicle-speed analysis. In order to improve the accuracy of accident reconstruction, a computer simulation model of pedestrian-vehicle accidents based on finite element (FE) method and human parameters of Chinese adult human body is established. In this article, based on the FE model, human-vehicle crash is simulated through involving the influence of braking deceleration of passenger-car. For the application of the vehicle-speed analysis, the motion performance of pedestrian after collision were studied and the correlation between the pedestrian throw distance and vehicle impact speed are investigated. The influence of braking deceleration in same impact speed is analyzed. Research results show that the vehicle brake deceleration has a certain influence on the throw distance of pedestrian and it should be taken into account on the accident reconstruction. We can conclude that pedestrian throw distance can be used to estimate the vehicle collision speed accurately when drivers take full braking measure during the crash.