Assessment and Improvement of Force Computations for Sheet Metal Extrusion

2009 ◽  
Vol 16-19 ◽  
pp. 490-494
Author(s):  
Zhen Zhao ◽  
Xin Cun Zhuang ◽  
Hua Xiang
Keyword(s):  
Sheet Metal ◽  
Shear Force ◽  
Numerical Solutions ◽  
Extrusion Force ◽  
Forming Force ◽  
Force Prediction ◽  
Area Reduction ◽  
Proposed Model ◽  
Metal Thickness ◽  
Metal Extrusion

On the basis of their similarities with forward rod extrusion, three analytical force computation models are introduced for the forming force prediction of sheet metal extrusion. By comparing with finite element solutions, it has been found that the forming forces obtained by these models deviate at more or less 30% from the numerical solutions under different area reductions. These deviations are due to the neglect of friction or shear force terms in the models. Therefore, a new model, one that fully considers the contributions of extrusion force, shear force, and friction terms to the forming force, is proposed. With tremendous numerical computations, the relationships between forming force and area reduction, sheet metal thickness, and penetration depth, among others are analyzed. Thereafter, the factors in the proposed model are determined. Additionally, a corresponding experiment work has been designed to validate the proposed model. Compared with the experimental results, the predicted results show a relative error of less than 15% under different extrusion ratios, which is acceptable in the industry.

Research on Influence of Process Parameters on Sheet Metal Extrusion Force

2009 ◽  
Vol 16-19 ◽  
pp. 515-519
Author(s):  
Hua Xiang ◽  
Xin Cun Zhuang ◽  
Zhen Zhao
Keyword(s):  
Sheet Metal ◽  
Process Parameters ◽  
Fem Simulation ◽  
Extrusion Process ◽  
Orthogonal Experimental Design ◽  
Extrusion Force ◽  
Influence Of Process Parameters ◽  
Tool Shape ◽  
Simulation And Experiment ◽  
Metal Extrusion

Extrusion force plays a significant role on sheet metal extrusion process. It is characterized by various process parameters including material properties, extrusion ratio, friction, tool shape etc. In this paper, a reasonable FEM model of sheet metal extrusion process was established and validated by comparing the results of simulation and experiment firstly. Based on the reliable model, the effect on extrusion force of various process parameters was investigated with orthogonal experimental design combined FEM simulation. The work presented in this paper has laid certain foundation for further work of modeling and optimizing extrusion force.

Some Phenomenological Characteristics of Medium-Thick Sheet Metal Extrusion Process

2009 ◽  
Vol 16-19 ◽  
pp. 485-489
Author(s):  
Xin Cun Zhuang ◽  
Hua Xiang ◽  
Zhen Zhao
Keyword(s):  
Sheet Metal ◽  
Extrusion Process ◽  
Shrinkage Cavity ◽  
Thick Sheet ◽  
Arbitrary Lagrangian Eulerian ◽  
Ale Finite Element Method ◽  
Area Reduction ◽  
Thick Sheet Metal ◽  
Simulation Results ◽  
Metal Extrusion

The medium-thick sheet metal extrusion has been a typical bulk forming feature used in the sheet metal forming industry while there isn’t enough know-how available. Therefore, the sheet metal extrusion process was simulated in this study by using an arbitrary Lagrangian-Eulerian (ALE) finite element method implemented in MSC. Marc. Firstly, the simulation results are compared with experimental data from a reference to verify the usefulness of the simulation. Then, based on the simulation results, some phenomenological characteristics of the sheet metal extrusion process, such as the material flow, shrinkage cavity and the effect of area reduction on the forming force, are present. The work presented in this paper might be used for as design fundamental of the sheet metal extrusion process.

scholarly journals System of Time Fractional Models for COVID-19: Modeling, Analysis and Solutions

Symmetry ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 787
Author(s):  
Olaniyi Iyiola ◽  
Bismark Oduro ◽  
Trevor Zabilowicz ◽  
Bose Iyiola ◽  
Daniel Kenes
Keyword(s):  
Fractional Order ◽  
Recovery Rate ◽  
Death Rate ◽  
Numerical Solutions ◽  
Complex Nature ◽  
Uniqueness Of Solutions ◽  
Fractional Equations ◽  
Effective Contact ◽  
Proposed Model ◽  
Fractional Models

The emergence of the COVID-19 outbreak has caused a pandemic situation in over 210 countries. Controlling the spread of this disease has proven difficult despite several resources employed. Millions of hospitalizations and deaths have been observed, with thousands of cases occurring daily with many measures in place. Due to the complex nature of COVID-19, we proposed a system of time-fractional equations to better understand the transmission of the disease. Non-locality in the model has made fractional differential equations appropriate for modeling. Solving these types of models is computationally demanding. Our proposed generalized compartmental COVID-19 model incorporates effective contact rate, transition rate, quarantine rate, disease-induced death rate, natural death rate, natural recovery rate, and recovery rate of quarantine infected for a holistic study of the coronavirus disease. A detailed analysis of the proposed model is carried out, including the existence and uniqueness of solutions, local and global stability analysis of the disease-free equilibrium (symmetry), and sensitivity analysis. Furthermore, numerical solutions of the proposed model are obtained with the generalized Adam–Bashforth–Moulton method developed for the fractional-order model. Our analysis and solutions profile show that each of these incorporated parameters is very important in controlling the spread of COVID-19. Based on the results with different fractional-order, we observe that there seems to be a third or even fourth wave of the spike in cases of COVID-19, which is currently occurring in many countries.

Theoretical Tire Model Considering Two-Dimensional Contact Patch for Force and Moment

2021 ◽  
Author(s):  
Y. Nakajima ◽  
S. Hidano
Keyword(s):  
Finite Element Method ◽  
Shear Force ◽  
The Self ◽  
Slip Angle ◽  
Force Distribution ◽  
Two Dimensional ◽  
Tire Model ◽  
Side Force ◽  
Contact Patch ◽  
Proposed Model

ABSTRACT The new theoretical tire model for force and moment has been developed by considering a two-dimensional contact patch of a tire with rib pattern. The force and moment are compared with the calculation by finite element method (FEM). The side force predicted by the theoretical tire model is somewhat undervalued as compared with the FEM calculation, while the self-aligning torque predicted by the theoretical tire model agrees well with the FEM calculation. The shear force distribution in a two-dimensional contact patch under slip angle predicted by the proposed model qualitatively agrees with the FEM calculation. Furthermore, the distribution of the adhesion region and sliding region in a two-dimensional contact patch predicted by the theoretical tire model qualitatively agrees with the FEM calculation.

scholarly journals A level-set method for modeling the evolution of glacier geometry

2004 ◽  
Vol 50 (171) ◽  
pp. 485-491 ◽  
Author(s):  
Antoine Pralong ◽  
Martin Funk
Keyword(s):  
Steady State ◽  
Mass Balance ◽  
Level Set Method ◽  
Level Set ◽  
Numerical Solutions ◽  
Glacier Surface ◽  
Surface Evolution ◽  
Proposed Model ◽  
Steady State Solutions ◽  
Over Time

AbstractA level-set method is proposed for modeling the evolution of a glacier surface subject to a prescribed mass balance. This leads to a simple and versatile approach for computing the evolution of glaciers: the description of vertical fronts and overriding phenomena presents no difficulties, topological changes are handled naturally and steady-state solutions can be calculated without integration over time. A numerical algorithm is put forth as a means of solving the proposed model of glacier surface evolution. It is evaluated by comparing different numerical solutions of the model with analytical and published numerical solutions. The level-set method appears to be a reliable approach for dealing with different glaciological problems.

scholarly journals Dynamics Analysis of Unbalanced Motorized Spindles Supported on Ball Bearings

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Junfeng Liu ◽  
Tao Lai ◽  
Xiaoan Chen
Keyword(s):  
High Speed ◽  
Magnetic Force ◽  
Numerical Solutions ◽  
Dynamic Properties ◽  
Lyapunov Stability Theory ◽  
Force Model ◽  
Proposed Model ◽  
Dynamic Operating ◽  
Motorized Spindles ◽  
Good Agreement

This paper presents an improved dynamic model for unbalanced high speed motorized spindles. The proposed model includes a Hertz contact force model which takes into the internal clearance and an unbalanced electromagnetic force model based on the energy of the air magnetic field. The nonlinear characteristic of the model is analysed by Lyapunov stability theory and numerical analysis to study the dynamic properties of the spindle system. Finally, a dynamic operating test is carried out on a DX100A-24000/20-type motorized spindle. The good agreement between the numerical solutions and the experimental data indicates that the proposed model is capable of accurately predicting the dynamic properties of motorized spindles. The influence of the unbalanced magnetic force on the system is studied, and the sensitivities of the system parameters to the critical speed of the system are obtained. These conclusions are useful for the dynamic design of high speed motorized spindles.

PREDICTION OF CONVECTIVE HEAT TRANSFER OF NANOFLUIDS BASED ON FRACTAL-MONTE CARLO SIMULATIONS

2013 ◽  
Vol 24 (01) ◽  
pp. 1250090 ◽  
Author(s):  
BO-QI XIAO ◽  
GUO-PING JIANG ◽  
YI YANG ◽  
DONG-MEI ZHENG
Keyword(s):  
Heat Transfer ◽  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Numerical Solutions ◽  
Probability Model ◽  
Average Diameter ◽  
Physical Mechanisms ◽  
Proposed Model

With the consideration of the Brownian motion of nanoparticles in fluids, the probability model for the size of nanoparticles and the model for convective heat transfer of nanofluids are derived based on the fractal character of nanoparticles. The proposed model is expressed as a function of the size of nanoparticles, the volumetric nanoparticle concentration, the thermal conductivity of base fluids, fractal dimension of nanoparticles and the temperature, as well as the random number. It is found that the convective heat flux of nanofluids decreases with increasing of the average diameter of nanoparticles. This model has the characters of both analytical and numerical solutions. The Monte Carlo simulations combined with the fractal geometry theory are performed. Every parameter of the proposed formula on convective heat transfer of nanofluids has clear physical meaning. So the proposed model can reveal the physical mechanisms of convective heat transfer of nanofluids.

Experimental Study on the Crash Performance of Aluminum and Steel Rails

2002 ◽  
Author(s):  
Chelliah Madasamy ◽  
Omar Faruque ◽  
Tau Tyan
Keyword(s):  
Mild Steel ◽  
Energy Absorption ◽  
Sheet Metal ◽  
High Strength Steel ◽  
High Strength ◽  
Maximum Load ◽  
Design Parameters ◽  
Impact Speed ◽  
Automotive Body ◽  
Metal Thickness

Increasing government mandated CAFE´ standards are forcing the OEMs to aggressively reduce vehicle weight. Aluminum, with a density of about a third of that of steel, has been established as a viable alternative to steel for the construction of the automotive body structure. However, for aluminum sheet metals, there are still lingering concerns about the reliability and robustness of the available joining techniques such as spot-welding, riveting etc. The investigation reported in this paper was aimed at evaluating the relative performance of self-pierced riveted aluminum rails as compared to spot-welded mild steel and high strength steel rails. A series of straight and curved (S-shaped) rails made of aluminum, mild steel, and high strength steel have been tested. Other design parameters considered in this study include sheet metal thickness, rivet/weld location, rivet/weld spacing, adhesives, temperature, and impact speed. As were observed from the tests, axial crush mode dominated the deformation of all straight rails while bending dominated the deformation of the curved rails. Statistical analysis was performed to find the relative importance and effects of each variable on the average crush load, maximum load and energy absorption. For aluminum rails, the thickness of the sheet metal was found to be the primary controlling factor for both straight and S-rails. Other factors i.e. rivet spacing/location, adhesives, temperature and impact speed, had no significant affect on the performance of the rails. For the steel rails, the sheet metal thickness, impact speed, temperature and material properties, were all found to be significant for the crash behavior. It was also found that the aluminum rails have higher specific energy absorption than the steel rails confirming that aluminum as a material is more efficient in absorbing crush energy than steel.

scholarly journals Study of Microstructure and Mechanical Properties Effects on Workpiece Quality in Sheet Metal Extrusion Process

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Chatkaew Suriyapha ◽  
Bopit Bubphachot ◽  
Sampan Rittidech
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Sheet Metal ◽  
Material Flow ◽  
Flow Behavior ◽  
Fem Simulation ◽  
Localized Plastic Deformation ◽  
Metal Extrusion ◽  
Microstructure Effect ◽  
1045 Steel

Sheet metal extrusion is a metal forming process in which the movement of a punch penetrates a sheet metal surface and it flows through a die orifice; the extruded parts can be deflected to have an extrusion cavity and protrusion on the opposite side. Therefore, this process results in a narrow region of highly localized plastic deformation due to the formation and microstructure effect on the work piece. This research investigated the characteristics of the material-flow behavior during the formation and its effect on the microstructure of the extruded sheet metal using the finite element method (FEM). The actual parts and FEM simulation model were developed using a blank material made from AISI-1045 steel with a thickness of 5 mm; the material’s behavior was determined subject to the punch penetration depths of 20%, 40%, 60%, and 80% of the sheet thickness. The results indicated the formation and microstructure effects on the sheet metal extrusion parts and defects. Namely, when increasing penetration, narrowing the die orifice the material flows through, the material was formed by extruding, and defects were visibility, and the microstructure of the material’s grains’ size was flat and very fine. Extrusion defects were not found in the control material flow. The region of highly localized plastic deformation affected the material gain and mechanical properties. The FEM simulation results agreed with the experimental results. Moreover, FEM could be investigated as a tool to decrease the cost and time in trial and error procedures.

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