Three-dimensional Rigid-plastic Finite Element Research Articles

Numerical Simulation of Fine Blanking Die Wear and Die Performance Analysis

In order to study the die wear law of rotary fine blanking helical cylindrical gear, a three-dimensional rigid plastic finite element model of rotary fine blanking helical cylindrical gear is established on the Deform-3D software platform. Based on the Archard wear model, this paper analyzes the die wear in the fine blanking process, obtains the wear distribution of each point on the working surface of the die, determines the maximum wear area, and makes a comparative analysis with the fine blanking die wear of spur gear. Through the single factor variable method, this paper studies the effects of reverse jacking force, blank holder force, blanking speed, punch and die clearance, die fillet radius, and die initial hardness on die wear. The test results show that when the punch reduction is the same, the wear of the female die of fine blanking helical cylindrical gear is greater than that of fine blanking spur cylindrical gear. When the counter jacking force increases from 100 kN to 200 kN, the maximum wear of the die gradually increases from 6.91 × 10–6 mm to 9.38 × 10–6 mm; when the blank holder force increases to 3/4 of the blanking force, the die wear decreases with the increase of blank holder force; it is ideal when the blanking clearance is 0.5% t (0.02 mm). Conclusion. The wear model can accurately predict the relationship between main process parameters and wear in the process of rotary fine blanking, and the measures to reduce die wear are put forward from the aspect of process design.

Numerical analysis of twisted profile drawing process using rotating die

In this paper, twisted profile drawing process using free-to-rotate converging die was presented. In addition, numerical analysis of the twisted profile drawing process was presented. The twisted profile drawing process utilizes a free-to-rotate die to produce a twisted pattern with a trochodial cross-section on the surface of the rod. In order to analyze the twisted profile drawing process, a method to define a die for the twisted profile drawing process by considering a twisted die and a bearing part has been proposed. The twisted profile drawing processes were investigated by using the three-dimensional rigid-plastic finite element (FE) simulation. The effects of process variables, such as half die angle and twisted angle, on twisted profile angle in the twisted profile drawing process were investigated. From the results of FE simulation, process conditions of the twisted profile drawing process for polygonal and trochoidal cross-section with 3- to 5-tooth were optimized.

Finite element simulation based plate edging model for plan view pattern control during wide and heavy plate rolling

From a new viewpoint to improve plate plan view pattern during hot rolling, a plate edging process was proposed to roll back only the plate width spread of conventional rolling in this paper. Using commercial finite element (FE) analysis software DEFORM-3D, a three-dimensional rigid plastic FE model for vertical–horizontal (V–H) hot rolling was developed on the basis of a 5 m wide and heavy plate mill. Three hundred and twenty kinds of different V–H rolling processes were simulated by the FE model. Basing on the simulation results, the formation laws of dog bone shape during the vertical rolling and the width spread behaviours during the horizontal rolling were clarified. A plate edging model predicting the plate edging efficiency was established with the aid of an artificial neural network. The plate edging efficiency predicted by this plate edging model agreed well with those predicted by the existing strip edging models when the slab width/thickness ratio was small, which confirmed the validity of the plate edging model. The plate edging model expanded its application scope into the wide and heavy plate hot rolling.

Numerical Study on the Comparison of Deformation Characteristics during the Fine Blanking Process of Spur Gears and Helical Gear

As important transmission components, helical gears have been widely applied to mechanical and automotive fields. The traditional manufacturing process for helical gears is machining, which is time-consuming and result in the high cost of gears. In order to improve the production efficiency and product quality of helical gears, a novel forming process principle for the fine blanking of helical gears was developed. In this study, reliable three-dimensional (3D) rigid-plastic finite element (FE) models of single tooth and complete gears were set up and investigated using the software Deform-3D, the deformation characteristics of fine blanking of spur gears and helical gears were compared. Based on the valid numerical models, variation tendency of different field variables such as damage material flow velocity, and mean stress were obtained, as well as the feature of the tooth section, which provides a better understanding of the deformation mechanism of rotational fine blanking process.

Effects of parameters on rotational fine blanking of helical gears

The application of fine blanking to the manufacturing of helical gears directly from a strip has been restricted due to the traditional linear cutting stroke of the punch and die. In this work, rotational fine blanking which combined the linear and rotational motion of punch and counterpunch was applied for the forming of helical gears. A three-dimensional (3D) rigid-plastic finite element model was developed on the DEFORM-3D platform. By finite element simulation and analysis, the influences of key parameters on the punch load and cut surface were investigated. It is shown that: 1) with increasing the counterforce or helical angle, the punch load and the depth of die roll increase; 2) with increasing blank holder force, the punch load increases while the depth of die roll decreases; 3) V-ring indenter facilitates an improvement in the quality. The results of this research reveal the deformation mechanism of rotational fine blanking of helical gears, and provide valuable guidelines for further experimental studies.

Establishment of models for plan view pattern control in heavy plate rolling process based on 3-D FEM simulation

Basing on a 5 m heavy plate mill, a three-dimensional (3-D) rigid-plastic thermo-mechanical finite element (FE) model was developed to investigate plate plan view pattern (PVP) during hot rolling process. The vertical-horizontal (V-H) rolling was employed to improve plate PVP by preventing width spread. Basing on the FE simulation results of different V-H rolling processes, the plate edging model with short stroke control (SSC) was established with the aid of an artificial neural network (ANN). The compensation rolling was adopted to improve plate PVP by decreasing plate end convexity. The compensation rolling model was established on the basis of the plate PVP prediction model which was formulated by regression analysis of the simulation results of conventional rolling processes with different broadside rolling ratios. Simulation results showed that optimal combination of V-H rolling and compensation rolling can improve the plate PVP to a large extent.

Influence of tool parameters on tool wear in two-roll cross-wedge rolling

A simulation model for two-wedge two-roll cross-wedge rolling was presented by using three-dimensional rigid plastic finite element method. Based on the simulation results, the influence of three tool parameters—the forming angle α, the spreading angle β, and the area reduction Ψ on tool wear—is ascertained and discussed. The study results indicate that the tool wear depth increases with larger α, β, and Ψ. Simultaneously, tool wear can be improved under the condition of α = 28°, β = 8°, Ψ1 = 48.6 %, and Ψ2 = 53.3 %. Subsequently, blank forming for the engine connect rod was produced in the factory and statistical data from the factory manifests the feasibility of study results.

Optimisation of spiral forging process design for ensuring uniform quality of forged round billet by three-dimensional rigid–plastic finite element analysis

Focusing on the spiral forging stage of the hot open die forging process, which is the final stage of finishing round billets from ingots, the influence of operational conditions on the distribution of equivalent plastic strain has been numerically analysed using a three-dimensional rigid–plastic finite element method. The mechanism via which equivalent plastic strain is accumulated at the surface of the workpiece during spiral forging is clarified. The independent influence of each major operational parameter, i.e. rotational angle and feed, is revealed, and the optimum combination of these two parameters is clarified. The influence of the coefficient of friction is also discussed, and, as a result, a fundamental scheme to optimise spiral forging process design is suggested, taking account of not only uniformity of quality but also dimensional precision of the forged round billet.

Optimisation of open die forging condition and tool design for ensuring both internal quality and dimensional precision by three-dimensional rigid–plastic finite element analysis

Focusing on the rough forging stage of the hot open die forging process, the influences of anvil design and pass schedule on the internal quality of forged billet have been numerically analysed using a three dimensional rigid-plastic finite element method. By analysing the strain distribution newly added by one forging stroke, it has been clarified that the region where a workpiece contacts an anvil can be divided into four zones according to the deformation and, in the zone where a dead metal region arises at the surface, high strain is obtained at the centre. As a result, as regards the anvil edge shape design, it was found that it is effective to select an arc of small radius to obtain high strain at the centre. Moreover, in order to ensure both internal quality and dimensional precision of a forged surface, it has been revealed that it is effective to apply a small curvature to the flat surface of an anvil. The results have enabled a fundamental scheme to optimise tool design for ensuring both internal quality and dimensional precision to be established.

Optimisation of spiral forging process design for ensuring dimensional precision of forged round billets by three-dimensional rigid–plastic finite element analysis

Focusing on the spiral forging stage of the hot free forging process, which is the final stage to finish round billets from ingots, the optimisation of the operational conditions for ensuring dimensional precision of the final round billet has been carried out mainly by numerical analysis. In the analysis, a three-dimensional rigid-plastic finite element method was used and the validity of the analysis was examined by laboratory experiments using lead billets. The independent influence of each chosen major operational parameter, i.e. the rotational angle and the feed, has been clarified and critical and suitable ranges of the operational parameters for ensuring dimensional precision have been specified. As a result, the optimum combination of rotational angle and feed has been clarified and a fundamental scheme to optimise spiral forging process design has been suggested taking account of not only dimensional precision but also productivity. Moreover, it is suggested that the optimum rotational angle can be determined independently of the anvil geometry.

Three-dimensional rigid–plastic finite element simulation for the two-roll cross-wedge rolling process

In this paper, the process of cross-wedge rolling (CWR) has been simulated and analyzed by the 3D rigid–plastic finite element method. Considering the characteristic of CWR, the static implicit FEM program DEFORM-3D is selected. To simulate all forming stages in the CWR process, dynamic adaptive remeshing technology for tetrahedral solid elements was applied. The stress distributions in the cross-section of the forming workpiece are analyzed to interpret fracture or rarefaction at the center of workpiece. The authors have also analyzed the time–torque curve and the laws of load changing.

Simulation and analysis of rotary forging a ring workpiece using finite element method

The methods of dealing with some key problems in analyzing a rotary forging process with a finite element method are given. The presented mechanical model of the finite element analysis is in accordance with the actual conditions of the rotary forging process. A three-dimensional rigid–plastic finite element analysis code is developed in FORTRAN language and used to analyze the rotary forging process of a ring workpiece. Velocity fields and stress–strain fields of both contact and non-contact zones of the ring workpiece in the rotary forging are obtained. The deformation mechanism and metal flow laws of the contact zone surface of the ring workpiece in the rotary forging process are revealed. The pressure distributions of the contact surface along the radial and tangential directions and effects of rotary forging parameters on deformation characteristics are given.

Analysis of the non-steady state vertical–horizontal rolling process in roughing trains by the three-dimensional finite element method

The vertical–horizontal rolling process is often used to accomplish width reduction so as to provide a synchronising operation between the continuous slab casting and hot rolling processes. Numerical simulation of the non-steady state deformation behaviour around the head and tail ends during this process is made by the full three-dimensional rigid–plastic finite element method. An explanation is provided in the theory for the ‘thin element technique’ at the inlet surface of velocity discontinuity. To deal with the interpolation of friction within a surface of an element contacting partly with the roll, a new term, so-called ‘pseudo shape function’, is presented and a related new equation formula is deduced. The calculated shape of the slab edge, the separating force and the rolling torque are consistent with those measured experimental ones for the model material lead.

Three-dimensional rigid–plastic finite element method using diagonal matrix for large-scale simulation of metal-forming processes

A rigid–plastic finite element method using a diagonal matrix is proposed to perform large-scale three-dimensional simulation of metal forming processes in a realistic computing time. Uncoupled equilibrium equations of forces at one nodal point are repeatedly calculated in turn without solving the large global matrix. In the equilibrium equations, three corrective velocities at the nodal point are determined in order to eliminate imbalanced forces for trial velocities. This formulation leads to reduction in the increase rate of the computing time with the number of nodal point. In addition, the program for the developed simulator is much simpler than that of the conventional method and the memory size is very small because the global simultaneous equations are not solved at a time. To examine the convergence of solution in the present method, three-dimensional deformation in upsetting of a rectangular block with flat dies is simulated under non-sliding contact over the die surface. The effects of the initial nodal velocities, the order of nodal points for solving the equilibrium equations and the modification factor for the corrective velocities on the convergence are evaluated.

Three-dimensional rigid-plastic finite-element analysis of the isothermal precision forging of a cylindrical housing

An aluminium alloy cylindrical housing, a key component of a helicopter, has such complex geometry that its forming and die design are difficult. In this paper, a three-dimensional rigid–plastic finite element simulation program has been developed to analyse the forming process of the cylindrical housing. The technological conditions of isothermal precision forging are established and forging quality is improved according to the above results.

A three-dimensional finite element simulation of the vertical–horizontal rolling process in the width reduction of slab

A thermal coupling analysis is carried out by the full three-dimensional rigid–plastic finite element method to simulate vertical–horizontal rolling process during width reduction in the roughing stands of a hot strip mill. The slab shape, the spread and temperature as calculated are in good agreement with the experimental results in production mills, and the sectional distribution of temperature is given.

A three-dimensional rigid–plastic FEM analysis of rotary forging deformation of a ring workpiece

The deformation of a ring workpiece by the rotary forging process is analyzed using a three-dimensional rigid–plastic finite element method. Velocity fields and stress–strain fields of the ring workpiece in the rotary forging deformation are obtained. The new metal flow demarcation model obtained in this paper is different from that ever provided before. The deformation mechanism of the rotary forging of the ring workpiece is revealed thoroughly.

Three-dimensional rigid–plastic finite element analysis of non-steady-state shaped drawing process

In this paper, non-steady-state shaped drawing processes have been investigated by using the three-dimensional rigid–plastic finite element (FE) method. In order to analyze the shaped drawing process, a method to define a straight converging die by considering a straight die part, a die radius part and a bearing part has been proposed. In addition, the modeling of the initial billet and the generation procedure of the mesh system have been suggested. The three-dimensional rigid–plastic FE simulation has been performed for a square sectional drawing process and its validity has been confirmed by comparison with existing experimental results. Under the same process conditions, the effect of perimeter ratio and drawing stress in the shaped drawing process has been investigated. Also, the effects of process variables, such as the reduction in area and semi-die angle, on drawing stress and corner filling in the drawing process of a square rod from a round bar have been investigated by using the rigid–plastic FE code developed. In order to investigate corner filling, the diagonal ratio is calculated and compared with the results of the FE simulations. Furthermore, limits of the process variables are determined by considering bulging and necking. From the results, an optimal process condition satisfying reasonable corner filling and a minimum value of drawing stress is suggested.