The efficiency and clash load of impact forming machines to the second order of approximation

Vajpayee, S Kant; Sadek, M. M.; Tobias, S. A.

doi:10.1016/0020-7357(79)90013-1

Cited by 10 publications

(11 citation statements)

References 2 publications

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“…Two degrees of freedom models are commonly used in the literature to describe hammers [5,11,15,17]. These models are good tools for predicting forging variables and blow efficiency, supporting the choice of a two degrees of freedom model in the present study.…”

Section: Identification Of the Model And Its Parametersmentioning

confidence: 56%

“…With only the measurement of the load signal, the impact velocity, the friction coefficient, and the material characteristics for one blow, it is possible to determine a model and its associated parameters. Dynamic models for forging machines were developed for laboratory drop hammer [7], single-acting hammer [5] and industrial hammers by focusing on foundation behaviour [11]. However, model parameters were not determined from experimental measurements and do not consider the specificities of the machine.…”

Section: Identification Of the Model And Its Parametersmentioning

confidence: 99%

“…Moreover, knowledge of the actual energy transmitted to the billet will allow better prediction of the thermomechanical path during forging operations and may improve the microstructure control for high-performance materials forging. Process efficiency is influenced by process parameters, such as impact velocity and initial billet geometries [5]. Thanks to the BIM model, these parameters could be optimised, to maximise efficiency for a sequence of forging operations.…”

Section: Prediction Of Consecutive Blows For the Upsetting Of An Aluminium Billetmentioning

confidence: 99%

“…This implies that the instrumentation of forging machines is difficult, which is why theoretical models are used to describe dynamic machine behaviour. Tobias [4] developed a one degree of freedom model with one mass and one spring to represent hammer behaviour and Vajpayee et al [5] proposed a model comprising one spring and two masses to describe hammer-forging operations. The masses and the stiffness were obtained from the machine specifications and the machine model was coupled with the billet behaviour.…”

Section: Introductionmentioning

confidence: 99%

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A new tailored solution to predict blow efficiency and energy consumption of hammer-forging machines

Mull

Durand

Baudouin

et al. 2020

Int J Adv Manuf Technol

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Energy saving has become a real issue in process management and has led to the analysis of the energy consumption of forging machines, for the purpose of optimization. This study focuses on the amount of energy lost due to machine behaviour during the forming process. A spring-mass-damping model of the machine and tools system is associated with a billet model to describe hammer-forming operations only during the forging phase. The model parameters are identified with experimental measurements of process variables during a stroke, providing parameters specifically adapted to the machine-tools system. Then, model predictions are validated by the experimental upsetting of steel and aluminium billets. The model accurately predicts forging process variables for consecutive blows with different materials. The decrease in process efficiency and the evolution from inelastic to elastic blows after several strokes on the same billet are also predicted by the model. This methodology provides a new, tailored solution that enables forging manufacturers to predict the forging energy consumption of their own machines. The approach developed in this work concerns gravity drop hammers but is also transferable to other energy-driven machines.Jean-François Mulljeanfrancois.mull@ens am.eu

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Section: Identification Of the Model And Its Parametersmentioning

confidence: 56%

Section: Identification Of the Model And Its Parametersmentioning

confidence: 99%

Section: Prediction Of Consecutive Blows For the Upsetting Of An Aluminium Billetmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A new tailored solution to predict blow efficiency and energy consumption of hammer-forging machines

Mull

Durand

Baudouin

et al. 2020

Int J Adv Manuf Technol

View full text Add to dashboard Cite

show abstract

“…Major areas of application of this method are open‐die forging and closed‐die forging. However, the research works relating to this process have remained rather limited[2, 3, 4, 5, 6, 7]. With the intention of analysing the impact forging process, the implicit type of rigid‐plastic finite element codes[8], which are commonly used in metal forming analysis, can be applied to the analysis, but most metal forming analyses using these codes are restricted to cases with constant die velocity and they cannot provide sufficient information about the complex dynamic phenomena such as contact and separation between the workpiece and the dies during impact operation.…”

Section: Introductionmentioning

confidence: 99%

Numerical simulation of multi‐blow forging processes using the explicit time integration finite element method

Yoo

Yang

Chung

1997

Engineering Computations

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Describes simulations of impact forging processes. Uses the explicit time integration finite element method, which is based on direct time integration of equation of motion, to compute the deformation of the workpiece and the dies. Uses the program developed to simulate the copper blow test performed on a 350,000J counter‐blow hammer. The calculated result reveals a good agreement in the final deformed configurations between the experiment and the explicit simulation. In order to compare this with the explicit method, the implicit time integration rigid‐plastic finite element program considering the inertia effect is also applied to the copper blow test simulation. As a result of the copper blow test simulation using the explicit program and the implicit program, finds that the calculated results have good agreements in available plastic deformation energy, forging load and equivalent plastic strain distribution. Finally, applies the developed program to simulations of multi‐blow forging processes. Presents three major findings from the multi‐blow forging simulations: (1) the continuous analysis technique used for the multi‐blow forging simulations works well; (2) the blow efficiency and the forging load generated by blow operations can be analysed efficiently and simulated results coincide with previous experimental and analytical ones; (3) the geometrical configuration of the workpiece is closely related to blow efficiency.

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A FE Billet Model and a Spring-Mass-Damper Model for the Simulation of Dynamic Forging Process: Application to a Screw Press

et al. 2021

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In forging processes, the determination of blow efficiency is very important, as it quantifies the part of the stroke energy actually transmitted to the billet. Thus, forging processes should be deeply analyzed in order to better understand the stroke energy conversion, accurately estimate blows efficiency and thus better predict process parameters. In this paper, a spring-mass-damper vibration model is proposed to describe forming operations of a screw press. Parameters specially adapted to the machine-tools system are identified thanks to a stroke without billet. Thereafter, the experimental upsetting of a copper cylinder is realized, and two independent numerical simulations are performed. First, the billet upsetting is simulated by FE simulation with no consideration of the elastic and damping effect due to the machine-tools behavior in order to determine a relation between the load and the billet height. Then, forging load from the FE simulation is used to perform another simulation of the forging process with the spring-mass-damping model. Results show that the model is relevant to simulate load and ram displacement. Moreover, simulation can predict the distribution of the energy during the simulation and the blow efficiency can be calculated. This new way to obtain blow efficiency might improve productivity in process development and provide a better understanding of energy driven machine.

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The efficiency and clash load of impact forming machines to the second order of approximation

Cited by 10 publications

References 2 publications

A new tailored solution to predict blow efficiency and energy consumption of hammer-forging machines

A new tailored solution to predict blow efficiency and energy consumption of hammer-forging machines

Numerical simulation of multi‐blow forging processes using the explicit time integration finite element method

A FE Billet Model and a Spring-Mass-Damper Model for the Simulation of Dynamic Forging Process: Application to a Screw Press

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