Discrete/finite element modelling of rock cutting with a TBM disc cutter

The final publication is available at Springer via http://dx.doi.org/10.1007/s00603-016-1133-7This paper presents advanced computer simulation of rock cutting process typical for excavation works in civil engineering. Theoretical formulation of the hybrid discrete/finite element model has been presented. The discrete and finite element methods have been used in different subdomains of a rock sample according to expected material behaviour, the part which is fractured and damaged during cutting is discretized with the discrete elements while the other part is treated as a continuous body and it is modelled using the finite element method. In this way, an optimum model is created, enabling a proper representation of the physical phenomena during cutting and efficient numerical computation. The model has been applied to simulation of the laboratory test of rock cutting with a single TBM (tunnel boring machine) disc cutter. The micromechanical parameters have been determined using the dimensionless relationships between micro- and macroscopic parameters. A number of numerical simulations of the LCM test in the unrelieved and relieved cutting modes have been performed. Numerical results have been compared with available data from in-situ measurements in a real TBM as well as with the theoretical predictions showing quite a good agreement. The numerical model has provided a new insight into the cutting mechanism enabling us to investigate the stress and pressure distribution at the tool–rock interaction. Sensitivity analysis of rock cutting performed for different parameters including disc geometry, cutting velocity, disc penetration and spacing has shown that the presented numerical model is a suitable tool for the design and optimization of rock cutting process.Peer ReviewedPostprint (published version

Kryteria perspektywicznej oceny efektywności ekonomicznej prac badawczych i rozwojowych w zakresie konstrukcji maszyn

Celem pracy jest udoskonalenie istniejących syntetycznych kryteriów perspektywicznej oceny efektywności ekonomicznej prac badawczych i rozwojowych, w wyniku których ma powstać nowy wyrób o charakterze środka trwałego (maszyna, urządzenie produkcyjne) przeznaczony dla użytkownika krajowego

Development of local models and their computational implementation for polymer coated steel sheets

This report present review of the state of the art of numerical modelling of polymers and polymer coated metal laminates and gives details of selected numerical models including those that will be used in the work in the project POLYCOAT. The first sections studied in the project. Basic mechanical and thermal properties of the polymers are reviewed. Then constitutive models developed for polymers are reviewed based on literature and own work. Details of selected models are given. Deformation behaviour of polymer coated metal laminates is considered with special attention to the phenomena observed at the polymer-metal interface. The numerical models for the interface are presented finally

Application of explicit FE codes to simulation of sheet and bulk metal forming processes

This paper presents the application of an explicit dynamic finite element code for simulation of metal forming processes, of both sheet and bulk forming. The experiences reported here have been gained during the development and use of our own explicit program Stampack. An original formulation of a triangular shell element without rotational degrees of freedom is reviewed combining the explicit sheet forming simulation with the implicit springback analysis as well as the parallelization of the explicit program described. An extension of a finite element code for coupled thermomechanical analysis is discussed. A new thermomechanical constitutive model developed by the authors and implemented in the program is presented. Numerical examples illustrate some of the possibilities of the finite element code developed

CBS‐based stabilization in explicit solid dynamics

The characteristic‐based split (CBS) stabilization procedure developed originally in fluid mechanics has been adapted successfully to solid mechanics problems. The CBS algorithm has been implemented within a finite element program using an explicit time integration scheme. Volumetric locking of linear triangular and tetrahedral elements has been successfully eliminated. The performance of the numerical algorithm is illustrated with numerical results. Comparisons with an alternative stabilization technique based on the finite calculus method also are given. Copyright © 2006 John Wiley & Sons, Ltd

NUMISTAMP: a research project for assessment of finite-element models for stamping processes

This paper describes the objectives and current status of the research project NUMISTAMP currently under development at the International Center for Numerical Methods in Engineering of (CIMNE) located in Barcelona, Spain. The aim of this project is the assesment of different finite element models for simulation of sheet stamping processes. The models currently analyzed include: quasistatic viscoplastic flow and elastoplastic solid models and explicit dynamic models. Both shell and continuum elements are considered in most of these cases. The paper presents an overview of the basic features of the different models. Examples of application including some benchmark test cases proposed at NUMISHEET are also presented

Industrial applications of sheet stamping simulation using new finite element models

The paper is aimed to present industrial applications of sheet stamping simulation using new finite element formulations developed in the International Center for Numerical Methods in Engineering in Barcelona. Theoretical formulation is briefly reviewed. Both continuum and shell elements have been considered. The new shell elements developed are based on a geometrically exact shell model treating the shell as one-director Cosserat surface. The formulation of the continuum elements employs the multiplicative decomposition of the deformation gradient tensor into its elastic and plastic parts. The new finite element models have been implemented in the in-house explicit dynamic code STAMPACK. A number of practical problems of sheet metalforming have been solved with the program. Some of the problems, namely stamping of a kitchen sink, hydraulic forming of an aeronautical part and stamping of a food can, have been presented in the paper. The examples give an idea of practical information that can be obtained from the computer simulation of a forming process. The results confirm a good behaviour of the formulation and program used in the industrial applications

Advances in discrete element modelling of underground excavations

The paper presents advances in the discrete element modelling of underground excavation processes extending modelling possibilities as well as increasing computational efficiency. Efficient numerical models have been obtained using techniques of parallel computing and coupling the discrete element method with finite element method. The discrete element algorithm has been applied to simulation of different excavation processes, using different tools, TBMs and roadheaders. Numerical examples of tunnelling process are included in the paper, showing results in the form of rock failure, damage in the material, cutting forces and tool wear. Efficiency of the code for solving large scale geomechanical problems is also show