Material Flow Simulation Research Articles

Real-time dynamic simulation of continuous bulk material flow to improve the statistical modelling of final product strength properties

In regression analyses, correlations between independent variables (e.g. process variables) and dependent variables (e.g. product quality) are of major interest. However, only statistically significant correlations ensure a reliable interpretation of how process variables affect product qualities. In this respect, accurate time alignment of independent variables is crucial to obtain regression models with acceptable validation that are influenced by temporal phenomena (e.g. industrial processes) only. In this study, the commonly used static form of time alignment, where only the distances between consecutive process parameters and the average production speed are considered, is compared to a newly developed dynamic calculation of time lags. The dynamic calculation of time lags was achieved by modelling the continuous bulk material flow. The two different methods of calculation were then applied on an industrial production of particleboards to predict final board strength properties. Results of regression models showed that the use of dynamically calculated time lags improved the predictability of the internal bond strength of boards by 67% compared to statically calculated time lags. Consequently, final product strength properties could be predicted more accurately, which should lead to lower costs of rejects and a higher efficiency of material inputs.

RETRACTED ARTICLE: Finite element simulation of material flow in friction stir process of nylon 6 and nylon 6/MWCNTs composite

AbstractIn the current study, a numerical model based on Lagrangian incremental formulation was developed for friction stir process (FSP) of nylon 6 and nylon 6/multiwalled carbon nanotube (MWCNT) composite to investigate the thermomechanical behavior of them (e.g. temperature, effective plastic strain distribution, material flow, and material velocity). For this purpose, FSP was used to disperse the MWCNTs among the polymer matrix of nylon 6, homogenously. The X-ray diffraction and scanning electron microscopy were used to investigate the properties of fabricated nanocomposite. The obtained results were then used to verify the objectives of numerical model. According to the results, the MWCNTs are separated from each other while passing the tool-pin due to high plastic strain applied on them and greater amount of the material accumulates in the AS of stirred zone after passing the tool-pin. Also, MWCNTs were homogeneously and straightly dispersed throughout the nylon 6. The straight and non-curved disper...

GRAMOSA framework for graphical modelling and simulation-based analysis of complex production processes

The adequate planning of production processes is a big challenge, in which model-based planning concepts help to manage and to structure the accruing data. By using conceptual process models, like Business Process Modelling Notation, Event-driven Process Chains, etc., the consistent description of material flows is often neglected, meaning that the transformation into material flow simulation models is often impossible. Complex production processes with branched material flows are particularly difficult to model in a simulation driven way. This paper presents the modelling concept GRAMOSA (graphical modelling and simulation-based analysis) as an integrated approach for the material flow-oriented modelling of complex production processes. A new notation as part of an overall factory data model is developed. By using GRAMOSA, the factory data model can be transformed directly into executable simulation models. This concept of automated model generation saves time and reduces transformation failures in comparison to manual programming. The modelling concept and its simulation feasibility is evaluated by a use case, which represents a flexible flow shop scenario with 3 × 3 paralleled machines and inventory control strategy.

Analysis of heat transfer and material flow in reverse dual-rotation friction stir welding

Reverse dual-rotation friction stir welding (RDR-FSW) is a novel variant of conventional FSW process. The key feature is that the tool pin and the assisted shoulder rotate reversely and independently during the process; thus, it has great potential to improve the weld quality and lower the welding loads through adjusting the rotating speeds of the tool pin and the assisted shoulder independently. In this study, a 3D model of RDR-FSW process is developed to conduct the numerical simulation of heat generation, material flow, and temperature profile during the process. Heat generated due to plastic deformation and friction at the tool-workpiece contact interfaces are both considered. Streamlines show that there are two material flows with reverse direction, which is beneficial to the uniformity of both the temperature and the microstructure at the advancing side and retreating side. The simulation results show that rotating speeds of the assisted shoulder and the tool pin have great effects on the shape and size of the thermo-mechanically affected zone (TMAZ). The calculated peak temperatures at typical locations match with the experimentally measured ones. It lays solid foundation to optimize the process parameters in RDR-FSW.

Co-Firing of Enteromorpha Prolifera Algae and RTC Coal in a Down Draft Gasifier: Material Characterization and Flow Simulation

Co-Firing of Enteromorpha Prolifera Algae and RTC Coal in a Down Draft Gasifier: Material Characterization and Flow Simulation

Modeling Processing Cell Architecture by Material Flow Simulation

This paper is based on specific applications of Material Flow Theory (MFT) in industrial engineering material flow management (MFM). The accent is put on exploring different possibilities to increase productivity and profit in processing architectures using the MFM approach based on virtual modelling and simulation. In this context the paper presents a case study using virtual modelling of a flexible processing architecture and MFM simulation algorithms for diagnosis and optimization. The virtual model of the processing architecture will be used as a tool for identifying and eliminating the flow concentrators and obtaining an improved productivity of the system.

Engineering Environment for Production System Planning in Small and Medium Enterprises

Today, factories have to be adapted permanently in order to follow the developments towards fast changing customer demands and faster life cycles of products. Key aspects to cope with these developments are the reduction of the unit costs and the planning duration as well as the improvement of the planning quality. In order to overcome these challenges, digital tools can support all phases of factory and process planning. Most of them provide a wide range of functionalities, which require a large invest in software and high operation costs to use them efficiently. Often, small and medium enterprises (SME) cannot afford such invests and operation costs. Therefore, new digital factory planning tools tailored for SMEs supporting the production system planning are required. Main goal of the “WiES-Pro” project, funded by the Ministry of Finance & Economics Baden-Württemberg, was to develop an engineering environment for production system planning suitable for SMEs. The “WiES-Pro” approach connects small specific software tools for production system planning in an integrated platform, capable to share information and knowledge easily. The challenges in the development are to cope with both the heterogeneous data from different sources like machine master data, work plans or product data and the applicability to SMEs. This paper presents the results of the project, consisting of the approach and its implementation. Also the architecture of the browser-based platform and the developed digital factory planning tools for priority graph optimization, assembly process time planning, similarity-based product search and material flow simulation are presented shortly.

Learning Factories and their Enhancements - A Comprehensive Training Concept to Increase Resource Efficiency

Learning factories have been developed to impart substantial knowledge about improvement processes and methods to students and especially industrial participants within a real-world manufacturing environment. Due to the rising significance of resource efficiency, this issue has become another main driver for learning factories. Therefore, a comprehensive training concept is necessary in order to build up a measurement system in order to determine key figures and derive optimization steps. A new material flow simulation approach, developed in the research project REBAS, is added to the training courses in order to extend optimizing possibilities.

Real-time Bottleneck Detection and Prediction to Prioritize Fault Repair in Interlinked Production Lines

To identify the momentary bottleneck of serial production lines with finite buffers is still a challenge in the automobile industry. In literature there are already some detection methods. However, these methods lack the applicability for a real-time fault repair prioritization. A new method is being developed because of this disadvantage to detect the bottlenecks by analyzing the increase and decrease of buffer levels. This method has the benefit of detecting the real-time bottlenecks as well as giving a forecast bottleneck emerging in the near future by indicating the remaining time until a machine becomes one. The new fault repair prioritization method was validated in a material flow simulation of a production line. This simulation indicates a significant output increase. In the following steps, the new method is going to be implemented in a case study.

Simulation-based Planning of Production Capacity through Integrative Roadmapping in the Wind Turbine Industry

The development and effective implementation of a production strategy requires an interdisciplinary planning of products, manufacturing technologies and factory concepts. The integrative roadmapping allows the merging of these planning areas and takes into account the occurring interactions. This article shows the concept and software implementation of the integrative roadmapping for a systematic creation of roadmaps using the example of rotor blade production in the wind turbine industry. To reduce planning time and cost the workflow in the rotor blade production has been transferred to a material flow simulation to estimate the mutual impact on the production capacity by product, technology and factory within the planning phase.

Complex material flow problems: a multi-scale model hierarchy and particle methods

Material flow simulation is in increasing need of multi-scale models. On the one hand, macroscopic flow models are used for large-scale simulations with a large number of parts. On the other hand, microscopic models are needed to describe the details of the production process. In this paper, we present a hierarchy of models for material flow problems ranging from detailed microscopic, discrete element method type, models to macroscopic models using scalar conservation laws with non-local interaction terms. Numerical simulations are presented at all levels of the hierarchy, and the results are compared to each other for several test cases.

Modern Planning and Control and Virtual Verification of Process Continuity of a New Production Line

The paper describes one practical implementation of the Digital Factory concept – design of a new production line using modern planning method of virtual testing and control of processes. The project covered graphical facility design, detailed design of operations and material flow simulation. This case study shows facility process planning, commission and in the end finding the optimization rules and corrective actions to increase existing casting line throughput. All phases of the project were carried out using simulation software, duration of the project was 6 months. Simulation software WITNESS has been used for material flow simulation.

Numerical Analysis of Multi-Field Coupled Phenomena in Friction Stir Welding and Applications

Friction stir welding (FSW) is an advanced solid state joining technology, which was invented by TWI in 1991. During the process, large amount of heat is generated due to the friction between the tool and the material. As a result, the metal around the tool is softened as the temperature rises, and significant plastic flow occurs. So FSW is a complex process with multi-field coupled phenomena. Material flow plays a central role in FSW. But it is still difficult to reveal the material flow regime and joining mechanism during FSW process. Numerical simulation is a powerful tool for investigating the metal-flow-related complex phenomena during FSW. Meanwhile, numerical simulation could also help to optimize FSW tool design and FSW parameters. In this paper, we review the recent development in simulation of material flow during FSW. Then, the important issues in modeling multi field coupled phenomena during FSW are summarized, which include the heat generation mechanism, the temperature and strain rate dependent material’s behavior, and the interaction between tool and material. Finally, a comprehensive simulation model is presented, which enables advanced study on the coupled phenomena of heat generation, temperature distribution, material flow, and defects formation. This model has shown potential applications in simulating the relation between the transport of material and the macrostructure formation or defects formation. In spite of these progresses, simulation of material flow during FSW still need quite a lot of researches to fulfill industry requirement.

On the use of artificial neural networks in simulation-based manufacturing control

The automatic generation of simulation models has been a recurring research topic for several years. In manufacturing industries, it is currently also becoming a topic of high practical relevance. A well-known challenge in most model generation approaches is the correct reproduction of the dynamic behaviour of model elements, for example, buffering or control strategies. This problem is especially relevant in simulation-based manufacturing control. In such scenarios, simulation models need to reflect the current state and behaviour of the real system in a highly accurate way, otherwise its suggested control decisions may be inaccurate or even dangerous towards production goals. This paper introduces a novel methodology for approximating dynamic behaviour using artificial neural networks, rather than trying to determine exact representations. We suggest using neural networks in conjunction with traditional material flow simulation systems whenever a certain decision cannot be made ex ante in the model generation process due to insufficient knowledge about the behaviour of the real system. In such cases the decision is delegated to the neural network, which is connected to the simulation system at runtime. Training of the neural network is performed by observation of the real systems decision and based on the evaluation of data that can be gained through production data acquisition. Our approach has certain advantages compared to other approaches and is especially well suited in the context of on-line simulation and simulation-based operational decision support. We demonstrate the applicability of our methodology using a case study and report on performance results.

Numerical Simulation of Temperature Distribution and Material Flow During Friction Stir Welding of Dissimilar Aluminum Alloys

Joining dissimilar materials is required in many engineering applications and conventional fusion welding of dissimilar materials often results in defective welds. Friction Stir Welding (FSW) has paved way for joining dissimilar alloys and defect-free joints have been obtained for a number of dissimilar material combinations. Numerical modelling of FSW process can provide reasonable insight into the physics of the process and will aid in minimising the number of experimental trials. In this paper, Computational Fluid Dynamics (CFD) based numerical model is developed to predict the temperature distribution and material flow during FSW of dissimilar aluminum alloys AA2024 and AA7075. Volume of fluid approach is used and the FSW process is modelled as a steady-state visco-plastic laminar flow past a rotating cylindrical tool. Results indicate that peak temperature in the welded plates increases with the increase of Tool Rotation Speed (TRS) and Shoulder Diameter (SD), whereas the peak temperature decreases with increase in Welding Speed (WS). Increasing TRS and SD increases material flow, while increasing WS decreases material flow in the stir zone.

Modeling, simulation and validation of material flow on conveyor belts

In this paper a model comparison approach based on material flow systems is investigated that is divided into a microscopic and a macroscopic model scale. On the microscopic model scale particles are simulated using a model based on Newton dynamics borrowed from the engineering literature. Phenomenological observations lead to a hyperbolic partial differential equation on the macroscopic model scale. Suitable numerical algorithms are presented and both models are compared numerically and validated against real-data test settings.

Planning and Simulation of High-Voltage Energy Storage Assembly for Automotive Industry - from Scalable Product Concepts via Assembly Planning and Material Flow Simulation through to Web-Based Assembly Information

Driven by the demand for green mobility alternatives and the claim to reduce the carbon footprint, technologies for electric mobility are on the advance. Although the idea of using electricity as drive energy came up more than 150 years ago, a considerable potential of development still remains. The automotive industry is in the midst of a time of transition, in which business may change fundamentally in order to meet the upcoming conditions.

Numerical Simulation of Hot Rolling

In the present paper actual demands for modern simulation strategies for hot rolling are discussed. The main focus of the discussion is on material flow simulation for hot rolling and the computation of material inhomogeneities. An overview on simulation techniques for material flow and microstructure evolution is given. Approaches for new simulation strategies which give fast results with a high modeling depth are discussed. As a result of actual investigations a fast model for material flow is presented.

Multidimensional Evaluation of the Changeability of Interlinked Production Processes with Material Flow Simulation

The increasing length and interconnectedness of process chains – caused by a rising product complexity – forces companies to operate in an environment with a growing number of change drivers interfering in their day-to-day business. These new business conditions characterized by a rising intensity and multidimensionality of changes do not allow covering all potential developments by the flexibility of the production economically. This circumstance requires new approaches for process planning and investment decisions for companies.This article introduces an integrated planning approach to evaluate the changeability of interlinked production processes ex ante using material flow simulation and scenario analysis. Based on the results process chains can be configured robust to future requirements, because changeability enablers for a quick and efficient adoption can be installed systematically. A major advantage of simulating multiple stages of a production process is not only that the changeability of single processes is evaluated, but also the interdependencies within the entire process chain are considered in the evaluation and the configuration of improved processes.

The Combined Slip and Finite Sliding Models in a Frictional Contact Interaction of Two Spherical Particles

A simplified analytical modelling of tangential contact interaction of two elastic spheres was presented accounting for the kinematically induced sphere trajectory or a load controlled sliding process. The evolution of driving force in combined slip and finite sliding interaction was considered for both monotonic and reciprocal sliding motion. The analytical formulae and diagrams for the evolution of driving force along the sliding path in terms of the main contact geometry parameters were specified. The sliding trajectories and contact tractions were also determined. The analytical formulae were briefly presented for prediction of the tangential restitution coefficient and time of contact. The results presented can be applied in the experimental testing of frictional response of contacting bodies, wear studies of rough surfaces or in the contact interaction analysis of granular material during flow. The results can also be relevant for development of the discrete element method widely applied in simulation of granular material flow, where the sliding regime conditions prevail in intergranular contact interactions.