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A modular production plant consists of predefined apparatuses with a fixed design, called equipment modules. Selecting the equipment module with the appropriate suitable capacity to compensate fluctuations in production rate is one of the key challenges in module-based plant design. The equipment module’s operating window needs to fit and determines the point in time when a capacity expansion is required so that the operating window of the equipment module also affects a capacity expansion strategy. In order to avoid an unnecessary use of multiple apparatuses in parallel, equipment modules should be developed specifically for a large operating window in contrast to conventionally designed equipment. Therefore, an approach is required to design equipment modules for flexibility in production rate. In this work a method to design equipment modules for flexibility based on a global sensitivity analysis and the deduction of design rules of thumb is introduced. This method is applied to the design of a liquid/liquid heat exchanger without phase change. The resulting design for flexibility is compared to the conventional design with regard to the operating window and investment as well as operating costs. It is shown that for 14% higher annual costs a four-fold operating window can be obtained. This presents an important step towards increasing the competitiveness of modular production plants.

Continuously operated multi-product plants enable an efficient and flexible production of new products. As a future plant concept, a modular design allows the possibility of a stepwise capacity expansion when market demand is increasing. Choosing the right plant capacity combined with a suitable expansion strategy is a key challenge in this context. Therefore, additional costs for expansion have to be balanced against an achievable economic performance and a reduction of investment risk. In this work a framework to evaluate the production capacity of a continuously operated modular multi-product production line for a production line wise capacity expansion will be presented. As a result, a decision tree analysis integrating production planning by a capacitated lot sizing method is introduced to evaluate the economic performance of plants with different capacities in an uncertain market. The framework is applied for a case study considering a continuous production of a set of three different products. As a key result it can be said that the investment risk can be reduced by applying smaller scale modular production lines. However, the low scalability of investment costs of a small scale production line negatively affects an economic expansion strategy.

The paper deals with the analysis of the effective stiffness of stiffened metallic panels under combined compression and shear stress as used, e.g. in aircraft fuselages. An important criterion for sizing and certification of aircraft fuselages is the local and global buckling behaviour. For optimisation of stiffened metallic panels it is necessary to know the buckling and postbuckling behaviour as accurately as possible. Due to the fact that nonlinear FE analyses of a whole aircraft fuselage are too time consuming, a very fast quasi nonlinear FE analysis with a coarse mesh under consideration of semi-empirical methods for the effective skin-stiffness are used. At this point the effective stiffness method derived in this paper is used. Admittedly previous semi-empirical methods like the effective width method [J. Wiedemann, Leichtbau 1: Elemente, second ed., 1996; M.C.Y. Niu, Airframe Stress Analysis and Sizing, second ed., Commilit. Press Ltd., 1999] (only for pure compression load) or the method of Kuhn [P. Kuhn, J.P. Peterson, L.R. Levin, A summary of diagonal tension part I – methods of analysis, Technical Note 2661, NACA, 1952] (only for pure shear load) have disadvantages for the general combined compression and shear load case. This is improved in the current method. The first part of the paper deals with the realisation of the compression and shear test facility in a finite element model. The verification of the finite element model is important for subsequent parameter variations. The second part of the paper presents the approach of how to assess the effective skin-stiffness. In comparison to the paper in [M. Heitmann, P. Horst, D. Fitzsimmons, Effective stiffness of postbuckled stiffened metallic panels under combined compression and shear stress, J. Strain Anal. 38 (6) (2003) 534–555] many new parameters have been analysed. Therefore the new approach for the geometrically nonlinear analysis derived from the finite element results for combined compression and shear stress is considerably improved. At the end of the paper the great benefit of the new approach is shown. The results of very fast quasi nonlinear FE analyses under consideration of the new approach for the effective skin-stiffness on a coarse panel mesh agree well with the results of time expensive nonlinear FE analysis on a very fine panel mesh. Further studies are necessary to expand the new method to the influence of plasticity.

© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim www.cit-journal.com V2.03 Integration eines Mikroreaktor-basierten MultipurposeAufbaus in eine containerartige Produktionsinfrastruktur Dr. P. Lob (E-Mail: patrick.loeb@imm.fraunhofer.de), Dr. T. H. Rehm, Dr. A. Ghaini, Dr. T. Illg, Dr. J. Lang, Dr. H. Richert Fraunhofer ICT-IMM, Carl-Zeiss-Strase 18–20, D-55129 Mainz, Germany Evonik Industries AG, Rodenbacher Chaussee 4, D-63457 Hanau-Wolfgang, Germany DOI: 10.1002/cite.201450478