Fast and Reliable Development of Composite Structures , Using Concurrent/Integrated Engineering

Strong international competition in the civil aircraft market requires a continuous effort of the aircraft manufacturers to improving structural performance and reducing production costs of their products. A key step forward with great potential for achieving both goals is the application of composite materials to primary aircraft structures. However, designing and developing such structures is still a very demanding task, since the number of disciplines involved and the number of design alternatives are high, whereas experience is quite limited. The paper suggests a new Concurrent/Integrated Engineering (CIE) process that aims at applying advanced high-end simulation tools already very early in the design process. Whereas standard Concurrent Engineering approaches mainly focus on interdisciplinary co located teams, the CIE process concentrates on interdisciplinary tool integration and improvement, where the team members can be dispersed. By that means not only development costs and time are reduced but and this is specific for the new CIE process the development risk is reduced and the quality of the product is improved. Involving all disciplines early in the design process might increase problems with redundancy, consistency and actuality of information as compared to sequential engineering. This is prevented by an information system for CIE (ISCIE) which recognises data independencies and finds out an optimal schedule for performing the different tasks. The ISCIE is dynamic which means adaptability to changes of the development process and furthermore allows for hardware-in-the-loop. This is important since not all disciplines can be simulated with sufficient accuracy and early hardware is sometimes beneficial for concreteness and acceptance of new products. Nevertheless, for speeding up the CIE process a new generation of analysis tools is required for as many disciplines as possible. The paper introduces some advanced structural mechanics codes for thermal, stress, failure and damage tolerance analysis. All of them are based on a shell representation of thin-walled composite structures and utilise the finite element method. Thus, the potential for efficient integration is high, which is underlined by illustrative examples

Energy Storage as Part of a Secure Energy Supply

The current energy system is subject to a fundamental transformation: A system that is oriented towards a constant energy supply by means of fossil fuels is now expected to integrate increasing amounts of renewable energy to achieve overall a more sustainable energy supply. The challenges arising from this paradigm shift are currently most obvious in the area of electric power supply. However, it affects all areas of the energy system, albeit with different results. Within the energy system, various independent grids fulfill the function of transporting and spatially distributing energy or energy carriers, and the demand-oriented supply ensures that energy demands are met at all times. However, renewable energy sources generally supply their energy independently from any specific energy demand. Their contribution to the overall energy system is expected to increase significantly. Energy storage technologies are one option for temporal matching of energy supply and demand. Energy storage systems have the ability to take up a certain amount of energy, store it in a storage medium for a suitable period of time, and release it in a controlled manner after a certain time delay. Energy storage systems can also be constructed as process chains by combining unit operations, each of which cover different aspects of these functions. Large-scale mechanical storage of electric power is currently almost exclusively achieved by pumped-storage hydroelectric power stations. These systems may be supplemented in the future by compressed-air energy storage and possibly air separation plants. In the area of electrochemical storage, various technologies are currently in various stages of research, development, and demonstration of their suitability for large-scale electrical energy storage. Thermal energy storage technologies are based on the storage of sensible heat, exploitation of phase transitions, adsorption/desorption processes, and chemical reactions. The latter offer the possibility of permanent and loss-free storage of heat. The storage of energy in chemical bonds involves compounds that can act as energy carriers or as chemical feedstocks. Thus, they are in direct economic competition with established (fossil fuel) supply routes. The key technology here – now and for the foreseeable future – is the electrolysis of water to produce hydrogen and oxygen. Hydrogen can be transformed by various processes into other energy carriers, which can be exploited in different sectors of the energy system and/or as raw materials for energy-intensive industrial processes. Some functions of energy storage systems can be taken over by industrial processes. Within the overall energy system, chemical energy storage technologies open up opportunities to link and interweave the various energy streams and sectors. Chemical energy storage not only offers means for greater integration of renewable energy outside the electric power sector, it also creates new opportunities for increased flexibility, novel synergies, and additional optimization. Several examples of specific energy utilization are discussed and evaluated with respect to energy storage applications.The article describes various technologies for energy storage and their potential applications in the context of Germany's Energiewende, i.e. the transition towards a more sustainable energy system. Therefore, the existing legal framework defines some of the discussions and findings within the article, specifically the compensation for renewable electricity providers defined by the German Renewable Energy Sources Act, which is under constant reformation. While the article is written from a German perspective, the authors hope this article will be of general interest for anyone working in the areas of energy systems or energy technology