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1.
《International Journal of Hydrogen Energy》2019,44(17):9063-9070
University of Pisa (UNIPI) conducted a series of vented deflagration tests at B. Guerrini Laboratory. The tests were part of the experimental campaign performed by UNIPI for the European HySEA project (Hydrogen Safety for Energy Applications). Experiments included homogeneous hydrogen-air mixture contained in an about 1 m3 enclosure, called SSE (Small Scale Enclosure). The mixture concentration was variable between 10% and 18% vol. During the deflagrations, structural response was investigated by measuring the displacement of a test plate. The collected data were used to validate the FE model developed by IMPETUS Afea. In this paper experimental facility, displacement measurement system and FE model are briefly described, then comparison between experimental data and simulation results is discussed. 相似文献
2.
Ermittlung von Verfahrensgrenzen für das Fügen durch Knickbauchen anhand des Werkstoffes E235+N 下载免费PDF全文
B. Viehweger A. Sviridov P. Grützner B.‐A. Behrens A. Bouguecha A. Almohallami 《Materialwissenschaft und Werkstofftechnik》2015,46(8):804-812
Through a systematic approach and the consistent comparison of the results between experimental and numerical investigations, a deep understanding of the bulging mechanisms has been first developed. From these investigations process limitations were derived and presented in the form of a working diagram for the material E235+N. With regard to a wide industrial use of upset bulging as a joining technology, a technologically, productively as well as economically appropriate method could be developed and validated by means of practical and numerical experiments. 相似文献
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Poly(vinylidene fluoride), PVDF, and its copolymers are the family of polymers with the highest dielectric constant and electroactive response, including piezoelectric, pyroelectric and ferroelectric effects. The electroactive properties are increasingly important in a wide range of applications such as in biomedicine, energy generation and storage, monitoring and control, and include the development of sensors and actuators, separator and filtration membranes and smart scaffolds, among others. For many of these applications the polymer should be in one of its electroactive phases. This review presents the developments and summarizes the main characteristics of the electroactive phases of PVDF and copolymers, indicates the different processing strategies as well as the way in which the phase content is identified and quantified. Additionally, recent advances in the development of electroactive composites allowing novel effects, such as magnetoelectric responses, and opening new applications areas are presented. Finally, some of the more interesting potential applications and processing challenges are discussed. 相似文献
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Mazen Ayoubi 《Bautechnik》2016,93(11):817-827
Bond behaviour of self‐tapping screws being used as reinforcement in glue‐laminated timber elements – Part 2: Analytical and numerical investigations as well bond model derivation for the calculation of anchorage length In favor of the investigation of bond behaviour, force transfer and anchorage length of self‐tapping screws, several tests have been realized at the Chair of Structures and Structural Design in cooperation with the Institute for Building Material Research of the RWTH Aachen University. The experimental investigations comprise more than 160 pull‐out tests of screws with long embedment length and over 84 load distributions tests. Additionally, several tests displaying the effect of longitudinal cracks in the surrounding wood as well as the effect of the screw tip have been conducted. Through various analyses of the bond behaviour, the experimental investigations form the basis for the calibration and evaluation of the numerical models and allow a prediction of the force transfer of the screws in glue‐laminated elements. Design rules that enable the application of the self‐tapping screws as reinforcement in timber elements have been derived from the knowledge obtained in the experimental and numerical investigations. This paper, which results from a research project funded by the German Research Foundation [1], presents the results of investigations on the bond behavior of self‐tapping screws in glue‐laminated timber elements. Part 1 elaborates on the experimental investigations [2] whereas part 2 illustrates the numerical analyses and presents a bond model, which enables the design of the anchorage length and the safe application of the screws as reinforcement in timber elements. 相似文献
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Pubudu Jayawardana David P. Thambiratnam Nimal Perera Tommy Chan G.H.M.J. Subashi De Silva 《Soils and Foundations》2019,59(4):874-887
Development activities in a city often generate ground vibration that can cause discomfort to the occupants in nearby buildings, disturbances to the activities undertaken in the buildings and possible damage to nearby structures. This ground vibration is caused by construction activities such as pile driving, ground compaction etc., and road and rail traffic. The use of trenches has been an effective way to mitigate the adverse effects of such ground vibration. The effectiveness of the trench depends on many parameters including the properties of the vibration source, soil medium and trench in-fill material, trench dimensions and the requirements of the receiver. The process of selecting an effective trench for vibration mitigation can therefore become complex due to the influence of a number of parameters and their wide range of values. This paper investigates the use of artificial neural network (ANN) as a smart and efficient tool to predict the effectiveness of geofoam-filled trenches to mitigate ground vibration. Towards this end, a database is developed from an extensive study on the effects of the controlling parameters through numerical simulations with a validated finite element (FE) model. At a certain distance from the vibration source, a geofoam-filled trench is introduced to evaluate the efficiency of vibration mitigation with changes in key parameters such as excitation frequency, amplitude of load, trench configuration (i.e. depth and width), soil shear wave velocity, soil density and damping ratio. These were selected as the input parameters for the ANN while amplitude reduction ratio and peak particle velocity (PPV) were considered as outputs. A multilayer feed forward network was used and trained with the Levenberg-Marquardt algorithm. Neural networks with different configurations were evaluated by comparing coefficient of determination (R2) and mean square error (MSE). The optimum architecture was then used to predict previous results, which revealed the accuracy and the effectiveness of the ANN approach. The findings of this study will provide useful information for vibration mitigation using geofoam-filed trenches. 相似文献
7.
For fatigue damage prognosis of a long-span steel bridge, the dynamic stress analysis of critical structural components of the bridge under the future dynamic vehicle loading is essential. This paper thus presents a framework of dynamic stress analysis for fatigue damage prognosis of long-span steel bridges under the future dynamic vehicle loading. The multi-scale finite element (FE) model of the bridge is first developed using shell/plate elements to simulate the critical structural components (local models) and using beam/truss elements to simulate the rest part of the bridge (global model). With the appropriate coupling of the global and local models, the multi-scale FE model can accurately capture simultaneously not only the global behavior in terms of displacement and acceleration but also the local behavior in terms of stress and strain. A vehicle traffic load model is then developed for forecasting the future vehicle loading based on the recorded weigh-in-motion (WIM) data and using the agent-based traffic flow microsimulation. The forecasted future vehicle loading is finally applied on the multi-scale model of a real long-span cable-stayed bridge for dynamic stress analysis and fatigue damage prognosis. The obtained results show that the proposed framework is effective and accurate for dynamic stress analysis and fatigue damage prognosis. 相似文献
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紫坪铺泄洪洞穿越断层段新奥法设计与数值仿真分析 总被引:1,自引:0,他引:1
本文基于新奥法的基本原理 ,对紫坪铺水利工程 1 # 泄洪洞穿越 F3断层段的支护设计方案进行了有限元数值仿真分析和优化设计。分析结果表明 ,按照常规的支护不能保证围岩、支护的稳定。本文经过 4个支护方案的设计与仿真分析 ,提出了较为理想的支护方案 ;该支护方案已为工程实际所采用 ,取得了良好的实际效果。 相似文献