Simplified analytical method for the robustness assessment of precast reinforced concrete structural systems

The article presents the simplified implementation of alternative load path method based on the energy balance approach. This method should be used to check the global resistance of a damaged structural system after the occurrence of an accidental event. Basic assumptions of simplified analytical models for modelling resistance of horizontal ties in a damaged structural system, taking into account the membrane (chain) effects, were presented. An approach to modelling the dynamic resistance of a damaged structural system based on the energy balance method is described. Calculated dependencies for checking the robustness of a prefabricated multi-storey building with hollow-core slabs after the loss of the central column are proposed and considered using an example. On the considered example, a comparison of the required tie sections area with the dynamic resistance designed using the energy balance method (EBM) and according to the current standards, and a statistical assessment of the reliability of the load-bearing capacity models are carried out. In the end, a brief algorithm for the simplified calculation of the dynamic resistance of a damaged structural system is proposed.

Simplified calculation of friction mean effective pressure for fast simulation of fuel consumption

An environmentally friendly and economical ship operation can be accomplished through many different methods. Most of these approaches focus on technological solutions, e.g. internal engine measures in order to make the engine more eco-friendly, by changing engine control parameters for a better connection between propulsion system and ship, by usage of different fuels or fuel supplements or installation of exhaust gas-treatment systems. For many ships, it is neither efficient nor economically viable to replace or improve existing power generation or propulsion systems in order to improve efficiency or reduce emissions. Some of the internal measures used to reduce NOx-emissions like exhaust gas recirculation even lead to a higher fuel consumption. The vessel itself is still controlled by a crew and they should be kept in the loop to improve efficiency. Therefore optimal operational procedures for handling ships and specifically the outcome of engine manoeuvres is a substantial source for eco-friendly ship operations. The German research project MEmBran (Modelling Emissions and Fuel Consumption during Ship Manoeuvres) addresses especially the basis for optimising ship engine manoeuvres. It focusses on very detailed simulation of the processes of currently existing ship diesel engines, especially in a first step 4-stroke engines in order to implement models in wider comprehensive ship handling simulation software. As part of an existing planning and prediction software that can be used on board, it enables the watch keeping nautical officer and the shipping company to forecast and compare the fuel consumption of the ship for each manoeuvre. In order to reach this goal it is necessary to use fast calculating and stable methods that can be used to forecast the power output of the engine and the fuel consumption. This paper discusses an approach to calculate friction mean effective pressure.

Maximum Electrical Power Extraction from Sources by Load Matching

This paper describes the matching of various loads to sources (including nonlinear ones). The purpose of matching is to extract the maximum available power from the source. This has particular importance for renewable sources and energy-harvesting devices, in which unused energy is just wasted. The main innovations in this paper include (and followed by examples) simplified calculation of the matching parameter for a controllable load and matching by means of a family of power-conservative two-port networks, denoted POPI (Pin = Pout), such as transformers, gyrators, loss-free resistors (LFRs) and series LFRs (SLFRs). An additional innovation described in this paper is a new, simplified model of an HF power amplifier based on the series LFR concept. This model predicts that the efficiency of the HF power amplifier operated under the matched-mode condition can significantly exceed the 50% efficiency limit that is predicted by the conventional model. As HF power amplifiers drive antennas in transmission and some wireless power transfer (which uses radiative techniques) systems, it is clear that the operation of such systems in the matched-mode condition is not restricted to a 50% efficiency limit.

Application of Equivalent Simplified Calculation Model of Isolated Structure in Super High-rise Building

In this paper, the application of equivalent simplified calculation model of isolated structure in super high-rise building is studied. In this paper, the characteristics of isolation structures with different height width ratio are analyzed, and the relationship curve between the limit value of height width ratio of isolation structure and the distance of isolation support is established. From the curve, we can estimate the limit height of the isolated structure when the bearing does not produce tensile stress under different seismic intensities. This paper also analyzes the influencing factors of the height width ratio limit, and puts forward the method of increasing the height width ratio limit. In this paper, a vertical stiffness correction model of isolation bearing is proposed. Compared with the shaking table test results and time history analysis, the modified model can truly reflect the mechanical properties of the isolation bearing.