Improving the Energy Efficiency of an Existing Building by Dynamic Numerical Simulation

Nowadays, the enhancement of the existing building stock energy performance is a priority. To promote building energy renovation, the European Committee asks Member States to define retrofit strategies, finding cost-effective solutions. This research aims to investigate the relationship between the initial characteristics of an existing residential buildings and different types of retrofit solutions in terms of final/primary energy consumption and CO2 emissions. A multi-objective optimization has been carried out using experimental data in DesignBuilder dynamic simulation tool.

Difficulties in the Construction of Subway Tunnel Underpass Project and Research on Ecological Restoration Technology

Subway construction is a high-risk construction project, because there are many uncertain factors such as Undercrossing urban hinterland and geological conditions, which lead to the difficulty of organization and management and frequent safety accidents. Therefore, there is an urgent need for effective safety risk analysis model and risk management means to prevent accidents. Aiming at the mechanical problems of surrounding rock and supporting structure of subway tunnel under different construction methods, the dynamic numerical simulation of three pilot tunnel method and upper and lower step method is carried out by using finite element method. The transformation relationship between stress field and displacement field of subway tunnel under different construction procedures is established, and the two construction methods are compared. The test results show that the internal force, axial force and bending moment model of the subway tunnel support structure system established in this paper has a certain guiding significance for the design and safe construction of the subway tunnel.

Amplification Factor for Wood-Concrete Hybrid Structures Based on Dynamic Numerical Simulation

Extensive concerns on environmental protection have provoked low-carbon buildings to be the mainstream of building construction worldwide, and wooden structures in this sense outperform other structural forms. Wooden-concrete hybrid structures featuring distinct wooden and concrete stories typically exhibit uneven stiffness distribution along the structure height; in particular, abrupt stiffness changes occur at the wood-concrete transition stories. Therefore, structural designing of such hybrid structures must consider a stiffness amplification effect in the static structural calculation as well as complicated procedures in the dynamic analysis. To determine an appropriate amplification factor for design purpose, this study employed a dynamic numerical approach to determine the displacement response of wooden-concrete hybrid buildings and compared the results with the displacement response obtained from static analyses. According to the results, it is found that the appropriate amplification factor should beα= f (x) = 0.47x + 1.00.αcan be valued 1.94 at 2nd floor, 2.41 at 3rd floor and 2.88 at 4th floor. The results may serve as a reference for seismic designing of wooden-concrete hybrid structures.

A Numerical and Experimental Study of Kick Dynamics at Downhole

The early detection of a kick and mitigation with appropriate well control actions can minimize the risk of a blowout. This paper proposes a downhole monitoring system, and presents a dynamic numerical simulation of a compressible two-phase flow to study the kick dynamics at downhole during drilling operation. This approach enables early kick detection and could lead to the development of potential blowout prevention strategies. A pressure cell that mimics a scaled-down version of a downhole is used to study the dynamics of a compressible two-phase flow. The setup is simulated under boundary conditions that resemble realistic scenarios; special attention is given to the transient period after injecting the influx. The main parameters studied include pressure gradient, raising speed of a gas kick, and volumetric behavior of the gas kick with respect to time. Simulation results exhibit a sudden increase of pressure while the kick enters and volumetric expansion of gas as it flows upward. This improved understanding helps to develop effective well control and blowout prevention strategies. This study confirms the feasibility and usability of an intelligent drill pipe as a tool to monitor well conditions and develop blowout risk management strategies.