Advanced Materials Research Vol. 742

Abstract: Accidents caused by domestic gas explosions occur regularly enough. Gas explosion accidents indoors are defined as deflagration explosions. The formation of an explosive cloud depends on many factors inside the building. To understand why the buildings in one case withstand an explosion but collapse in another case, more precise design models and methods of their realization are needed. We used numerical modeling to calculate the blast load intensity and find out the impact of the actual environment parameters. For the model verification we referred to the full-scale experiment on the deflagration of domestic gas in enclosed space.

Abstract: Shanghai Shikumen house is a typical one of Chinese traditional residential architecture, which has a "two patios & one corridor" pattern adapting to the climate of Shanghai. In existing researches, most study of the thermal performance dwelling with courtyard is still qualitative. This research constructed the quantitative simulation of the " two patios & one corridor" pattern in Shanghai Shikumen house based on the mathematical model by the technical simulation software, and compared the above mode with the general courtyard house to test the advances of it. First of all, the research conduct a three-dimensional simulation analysis on the "two patios & one corridor" pattern and the general "Two patios" pattern. Then we compared the results of the wind environment of the two modes and found the "two patios & one corridor" mode has advances on ventilation. Secondly, we did thermal environment simulations of the rooms in the above two modes, and compared the analysis results of two modes. We found that the "two patios & one corridor" pattern did better in the room thermal. Finally, we hope this research can provide certain reference for the design of the sustainable residential architecture.

Abstract: The criterion for residual deformation of Substructure of ballasteless track on railway passenger dedicated line is extremely strict in order to satisfy the safety and comfort requirements of the high-speed train during operation period, urgent need to strengthen the ballastless track lines settlement deformation observation, prediction and assessment technology. Based on Chengdu-Guanxian line, this paper puts forward observation programs of subgrade settlement combined with the characteristics of Subgrade Settlement through the analysis of the influence factors of subgrade settlement deformation and key consideration about the factors of nighttime observation precision. It shows that the monitoring and assessment technology could meet the requirements through the analysis of field data, it can be guidance of railway management departments to make maintenance plan. Some advices provide reference for the monitoring and assessment of high-speed railway subgrade settlement during operation period.

Abstract: Underwater impact and explosion are the main methods that destroy the warships, it cause attention of countries with marine power. The all metal laser welded sandwich panels has the higher stiffness and better mechanical behavior, and be used to protect for warships against impact. This paper analyzed the displacement of sandwich panel on light impact object with different impact velocity , which show that: (1) The top plate penetrate at the impact velocity of 185m/s, then the bottom plate is penetrate when the impact velocity approaches to 275m/s. (2) The displacement of top plate is confined to the scope of 60mm along x-axis and 40mm along Y-axis from the impacting point at a high impact velocity, the failure mode of sandwich panel is serious partial destruction and obvious shear failure.

Abstract: The properties of the base metal, weld and joint of CCS-B material for sandwich plate used in ship structurewasconfirmedthrough the tensile test,which provided the data parameters for the finite element simulation;The three points bending test for laser-weldedI-coresandwich plate was simulated by ABAQUS,and two kinds of models were establishedby considering and without considering weld material properties, which load-displacement curve shows that the influence of the weld material properties is larger to plates stiffness, but less to bearing capacity; For the model whichwas considered the weld material property, the development of plastic zone and the measurement of stress state show:In the elastic stage, the localposition yield in the junction zone between the web and upper and lower weld; In the plastic stage,the large areayield in the panel and the web of T-joint zone; The mapping relationship from the stress state to macroscopic deformation shows that both of the panel and the web occur S shape deformation and the whole web plate occur inclination deformation.

Abstract: New approach in stormwater management is urgent to address those water related problems and supplement the limitations of existed water management system. It should have functions to restore water and heat cycles in urban areas, that is, to restore hydrological cycle by promoting infiltration and evaporation, to secure water resources, to alleviate heat island phenomena, to prevent urban flood, and to conserve and restore the ecosystem. LID practices are one of prominent measures to mitigate the impacts of development and urbanization. It is important to have a LID approach in the step of site development planning. LID facilities could be categorized as flow control devices, detention, retention, vegetated filtration, infiltration and treatment. LID emphasizes local, decentralized solutions that capitalize on the beneficial services that natural ecosystem functions can provide. LID also focuses on controlling urban runoff and pollution right at the source, rather than at the end of the storm drain outlet. Since there are many different aspects of LID approach, the policy to promote or regulate LID should consider water, energy and ecology conservation.

Abstract: A new damage-reduction based composite shear wall was proposed. It combines with three different energy dissipation units, which are the CFST column, SP deep beam and RC strip. The CFST column is set to be exposed outside or concealed inside the concrete. CFST columns and SP deep beams constitutes the core structure. During loading, RC strips between columns work with the core structure so as to reduce the damage and consume the energy. Four specimens with different design parameters, including 2 shear walls with exposed CFST columns and 2 with concealed CFST columns, were tested under horizontal cyclic loading. The load-bearing capacity, stiffness, hysteretic property, ductility, and failure characteristic of specimens have been analyzed. Results show that the deformation of this wall is just between that of the slotted shear wall and the entire shear wall. The RC strips reduce the damage and the core structure presents ductile behavior during load. The new wall is designed based on damage-reduction and it shows good seismic energy dissipation mechanics. It can be applied to the design of shear wall in high-rise buildings.

Abstract: Caisson is a commonly used foundation in modern bridge engineering. When the caisson is sinking towards the seabed, it will suffer from the coupled effects of wind, current and its mooring system, under which an intense horizontal oscillation might occur. The mechanism of this kind of oscillation can be concluded as Vortex Induced Motions (VIM) of a large floating object in resilience mooring system. In this paper, through numerical simulation of the viscous flow field around a certain caisson, the mechanism of vortex shedding under different current velocity is discussed.

Abstract: Collapse of buildings in earthquakes causes casualties and economic losses, the reinforced concrete columns damage models is a basis for the research of integer collapse. The major advantage of Park and Ang's method is the consideration of first exceedance failure and cumulative damage failure in terms of defining the structural damage under earthquake, however, it isn't consider the differences of structural failures by different displacement amplitudes and load sequence. By multiplying the effective energy dissipation factor and the load sequence factor, the modified Park-Ang seismic damage model is obtained. The comparison between the two models indicates that the modified Park-Ang model have mean value closer to 1 and smaller scatter, besides the effects of load path and load sequence on damage can be taken into account in the modified model.