Papers by Keyword: Consolidation

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Authors: Sayuri Kimoto, Fusao Oka, Young Seok Kim, Naoaki Takada, Yosuke Higo
Abstract: We propose a thermo-hydro-mechanically coupled finite element analysis method for clay with a thermo-elasto-viscoplastic model. The volume changes in soil particles and pore fluids are introduced into the analysis method. The instability of the problem is studied and a numerical simulation of the thermal consolidation is presented using the newly developed analysis method. It was confirmed that the analysis method can reproduce the thermal consolidation phenomenon well.
Authors: Ioana Huțanu, Liliana Nica, Ion Sandu, Viorica Vasilache, Andrei Victor Sandu
Abstract: The consolidation of the painting layer or plane and carved gildings which represent different types of detachments is an essential operation for the preservation and restoration of the cultural goods of polychrome wood. Our paper focuses on testing a new type of acrylic binder applied on cracks with blind detachments with an OMRON nebulizer with NE-C28P compressor which sprays microparticles of 3 μm under a hermetic film that covers the operated surfaces. The experiments have been performed on samples of old gilded wood. The results are compared to those obtained by using the traditional process of peliculization of the acrylic binder over the detached surfaces and with the process of spraying. The analysis techniques used are the optical microscope and SEM-EDX.
Authors: A. Kazakewitsch, Werner Riehemann
Abstract: Aluminum-matrix-nanoparticle-composites were produced by ball milling of micro scale aluminum powder in air atmosphere with subsequent consolidation by hot extrusion and also additional hot swaging. They were investigated in this condition after step by step isochronal annealing with successive increasing annealing temperature and quenching into water to room temperature. The material was investigated by amplitude dependent damping, hardness and density measurements, all at room temperature. For all measured amplitude dependent internal friction (ADIF) curves the damping increases with increasing strain amplitude. After some annealing treatments a knee occurs in the medium strain amplitude region of these curves. Moreover between annealing temperatures from 360°C to 480°C the strain dependent damping becomes a maximum, i.e. a peak in the ADIF curves occurs. Other ADIF curves of quenched and fatigued material show characteristic peaks that can be attributed to individual single cracks. It is shown that all these effects are due to the formation, opening and compression of cracks present in the sample or created by thermally exerted stresses.
Authors: Ben Niu, Xiao Wu Tang, Chao Jie Zhang, Xiu Liang Chen
Abstract: A new method that is to use soilbag filled with sludge instead of using jackstone has been proposed to construct the sea wall recently. With this new method, expenses of building the sea wall can be cut down and environment pollution around the sea wall can be reduced. An analytical solution for soilbag with semi-pervious boundary is proposed in this study. The cross-section of the soilbag in this theory is considered as a rectangle. By setting coefficients for consolidation solution of two square areas and summing the two parts, final solution of the rectangular area is obtained. Further research is made to compare calculation results from this study and other three methods. After the comparison, it concludes that calculation results from this study are very close with that of finite-element method, and also, the soilbag method possesses a giant economic benefit and has a possibility to replace the jackstone method to construct a sea wall.
Authors: Fei Liu, Hong Tao Bai, Lan Fang Ren
Abstract: The monitoring mechanisms of open-source IaaS software OpenNebula and monitoring system Ganglia were analysed. Reduce overload of retrieving resource usage information by deploying the Ganglia monitoring agent. And for improving the robustness of monitoring subsystem, we take measures on the privileged domain of virtualization nodes to hide the agent to prevent regular or malicious users checking, modifying, unloading or killing it. The mechanism is very helpful to enhance the effectiveness, reliability and sturdiness of the monitoring system of IaaS platforms.
Authors: Pei Sheng Xi, Bo Liu
Abstract: Based on the solution of one-dimensional consolidation model of T-shaped bidirectional soil-cement deep mixing column composite foundation and its calculating program deduced by the separation of variables and Laplace method. This paper discussed the consolidation and settlement characteristics of composite foundation under the conditions of different loading modes, foundation reinforcement modes, diameter of enlarged pile head and pile spacing. The results indicate, the soil layer in the region of enlarged pile head hardly be influenced by above factors, the lower soil layer and soft substratum soil are influenced greatly. Loading mode has a large effect on the consolidation, when loading instantaneously, the rate of consolidation is faster than that of loading constantly. The consolidation and settlement behavior of composite foundation reinforced by T-shaped bidirectional soil-cement deep mixing column and traditional bidirectional deep mixing column is much better than the original natural foundation. When the other parameters stay the same, consolidation degree and total settlement decrease with the increase of enlarged pile head diameter. With the increase of pile spacing, consolidation rate of the composite foundation decreases significantly, but the settlement value increases rapidly on the contrary.
Authors: Viktor Varyukhin, Yan Beygelzimer, Sergey Synkov, Dmitry Orlov
Abstract: Twist Extrusion (TE) is a process of severe plastic deformation (SPD) being developed by us during recent 5 years. Upon this time we published few papers on mechanics of the process and influence of the TE processing on materials structure and properties. Here we reported some results on application of the twist extrusion processing and made few general conclusions.
Authors: A.S. Ganapathi, Sunil C. Joshi, Zhong Chen
Abstract: Thick laminated composites are manufactured commonly by vacuum bagging of fiber-resin mix or prepregs on a suitable mould and, subsequently curing the lay-up at high temperature and pressure in an either autoclave or oven. At these pressures and temperatures, excess resin bleeds out of the lay-up during the initial stages of the curing. The amount of resin bleed is also a function of the bleeder parameters. Bleeder is a porous fibrous media that is laid around stacked lay-up to provide pathway for volatiles as well as absorb and hold the excess resin. Thicker or highly porous bleeders generally absorb higher amount of resin resulting in a resin starved laminate whereas very thin or denser bleeder leads to resin-rich areas within the laminate. It is thus important to select optimum bleeder parameters in order to achieve a desired resin volume fraction and its uniformity in a composite laminate upon curing. This paper details the simulation of the manufacturing of a thick laminated composite, where a significant amount resin is likely to flow out of a curing lay-up, leading to an optimization of bleeder parameters. A coupled, transient FE analysis is conducted that involves not only the heat transfer, resin flow and cure reaction kinetics simulation but also the simulation of the compaction of the wet laminate and the bleeder layers until the laminate is fully cured. Details of an experiment conducted to find compression characteristics of bleeder of varying thickness and the number of layers and related data that was used in the FE analysis are discussed in this paper. It is found that bleeder thickness significantly affects the amount of resin bleeding out from the curing laminate. As a result, the resin volume fraction of the laminate is affected. Case studies carried out to highlight the optimum bleeder thickness for a lay-up, and the method used to decide the thickness and the number of bleeder layers, are presented.
Authors: Kenong Xia
Abstract: The progress in bulk ultrafine and nanostructured materials through consolidation of particles by severe plastic deformation (SPD) is reviewed. The focus is on the processes of high pressure torsion (HPT) and equal channel angular pressing (ECAP) with or without the application of a back pressure. Various materials consolidated are described in terms of their densities, microstructures and mechanical properties. The important processing parameters and their effects on the resulting materials are discussed. It is shown that SPD consolidation of particles is an effective way of producing bulk nanostructured materials although much work is needed to understand the consolidation behaviour and to design the optimum compositions and microstructures.
Authors: Cun Gang Lin, Zhong Miao Zhang, Shi Ming Wu
Abstract: The Qing-chun Road Cross-river Tunnel is the first road tunnel under the Qiantang River in Hangzhou, and it is also the first experiences of slurry shield tunnelling in Hangzhou soft ground. In order to ensure the safety of construction and reduction of environmental impacts while shield tunnelling, a comprehensive monitoring system was carried out during construction, which included ground settlements, displacements and deformations of installed linings and so on. In this paper, the long-term ground settlements induced by slurry shield tunnelling were described in detail, and careful analysis of monitoring ground settlements was made. This case study shows that: 1. The surface transverse consolidation settlements do not follow the Gaussian curve; usually the largest settlements exist above the centerline of the tunnel or nearby, from where settlements descend outwards. Due to consolidation, the surface settlement troughs widen with time.2. Shield tunneling in soft ground, the turning point in settlement-time curves or settlement rate-time curves can be chosen as the time divides the immediate and long-term consolidation settlements.
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