Authors: Andrzej Litewka, Janusz Debinski
505
Authors: Li Jun Han, Yong Nian He, Hou Quan Zhang
Abstract: A complete stress-strain experiment curve, gained through exerting low confining pressure
on brittle rock, reflects the deformation and destruction process of rock under different confining
pressure, and reveals that after the destruction of rock, not only slip deformation but also
re-destruction process will take place, which would possibly lead to further reduction of the
mechanical properties of the rock mass. Through the analysis of the relation between complex failure
modes, load carrying capacity after rock destruction and the volumetric strain, the paper gives us a
further explanation of the complex destructive process of rock. The basis for the rock’s load-carrying
capacity after destruction is an effective restraint stress, which shows that effective supporting in
underground engineering is the key factor for providing the cracked surrounding rock with
load-carrying capacity and guaranteeing the stability of the structure.
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Authors: S.M.H. Seyedkashi, Golam Hosein Liaghat, Hassan Moslemi Naeini, M. Hoseinpour Gollo
Abstract: Tube hydroforming technology is still considered a new technique growing fast in automotive and aircraft industries. Many researches on all aspects of this process are still required. Contact friction is one of the most effective parameters on tube wall thinning. To successfully fulfill the process without any common defects, it is very important to determine the proper internal pressure and axial feeding loading paths. In this paper, the effect of lubrication on tube wall thinning on ASTM C11000 copper alloy is discussed as well as the effect of internal pressure and axial feeding. An axisymmetric bulged tube is investigated using theoretical, numerical and experimental methods. Improved linear and non-linear pressure and feeding loading paths are applied and the predicted results are experimentally proved. It is observed that non-linear pressure application gives smoother results. Also proper lubrication plays an important role in success of the process.
133
Authors: Behzad Ghadimi, Umair Hasan
Abstract: The behaviour of granular materials especially under dynamic loading has been under investigation for years. In recent years, the advancing computer technology makes it possible to model complicate behaviour under different loadings. In this review paper, major advances and researches in the field of providing conceptual model for behaviour of granular materials have been reviewed. The reviewers have tried to categorise the researches in term of their approach to modelling the mechanical behaviour of granular materials and then identify the gaps to provide ground for the future researches.
219
Authors: Gabriele Bertagnoli, Diego Gino, Luca Giordano, Dario La Mazza, Giuseppe Mancini
Abstract: According to Eurocode, robustness is the ability of a structure to withstand events like fire, explosions, impact or the consequences of human error, without being damaged to an extent disproportionate to the original cause.Avoiding the progressive collapse of a building in presence of accidental loading conditions is one of the challenges for the designers.The tie-force method is actually one of the most used design techniques for resisting progressive collapse, whereby a statically indeterminate structure is designed with reference to local simplified models determined in accordance to the failure mode considered.In this work a computational study of a reinforced concrete frame is presented. The beam-column assembly represents a portion of the structural framing system of a ten-story reinforced concrete frame building and is subjected to monotonically increasing vertical displacement of the center column to simulate a column removal scenario.Two different finite element models, with distinct levels of modeling, are used in order to compare the numerical results with the experimental ones coming from a full-scale test, and evaluate the ability of the models to simulate the structural behavior of the frame.
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