Tensile Failure (tensile + failure)

Distribution by Scientific Domains


Selected Abstracts


Failure Mechanism of Deformed Concrete Tunnels Subject to Diagonally Concentrated Loads

COMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 6 2009
Wei He
Based on the experimental findings, an extended discussion is carried out to select a rational compressive model for concrete that represents the dominant failure modes of deformed concrete tunnels. Three main dominant final failure modes are described: structural failure due to the plastic rotation of softening hinges, tensile failure caused by localized cracks, and material failure due to concrete deterioration. A parametric analysis of the material properties of concrete shows that the compressive strength of concrete has a dominant effect on the load-carrying capacity, although the compressive fracture energy of concrete remarkably influences the post-peak deformation behavior of the tunnel. Moreover, the soil pressure, which is regarded as a distributed external load, plays an important role in controlling the final failure modes and the deformation behavior of concrete tunnels. The size effect on the load-carrying capacities of different-sized concrete tunnels is also discussed based on the numerical simulations. [source]


Considerations of the discontinuous deformation analysis on wave propagation problems

INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 12 2009
Jiong Gu
Abstract In rock engineering, the damage criteria of the rock mass under dynamic loads are generally governed by the threshold values of wave amplitudes, such as the peak particle velocity and the peak particle acceleration. Therefore, the prediction of wave attenuation across fractured rock mass is important on assessing the stability and damage of rock mass under dynamic loads. This paper aims to investigate the applications of the discontinuous deformation analysis (DDA) for modeling wave propagation problems in rock mass. Parametric studies are carried out to obtain an insight into the influencing factors on the accuracy of wave propagations, in terms of the block size, the boundary condition and the incident wave frequency. The reflected and transmitted waves from the interface between two materials are also numerically simulated. To study the tensile failure induced by the reflected wave, the spalling phenomena are modeled under various loading frequencies. The numerical results show that the DDA is capable of modeling the wave propagation in jointed rock mass with a good accuracy. Copyright 2009 John Wiley & Sons, Ltd. [source]


A plasticity based model and an adaptive algorithm for finite element analysis of reinforced concrete panels

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 11 2002
J. Pravida
Abstract This paper deals with an adaptive finite element procedure for the analysis of plain and reinforced concrete panels in a state of plane stress. Therefore, we will present a plasticity based model for plain concrete which captures the two failure modes of concrete within one formulation. In spite of a simple formulation the model is capable to describe the different mechanisms for tensile failure as well as for compression fracture. To restrict the time discretization error and the spatial discretization error to certain tolerances, the constitutive model is embedded in an adaptive algorithm which controls the size of the incremental load steps and leads to a hierarchical mesh refinement if necessary. The application of the model will be shown by various numerical examples. Copyright 2002 John Wiley & Sons, Ltd. [source]


Influence of Particle Morphology and Flow Conditions on the Dispersion Behavior of Fumed Silica in Silicone Polymers

PARTICLE & PARTICLE SYSTEMS CHARACTERIZATION, Issue 3 2004
John Boyle
Abstract The dispersion behavior of agglomerates of several grades of fumed silica in poly(dimethyl siloxane) liquids has been studied as a function of particle morphology and applied flow conditions. The effects of primary particle size and aggregate density and structure on cohesivity were probed through tensile and shear strength tests on particle compacts. These cohesivity tests indicated that the shear strength of particle compacts was two orders of magnitude higher than the tensile strength at the same overall packing density. Experiments carried out in both steady and time-varying simple-shear flows indicate that dispersion occurs through tensile failure. In the steady-shear experiments,enhanced dispersion was obtained at higher levels of applied stress and, at comparable levels of applied stress, dispersion was found to proceed faster at higher shear rates. Experiments conducted in time-varying flows further corroborated the results obtained in tensile cohesivity tests. Experiments in which the mean and maximum stresses in the time-varying flows were matched to the stresses produced in steady shear flows highlight the influence of flow dynamics on dispersion behavior. [source]