Damage Assessment in Concrete Using Acoustic Emission
An acoustic emission (AE) is a localized rapid release of strain energy in a stressed material. This energy release causes stress waves to propagate through the specimen. These acoustic...
Concrete Surface Characterization Using Optical Metrology
The displacement of the surface of a concrete specimen is measured as it cures using an optical method. This method, known as optical metrology, is one in which a line is projected onto...
Large Deformation Elastic Behavior of Low-Density Solid Foams
A strain energy function that describes the nonlinear elastic response of a three-dimensional open-cell foam is developed. A tetrahedral unit cell containing four half-struts that join...
Rate-Dependent Plasticity Representation for Energy-Absorbing Materials
A three dimensional rate-dependent plasticity constitutive model is developed for rigid polyurethane foams. In the model, the material is decomposed into skeleton and solid matrix from...
Constitutive Modeling and Simulation of Energy Absorbing Polyurethane Foam Under Impact Loading
The compressive-stress strain response of polyurethane foam under uniaxial compressive impact loading has been studied. The development of a uniaxial constitutive model from strain rate...
Use of Hierarchical Lattices for Predicting the Fluid or Stress Transfer in Concrete
Hierarchical lattices are used to study the influence of local disorder on the transfer of properties (stresses, strains, permeability) from the micro-scale to the macro-scale. They are...
Comparative Evaluation of Plasticity Theories Against Tension-Torsion Test at Finite Strain
This paper investigates and evaluates three hardening theories against a variety of nonproportional loading experiments on tubes made of annealed copper. It was concluded that the isotropic...
Nonisothermal Viscoplasticity
A nonisothermal theory of viscoplasticity is formulated for a medium subjected to finite deformation. The basic system of equations consists of the laws of conservation of linear and angular...
Numerical Implementation of Nonlocal Elastoplastic Damage Theory
A nonlocal elastoplastic damage theory recently proposed by Valanis (1992) is implemented into a finite element wave code. The model retains hyperbolicity even under strain softening,...
Debonding of a Inhomogeneity from a Plastic Matrix
Inclusion debonding is addressed through the formulation and solution of the planar elastic and elastic uniform plastic problems. These problems are variants of the standard transformation...
Size, Temperature and Rate Effects on the Fracture Toughness of Saline Ice
This paper presents the results of an extensive experimental study performed with the aim of investigating the effects of temperature, size and loading rate on the fracture toughness of...
Relationships Between Error Estimation and Adaptive Computations in Strain Localization
In this work, the a posteriori error estimates and the h mesh refinement techniques using hierarchical finite element shape functions are tailored for numerical simulations of strain localization...
Direct Tensile Test: Stability and Bifurcation
Unnotched specimens of quasibrittle materials that exhibit post-peak strain softening do not deform symmetrically in a direct tension test. The phenomenon (which is similar to the recently...
Softening Models for Concrete: Stability and Uniqueness
A microstructurally-based, numerically oriented, fracture-induced softening model for concrete is presented. Rate-dependent evolution equations for microcrack nucleation, growth, and coalescence...
Neural Network Modeling of the Mechanical Behavior of Sand
Given a set of triaxial test data, an artificial neural network (ANN) has been trained to model the mechanical behavior of a medium-to-fine sand. Once trained, the ANN was tested by simulating...
Strain-Based Damage Deactivation in Concrete
Motivated by the 'mode I' microcrack opening and closing mechanism, a procedure for the deactivation of the damage is developed. Strain based projection operators are used to negate the...
Nonlinear Analysis of Strain-Softening Damage under Monotonic and Cyclic Loading
The paper reviews the modeling of damage by the microplane model and presents extensions required for cyclic loading. The general microplane constitutive model is implemented in a three-dimensional...
Mechanics of Growing Deformable Solids: A Review
An attempt is undertaken to summarize the contemporary knowledge in mechanics of deformable solids of accruing mass. A general mathematical model of an abstract growing deformable solid...
Estimating Damage and its Influence on Fracture Toughness
To estimate damage in a quantitative manner, a technique used whereby six values of linear strain are measured on a material element as a function of hydrostatic pressure. The high precision...
Nonlinear Geometric and Material Considerations in Shell Structures
A geometrically and materially nonlinear static shell theory allowing large displacements, rotations, and strains with parabolic shear is developed. The theory is cast into a total Lagrangian...
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