A damage interface model with cohesive-frictiona continuous transition

XFEM approach to nonlinear analysis of composite structures

Adhesive inter-laminar and cohesive inner-layer damage mechanisms for composite materials

Extended finite element method for cohesive-frictional delamination processes

Constitutive modelling of cemented granular materials with transitions from cohesive to frictional behaviour

Interlaminar decohesion and inner-layer damage in composite structures

Material Internal Frictional Dissipation Modelling

This presentation is concerned with a first introductory study devoted to internal frictional dissipation modelling of cracked materials. The problem is set as periodic Representative Volume Element (RVE) with oriented cracks diffused in the bulk material. As first stage, useful for moderate loading levels, cracks are considered fixed and stable at certain position and are modelled as perfect frictional mechanical interface with unilateral contact features. Analyses on cyclic material response are discussed for 2D problems. A second type of analyses is performed considering a further cohesion strength and a crack propagation criteria, which are typical of interface damage mechanical approac…

Cohesive-frictional interface model with oligocyclic degradation of surfaces roughness

The present work is devoted to the constitutive modelling, through the classical interface kinematical formulation, of the mechanical behaviour of the internal adhesive layers, connecting different bodies. The proposed interface constitutive model couples a cohesive behaviour with a frictional one and it is able to follow the transition from the sound condition to the fully cracked one by means of a specific interpretation of the damage variable. In the fully cracked condition, the dilatancy exhaustion and the frictional strength degradation are also modelled.

Un modello di interfaccia elasto-danneggiativo con effetti termo-meccanici

Nonlocal Interface Mechanical Model

The paper presents a nonlocal elastic damage-frictional interface model. The reason to introduce nonlocal mechanical features inside the constitutive relations is justified by the fact that there are several circumstances, in which the interface displays inside an extended process zone with microstructural spatial interactions. Typically, spatial bridging mechanical effects can be effectively modeled by integral (strongly nonlocal) stress-strain relations. The paper develops an elastic nonlocal model with local isotropic damage and the relations are constructed following a thermodynamical consistent approach.

A symmetric nonlocal damage theory

The paper presents a thermodynamically consistent formulation for nonlocal damage models. Nonlocal models have been recognized as a theoretically clean and computationally efficient approach to overcome the shortcomings arising in continuum media with softening. The main features of the presented formulation are: (i) relations derived by the free energy potential fully complying with nonlocal thermodynamic principles; (ii) nonlocal integral operator which is self-adjoint at every point of the solid, including zones near to the solid's boundary; (iii) capacity of regularizing the softening ill-posed continuum problem, restoring a meaningful nonlocal boundary value problem. In the present app…

An elastic-damage interface model with thermo-mechanical coupled effects

A Computational Two-Scale Approach to Nonlinear Analysis of Etherogeneous Composite Structures

Nonlocal Elastic-Damage Interface Mechanical Model

The paper presents a nonlocal extension of the elastic-damage interface mechanical model, which is able to describe the effects of the spatially extended microstructure on the decohesion (or fracture) process along a surface. The key feature of the proposed model is an integral constitutive relation between tractions and displacement jumps at the interface. The presence of an integral kernel brings in the model an internal length measure, which characterizes the transition from the microscale, dominated by heterogeneities and discontinuous media, to the mesoscale, characterized as an enhanced homogenized continuum with nonlocal features. The motivations and the fields of applications of the…

An Interface Mechanical Model with a Cohesive to Frictional Transition

A thermodynamically consistent mechanical interface model is presented. The model is based on the interface damage mechanic theory applied in a special fashion such that the interface damage variable is also used as a parameter which drives the continuous and smooth transition from the sound initial cohesive state to the final fully fractured frictional state. Interface damage activation and fictional sliding are promoted by a damage activation function and a Coulomb frictional yielding function. The main features of the model are discussed in details and some numerical results for the material response are shown in monotonic and cyclic loading regimes.

An elastic interface model with nonlocal integral damaging effects

Cohesive–frictional interface constitutive model

AbstractIn the framework of numerical analysis of joined bodies, the present paper is devoted to the constitutive modeling, via an interface kinematic formulation, of mechanical behaviour of internal adhesive layers. The proposed interface constitutive model couples a cohesive behaviour, based on the damage mechanics theory, with a frictional one, defined in a non-associative plasticity framework. Namely, the interface formulation follows the transition of the adhesive material from the sound elastic condition to the fully cracked one. This formulation is able to model, by means of a specific interpretation of the damage variable and in a relevant mathematical setting, the interface interme…

A nonlocal damage interface model

Nonlocal interface mechanical models

The paper presents a nonlocal elastic damage-frictional interface model. The reason to introduce nonlocal mechanical features inside the constitutive relations is justified by the fact that there are several circumstances, in which the interface displays inside an extended process zone with microstructural spatial interactions. Typically, spatial bridging mechanical effects can be effectively modeled by integral (strongly nonlocal) stress-strain relations. The paper develops an elastic nonlocal model with local isotropic damage and the relations are constructed following a thermodynamical consistent approach.

Una interfaccia elasto-danneggiativa arricchita con termini gradiente