Nunziante Valoroso

Parthenope University of Naples | Università Parthenope · Department of Engineering

A method is presented for studying bonded assemblies under pure mode III loading. It is based upon a novel fixture that can be mounted on a common universal testing machine and is able of realizing pure anti-plane shear conditions. Twisting of the bonded assembly generates a smoothly propagating circular crack front that allows for accurate measure...

We present a procedure for the assessment of reinforced concrete structures in terms of seismic capacity based on the nonlinear pushover method. Structural systems containing shear walls are dealt with by adopting a newly developed reinforced shell element in which arbitrary distributions of steel reinforcement and nonlinear material behavior for b...

A regularized damage model is considered named Graded damage in which the gradient enhancement has the form of an explicit bound for the spatial gradient of damage. The key features of the proposed approach are demonstrated by computing the analytical solution of two problems that are one-parameter dependent. The first one is the classical one-dime...

A regularized damage model is considered named "Graded damage" in which the gradient enhancement has the form of an explicit bound for the spatial gradient of damage. The key features of the proposed approach are demonstrated by computing the analytical solution of two problems that are one-parameter dependent. The first one is the classical one-di...

A novel approach to damage modeling for quasi‐brittle solids is presented relying upon a differential inclusion that is closely related to the one of implicit gradient models. The proposed formulation naturally fits in the so‐called non‐local standard approach, whereby the framework of Generalized Standard Materials is extended to include gradients...

We present a model of material degradation relying upon a local damage law supplemented by convex constraints. This results in a damage model with bounded variation that is shown to share the same features of the so-called Thick Level Set approach. Unlike the original model, in the present formulation the level set-based representation is abandoned...

A procedure for computing the surrogate response of Finite Element models based on kriging interpolation is presented. A set of computer experiments is run for random occurrences of a target material parameter in order to build the data set necessary to the calibration of the interpolation model. Kriging parameters are defined via the Matérn 5/2 va...

Cohesive-zone models have been widely used for the analysis of interface debonding. In this paper, three of these models are used to study a set of debonding problems. A comparative analysis of the three models is carried out; results are presented and discussed for numerical simulations referring to both single-mode and mixed-mode situations. The...

Background: The cohesive zone approach has gained increasing success in recent years for simulating debonding and fracture via finite element methods and is ideally suited for simulating adhesive joints, the potential crack paths being generally known in advance in most cases. In the paper the determination of the size of the so-called cohesive pro...

Mainly due to their low weight, low cost and ease of assembly, the adhesive bonds have emerged as a promising technology. However, the lack of adequate tools of design and control remain an obstacle to the use of the adhesives. In this work a cohesive interface model formulated within the framework of damage mechanics is applied for the simulation...

We consider the identification problem of a cohesive model using kinematic full-field data obtained via digital image correlation during the fracture test of an adhesive joint. A criterion is presented for selecting measurements that exhibit optimal features for identification purposes. The proposed selection scheme is constructed using the sensiti...

. A new strategy for in–situ testing of engineering structures is presented with the ultimate goal of providing real-time information on the structural behaviour during the test. The proposed procedure relies upon a probabilistic formulation and takes advantage of the Bayesian Network theory to account for uncertainties. An application is shown tha...

The identification of mode-I parameters of a cohesive-zone model for the analysis of adhesive joints is presented. It is based on an experimental–numerical methodology whereby the optimal parameters are obtained as the solution of a nonlinear programming problem. The data set for inverse analysis is provided either by local kinematic data, by globa...

RIASSUNTO. In questa comunicazione si presenta l'applicazione di una metodologia di analisi inversa ai modelli di zona coesiva utilizzando come dati misure cinematiche a tutto campo. L'analisi di sensitività e l'identificazione parametrica vengono condotte con riferimento a dati pseudo-sperimentali disturbati da rumore e consentono di apprezzare l'...

The implementation of the projected algorithm and of the consistent tangent tensor for general isotropic three-invariant elastoplastic models under plane stress conditions discussed in Part I of this paper [Valoroso, N., Rosati, L., 2008. Consistent derivation of the constitutive algorithm for plane stress isotropic plasticity. Part I: Theoretical...

A derivation of the projected algorithm for general isotropic three-invariant plasticity models under plane stress conditions is presented. It is obtained by consistently specializing the 3D formulation to the 2D subspace defined by the plane stress condition. Closed-form intrinsic algorithm linearization and a novel expression of the consistent ta...

Cohesive elements are developed for the analysis of adhesive joints configurations failing in the fully nonlinear regime. The core of the adopted approach is that of using a corotational formulation to mimic the behavoiur of the adhesive layer during deformation and fracture. The performances are demonstrated by means of a representative numerical...

A cohesive interface model formulated within the framework of damage mechanics is presented for the simulation of decohesion in adhesively bonded assemblies. Characteristic features of the model are: the introduction of a single energy-based damage variable for describing the damage state of the interface; use of a decohesion propagation condition...

The implementation of plasticity models with general isotropic yield surfaces is discussed. The computation of the return map solution and the algorithm linearization are carried out by suitably exploiting the isotropic character of the elastic constitution and of the yield function; the consistent tangent tensor is given an intrinsic explicit repr...

An interface model for the analysis of adhesively bonded assemblies accounting for damage as well as irreversible frictional sliding is presented. Decohesion at bonded interfaces is simulated via the damage mechanics-based approach developed by the authors whereas stick-slip motion is introduced after complete separation by analogy with plasticity...

In this work use is made of a cohesive-zone approach for the simulation of adhesive damage in adhesively bonded joints. The interface relationship relating tractions to displacement discontinuities is derived within the framework of damage mechanics and the constitutive model is formulated in a way that the advancement of the decohesion front takes...

We describe a methodology for solving the constitutive problem and evaluating the consistent tangent operator for isotropic elasto/visco-plastic models whose yield function incorporates the third stress invariant . The developments presented are based upon original results, proved in the paper, concerning the derivatives of eigenvalues and eigenpro...

Two cohesive-zone models, one developed by Valoroso & Champaney and the other initially proposed by Crisfield and co-workers and later modified by Alfano & Crisfield, are used for studying a set of delamination problems. Both models consider irreversible damage of the interface and account for mixed-mode debonding by satisfying a generalised ellips...

This chapter presents an extension of RL models of pseudoelasticity accounting for large strains. The mechanical model is reformulated in an intermediate configuration to recover a small strain-like format of the constitutive relationship. Alloys capable of undergoing phase transformations between a highly ordered austenitic (parent) phase and a le...

This chapter presents an extension of RL models of pseudoelasticity accounting for large strains. The mechanical model is reformulated in an intermediate configuration to recover a small strain-like format of the constitutive relationship. Alloys capable of undergoing phase transformations between a highly ordered austenitic (parent) phase and a le...

We present an original approach to the computational analysis of isotropic elasto/visco-plastic models depending upon all of the three invariants of the stress tensor. It is based upon some recent results, contributed by the authors, concerning the spectral decomposition of symmetric positive-definite rank-four tensors. They are used to provide the...

A solution strategy for plasticity and viscoplasticity models with isotropic yield surfaces depending upon all the principal invariants of the stress tensor is presented. Basically, it requires the inversion of a fourth-order positive definite tensor G both for the solution of the constitutive problem and for the evaluation of the consistent tangen...

We present an algorithmic procedure for the finite element solution of structural problems for no-tension materials. The approach is based upon a suitable modification of the tangent strategy which is shown to be computationally superior to conventional procedures for non-linear material models, namely the tangent strategy enhanced with line search...

We illustrate the principal space specialization of a recently proposed solution strategy for elastoplasticity with isotropic yield surfaces depending upon all the three invariants of the stress tensor. The main issue to address, for computing both the return map solution and the consistent tangent operator, is the inversion of a fourth-order posit...

A general and robust solution procedure for nonlinear finite element equations in small strain elastoplastic structural problems is presented. Its peculiar feature lies in the choice of the most suitable constitutive operator to be adopted at each iteration of a generic load step in order to ensure the utmost stability and convergence rate. Namely,...

The displacement-like finite element formulation for finite-step J2 elastoplasticity is revisited in this paper. The classical computational strategy, according to which, plastic loading is tested at the Gauss points of each element and an independent return mapping algorithm is performed for given incremental displacements, is consistently derived...

. Two aspects of finite element analysis of adhesive joints are discussed as different as computational failure analysis and parameter identification. Use is made of a novel cohesive element with rotational dofs whose performances are shown with reference to mode-I fracture tests. 1 INTRODUCTION The development of high-strength structural adhesives...

Purpose of this communication is to discuss the performaces of a novel interface ele-ment, recently proposed by the author, that possesses drilling degrees of freedom. The capabilities of the proposed element are demonstrated with reference to a typical delamination problem where fracture propagation is simulated using the cohesive-zone approach.

This paper describes a geometrically nonlinear formulation for an interface and its applica- tion to the analysis of adhesive joints configurations failing in the fully nonlinear regime. The core of the adopted approach is that of using a cohesive-zone model to mimic the behaviour of the adhesive layer within a corotational-like element formulation...

A cohesive model formulated within the framework of damage mechanics is presented for the simulation of decohesion in adhesively bonded assemblies. The treatment for the mixed-mode situation is based upon the introduction of a single damage variable and a consistently defined equivalent energy release rate. The comparison between numerical and expe...

The material parameters of an interface model are identified using experimental re-sults referred to a double-cantilever beam (DCB) bonded specimen. Global load-displacement data and full-field kinematic data obtained via Digital Image Correlation (DIC) are considered. Experimental and numerical results are presented that show the features of the a...