Raffaella Rizzoni

Raffaella Rizzoni
University of Ferrara | UNIFE · Department of Engineering

Doctor of Engineering

About

99
Publications
7,235
Reads
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889
Citations
Citations since 2016
45 Research Items
605 Citations
2016201720182019202020212022020406080100120
2016201720182019202020212022020406080100120
2016201720182019202020212022020406080100120
2016201720182019202020212022020406080100120
Introduction
- solid and structural mechanics - contact problems - shape memory alloys - elasticity
Additional affiliations
February 2001 - present
University of Ferrara
Position
  • Research Assistant
February 2001 - November 2020
University of Ferrara
Position
  • Assistant Professor
Education
January 1996 - March 1999
University of Florence
Field of study
  • Engineering of Structures
October 1989 - July 1995
University of Ferrara
Field of study
  • Engineering of materials

Publications

Publications (99)
Preprint
Full-text available
Since the beginning of the 20th century, it is known that the spontaneous bending of heterogeneous bilayered plates correlates with the self-stress due to the contrast in the material properties of the two layers, and that this correlation can be exploited to gauge the internal stress state. Over the last decades, ever-growing device miniaturizatio...
Article
Full-text available
Adhesive interfaces are suitable modelling tools to describe very thin elastic layers and the related occurring phenomena (such as damage, viscosity, friction, etc.), without using a volumetric description, which is often computationally prohibitive in a large-scale numerical simulation. A major drawback of these kinds of models is the identificati...
Article
Flexoelectric materials exhibit coupling between electric polarization and mechanical strain gradient. At the nano-scale and micro-scale, these materials offer a promising potential for the development of mechanical transducers and energy harvesters. This work proposes a new imperfect interface model simulating the behavior of a thin flexoelectric...
Article
A two-scale model for clusters of degenerated graphite in gray cast iron is presented. The novelty of the model is that, at the mesoscale, a single cluster is described as a spheroidal inclusion made of porous materials. At the microscale, the porous material contains a random distribution of randomly oriented spheroidal voids modeling the graphite...
Article
We report on an analytical model for damage description in adhesive butt joints. In themodel, the thin adhesive layer is replaced by a damaging bonding interface. The mechanical behaviorof the interface is described by a nonlinear and rate­dependent imperfect contact law. The law takesinto account both stress and displacement jumps, and it can desc...
Article
Full-text available
Interfaces play an essential role in determining the mechanical properties and the structural integrity of a wide variety of technological materials [...]
Article
This work is concerned with the equilibrium problem of a composite body comprising two linear elastic adherents joined by an adhesive of small thickness ɛ and made of a conewise linear elastic material (Curnier et al., 1995). The elasticity coefficients of the adhesive material are chosen to simulate soft behavior in traction and hard behavior in c...
Research Proposal
Interfaces/interphases play a crucial role in the global behaviour of materials and structures within many engineering fields. Suitable models are required to accurately take into account their multi-scale and multi-physic nature. The dual purpose of the present mini-symposium is to collect recent analytical and computational models of imperfect in...
Article
The paper describes the mechanical behavior of composites made of piezoelectric spheres in perfect or imperfect contact. The imperfect contact is achieved by interposing piezoelectric thin adhesive layers between the spheres. First, using asymptotic analysis, transmission conditions of imperfect interface equivalent to the behavior of piezoelectric...
Article
Full-text available
We extend previous results for the stress analysis of a cluster of degenerated graphite in spheroidal cast iron, modelled as a multiscale three-dimensional composite. At the microscale, precipitates of degenerated graphite are modelled as spheroidal voids in a linear elastic matrix. At the mesoscale, clusters of degenerated graphite are aggregates...
Article
Bonding techniques are increasingly used in many industrial fields. Modelling the under-load damaging behavior of hard structural adhesives is still an open challenge. This work proposes a new hard interface analytical model with evolutive micro-cracking damage. The model is obtained within a rigorous theoretical framework combining asymptotic theo...
Preprint
Bonding techniques are increasingly used in many industrial fields. Modelling the under-load damaging behavior of hard structural adhesives is still an open challenge. This work proposes a new hard interface analytical model with evolutive micro-cracking damage. The model is obtained within a rigorous theoretical framework combining asymptotic theo...
Article
Full-text available
The paper presents a new analytical model for thin structural adhesives in glued tube-to-tube butt joints. The aim of this work is to provide an interface condition that allows for a suitable replacement of the adhesive layer in numerical simulations. The proposed model is a nonlinear and rate-dependent imperfect interface law that is able to accur...
Article
Full-text available
This work proposes new interface conditions between the layers of a three-dimensional composite structure in the framework of coupled thermoelasticity. More precisely, the mechanical behavior of two linear isotropic thermoelastic solids, bonded together by a thin layer, constituted of a linear isotropic thermoelastic material, is studied by means o...
Article
Full-text available
We propose a multiscale three-dimensional model for the stress analysis of a cluster of degenerated graphite in spheroidal cast iron. The model allows to study the effect of graphite microstructure on the average stress distribution inside the cluster. At the microscale, precipitates of degenerated graphite are modelled as spheroidal voids. At the...
Article
Composite adhesive bonded joints are widely used in various industrial and technological applications, including aerospace, electronics, biomedical, automotive, ship building and construction. In this paper, the attention is focused on layered structures consisting of two adherent beams bonded together by an adhesive layer. For such structures, a m...
Article
Full-text available
The present paper reports an experimental study coupled with a numerical modelling approach to simulate masonry walls strengthened with textile-reinforced mortar (TRM). This innovative reinforcing technique is based on high-strength fibre grids embedded into inorganic matrices, and it has recently been promoted for the seismic retrofitting of histo...
Article
We develop a hierarchical model for the description of the stress state inside a cluster of degenerated graphite in spheroidal cast iron. The model is based on the following simplifying assumptions: at the microscale, the graphite particles are viewed as elliptical pores; at the mesoscale, clusters of graphite particles are modeled as elliptical in...
Chapter
Full-text available
In the present study, we focus our attention to a specific type of composite, constituted by two media, called the adherents, bonded together with a thin interphase layer, called the adhesive. We assume that the composite constituents are made of different multi-physic materials with highly contrasted constitutive properties. The study considers a...
Article
Full-text available
We investigate some mathematical and numerical methods based on asymptotic expansions for the modeling of bonding interfaces in the presence of linear coupled multiphysic phenomena. After reviewing new recently proposed imperfect contact conditions (Serpilli et al., 2019), we present some numerical examples designed to show the efficiency of the pr...
Chapter
Full-text available
The paper describes the mechanical behavior of a composite constituted by two solids, bonded by a thin adhesive layer in a general multi-physic framework, by employing the asymptotic expansion technique. After defining a small parameter \(\varepsilon \), which will tend to zero, associated with the thickness and the constitutive coefficients of the...
Article
Full-text available
We report on experimental and numerical investigations of textile reinforced mortar (TRM) strengthening systems, an innovative solution for reinforcing historical masonry structures. The experimental campaign presented in this paper is original and concerns two commercial TRM applications to single-leaf clay masonry panels. The proposed FE modellin...
Article
The paper is concerned with the derivation of a general imperfect interface law in a linear multiphysics framework for a composite, constituted by two solids, separated by a thin adhesive layer. The analysis is performed by means of the asymptotic expansions technique. After defining a small parameter ε, which will tend to zero, associated with the...
Article
Full-text available
To take into account the weakening effect of defects clusters in real microstructures, we propose a multiscale model in a two-dimensional setting. At a small scale, single defects are described as elliptical voids randomly distributed and randomly oriented in an isotropic matrix. Using an effective field method proposed by Tandon and Weng [5,6], the...
Article
In this paper, the bending behavior of an active SMA-based beam, made up of a NiTi alloy strip externally joined to a PA66-GF30 polymeric lamina, is examined. Firstly, experimental investigations were conducted in a purpose-built test bench where a forced airflow promoted the reverse and forward phase transformations of the NiTi strip via heating a...
Article
The present paper deals with the modeling of bonded interfaces adopting the asymptotic expansion technique. The equilibrium problem of a composite body made of two adherents issn perfect contact with an elastic interface is considered and a classical rescaling technique is introduced. The asymptotic expansion method is reviewed; in fact, the repres...
Article
Full-text available
The proposed study aims to derive an imperfect interface model which couples finite strain and damaging. The governing equations are obtained via an asymptotic approach within the finite strain theory. Theoretical findings have been numerically validated within an original application to brick/mortar interfaces in masonry walls in shear loading con...
Article
This work proposes new transmission conditions at the interfaces between the layers of a three-dimensional composite structures. The proposed transmission conditions are obtained by applying the asymptotic expansion technique in the framework of Lagrange-Hamilton's principle. The proposed conditions take into account interfacial effects of higher o...
Article
Full-text available
The present paper deals with a general asymptotic theory aimed at deriving some imperfect interface models starting from thin interphases. The novelty of this work consists in taking into account some non-standard constitutive behaviors for the interphase material. In particular, micro-cracks, surface roughness and geometrical nonlinearity are incl...
Article
Full-text available
In this paper a composite body is considered. This body is made of three solids: two linear elastic adherents and a piecewise linear thin adhesive. The composite occupies a bounded domain depending naturally on a small parameter ε, which is the thickness, assumed constant, of the adhesive. Classically, it is possible to derive an interface imperfec...
Article
Full-text available
A new strategy for the numerical modelling of brick/mortar interfaces at the macro-scale taking into account finite strains and evolving microcracking phenomena is introduced. A numerical validation of the non-linear-imperfect interface model formulated in Part I of the present paper, is proposed. Well-established experimental data concerning diago...
Article
The paper focuses on the calculation of the effective elastic properties of a laminated composite shell with imperfect contact between the layers. To achieve this goal, first the two-scale asymptotic homogenization method (AHM) is applied to derive the solutions for the local problems and to obtain the effective elastic properties of a two-layer sp...
Article
Full-text available
Defects morphology primarily affects the mechanical properties of grey cast iron. In large castings, porosity and clusters of degenerate graphite are heterogeneously dispersed into the ferrous matrix and serve as initiation sites for fatigue and fracture processes. Strength and toughness of nodular cast iron compare to many grades of steel but expe...
Article
Using matched asymptotic expansions with fractional exponents, we obtain original transmission conditions describing the limit behavior for soft, hard and rigid thin interphases obeying the Saint Venant-Kirchhoff material model. The novel transmission conditions, generalizing the classical linear imperfect interface model, are discussed and compare...
Article
The elastic properties of a spherical heterogeneous structure with isotropic periodic components is analyzed and a methodology is developed using the two-scale asymptotic homogenization method (AHM) and spherical assemblage model (SAM). The effective coefficients are obtained via AHM for two different composites: (a) composite with perfect contact...
Article
In this paper two models of damaged materials are presented. The first one describes a structure composed by two adherents and an adhesive which is micro-cracked and subject to two different regimes, one in traction and one in compression. The second model is a model of interface derived from the first one through an asymptotic analysis, and it can...
Article
Full-text available
In this paper, a nonlinear-imperfect interface model is proposed in order to model brick/mortar-interface behavior in small masonry assemblies. The proposed model, formulated according a micromechanical strategy, derives from a consolidated approach coupling arguments of asymptotic analysis and homogenisation method. The adopted asymptotic techniqu...
Chapter
Full-text available
Modeling interfaces between solids is of great importance in the fields of mechanical and civil engineering. Solid/solid interface behavior at the microscale has a strong influence on the strength of structures at the macroscale, such as gluing, optical systems, aircraft tires, pavement layers and masonry, for instance. In this lecture, a deductive...
Conference Paper
In this paper, a new imperfect interface model is presented. The model includes finite strains, micro-cracks and smooth roughness. The model is consistently derived by coupling a homogenization approach for micro-cracked media and arguments of asymptotic analysis. The model is applied to brick/mortar interfaces. Numerical results are presented.
Article
Full-text available
For a large class of composites, the adhesion at the fiber–matrix interface is imperfect i.e. the continuity conditions for displacements and often for stresses is not satisfied. In the present contribution, effective elastic moduli for this kind of composites are obtained by means of the Asymptotic Homogenization Method (AHM). Interaction between...
Article
Full-text available
Two constitutive models representative of two well-known modeling techniques for superelastic shape-memory wires are reviewed. The first model has been proposed by Kim and Aberayatne in the framework of finite thermo-elasticity with non-convex energy [1]. In the present article this model has been modified in order to take into account the differen...
Article
Full-text available
This paper discusses the effect of different surface treatments on shape memory alloy wires embedded in PolyEster (PE) and VinylEster (VE) polymeric matrices. In particular, two types of chemical etching and a chemical bonding with a silane coupling agent have been performed on the surfaces of the wires. Pull-out tests have been carried out on samp...
Article
This paper presents a thermodynamical formulation for the one-dimensional constitutive model for shape memory alloys (SMAs) proposed by the authors in Marfia and Rizzoni (Eur J Mech A Solids 40:166–185, 2013) and able to describe the pseudo-elastic and shape memory effects and the martensite detwinning. The model takes into account the asymmetric b...
Article
The present paper deals with the derivation of a higher order theory of interface models. In particular, it is studied the problem of two bodies joined by an adhesive interphase for which “soft” and “hard” linear elastic constitutive laws are considered. For the adhesive, interface models are determined by using two different methods. The first met...
Article
Full-text available
This paper deals with the two-way shape memory effect (TWSME) induced on a strip of a near-equiatomic NiTi alloy by means of the shape memory cycling training method. This procedure is based on the deformation in martensite state to reach the desired cold shape followed by cycling the temperature from above Af to below Mf . To this end, the sample...
Article
In this paper, some results on the asymptotic behavior of stiff thin interfaces in elasto-statics are recalled. A specific study of stiff interfaces in elastodynamics is presented and a numerical procedure is given.
Article
Full-text available
In this paper, some results obtained on the asymptotic behavior of hard, thin curvilinear interfaces i.e., in cases where the interphase and adherents have comparable rigidities, are presented. The case of hard interfaces is investigated in terms of cylindrical coordinates and some analytical examples are presented.
Article
This paper deals with the one-dimensional modeling of a shape memory alloy (SMA) in order to reproduce the special thermo-mechanical response of the material. In particular, new analytical solutions are developed using a simple one-dimensional SMA model based on the introduction of three phases: tensile martensite, compressive martensite and austen...
Article
In this paper, the asymptotic first order analysis, both mathematical and numerical, of two structures bonded together is presented. Two cases are considered, the gluing of an elastic structure with a rigid body and the gluing of two elastic structures. The glue is supposed to be elastic and to have its stiffness of the same order than those of the...
Article
Full-text available
We present a theoretical and experimental investigation of the bending recovery performances for a commercial NiTi shape memory alloy strip. We evaluate the mechanical properties and the shape setting parameters and estimate the evolution of the curvature during heating in an Ethylene Glycol-based water solution. To model the strip bending response...
Article
This paper proposes the study of the equilibrium problem, where two elastic bodies are bonded to a thin elastic film under mismatch strain conditions resulting in a state of residual stress. The asymptotic behavior of the film/adherent system is modeled as the film thickness tends to zero, using a method based on asymptotic expansions and energy mi...
Conference Paper
Full-text available
This work addresses a comparison between the theoretical responses of two different one-dimensional constitutive models for shape memory alloys (SMAs) and a set of experimen- tal data obtained for superelastic SMA wires used in seismic applications. The first model, proposed by Abeyaratne and Kim [1] and modified in [2], is based on a micro-mechanica...
Conference Paper
Full-text available
A common approach to the modeling of very thin adhesive films is their replacement with an equivalent contact law, prescribing the jumps in the displacement and traction vector fields at the limit interface as the film thickness goes to zero. From the geometrical point of view, the adhesive film is eliminated, although it is accounted for mechanica...
Conference Paper
Full-text available
In the framework of the MAMAS Project (“Advanced Multi-task Materials for Structural Applications in Construction”), a scientific team (CETMA, ENEA, Ferrara and Florence Universities) realised a prototypal device made by CFRP (Carbon Fibre Reinforced Polymers) strips in series with SMA (Shape Memory Alloy) NiTi wires, devoted to strengthening mason...
Article
Full-text available
A one-dimensional model for the evolution of microstructure in single crystal shape memory wires has been recently proposed in (Rizzoni (2011)). The model is based on the constrained theory of martensite introduced by (Ball et al. (1995); De Simone and James (2002)) and on the assumption that stable equilibrium configurations are deformations lying...
Chapter
In a first part, we consider a bar with extremities subject to a given displacement and made by two clastic bodies with linear stress-strain relation separated by an adhesive layer of thickness h. The material of the adhesive is characterized by a non convex (pieccwise quadratic) strain energy density with clastic modulus k. After considering the e...
Conference Paper
Full-text available
Results of an experimental and analytical study on the free bending recovery of shape memory alloy strips are presented. Nitinol strips have been trained to memorize a bending shape and the best recovery performances have been obtained by heat-treating at 450 °C for 25 minutes. Free recovery has been observed during heating in an Ethylene Glycol ba...
Article
Full-text available
The theory of thin wires developed in Dret and Meunier (Comptes Rendus de l’Académie des Sciences. Série I. Mathématique 337:143–147, 2003) is adapted to phase-transforming materials with large elastic moduli in the sense discussed in James and Rizzoni (J Elast 59:399–436, 2000). The result is a one-dimensional constitutive model for shape memory w...
Article
The mechanical problem of two elastic bodies separated by a thin elastic film is studied here. The stiffness of the three bodies is assumed to be similar. The asymptotic behavior of the film as its thickness tends to zero is studied using a method based on asymptotic expansions and energy minimization. Several cases of interphase material symmetry...
Chapter
In this chapter, a review of theoretical and numerical asymptotic studies on thin adhesive layers is proposed. A general mathematical method is presented for modelling the mechanical behavior of bonding and interfaces. This method is based on a simple idea that the adhesive film is supposed to be very thin; the mechanical problem depends strongly o...
Article
Full-text available
In this paper, some results on the asymptotic behavior of hard and soft thin interfaces are recalled. A specific study of soft interfaces in cylindrical coordinates is presented and an analytical example is studied.
Article
Full-text available
This paper proposes the study of the equilibrium problem, where two elastic bodies are bonded to a thin elastic film under mismatch strain conditions resulting in a state of residual stress. The asymptotic behavior of the film/adherent system is modeled as the film thickness tends to zero, using a method based on asymptotic expansions and energy mi...