Publications de Anastasios Vassilopoulos

Publications associées (183)

Manufacturing and toughening effects on the material properties of wind turbine blade adhesives

Anastasios Vassilopoulos, Dharun Vadugappatty Srinivasan

Hybrid adhesives can be developed using commercially available adhesive materials and customized to the required loading conditions. In this paper, SPABONDTM 820HTA (non-toughened) and SPABONDTM 840HTA (toughened) adhesives are hybridized by two strategies ...

2022

Numerically-based method for fracture characterization of Mode I-dominated two-dimensional delamination in FRP laminates

Thomas Keller, Anastasios Vassilopoulos, Aida Cameselle Molares

A new numerically-based method suitable for determining the total strain energy release rate (SERA) involved in two-dimensional (2D) Mode I-dominated delamination under opening loads in FRP laminates is presented. The method is based on the mutual dependen ...

2019

Random field-based modeling of size effect on the longitudinal tensile strength of clear timber

Thomas Keller, Anastasios Vassilopoulos, Alireza Farajzadeh Moshtaghin

In the current study, a random field-based size effect model has been proposed for the longitudinal tensile strength of clear timber. Since the failure mode is brittle, the problem is basically an extreme value problem of finding the distribution of minima ...

Elsevier2016

Effects of core air gaps and steel inserts on thermomechanical response of GFRP-balsa sandwich panels subjected to fire

Thomas Keller, Anastasios Vassilopoulos, Niloufar Vahedi

Composite sandwich panels composed of a balsa core and glass fiber-reinforced polymer (GFRP) face sheets may offer attractive applications for building slabs and bridge decks. Such composite panels may contain air-filled gaps (caused by initial defects or ...

ELSEVIER SCI LTD2023

Shear mechanical characterization of balsa wood as core material of composite sandwich panels

Thomas Keller, Anastasios Vassilopoulos, Julia De Castro San Roman Fest, Michael Osei-Antwi

An experimental study was performed using Iosipescu specimens to evaluate the effects of parameters such as shear plane, density and adhesive joints on the shear stiffness and strength of balsa wood panels as well as the variation of ductility with respect ...

Elsevier2013

Thermophysical properties of balsa wood used as core of sandwich composite bridge decks exposed to external fire

Thomas Keller, Anastasios Vassilopoulos, Niloufar Vahedi

The load-bearing performance of sandwich bridge decks comprising a balsa core and fiber-reinforced polymer composite face sheets exposed to fire is a main concern regarding the application of these deck systems. In order to obtain the thermal responses of ...

ELSEVIER SCI LTD2022

Thermomechanical characterization of a balsa-wood-veneer structural sandwich core material at elevated temperatures

Thomas Keller, Anastasios Vassilopoulos, Niloufar Vahedi

The tensile, compressive and shear behavior of standardized specimens cut from a veneered balsa wood used as structural sandwich core was investigated at ambient temperatures of up to 250 degrees C. The average moisture content was 9.1%. The specimens' res ...

ELSEVIER SCI LTD2020

Physically Based Modeling of Shear Modulus-Temperature Relationship for Thermosets

Thomas Keller, Anastasios Vassilopoulos, Wei Sun

A new physically based model for the simulation of the imaginary part of the shear modulus-temperature (G ''-T) curve of thermosets is introduced in this paper. The model is based on the modification of the G ''-T equation used for thermoplastic polymers v ...

Wiley-Blackwell2015

Fabrication and curing conditions effects on the fatigue behavior of a structural adhesive

Anastasios Vassilopoulos

This paper investigates the effects of degassing, curing and post-curing conditions on the tensile quasi-static and fatigue behavior of a cold-curing structural epoxy adhesive. Quasi-static experiments performed at standardized and high displacement rates ...

2020

Probabilistic fatigue model for composites based on the statistical characteristics of the cycles to failure

Anastasios Vassilopoulos

A probabilistic model for estimating the fatigue life of composite laminates based on the mean value and standard deviation of the fatigue life is introduced here for predicting the distribution of fatigue life at any stress level for a constant stress rat ...

ELSEVIER SCI LTD2022

Effect of thermal lag on glass transition temperature of polymers measured by DMA

Thomas Keller, Anastasios Vassilopoulos, Wei Sun

This paper investigates the influence of thermal lag on the glass transition temperature of polymers measured under different heating rates during dynamic mechanical analysis (DMA). The E-modulus-temperature curves of a two-component epoxy adhesive and a p ...

Elsevier2014

Numerical modeling of two-dimensional delamination growth in composite laminates with in-plane isotropy

Thomas Keller, Anastasios Vassilopoulos, Congzhe Wang

The two-dimensional (2D) delamination growth in fiber-reinforced polymer (FRP) laminates with in-plane isotropy under Mode I loading condition was numerically investigated using finite element analyses. Two sizes of plate models were developed, focusing on ...

2021

Experimental investigation of two-dimensional Mode-II delamination in composite laminates

Thomas Keller, Anastasios Vassilopoulos, Congzhe Wang

The two-dimensional (2D) delamination growth in composite laminates under the Mode-II fracture condition was experimentally investigated using a novel set-up. Circular plate specimens with a centrally embedded pre-crack of two sizes were semi-clamped along ...

2023

Damage-tolerant behavior of structural epoxies with thin PEI and PVDF interlayers

Anastasios Vassilopoulos, Dharun Vadugappatty Srinivasan

This work examines the crack-arresting capability of PEI and PVDF thermoplastic interlayers in short-glass fiber modified and core-shell rubber toughened epoxy materials under mode-I fracture loading. Experimental results show that the initial crack can be ...

London2024

Creep effects on tension-tension fatigue behavior of angle-ply GFRP composite laminates

Thomas Keller, Anastasios Vassilopoulos, Abdolvahid Movahedirad

Angle-ply (±45)2S glass/epoxy composite specimens have been subjected to pure creep and tension-tension constant amplitude fatigue loading interrupted at max by creep intervals lasting for 2 or 48 hours in order to examine the effects of creep loading on ...

2019

Review of fatigue of bulk structural adhesives and thick adhesive joints

Anastasios Vassilopoulos

Fatigue of structural adhesives has been investigated through joints and a little number of works investigate bulk adhesive behaviour itself. Aerospace and automotive engineering focuses more on joint configuration studies, which are correlated with practi ...

TAYLOR & FRANCIS LTD2021

Influence of curved delamination front on R-curve of DCB specimen

Thomas Keller, Anastasios Vassilopoulos

This work investigated the evolution of the non-uniform distribution of Mode-I strain energy release rate (SERR) along a straight pre-crack front of double cantilever beams (DCB), caused by the anticlastic deformation and the longitudinal free-edge effects ...

ELSEVIER SCI LTD2019

Combining X-ray micro-CT and microscopy-based images of two lianas species to derive structural, mechanical and functional relationships

Alexandre Buttler, Anastasios Vassilopoulos, Pascal Turberg, Claudine Bettina Karlen

This paper presents a biomechanical study of stems of two liana species, Clematis vitalba and Vitis vinifera, investigates the mechanical performance of these two liana species and attempts to enhance the understanding of structure-function relationships. ...

2024

Two-dimensional analytical stress distribution model for unbalanced FRP composite single-lap joints

Thomas Keller, Anastasios Vassilopoulos

A two-dimensional analytical stress distribution model taking into account the effects of large deformation, bending-tension coupling and interfacial compliance on the quasi-static behavior of unbalanced FRP composite single-lap joints (SLJs) under tension ...

Elsevier2017

Modeling of axial and shear stresses in multilayer Sandwich beams with stiff core layers

Thomas Keller, Anastasios Vassilopoulos, Julia De Castro San Roman Fest, Michael Osei-Antwi

In order to optimize the load-bearing behavior of sandwich structures and adapt it to specific requirements, their core may be composed of layers of different materials with tailored properties. These layers may consist not only of soft foam or honeycomb m ...

Elsevier2014