Publications de Anastasios Vassilopoulos

A conditional diffusion model-based data augmentation method for structural health monitoring of composites

To address the data scarcity in structural health monitoring (SHM), this study proposes a health index (HI) prediction framework based on a feature-transfer-based conditional denoising diffusion probabilistic model (Conditional DDPM) for data augmentation. ...

2025

On the fatigue behavior of thin and thick adhesively bonded composite joints

Anastasios Vassilopoulos

Investigations of the fatigue performance of adhesively bonded joints were initiated since the 1950 s. An abundance of publications has emerged dealing with the experimental investigation of the fatigue performance of adhesively bonded joints of various ge ...

2025

Standard specimen geometries do not always lead to consistent fatigue results for epoxy adhesives

Anastasios Vassilopoulos, Dharun Vadugappatty Srinivasan

This paper questions the recommendation regarding the use of standard specimen geometries, (Type I, Type II, and Type IV), for estimating the tensile quasi-static and fatigue properties of structural epoxy adhesives. The work presents results from an exper ...

2025

Transfer learning-based approach for evaluating residual stiffness in carbon fiber reinforced composites and adhesives

Anastasios Vassilopoulos

This work proposes a transfer learning-based encoder-decoder framework to predict the relationship between loading conditions and residual stiffness in carbon fiber reinforced composites and adhesives. The encoder, built from a Convolutional Neural Network ...

2025

Toughening of thick bonded interfaces through architected crack-arresting features

Anastasios Vassilopoulos, Dharun Vadugappatty Srinivasan

This research investigates the application of additively manufactured crack-arresting features (CAFs), designed from tough and soft polymers, in enhancing the performance of thick glass fiber-reinforced polymer composite-epoxy adhesive joints found in wind ...

2025

Combined computational-experimental investigation of residual stresses and pre-cracking in mode I behaviour of thick adhesively bonded GFRP composite joints

Véronique Michaud, Anastasios Vassilopoulos, Jialiang Fan

This paper presents a novel Finite Element (FE) simulation approach to examine the mode I fracture of thick adhesive joints used particularly in the trailing edge of the wind turbine blades. The approach involved FE models of the DCB specimens focusing on ...

Elsevier BV2025

A new equivalent crack length technique for mode I fracture of adhesively bonded joints

Véronique Michaud, Anastasios Vassilopoulos, Jialiang Fan

The current investigation introduces the concepts of the equivalent crack length approach for thin and thick adhesive joints. Its applicability is assessed for adhesively bonded composite and steel joints with a bondline thickness ranging from 0.4 mm to 10 ...

2025

An experimental and analytical study of mode I fracture and crack kinking in thick adhesive joints

Véronique Michaud, Anastasios Vassilopoulos, Jialiang Fan

This study investigates the fracture behavior of thick adhesive joints manufactured with composite adherends and bonded with an epoxy-based structural adhesive common to the wind turbine industry. For that purpose, double cantilever beam specimens with an ...

Elsevier BV2024

Experimental and numerical investigation of an additively manufactured sandwich composite bridge deck utilizing gyroid building blocks

Anastasios Vassilopoulos

This work investigates the integration of Additive Manufacturing (AM) techniques with cellular metamaterials integrated into composite sandwich beam systems. The study proposes an approach that combines composite materials for the face sheets with cellular ...

2024

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

Thomas Keller, Anastasios Vassilopoulos, Congzhe Wang

Existing standards for delamination tests on composite materials typically employ one-dimensional (1D) beam specimens. However, such specimens may not represent real delamination scenarios in composite structures, where cracks tend to propagate in two dime ...

Elsevier Sci Ltd2024

A generalized machine learning framework to estimate fatigue life across materials with minimal data

Anastasios Vassilopoulos, Dharun Vadugappatty Srinivasan

In this research, a generalized machine learning (ML) framework is proposed to estimate the fatigue life of epoxy polymers and additively manufactured AlSi10Mg alloy materials, leveraging their failure surface void characteristics. An extreme gradient boos ...

2024

Influence of Thermoplastic Interlayers on Fatigue Crack Growth in Epoxy Materials

Anastasios Vassilopoulos, Dharun Vadugappatty Srinivasan

This work examines the fatigue crack-arresting capability of thin PEI and PVDF thermoplastic interlayers in short-glass fiber-modified epoxy and core-shell rubber-modified epoxy materials. Singleedge notch bending epoxy specimens with and without interlaye ...

2024

Healable adhesive paste development for thick adhesive joints

Véronique Michaud, Anastasios Vassilopoulos, Jialiang Fan

A new adhesive formulation is developed, enabling assisted self-healing for wind turbine rotor blade (WTRB) applications. The properties of this epoxy based formulation are compared to those of a state-of-the-art toughened epoxy adhesive (Sikapower (R)-830 ...

ELSEVIER SCI LTD2024

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

Behavior of CFRP composites and epoxy adhesives after long-term exposure to outdoor and laboratory-controlled environments

Anastasios Vassilopoulos, Joao Gomes Pereira Junior

Carbon fiber reinforced polymer (CFRP) composites have shown desirable properties in aerospace, automotive, and construction industries. Focusing on the latter and in the context of strengthening existing structures, CFRP composites are typically bonded to ...

Elsevier BV2024

Mode-I Fracture Analysis of thick Advanced Joints Toughened With Thermoplastic Layers

Anastasios Vassilopoulos, Dharun Vadugappatty Srinivasan

This work aims to investigate the quasi-static mode-I fracture behavior of thick glass fiber-reinforced polymeric composite-epoxy adhesive joints having a nominal bond line thickness of 10 mm, focused on wind turbine rotor blade applications. The thick adh ...

2024

Void content and displacement ratio effects on fatigue crack growth in thick adhesively bonded composite joints under constant amplitude loading

Véronique Michaud, Anastasios Vassilopoulos, Jialiang Fan

This article investigates the influence of displacement ratio (R d-ratio) and void content on the fatigue behavior of Double Cantilever Beam (DCB) joints with thick adhesive layer (10 mm). Two R d-ratios and two different void contents were studied. To ach ...

2024

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

Alexandre Buttler, Pascal Turberg, Anastasios Vassilopoulos, 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

Mode I fracture of thick adhesively bonded GFRP composite joints for wind turbine rotor blades

Véronique Michaud, Anastasios Vassilopoulos, Jialiang Fan

This article investigates the effects of voids, joint geometry, and test conditions on the quasi-static Mode I fracture performance of thick adhesive Double Cantilever Beam (DCB) joints such as those prevailing in wind industry and shipbuilding. The specim ...

2024

Fatigue performance of wind turbine rotor blade epoxy adhesives

Anastasios Vassilopoulos, Dharun Vadugappatty Srinivasan

2023