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Article
Publication date: 12 June 2019

Georgios I. Giannopoulos, Stelios K. Georgantzinos, Androniki Tsiamaki and Nicolaos Anifantis

The purpose of this paper is the computation of the elastic mechanical behaviour of the fullerene C60 reinforced polyamide-12 (PA-12) via a two-stage numerical technique…

Abstract

Purpose

The purpose of this paper is the computation of the elastic mechanical behaviour of the fullerene C60 reinforced polyamide-12 (PA-12) via a two-stage numerical technique which combines the molecular dynamics (MD) method and the finite element method (FEM).

Design/methodology/approach

At the first stage, the proposed numerical scheme utilizes MD to characterize the pure PA-12 as well as a very small cubic unit cell containing a C60 molecule, centrally positioned and surrounded by PA-12 molecular chains. At the second stage, a classical continuum mechanics (CM) analysis based on the FEM is adopted to approximate the elastic mechanical performance of the nanocomposite with significantly lower C60 mass concentrations. According to the computed elastic properties arisen by the MD simulations, an equivalent solid element with the same size as the unit cell is developed. Then, a CM micromechanical representative volume element (RVE) of the C60 reinforced PA-12 is modelled via FEM. The matrix phase of the RVE is discretized by using solid finite elements which represent the PA-12 mechanical behaviour predicted by MD, while the C60 neighbouring location is meshed with the equivalent solid element.

Findings

Several multiscale simulations are performed to study the effect of the nanofiller mass fraction on the mechanical properties of the C60 reinforced PA-12 composite. Comparisons with other corresponding experimental results are attempted, where possible, to test the performance of the proposed method.

Originality/value

The proposed numerical scheme allows accurate representation of atomistic interfacial effects between C60 and PA-12 and simultaneously offers a significantly lower computational cost compared with the MD-only method.

Details

International Journal of Structural Integrity, vol. 10 no. 3
Type: Research Article
ISSN: 1757-9864

Keywords

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Article
Publication date: 4 September 2019

Konstantinos Stamoulis, Stelios K. Georgantzinos and G.I. Giannopoulos

The present study deals with the numerical modeling of the low-velocity impact damage of laminated composites which have increasingly important applications in aerospace…

Abstract

Purpose

The present study deals with the numerical modeling of the low-velocity impact damage of laminated composites which have increasingly important applications in aerospace primary structures. Such damage, generated by various sources during ground handling, substantially reduces the mechanical residual performance and the safe-service life. The purpose of this paper is to present and validate a computationally efficient approach in order to explore the effect of critical parameters on the impact damage characteristics.

Design/methodology/approach

Numerical modeling is considered as one of the most efficient tool as compared to the expensive and time-consuming experimental testing. In this paper, a finite element model based on explicit dynamics formulations is adopted. Hashin criterion is applied to predict the intralaminar damage initiation and evolution. The numerical analysis is performed using the ABAQUS® programme.

Findings

The employed modeling approach is validated using corresponding numerical data found in the literature and the presented results show a reasonable correlation to the available literature data. It is demonstrated that the current model can be used to capture the force-time response as well as damage parameter maps showing the intralaminar damage evolution for different impact cases with respect to the physical boundary conditions and a range of impact energies.

Originality/value

Low-velocity impact damage of laminated composites is still not well understood due to the complexity and non-linearity of the damage zone. The presented model is used to predict the force-time response which is considered as one of the most important parameters influencing the structural integrity. Furthermore, it is used for capturing the damage shape evolution, exhibiting a high degree of capability as a damage assessment computational tool.

Details

International Journal of Structural Integrity, vol. 11 no. 5
Type: Research Article
ISSN: 1757-9864

Keywords

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Article
Publication date: 10 August 2015

Stelios K. Georgantzinos, G. I. Giannopoulos, P. K. Pierou and N. K. Anifantis

A computational structural mechanics approach, based on the exclusive use of standard bar elements is utilized in order to investigate the elastic stability of…

Abstract

Purpose

A computational structural mechanics approach, based on the exclusive use of standard bar elements is utilized in order to investigate the elastic stability of single-walled carbon nanotubes (SWCNTs) with atom vacancy defects under axial compressive loads. The paper aims to discuss this issue.

Design/methodology/approach

The proposed model uses three dimensional, two nodded, linear truss finite elements of three degrees of freedom per node to represent the force field appearing between carbon atoms due to the basic interatomic interactions.

Findings

Numerical results concerning the critical forces which cause instability of pristine nanotubes are compared with corresponding data given in the open literature in the effort to demonstrate the good accuracy of the method. Then, it is assumed that SWCNTs present-specific structural defects defined by their length, width, orientation and longitudinal position. The influence of these four geometric parameters of the imperfections considered on the stability of SWCNTs is investigated in detail and essential conclusions are revealed.

Originality/value

To the authors’ best knowledge, is the first time that the specific method is introduced for the prediction of buckling behavior of defective SWCNTs. The structural defect here is considered as atoms vacancy that forms a like-crack defect having a specific length, width, orientation and position along the nanotube length.

Details

International Journal of Structural Integrity, vol. 6 no. 4
Type: Research Article
ISSN: 1757-9864

Keywords

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