# Mechanical effect and shielding effectiveness of the insertion of metallic screen in glass and carbon composite

Matthieu Grésil, Patrick Parneix, Jean-Luc Boulay, Cyril Cheype, Jean-Christophe Walrick, Bertrand Lascoup, Michel Lemistre

<figure><img src="image_1.png" /></figure>

## ► To cite this version:

Matthieu Grésil, Patrick Parneix, Jean-Luc Boulay, Cyril Cheype, Jean-Christophe Walrick, et al. Mechanical effect and shielding effectiveness of the insertion of metallic screen in glass and carbon composite. ECCM13 13ème Conférence Européenne sur les Matériaux Composites, Jun 2008, Biarritz, France. hal-04598093

HAL Id: hal-04598093

https://hal.science/hal-04598093v1

Submitted on 19 Jul 2024

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers.

L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

<figure><img src="image_2.png" /></figure>

Distributed under a Creative Commons Attribution 4.0 International License
MECHANICAL EFFECT AND SHIELDING EFFECTIVENESS OF THE
INSERTION OF METALLIC SCREEN IN GLASS AND CARBON
COMPOSITE

M. Gresil ¹, P. Parneix ¹, J.L. Boulay ², C.Cheype ², J.C. Walrick ³, B. Lascoup ³
and M. Lemistre ⁴

¹ Whole war ship Engineering, DCNS, 56311 Lorient, France

² CERPEM, 53606 Laval, France

³ Structural Material Dep., ESTACA, 53061 Laval, France

⁴ SATIE ENS-Cachan, 94 Cachan, France

**KEYWORDS:** Shielding effectiveness, Mechanical effect, Glass, Carbon, Electromagnetic.

INTRODUCTION

Warships are equipped with more and more electronic equipments which generate electromagnetic fields of various intensity. The superstructures support several contributors such as radar antennas, high frequency antennas and electronic warfare equipment... each being susceptible to interfere or hinder the other equipments but also perturb the operation of the equipment installed in the living spaces. It is also susceptible to impair the health of the personnel living in these spaces. In the case of Glass Reinforced Plastics, the structure does not conduct electricity and is particularly transparent to electromagnetic radiation. In the case of Carbon Reinforced Plastics, the structure is not enough conductive to obtain a good Shielding Effectiveness. Therefore one of the ways considered is to insert a metallic screen in the composite material.

The present work presents the electrical and mechanical influence due to the
insertion of this material. The objective of this study is to increase the electrical conductivity,
then to show the effect on the mechanical behaviour of the insertion of the metal screen
compared to the original structure. Experimental and numerical effects of the position of the
metallic screen in composite materials will be described.

STRUCTURE PRESENTATION

The first composite material was manufactured from a Glass/vinylester composite. The
second was manufactured from Carbon/Vinylester composite.

To increase the conductivity of the material, we propose in this study to integrate metallic
screen in the structure. These metallic screen are made of a polyester coated copper or bronze
and are inserted in several levels between two layers in the thickness of the structure. Figure 1
shows a screen embedded in a Glass composite.

<figure><img src="image_3.png" /><figcaption>Fig. 1: Metallic screen embedded in Glass composite</figcaption></figure>
## SHIELDING EFFECTIVENESS

The surface impedance of the composite material is measured using a specific probe developed by ONERA [1]. The surface impedance is measured using a data acquisition system and ranges from 5 to 20 mΩ / sq according to various composite materials and screen. The electromagnetic shielding efficiency (SE) is defined [2, 3] as the ratio of the incoming and outgoing waves power by the relation (1)

$$SE = 10 \log \left( \frac{P_i}{P_0} \right) = 20 \log \left( \frac{E_i}{E_0} \right) \quad (\text{Expressed in dB}) \quad (1)$$

Here, $P_i, P_0$ are the electromagnetic power and $E_i, E_0$ are the electric field of incoming and outgoing waves, respectively.

The electromagnetic shielding efficiency is measured in an anechoic room. The frequency band of measurement ranges from 500MHz to 3GHz. The first results (Figure 2) show the SE for a composite carbon material and the SE increases with the frequency.

<figure><img src="image_4.png" /><figcaption>Fig. 2: SE of Carbon material.</figcaption></figure>

## MECHANICAL EFFECT

The mechanical tests performed include: Tensile Test, Short Beam Shear Test and Impact Test.

The purpose of these tests is to show the mechanical influence of the insertion of these screen compared to the original materials. Moreover, the position of the screen in the composite will be mechanically studied in order to determine the best position in the structure. The first tests of short beam shear showed a 10-15% loss compared to the original material.

## REFERENCES

1. Gobin V., "Diffraction par des ouvertures et par des objets tridimensionnels. Application à la mesure des impédances de surface des matériaux bons conducteurs", PhD at ONERA, 1989.

2. Joo J. and Epstein A.J., Appl. Phys. Lett. 65 (1994).

3. Schulz R.B., IEEE Trans. Elec. Comp. EMC-10 (1968).