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DEVELOPMENT AND TESTING OF NUMERICAL MODELS FOR JOINT DESIGN IN COMPOSITE MATERIAL STRUCTURES

Objective


In order to design joints, an interactive graphic mesh generator system (MGS) has been developed. This software package is now interfaced with a well known finite element method (FEM) code selected at the beginning of the research. During this research, several 3-dimensional joints were designed by MGS, then manufactured and tested in order to verify and finalise the developed design method. With MGS it is possible to optimise the design of joints, using FEM code, and to examine the results clearly. The first results of the last testing phase are confirming a good approximation between theoretical predictions and experimental results in accordance with the imposed tolerance.

In the field of polymeric matrix composite materials, very high mechanical performance beams are available. For their wide use, a reliable, cheap and low weight joint is necessary. Industrial, technological and economic considerations led to the use of sheet moulding compound (SMC) material with short glass fibre reinforcement for this purpose.

The selected material was subjected to orthotropic, short term static and nonlinear characterization and its performance under fatigue was determined. Weathering effects were also investigated.
2 different prototype joints were built and subjected to static and dynamic testing and results were compared to theoretical predictions.
Finally, an abacus was designed to enable the choice of the proper joint depending on the function of the bars to be connected and the loads to be applied.
A prototype was made available on 12/02/92
THE USE OF COMPOSITE MATERIALS OFFERS EVIDENT ADVANTAGES IN FIELDS WHERE LOW WEIGHT STRUCTURES ARE REQUIRED TO COMBINE HIGH STRENGTH IN SERVICE LOADS AND GOOD RESISTANCE TO CORROSIVE AGENTS.

IN PARTICULAR IN THE FIELD OF POLYMERIC MATRIX COMPOSITE MATERIALS VERY HIGH MECHANICAL PERFORMANCE BEAMS ARE AVAILABLE ON THE MARKET. HOWEVER TODAY VERY EXPENSIVE JOINTS ARE USED TO CONNECT THESE BEAMS TO REACH A GOOD RELIABILITY OF THE WHOLE STRUCTURE.

TO WIDEN THE USE OF THESE BEAMS A RELIABLE, CHEAP AND LOW WEIGHT JOINT MUST BE PRODUCED.

THE OBJECTIVE OF THIS RESEARCH IS TO FINALIZE A METHOD, BASED ON MODELLING TECHNIQUES, TO CORRECTLY DESIGN THE JOINTS IN ORDER TO EXTEND THE HIGH PERFORMANCE OF EACH SINGLE STRUCTURAL ELEMENT TO THE WHOLE STRUCTURE.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

Stin SpA
Address
Via Della Bufalotta 336
00139 Roma
Italy

Participants (4)

METRAVIB RECHERCHE DÉVELOPPEMENT SERVICE SA
France
Address
Chemin Des Ormeaux 200
69760 Limonest
Sistema Compositi SpA
Italy
Address
Via Casilina Km 57.500
00030 Castellaccio Di Paliano Roma
UNIVERSIDAD DE OVIEDO
Spain
Address
San Francisco 1-5
33003 Oviedo
Zollet Lucio e C. Snc
Italy
Address
Viale Stazione 40
32035 Santa Giustina Belluno