The paper illustrates the results of a theoretical-experimental research covering the mechanical behaviour of glass-fiber fabrics. Owing to the complex geometry of the reinforcement, the different properties of warp and weft, and the frequently observed nonlinear response, these materials need to be carefully characterized in order to fully exploit their mechanical properties. Particular attention was given in the experimental activities to the sources of nonlinearity, to define a limit stress for design purposes. During tension tests, a testing device was employed to monitor the acoustic emissions that accompany local fiber failures often responsible for the nonlinear response. This allowed the identification of the position and the number of microfractures in the specimens at different load levels and the correlation of the final failure to the localization of the microfractures. A finite element numerical model was also developed to describe the global (or ‘macroscopic’) response of the fabric under any loading condition. The model takes a single 3D ‘Representative Volume Element’ (RVE) of fabric into account. By imposing suitable displacement conditions at the boundary of the RVE, the macroscopic properties of the composite can be predicted based on the properties of the components and the geometry of the reinforcement.
Analisi sperimentale e modellazione micromeccanica di tessuti laminati in fibra di vetro
POGGI, CARLO;TALIERCIO, ALBERTO
1997-01-01
Abstract
The paper illustrates the results of a theoretical-experimental research covering the mechanical behaviour of glass-fiber fabrics. Owing to the complex geometry of the reinforcement, the different properties of warp and weft, and the frequently observed nonlinear response, these materials need to be carefully characterized in order to fully exploit their mechanical properties. Particular attention was given in the experimental activities to the sources of nonlinearity, to define a limit stress for design purposes. During tension tests, a testing device was employed to monitor the acoustic emissions that accompany local fiber failures often responsible for the nonlinear response. This allowed the identification of the position and the number of microfractures in the specimens at different load levels and the correlation of the final failure to the localization of the microfractures. A finite element numerical model was also developed to describe the global (or ‘macroscopic’) response of the fabric under any loading condition. The model takes a single 3D ‘Representative Volume Element’ (RVE) of fabric into account. By imposing suitable displacement conditions at the boundary of the RVE, the macroscopic properties of the composite can be predicted based on the properties of the components and the geometry of the reinforcement.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
