Acoustic emission (AE) was used to monitor damage development in a glass fiber/epoxy composite during monotonic and cyclic Mode II loadings of DCB specimens. AE parameters such as event count rates and accumulative event counts together with the distribution of events by time and location in the DCB specimen were used as proper indicators of the damage growth at various stages during testing. AE proved to be a powerful technique to predict in real time the interlaminar failure stress (delamination in Mode II) in both the static and the dynamic tests. An S‐N curve constructed entirely on the AE signatures recorded during fatigue testing exhibits three distinct stages enabling delineation of period of damage initiation, the period of damage growth, and finally the occurrence of delamination. A generalized expression based on the nonlinear cumulative damage model was developed to correlate AE activity with the damage development in the composite during cyclic loading. The fatigue data to date agree well with this method of prediction of the fatigue life.

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The development of polymers has not stopped growing and taking more and more emphasis in our lives. From high-performance industries to mass-market industries, polymers are ubiquitous in every aspect of our lives, from where comes the pressing need to know their properties, characteristics, and behaviors more rigorously. This work is based on a study of the mechanical characterizations of thermoplastic polymers under the effects of damage. To serve this purpose, an experimental study was carried out on thermoplastic ABS (Acrylonitrile Butadiene Styrene) specimens. At first, we worked on altered specimens to define the mechanical characteristics of our material such as the elastic limit, the stress maximum, the breaking stress and the Young's modulus. On the one hand, and on the other hand we have created geometrical defects (discontinuity) on specimens in (ABS), to have the effect of defects on the mechanical characteristics of the material, afterwards a study of damage carried out by two methods to determine the critical fraction of life. To determine the lifetime of the ABS.

Plastics is very important in our lives; they used in all sectors from the high-performance industry to the mass-market industry. In this article, we will interest on the thermoplastic Acrylonitrile Butadiene Styrene (ABS) polymer; this choice is justified by the compatibility of ABS with a wide range of materials. The aim of this work is to evaluate the damage and the reliability of ABS for predict its residual lifetime.To do this, we used notched specimens of ABS prepared according to the ASTM standard, these last one are subject to tensile test at different ray of notch, The experimental results obtained have allowed us to follow the evolution the ultimate stress and then to calculate the damage. Thereafter, it was possible to identify three stages of damage that can predict at first initiation of the damage and the critical damage. Therefore, be able to intervene in time for predictive maintenance. This study also includes a correlation between two methods of calculating the damage namely static damage and damage by unified theory and this by analogy to cyclical behavior. The comparison showed good agreement.