Finite Element Modeling Geometric Defects in Composite Cylindrical Shells Under Effect of Buckling

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Prediction of notched strength for cylindrical composites pipes under tensile loading conditions

International audienceIn this paper, an experimental study has been performed on thick, ±55° filament wound glass/epoxy tubes using quasi-static tests to examine their offshore applications. A new design for the experimental test is developed in which the end tabs and fixture system are made in a way that the stress concentration at the edges of the composite pipe can be reduced. Split disk uniaxial tensile test has been performed on composite pipes with 86 mm of the internal diameter and the thickness of 6.2 mm, in order to evaluate the mechanical properties and to quantify the effect of geometric non-linearities. These pipes can be subjected to different phenomena which can result in introducing a defect in the structure. Two types of pipe specimens are tested which include the composite with notch and the other without notches. The objective of the using a notched specimen is to examine the evolution of the damage and to study the mechanical properties as a function of this damage. The experimental results are described as the influence of the number and the size of notches on the mechanical behavior. These results have shown that the yield stress decreases and yield strain increase with increasing of the notch size and number. The evolution of damage showed that the presence of notches plays an unfavorable role in the integrity of the structure

Mechanical properties of offshoring polymer composite pipes at various temperatures

International audiencePolymer composite pipes can be exposed to the thermomechanical loading due to hot and cold fluid flow, which results in the degradation of their properties. In this paper, effect on mechanical properties of composite pipes under different temperatures ranging from −40 to 80 °C is studied experimentally. The composite pipes consist of glass/epoxy tubes having 86 mm internal diameter and 6.2 mm of thickness with ±55° glass filament winding, intended for offshoring applications. TEMA TTC machine and split disk are used for uniaxial tensile tests and the thermal aging is considered with the help of SERVONTAN climatic chamber. Thermal aging is carried out on these specimens in climatic chamber for 8 h at different temperatures and then uniaxial test is performed. Experimental results have shown degradation in the mechanical properties of polymer pipes with an increase in the temperature. For pipes at colder temperature, the rigidity of composite increases progressively with the temperature and results in drastic decrease in the displacement at break. Also there is a decrease in the yield stress and an increase in yield strain with an increase in the temperature