The influence of service solutions on the longitudinal and circumferential tensile properties of glass-polyester composite pipes

Abstract

Traditionally used metals and alloys as constructive materials in process equipment can nowadays be successfully replaced in many cases by non-metallic composite materials. The influence of service solutions on the state of stress and tensile properties in longitudinal and circumferential direction of glass-polyester pipes is studied in this paper. These analyses are of great importance for the use of examined pipes in chemical industry. The pipes were produced by Corporation "Poliester" Priboj. The influence of two solutions, methanol and ammonia, was studied. The samples were treated in solutions for three, seven and ten days. After that, the samples were subjected to tensile testing by the standard procedure. The stresses and strengths were determined in longitudinal direction (testing on flat test specimens) and in circumferential direction (ring test). The analysis of test results, according to the type of solution and period of exposure, was done in comparison with the results obtained by virgin pipes testing (without the influence of the solution). Micromechanical analysis on broken samples helped to determine the influence of the solution on the structure of composite pipe and to find out the models and mechanisms which produced decrease of strength. Keywords: glass-polyester composite pipe, tension test, ring test, influence of solution, micromechanical analysis.Intensive development of polymer engineering, as well as capabilities of polymers in combination with other materials to form new, synthetic structures of improved mechanical properties, led to a real expansion in use of composite materials, followed by continuous improvement of technology of their manufacturing and application. Composite materials have a wide range of usage, thanks to their good properties under external loading, specific mechanisms of cracking and capability for accumulation of energy, and they pose the greatest competition to the classical construction materials. The advantages are: relatively small mass, good balance strength/mass and stiffness/ mass, good static and dynamic properties, good resistance to corrosion, simplified fabrication and time of assembling.All stated advantages led to the fact that composite pipes are very much used today in chemical, building, infrastructure and military industry. An important use of pipes made of composites glass fibres-polyester resin is in chemical industry. Pipes made for this usage are, during their exploitation, subjected to the influence of static and dynamic loading. Considering the conditions of possible exploitation in chemical industry, the subject of this paper is the determination of the influence of solution, as fluid which is transported through the glass-polyester composite pipes, on their tensile properties in longitudinal and circumferential direction.Different structure of composite pipes causes different distribution of stress, and the development of failure after the initiation of the first cracks. In the last few decades,

Effect of different acid solutions on glass/epoxy composites

“…In terms of matrix, the solution penetrates through the resin and separates out in micro-cracks. 9 On the other hand, the degradation of the fibre/matrix interface is caused by the dehydration of the matrix and the penetration of solutions through the micro-cracks, 1,23 crazes or similar voids in the matrix. 9 However, for Stamenovic et al., 1 the most significant influence is verified in terms of fibre-matrix connection and consequent weakness of the load-carrying capacity of the laminate.…”

Dynamic Mechanical Behaviour of Coir and Coconut Husk Particulate Reinforced Polymer Composites: The Effect of Exposure to Acidic Environment

“…These assertions have also been buttressed by [31,34]. Also similar pathways can be attributed to the degradation of the fiber/filler/matrix interface which is caused by the penetration of the acid solution through cracks which may have gained entry through voids in the matrix [17,22,35]. According to Hammami and Al-Ghilani [36], the degradation of the mechanical properties of polymers can occur in two stages.…”

Effects of alkaline and acid solutions on glass/epoxy composites

“…In terms of matrix, the solution penetrates through the resin and separates out in micro-cracks [11]. On the other hand, the degradation of the fibre/matrix interface is caused by the dehydration of the matrix and penetration of solutions through micro-cracks [1,25], crazes or similar voids in the matrix [11]. For Hammami and Al-Ghilani [22] the degradation takes place via two stages.…”