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Pultruded glass-fibre reinforced polymer (pGFRP) composites are classified as lightweight material, which exhibit high strength-to-weight ratio for structural usage. This composite material has been applied as cross-arm members in transmission towers due to its ability in thermal and electrical insulation. However, the influence of the stacking sequence of pGFRP composite on its mechanical performance has not been fully covered in the literature to explain the long-term durability of the current cross-arm designs. The study expected to evaluate five fiber layers with various stacking sequences in terms of quasi-static and creep tests in a four-point bending mode. The creep test was performed for 1440 h (60 days). These composites were fabricated using the pultrusion process in the form of a square hollow structure. Later, it was cut into composite coupons with various sizes depending on the test conducted. The results showed that nine layers with 0°/45°/0°/−45°/0°/−45°/0°/45°/0° had the ultimate flexural strength. This stacking sequence configurations seemed to be optimally manufactured in continuous roving fibre by alternating between 0° and ±45° fiber orientations. Additionally, the S-9 pGFRP composite sample showed that it had a low-creep deflection with high elastic and apparent creep moduli in 1440 h. In terms of strength reduction factor, this configuration was recorded as the highest. The findings showed that the nine layers of pGFRP composites with alternation of 0° and ±45° fiber orientations were highly suitable for structural application at transmission towers for a long-term operation. [ABSTRACT FROM AUTHOR]

Pultruded glass fibre reinforced polymer (pGFRP) composites provide outstanding properties for composite polymer cross arms in power transmission line applications. This study has investigated the effects of various stacking sequences of fibres directions of pGFRP on flexural strength and creep behaviour. The use of static four-point bending flexural tests revealed that Stacking Sequence 2 (±45/0/90/0/90/0) had a significant flexural strength of 399.9 MPa while Stacking Sequence 1 (±45/90/0/±45) had a flexural strength of 242.5 MPa. Furthermore, the four-point bending creep experiments were performed at three distinct stress levels, notably 12%, 24%, and 37% of the ultimate flexural strength, to characterise the creep behaviour of distinct stacking sequences. Moreover, Findley's power law equation for bending creep behaviour has revealed that the time-dependent reduction factor of Stacking Sequence 1 and Stacking Sequence 2 estimates a drop in flexural modulus of 23% and 10% respectively. [ABSTRACT FROM AUTHOR]