Analysis of the cracking of FRP supports in Converter Valves

The fiber reinforced plastics (FRP) support is an important component of the converter valve, due to the gravitational effect of the reactor and the role of violent vibration, the mechanical properties of the support is essential to ensure the stable operation of the converter valve. In February 2022, during an inspection in the converter valve, the FRP support was found to be cracked, which showed that the mechanical properties of the support were problematic and posed a serious threat to the normal operation of the converter valve, therefore research and analysis has been carried out to the cracking of the supports. Firstly, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), bending strength, tensile strength, elongation at break and other physical and chemical properties tests were carried out on the cracked support and the spare support, according to the analysis of the test results, it was found that the main chemical composition and thermal properties of the cracked support did not change significantly compared to the spare support, but the mechanical properties of the cracked support showed an overall decrease compared to the spare support. Subsequently, a structural mechanics simulation of the FRP support was established based on COMSOL Multiphysics and the maximum stress of the FRP support was calculated to be
$2.33^{\ast}10^{7}$
N/m
²
by simulation. Combined with the results of the mechanical properties test to obtain the cracked support to bear the maximum stress as a percentage of the damage load (
$5.46^{\ast}10^{7}$
N/m
²
) is 42.67 %, the spare support member to bear the maximum stress as a percentage of the damage load (
$7.85^{\ast}10^{7}$
N/m
²
) is 29.68 %, in general when the external load as a percentage of the damage load is greater than 40 % need to consider the creep movement of FRP, support The creep of the connection will form a local glass fiber fracture zone, the local glass fiber fracture zone will gradually develop into a local crack, eventually causing the support connection to fracture as a whole.