Elevated-temperature mechanical property and constitutive model of galvanized parallel wire strands

High-temperature conditions lead to severe degradation of the mechanical properties of steel cables. This study conducted uniaxial tensile tests on 19-wire galvanized parallel wire strands (GPWSs) at elevated temperatures. Using a non-contact measurement system, the failure modes under high-temperature conditions were observed, and stress-strain curves were obtained for 12 temperature levels ranging from 20 °C to 700 °C. The yield strength corresponding to a strain level of 1.5% was determined as the nominal yield strength, which ensures both material strength and sufficient safety. By analyzing the stress-strain curves, reduction factors for the proportional limit, elastic modulus, nominal yield strength, and ultimate strength at various temperatures were obtained for the GPWS. Additionally, a Boltzmann curve was used to fit the reduction factors of the mechanical properties of the GPWS. A constitutive model for the entire process of the GPWSs was established through the segmented fitting of the elastic, plastic hardening, and necking stages. High temperatures severely affect the tensile strength of the GPWS. When the temperature reaches 400 °C, the ultimate tensile strength of the GPWS is only about 50% of that at room temperature. At 700 °C, the ultimate tensile strength of the GPWS is reduced to only 2.5%.