NiTiNb shape memory alloy pipe fittings strength of the system model and optimization design

NiTiNb shape memory alloy pipe fittings strength of the system model and optimization desigNiTiNb pipe joints is a new shape memory alloy pipe joints in piping connections has a good application prospect. The strength of fittings and system optimization design of its structure in its nuclear reactor steam generator vessel piping connections on the application of great significance . This paper studies the NiTiNb alloys at high temperatures sag resistance , and shape memory alloy NiTiNb the response characteristics of various constraints , then the use of solid mechanics knowledge to build up strength NiTiNb fitting a mathematical model system to study the strength of the pipe joint system the variation with temperature , and Hydraulic tube fittings were optimized . NiTiNb alloy sag resistance will affect the high-temperature strength NiTiNb fittings , so first NiTiNb alloy at different temperatures under different initial anti- stress relaxation properties have been studied , the results showed that: the temperature at 300 ~ 400 ℃, the initial stress at 260 when ~ 360MPa , NiTiNb good stress relaxation resistance alloys , used to prepare the pipe joint in temperature does not exceed 300 ℃, stress does not exceed 360Mpa conditions safely. Shape memory alloy pipe fittings hold on power was taken over from a shape memory alloy phase transition temperature , the restoring force generated constraints