To investigate the performance of utilizing the shape memory effect of SMA(Shape Memory Alloy)wire to generate recovery stress,this paper performed single heating recovery stress tests and reciprocating heating-coolin...To investigate the performance of utilizing the shape memory effect of SMA(Shape Memory Alloy)wire to generate recovery stress,this paper performed single heating recovery stress tests and reciprocating heating-cooling recovery stress tests on SMA wire under varying initial strain conditions.The effects of various strains and different energized heating methods on the recovery stress of SMA wires were explored in the single heating tests.The SMA wire was strained from 2%to 8%initially,and two distinct heating approaches were employed:one using a large current interval for rapid heating and one using a small current interval for slower heating.The experimental outcomes reveal that during a single heating cycle,the temperature-recovery stress relationship of SMA wire exhibits three distinct stages:the martensite phase stage,the transition stage from martensite to austenite phase,and the austenite phase stage.Notably,the choice of heating method does not influence the maximum recovery stress value,and the correlation between initial strain and maximum recovery stress is predominantly linear.Moreover,conducting the reciprocating temperature rise and fall performance test is important to better simulate the scenario in practical engineering where multiple recovery stress in SMA wires for structural repair.In this test,two temperature cycling methods were studied:interval rise and fall,as well as direct rise and fall.In the case of utilizing the interval temperature rise and fall method,it was observed that the recovery stress associated with cooling was significantly higher than that corresponding to heating at the same temperature.Furthermore,the recovery stress was lower upon subsequent heating than that measured during the previous heating cycle.Based on the experimental results,a prediction model for the temperature-recovery stress relationship has been proposed to simplify numerical calculations.It is hoped that an approximate temperaturerecovery stress curve can be obtained from the parameters of the SMA wire.The calculated values derived from this model show good alignment with the measured values,indicating its reliability.展开更多
基金financially supported by National Natural Science Foundation of China(Project No.51878156).
文摘To investigate the performance of utilizing the shape memory effect of SMA(Shape Memory Alloy)wire to generate recovery stress,this paper performed single heating recovery stress tests and reciprocating heating-cooling recovery stress tests on SMA wire under varying initial strain conditions.The effects of various strains and different energized heating methods on the recovery stress of SMA wires were explored in the single heating tests.The SMA wire was strained from 2%to 8%initially,and two distinct heating approaches were employed:one using a large current interval for rapid heating and one using a small current interval for slower heating.The experimental outcomes reveal that during a single heating cycle,the temperature-recovery stress relationship of SMA wire exhibits three distinct stages:the martensite phase stage,the transition stage from martensite to austenite phase,and the austenite phase stage.Notably,the choice of heating method does not influence the maximum recovery stress value,and the correlation between initial strain and maximum recovery stress is predominantly linear.Moreover,conducting the reciprocating temperature rise and fall performance test is important to better simulate the scenario in practical engineering where multiple recovery stress in SMA wires for structural repair.In this test,two temperature cycling methods were studied:interval rise and fall,as well as direct rise and fall.In the case of utilizing the interval temperature rise and fall method,it was observed that the recovery stress associated with cooling was significantly higher than that corresponding to heating at the same temperature.Furthermore,the recovery stress was lower upon subsequent heating than that measured during the previous heating cycle.Based on the experimental results,a prediction model for the temperature-recovery stress relationship has been proposed to simplify numerical calculations.It is hoped that an approximate temperaturerecovery stress curve can be obtained from the parameters of the SMA wire.The calculated values derived from this model show good alignment with the measured values,indicating its reliability.
