Because of the generated residual stress after applying cold expanded technique with split sleeve, fatigue life of joint hole in aircraft can be distinguishedly prolonged. To study residual stress around cold expan...Because of the generated residual stress after applying cold expanded technique with split sleeve, fatigue life of joint hole in aircraft can be distinguishedly prolonged. To study residual stress around cold expanded hole, some hypothesises such as small deformation in radial symmetry, plane stress, plane strain, uniform distribution pressure have been presented in most papers. However, accurate result cannot be gained based on these hypothesises. In order to overcome the shortage, a 3 dimensional model is proposed which takes into consideration of the effect on split sleeve and the different distribution pressure along thick direction of specimen. The stress distributions of cold expanded hole with split sleeve under loading or unloading, as well as under fatigue tension have been stu died. To reveal the advantage of cold expanding process with split sleeve, the expansion without split sleeve has also been studied and compared with the former.展开更多
The effect of strain hardening and strain softening behavior of flow stress changing with temperature on welding residual stress, plastic strain and welding distortion of ATN0 1-T4 aluminum alloy was studied by finite...The effect of strain hardening and strain softening behavior of flow stress changing with temperature on welding residual stress, plastic strain and welding distortion of ATN0 1-T4 aluminum alloy was studied by finite simulation method. The simulation results show that the weld seam undergoes strain hardening in the temperature range of 180-250 ℃, however, it exhibits strain softening at temperature above 250 ℃ during welding heating and cooling process. As a result, the strain hardening and strain softening effects counteract each other, introducing slightly influence on the welding residual stress, residual plastic strain and distortion. The welding longitudinal residual stress was determined by ultrasonic stress measurement method for the flat plates of A7N01-T4 aluminum alloy. The simulation results are well accordant with test ones.展开更多
文摘Because of the generated residual stress after applying cold expanded technique with split sleeve, fatigue life of joint hole in aircraft can be distinguishedly prolonged. To study residual stress around cold expanded hole, some hypothesises such as small deformation in radial symmetry, plane stress, plane strain, uniform distribution pressure have been presented in most papers. However, accurate result cannot be gained based on these hypothesises. In order to overcome the shortage, a 3 dimensional model is proposed which takes into consideration of the effect on split sleeve and the different distribution pressure along thick direction of specimen. The stress distributions of cold expanded hole with split sleeve under loading or unloading, as well as under fatigue tension have been stu died. To reveal the advantage of cold expanding process with split sleeve, the expansion without split sleeve has also been studied and compared with the former.
基金Project(2007DFR70070) supported by China-Russia Government-to-Government Scientific and Technical Cooperation Foundation
文摘The effect of strain hardening and strain softening behavior of flow stress changing with temperature on welding residual stress, plastic strain and welding distortion of ATN0 1-T4 aluminum alloy was studied by finite simulation method. The simulation results show that the weld seam undergoes strain hardening in the temperature range of 180-250 ℃, however, it exhibits strain softening at temperature above 250 ℃ during welding heating and cooling process. As a result, the strain hardening and strain softening effects counteract each other, introducing slightly influence on the welding residual stress, residual plastic strain and distortion. The welding longitudinal residual stress was determined by ultrasonic stress measurement method for the flat plates of A7N01-T4 aluminum alloy. The simulation results are well accordant with test ones.
