Abstract:

The bilateral rolling process as a correction method is widely used in the production of aerospace structural parts. However， because the evolution mechanism of the internal physical and mechanical properties of the material is unclear， such as the coupling effect of the original stress field and the rolling stress field， the improvement of the stability of the rolling correction process is limited. So， a verified bilateral rolling finite element model of T-shaped part with 7050-T7451 aluminum alloy under three initial stress states， i.e.， no initial stress， only blank stress， coupling blank stress and machining stress， was established， and the rolling deformation and residual stress distribution of the part are obtained. The results show that the maximum bending deformation caused by rolling is 2.56×10^-1， 2.76×10^-1， 2.49×10^-1 mm respectively under the three initial stress states. The influence degree of blank stress on rolling deformation is about 7.8%. On this basis， the influence of machining stress is about 9.8%， and the action direction is opposite. The residual stress in the rolling area is mainly concentrated in the rolling direction and vertical rolling direction， and the surface is usually compressive stress， which reaches the maximum value on the subsurface. In addition， the initial stress could cause the stress value increase within the full thickness in rolling direction， while， the initial stress mainly causes the change of the surface stress in vertical rolling direction. Finally， the evolution of the strain-stress field during the rolling process was analyzed， and the mechanism of the blank stress and the machining stress effect on the rolling process were revealed. The results have important significance for further improving the rolling correction accuracy.

Key words: bilateral rolling process, machining deformation, finite element method, residual stress, aeronautical structural component