چكيده به لاتين
In this thesis, we have tried to introduce the phenomenon of scratching in the railways as to how this phenomenon occurs in the railways and its effects on the damage to the railways, as well as a model for predicting the progressive deformations of the material layer near the surface and determining the increase of displacement in the surface with Pay attention to plastic shear deformation.
Also, cyclic plasticity has been simulated by 3D modeling of finite element in Abacus software, so that 80 mm of the rail under the distribution of contact with the wheel is obtained using the Hertz theory, and this loading is done using a sub-rutin in such a way that Each cycle takes place every 0.5 seconds, and the corresponding hardness model is applied to the software. In this thesis, we used 3D modeling as well as compound hardness to simulate the phenomenon of scoring, and we observed that with increasing friction coefficient and tightening tensile force of scoring, depth of tensile stress is also noticeable. In the following, the results of this modeling were used to predict the start of the turmoil using the history of the strain and its accumulation to achieve a steady amount in the rails.
Keywords:
ratcheting, cyclic plasticity, strain accumulation, cyclic hardness, crack start
