The Dynamic Response Analysis Of MSS's Nose Girder Under Crab Crane's Impact

Because the lag of the technical development for MSS in our country,there are no uniform criterion and technic standard to follow. The MSS usually works in a poor environment and is always subjected to various impact load, so its capability of counter-impact is getting more and more attention by the engineering sector. There are some main impact load to MSS when the crab crane brakes, starts, or lifts models on the nose girder. It is necessary to carry on an investigation in the dynamic response of the nose girder when the crab crane brakes or lifts models in different velocity, so as to supply the theoretical and technical support for the counter-impact design and safe operation of MSS.This dissertation bases on 3D dynamic explicit CAE code LS-DYNA. The dynamic coupling system compsed of the crab crane and nose girder is three-dimensional modelled, computed and analysed. In order to simulate the mutual friction between wheels and rail and make the crab crane moves on the MSS, the rail is three-dimensional modelled with entity and the mutual friction is dealt with surface to surface contact. The dynamic coupling system's dynamic response which is caused by the acceleration of braking and rising has been focused on. The dynamic computation show these: (1) The acceleration of braking have an important impact on the value and distribution of dynamic stress in MSS. When crab crane is moving on nose girder in normal speed and suddenly braked, the maximum stress of the nose girder would exceed the material's allowable stress if the acceleration of braking is more than 15 m/s2. For the weld zone between nose girder and main girder, the major stress always appears in the inner side of the boom support.(2) The acceleration of rising have an important impact on the value and distribution of distortion in MSS. When crab crane lifts models up within 0.05 s and 0.2 s separately, the maximum value of distortion on nose girder caused by former is 16.7 % more than the latter. The maximum dynamic stress is all less than 210 MPa, which is in safe range.