Structural Design And Analysis Of The Overloaded Multilayer Overconstrained Schnabel Car

Due to the transport capacity,Schnabel car plays a very important role in the project of UHV transmission,atomic energy equipment,aircraft carrier manufacturing and other important projects.With the rapid development of national industry,the weight of special goods is increasing,and the domestic existing Schnabel car can not been able to meet the demand for railway transportation which seriously restrict the implementation and progress of China's major projects.So the carrying capacity of the Schnabel car is urgent to be improved.Facing to the urgent need of the high load and high-security needs of special railway transportation in our country,and in order to solve the basic scientific problems of the current Schnabel car,such as the insufficient carrying capacity,asymmetric load distribution,the unclear stable gripping principle and so on,the basic theory of mechanism research of super heavy loading equipment is carried out.The main research contents are as follows:Firstly,the domestic existing Schnabel car mechanism is systematically analyzed.A three layer parallel constraint Schnabel car mechanism is designed based on the existing mechanism.Then a novel parallel Schnabel car mechanism is innovatively proposed,and the best model is selected.The kinematic analysis of the lifting mechanism is carried out based on the Complex vector method,including the position,speed,acceleration,and the force mapping relation in ideal case.The kinematics simulation verification is developed using the software of Recurdyn.Secondly,the relation between the output force and the load is obtained through establishing the static equilibrium equation and deformation compatibility equation.On this basis,the load-sharing coefficient is defined through combining the mean square deviation.Based on the theory of spatial performance spectrum,the non dimensional treatment of the clamped beam is carried out,and the effect of eccentricity and stiffness of beam clamp on load sharing mechanism is discussed.Then,the stable gripping principle of the hook is carried out,and the gripping force balance equation and gripping matrix is obtained based on the established gripping force simplified model of the gripping mechanism.Then,the force closure principle is discussed,and the stable gripping conditions are put forward.According to the findings of Buss et al,The nonlinear friction cone constraint is equivalent to the positive definiteness of the equivalent symmetric matrix.The contact force and contact position are optimized based on the linearly constrained gradient flow method.Finally,the rigid flexible coupling simulation of the lifting mechanism is carried out using the Recurdyn software,including the dynamics simulation and the asymmetric load distribution simulation.The lifting mechanism working state is developed when the schnabel beam is flexible body,and the results are compared with the theoretical results.The theoretical results are modified,and based on the comparison between the modified results and simulation results,the correctness of theoretical calculation and simulation is verified.