Research On Influences Of Deformation Defects On Safety Performance Of Grab Ship Unloader Front Beam

Grab ship unloaders are widely used in loading and unloading process and play a very important role.The front beam as the main load-bearing metal structure,has a variety of deformation under the frequent action of self weight and lifting load.These deformations especially deflection deformation and partial wave deformation,will have an adverse impact on the safety performance of the metal structure.We will quantitatively analyse their impact on the metal structure by researching deflection deformation effect on fatigue and wave deformation effect on local stability.The main research and achievements in this paper are as follows:(1)Understand the structural characteristic of front beam and its common deformation.Utilize ANSYS to complete the finite element models of the front beam based on its actual size and deformation.(2)Prepare the fatigue load spectrum according to the operation characteristics of the Grab ship unloader,and division of its load step.Select appropriate method to conduct the transient dynamic analysis of the front beam.The results of transient dynamic analysis will be used for fatigue life analysis.(3)Analyse the fatigue life of front beams before and after deflection deformation based on the transient dynamic analysis results and the modified S-N curve.Conduct the reliability analysis by using the theory of fracture mechanics and reliability analysis method.After obtaining the results of their fatigue life and reliability,analyse the influence of deflection deformation.(4)Understand the concept of local stability of sheet metal and the stability analysis method in ANSYS.Then simulate different degree of local warping deformation by uniform defect method and use arc length method to solve their nonlinear finite element problems.Analyse the influence of local warping deformation on local stability by comparing with nonlinear analysis result.