The Improvement And Simulation Research On Four Rope Type Grab Based On Virtual Prototype Technology

Among all lifting facilities,the grab-ship unloader of bridge type is the most widely used one.As the core mechanism of grab ship unloader,the grab-ship unloader,with its wide variety,strong flexibility and high reliability advantages,is widely used in material grabbing work.In the traditional mechanical design,designers prefer to increase safety factors and make grap institutions heavy and clumpy to ensure the security which both waste the steel resource and lower the efficiency of grap.Given that the lightening weight of strength and stiffness to meet the available use has a great significance.Taking the 25 t grap with four poles and double discs as an example,the project firstly analyzed the traditional design and figured out the theory quality as its theory lifting capacity,as well as distributed weights of its all parts according to the weight distribution coefficient of grab bucket.Secondly,the paper also presents the establishment of the 25 t grab's three-dimensional model,the analysis of the grap model's weight and size,and compares theory grab design to prove the match of real model and theoretical model of grab.Then,the static analysis and modal analysis of grab bucket model are conducted to show the required strength of the original model is reached.By this note,the paper concludes four improved methods,which includes that reducing sizes of the pole and the bucket body respectively,and static analysis of the improved model.After the analysis and comparison of four kinds of improved schemes,this paper proposed the thickness of grab bar will reduce 6mm and the bucket body thickness will be reduced 3mm.Finally the fatigue analysis and the safety analysis under 3 non-normal working conditions prove that the improved scheme has a high reliability,and the final solution that the quality of the grab bucket is reduced by 704 kg through lessening the thickness is set.Through a series of simulation studies,the paper presents the grap's final improvement scheme of reducing the quality of grab and verifies the reliability of the improved model,which provides a research method for the lightweight of similar grabs.