Nonlinear Mechanical Behavior Research On Connection Between Pin And Pull-plate Of Crane

As an important force-transfer structure of crane, the safety and reliability ofpinned-connection is directly related to the entire life of the machine and personalsafety, and its importance is self-evident. The contact process interactions of pin andpull-plate are complex mechanical phenomenon, and also the reasons of theirdamage or even failure and destroy. So far, there are no standard design code andstrengh checking criterion for pull-plate of crane in China, and also many of the keytechnical issues still need to be resolved, such as the law of pressure distributionbetween the pin and the plate. In this paper, the key issues of pinned connectionespecially the pull-plate is studied through numerical analys is approach.In this paper, the contact element method is selected to do a numerical analys isand calculation between the pin and plate. The compatibility equation of incrementalform of contact points is estabilised through the definite condition and checkingcondition of the contact interface. Many techniques,such as the division of the gridand the establishment of the initial condition of contact pair,which are addressed inthe contact analysis are discussed, and the stress consequence of pinned connectionbased on parameter settings like the contact stiffness factor is considered, with theconsqence that selecting appropriate parameters can contribute to the convergenceand accuracy of contact problems.Based on the establishment of plane model, the dissimilarity beween the elasticcurved beams formula which based on the cosine load distribution and thecalculation results with the same kind of loading case is analysed, questioning thevalidity of the law or the scope that it can not fully reflect the pressure distribution ofof contact surface between the pin and the plate. The influence to the pressuredistribution caused by the structure form and the friction coeffcient is discussed andalso the equation of pressure distribution under different sizes of round-pull-plate isinductively obtained. The scope of load distribution with the change of the radiusratios of pin and the outer edge of plate is characterized, fixing the cosine law.Taking the shear force of horizontal cross-section and the range of the loaddistribution into account, the section stress distribution is derived by the basicequation of force method in a new analysis model.Selected as the prototype, the complete structure model of ultra-pull-plate ofLR1750crawler crane from the company Liebherr is established by ANSYS.Simulating the real geometry and boundary conditions, the stress state of pull-plateis studied, and then the law the stress changes in pace with the radius of pin is calculated. According to the numerical results, it is recommended that the maximumdesign force of pinned connection is a little larger than what it should have been.Then the difference between numerical solutions and the European norms which isthe most advanced is compared, that provides certain reference value in the project.