Buckling Analysis And Optimization Design Of The Arm And Column Of BMU

With the rapid development of economy in China in recent years,mansions have been established in big cities,and the common feature of these buildings is using a large area of glass as their outer wall.And with the development of mansions,it's necessary to develop a piece of equipment,Building Maintenance Unit(BMU),to clean the glass walls of buildings.BMU has also developed from the previous simple clean maintenance to integrated equipment which combines clean,emergency,maintenance and transportation.With the continuous development of technology and applications of new materials,there are many strict requirements for safety,lightness and economics of BMU.However,current domestic BMU is large and bulky in general,so it's a good way to develop a thin wall to achieve lightness and economics of the equipment.But it inevitably will bring the local or overall stability of the structure.That is to say,it is of great significance to study the buckling stability of bearing structure in BMU structural design.In this paper,the experimental study and finite element simulation of the buckling limit load on Column and Arm,two main bearing structures in BMU are carried out.The concrete contents are as follows:(1)The dynamic model of the lifting process of BMU is set up,the equation of the hoisting dynamic load coefficient of impact load is derived,local and overall stability of BMU column and local stability in arm are analyzed to achieve the theoretical formula for its limit load.(2)The experimental study on the buckling limit load of axial compression and local compression between box section Colum of Q235 and stainless steel material and box-section cantilever of Q235 are carried out respectively.And test on basic mechanical properties is made towards the materials used in the experiment.Through the data of the main failure form,buckling limit load and load—displacement curve obtained from experiment,the buckling limit load value from experiment and the theoretical formula calculation value are compared and analyzed,and then the theoretical formula is corrected.And the experiment results are compared and analyzed with GB50017-2004 and AISI S100-2007,it is found that the results are more consistent with AISI S100-2007.(3)The finite element model of Colum and Arm are generated respectively in the classical environment of ANSYS.The initial geometric and residual stresses of the specimen are taken into consideration in the process of model analysis,and then the data which is obtained from simulation,received from experiment and picked from other scholars' experiments are compared and analyzed to verify the accuracy of the simulation in this paper.(4)A series of finite element models on Column and Arm are established based on the verified finite element model condition.And the effects on buckling limit load,which is caused by the aspect ratio,the residual stress,the initial geometric imperfections and the yield strength are analyzed in the specimen,and then the optimized suggestions on Colum and Arm are put forward in BMU in accordance with the result of the parameter analysis.