Analysis Of Local Deformation And Stress Of Roller Contacts Of BMU’s Box Type Telescopic Arm

This paper mainly studies the local deformation and stress problems of the building maintenance units(BMU)box type telescopic arm and the roller.The box-type telescopic arm is subjected to the reaction force of the roller support,and the local deformation of the bottom plate will occur.When the strength of the traditional telescopic arm is checked,the local deformation and its stress are often ignored,resulting in a large gap between the theoretical calculation results and the actual.The local deformation of the bottom plate is reduced to the bending problem of thin plates with elastic boundaries,and the calculation formulas of deflection and stress are derived to make the check calculation of the window cleaning box type telescopic arm more accurate.In order to study the local deformation of the telescopic arm of the window-cleaning box under the action of the roller,the calculation formula of the deformation and bending of the thin plate under elastic boundary conditions needs to be derived first.When the bottom plate of the window cleaning telescopic arm is deformed in contact with the roller,it will be subject to the force of the roller on the bottom plate and the side plate on the bottom plate.This restriction will cause both corners and bending moments at the boundary of the bottom plate.This boundary condition is regarded as an elastic boundary condition.The theoretical calculation formulas under four-side fixed support,two-side fixed support and two-side simple support and elastic boundary conditions are derived respectively,and the calculation results under different boundary conditions are used to verify the correctness of the solution results.In order to obtain the constrained stiffness of the box arm side plate to the bottom plate,a finite element model of the box telescopic arm and the roller contact is established,and the finite element solution is compared with the calculation results of the derived formula to obtain different types of box telescopic arm side The rigidity coefficient of the board-to-floor constraint.At the same time,the results of the finite element and theoretical calculation formulas are compared,and the error between the two is obtained,thereby further verifying the calculation results of the formula.Use Microsoft Visual Studio software to write application program,complete the development of window deformation box type telescopic arm and roller contact local deformation and stress analysis software system,which includes two modules of formula calculation and ANSYS finite element calculation,and is integrated in the laboratory development In the computer aided design system of the window cleaner,the precision and efficiency of the strength check calculation of the telescopic arm of the window cleaner is effectively improved.