Parameterized Finite Element Analysis On Belt Conveyor Drums

Thebelt conveyoris themost important translationequipment whichcancarrycategories of materials. Belt conveyor drums are the key driving parts in beltconveyor. Drums consist of axis, hubs, end disksand drum shells (or the releasablecone locking system-RCLS).The driven drums are only subject to the averagenormal loading. Compared to the condition of driven drums, the driving drums'loads are more complex, containing alternating normal loading and circumferentialloading. For the complexityof the pulleysystem, in addition tothe assemblystressfrom the interference assembly or RCLS, it's difficult to compute the strength andstiffness of the drums by analytics method. While lacking the suitable calculationmethodofstrengthandstiffnessaboutthedrums,ifweincreasethesafecoefficientwithout enough reason, the drums become bigger and heavier. However thereliability of the drums can't be increased. The technology of FEA can solve theproblems which theanalytic method can't. Because of high efficiencyand veracity,the technology of the FEA is used broadly in the engineering field in the pastdecades. It will be very significant to enhance the design capability of drums byusingthetechnologyofFEA.In the process of study, firstly, the computing method about belt conveyor wasinvestigated widely,and it was foundthat theapplicationofFEAis essential onthestudy of drums. Secondly, the relative content about drums was summarized.Thirdly, the contact problem in the method of finite element and the softwareANSYS was expatiated .Then the establishment principle and the method of FEMon belt conveyor drums were systematically summarized. Then the strength andstiffness about driving drum and driven drum were researched in detail, and theassembly stress which was cause by RCLS was tested. Last, a parameterized FEAsoftwarewasformed。The establishment of FEM is a primary step in CAE analyses. The quality ofmodels is directly related to the precision of the results, evenly the correctness.Each part of drum is assembled as a unit. The construction is verycomplicated. Sowe must do some simplification, but the purpose of analysis must be kept. In thispaper, less important parts were ignored, the axis is considered as the samediameter axis, and the bearings were simplified as constraint, the strength of theweld crack were supposed enough, so the two parts connected by welding wereconsidered as one continuous body. When choosing elements, we should firstconsiderthemechanicscharacteristic.Atthesametimeweshouldtrytousesimpleelements, in order to simplify models and reduce the expenditure of computation.Therefore in this paper when establishing the 3D FEM of drums, 3D entityelements were used to imitate all drum parts. The contact elements were used toimitate the contacts between axis and hubs, or between axis and inside cones ofRCLS, or between hubs and outside cones of RCLS, or between insider andoutsider of RCLS. For the regular structure of drums, SHELL63 from ANSYS isused as the transition elements to form 3D FEM by the method of drag and rotate.Work loads were put on the surface of drums as pressure. In the aspect ofmovement constraint on rigid body, we used the form of sphere coordinate toimitate the bearing constraint. And the couple free degree (CP DOF) is adopted tolimittherotationofthedrivingdrumaxis.In the analysis procedure of the driven drums with interference connection,firstly, using the interference connection theory introduced in the paper, we madean estimation of the contact surface pressure. Then we drew the conclusion on thesurface contact pressure, the distribution of the stress and the law of thedeformation of the driven drums by finite element computation. From the FEAresults, we realized that pressure is more concentrative in the two ends of the hub.If we took no account of concentrative pressure, the theoretical value and thecomputing value show consistency. So it's valid to use contact nonlinear methodwhenimitatinginterferenceconnection.Thepressureonenddisksismainlycausedby interference pressure;the work load has little effect on the maximum pressure,but causes the fluctuation of stress along the circumference with two times. Fromthe law of stress distribution along radial direction on the end disks, we can realizethattheenddiskwiththesamesectionisnotthebestdesign,therampingsectionisbetter.Compared to the driven drums, driving drums are subjected to bigger andmore complex loads, so the computing results have different points. In the analysisprocedureofthedrivingdrums withdoubleends,first content relativetotheRCLSis summarized, and then two conditions of the driving drums were computed,which included only work loads and assembly stress and work loads. The FEAresultsshowthatinthemiddleofthedrumshellwhichisfarfromassemblyregion,the stress and deformation is not affected by the assembly pressure. Thecircumferential stress and the axial stress, which vary periodically alongcircumference, are preponderant among all direction stresses in the middle ofdrums shell. But circumference stress on the different sections of the drum shellvaries different times. This law is meaningful to the fatigue damage of the drumshell.Theequivalent stress ontheenddisks whichis causedbywork load (withnoassemblystress) varies 4 times along circumference, but when assemblystress andwork load working together, it varies from 4 times to 2 times. So the variable lawof the equivalent stress along the circumference is related to the value of theassemblystressandworkload.Both interference connection and RCLS connection involve the contactproblem. In order to verify the validity of the FE nonlinear contact, we testedinstalling stress in a drum which uses RCLS. The test result and the FE result arecoincident. So the conclusions of stiffness and strength from the drums FEcomputation can be used as reference in the construction design of the beltconveyor.In this paper, we compute driven drum with interference connection and thedriving drum with RCLS connection by ANSYS. On the basic of this two drummodeling and analysis method, we developed parameterized FEA software usinginterface program language Visual Basic and the APDL from ANSYS. Thissoftware is parameterized completely, can compute the stiffness and strength of 5kind drums. The user only need to select the analysis type of drum, and input theconstruction,load,material and grid parameters according to the prompt of thesoftware interface. Then the FEAcomputation can be carried out. At last, user canobtainthecomputingresults. ThecodeoftheAPDLis publicto theusers, so it canberewrittenwhentheuserhavespecialanalysispurpose.By dint of FEA software –ANSYS, this paper computes two types of drum.The conclusions drawn from the law of stress and deformation, can explain thedamage reasons in some extent, and can be used as reference in the constructiondesign of drums. The drum parameterized FEAsoftwaresupplies a simulation basefor the reasonable design. This software can reduce the work intensity, shortendesign period, having definite benefit. This parameterized FEA system is also afavorable base for developingthe more perfect function roller's parameterized FEAsysteminthefuture.