End Effects And Rotation Effects Of The Force Transducers On A Build-up System

This research focused on the rotation effects on a build-up system and the end effects of the column load cells of the build-up system.The mathematical model of the column load cell was established for the solutions between the sizes of the load cell and end effect.Further,a simple and effective evaluation method for the rotation effect of build-up system was proposed,and was verified by the relative finite element modeling and experiments.End effect of the small aspect ratio(d0=0.6?1.0)column load cell was studied under the axisymmetric non-uniform loading.The mechanical model and boundary conditions were determined according to the actual dimension and working conditions of the column load cell.The loads were acted on the both end faces of the column load cell combined uniform axisymmetric distribution of zonal pressure force and uniform axisymmetric distribution of zonal tension force.Then,analytical solutions of the column load cell were derived on the basis of the general solutions of a finite length circular cylinder under arbitrary loads.The results revealed that Saint Venant principle did not apply to end effect of the small respect ratios.End effect became more drastic with the decreasing respect ratio.Size effect of the small aspect ratio(d0=0.6?1.0)column load cell on the end effect was studied under the axisymmetric non-uniform loading.One of the end faces was acted by uniform axisymmetric distribution of loading,while the other by non-uniform axisymmetric distribution of loading whose resultant force was zero.Then,analytical solutions of the column load cell were derived on the basis of the general solutions of a finite length circular cylinder under arbitrary loads.Results indicated that size effect had significantly effect on end effect.Larger size of the structure was beneficial to restrain the end effect.Moreover,end effect decayed rapidly with enlarging the size of the column load cell.An evaluation indicator for the rotation effect of the build-up system was proposed.The evaluation indicator was fluctuation quantity of additional lateral horizontal force on the three column load cells in the build-up system.Firstly,measurement model for the rotation effect was built.The model was simulated and analyzed under different parasitic components.Then,the main influencing factors were determined by the plate theory and the relations between the fluctuation quantity of additional lateral horizontal force and each factor on basis of FEM.Finally,effect law of all factors on the fluctuation quantity of additional lateral horizontal force was acquired using the orthogonal method.The evaluation indicator for the rotation proposed above was verified by experiments.Firstly,two different structures of build-up system were tested.The results showed that the balanced structure helped to weaken the rotation effect.Secondly,orthogonal experiments for the balanced structure were done,and it was indicated that the results were in accordance with the results of simulations.The height of bearing support was the most primary factor which accounted for more than 50%in all factors.Based on all above,the finite element model and the evaluation indicator were valid and reliable.