3-Dimensional Stress Analysis of Virial-Limit Coils

We computed the virial-limit coils which level the distribution of electromagnetic stress with a uniaxial model and a finite element method model. The model´s helical pitch number, N = 3, the aspect ratio, A = 2.17, and the number of coils was 8. In order to compare with other coil windings, we analysed additional two model coils whose aspect ratios are 1.68 and 3.0 with the same pitch number and the number of coils. We confirmed that VLCs achieve nearly uniform stress distribution from both analyses. And we found that large bending stress is generated in coils from FEM analysis. Distribution of bending stress was found to be different depending on the aspect ratio. The strain in the thickness direction is predominant with a lower aspect ratio while the strain in the width direction is largest with large one.