Update on ARIES-CS Coil Structural Analysis

X.R. Wang and A.R. Raffray

ARIES Meeting PPPL, NJ

October 4-5, 2006 

What is new?

The coil structure material has been updated to JK2LB.

2 maintenance ports have been included the latest 3D solid modelling in order to analysis the local impacts on the openings in the coil supporting tube.

Max. Von Mises stress of the coil structure without openings

Max. Von Mises Stress: 652 MPa

Max. Von Mises Stress: 652 MPaMax. Disp: ~2.0 cm

35 cm coil structure

30 cm strong-back

Finite element model including two openings

The magnetic force loads are the same as before.

The boundary conditions maintain the same:

Winding packs are fully bonded to the grooves in the coil tube;

Cyclic symmetry boundary are applied at the both ends of the coil supporting tube.

Cyclic symmetry

boundaryCyclic symmetry

boundary

Openings for maintenance ports:

2.2 m (toroidal) x 4.4 m (poloidal)

Material Properties for the Coil Supporting Structure*

The design stress is taken as 2/3 of the yield strength at 4 K.

Material Incoloy 908 (4K)

JK2LB(4K)

Yield strength 1227 MPa 1420 MPa

Tensile strength 1892 MPa 1690 MPa

Modulus of elasticity

1.823 x 1011 MPa ~2.0 x 1011 MPa *

Elongation 28.5%

Poisson’s ratio 0.303 0.3*

Design stress 818 MPa 946 MPa

* Recomondded by H. Nakajima, ITER Superconducting Magnet Technology Group, Japan Atomic Energy Agency (JAEA).

Max. Displacement of the Coil Structure

The results indicate the maximum displacement of 2.10 cm at the outboard of the coil supporting tube.

Contour shows a good symmetry because of the symmetric structure and EM loadings.

Max. Displacement: 2.1 cm

Max. Von Mises Stress of the Coil Structure

Max. Von Mises Stress: 656 MPa

Max. Von Mises Stress: 656 MPa

The Max. Von Mises stress of 656 MPa is found at inboard side of the coil supporting tube.

The Max. stress occurs locally at very small region only.

Most regions of the coil supporting tube including the inter-coil structure shell and strong-back are in a low stress level.

Comparison of the displacement contours between the two coil supporting tube

(With 2 openings at the ends, Max. Displacement ~2.1 cm)

(Without any openings, Max. Displacement ~2.0 cm )

Summary

The structural analysis results of the coil supporting tube with two major maintenance port openings show a small difference, ~5% in the maximum displacement and 1% in the maximum stress.

Maintenance port openings in the coil structure are not a major concern because the ports are in low stress regions.