Plastic stress analysis of pulse and resistive magnets

The primary consideration in the design and development of high field resistive and pulsed coil (30-100 tesla) is the stress and strain level in the winding and the reinforcement. Under such high loading conditions particularly for pulse coils, it is expected that the conductor material will exceed its elastic limit. The technique used here to calculate stresses beyond the elastic limit in a multi-region solenoid geometry is: The maximum load at the mid-plane is divided into many small load steps. When each load step is applied to the winding, the stresses and the strains are calculated based on the material properties at the end of the previous load step. If the effective stress in any region exceeds the elastic limit then the modulus of this region is redefined based on the slope of the stress-strain curve at that point. Using this technique of superposition, the stresses and strains are repeatedly calculated until maximum loading is reached. The procedure can also be reversed simulating the tail of a magnetic pulse, resulting in the conductor being under compression and the reinforcement in tension. It is possible to apply different cycles of loading and unloading using different elastic limits