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 le vel in the winding and the reinforcement, Under such high loading cond itions particularly for pulse coils, it is expected that the conductor material will exceed ils elastic limit. The technique used here to ca lculate stresses beyond the elastic limit in a multi-region solenoid g eometry is: The maximum toad at the mid-plane is divided into many sma ll load steps. When each load step is applied to the winding, the stre sses and the strains are calculated based On the material properties a t the end of the previous load step. If the effective stress in any re gion exceeds the elastic Limit then the modulus of this region is rede fined based on the slope of the stress-strain curve at that point. Usi ng this technique of superposition, the stresses and strains are repea tedly calculated until maximum loading is reached, The procedure can a lso 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 us ing different elastic limits.