## General Mechanical

#### Eddy Current and Lorentz Force Calculation

• dhruvdeshwal17
Subscriber
Hello,nHow to calculate the lorentz force and eddy current value in ANSYS APDL, if a 3D plate/disc is translating (at constant speed) in a magnetic field.? What will be the boundary conditions and loads that can be applied in this analysis to get the result ?.ote - As per I know, in this analysis Solid97 can only be taken as element and its analysis can be done preferably by transient analysisnPlease guide me for the samenYour Sincerelyn
• Bill Bulat
Ansys Employee
If any domains in the system you are considering are magnetically permeable (e.g., iron), the use of SOLID97 is highly discouraged. On material interfaces between air and iron, the nodal based formulation used by SOLID97 will force the tangential component of B to be continuous. Physically, on such an interface, there will be a discontinuous jump in the tangential component of B, so SOLID97 introduces an error in the field calculation.nAt V15, the new technology SOLID236/237, whose edge-flux degree of freedom properly calculates the jump in tangential B on material interfaces, was enhanced to include the velocity effect, which is applied as a body force using the BF command. nnThis feature allows you to account for velocity effects (motion-induced eddy currents and Lorentz forces) without moving bodies in a transient analysis - the effects can be determined in a steady state analysis. The attached zip file contains an example - a hollow electrically conductive cylinder is rotating about a cylindrical permanent magnet which is poled across its diameter. The presentation discusses a feature which was never documented/officially released but worked pretty well (ARMINT). ARMINT did require a transient analysis - parts were repositioned in a transient analysis to determine the motion effects. It then summarizes the result of the same model but using velocity effects instead of ARMINT. The Joule heat produced in the rotating cylinder is the same in both. Please use 3D_236_velocity_effect_v15b.inp - it shows that the torque implied by the Joule heat appearing in the cylinder equals the calculated torque using the EMFT command.nKind regards,nBillnArray
• dhruvdeshwal17
Subscriber