A new thermomechanical fracture analysis approach for 3D integration technology
In this study, the peridynamic framework is applied to model heat diffusion to derive peridynamic heat diffusion equations. A numerical scheme is put forward and implemented in order to establish the validity of these equations. Finally, an approach is developed for coupled solution of heat conduction and solid mechanics equations in the realm of peridynamics.
The peridynamic formulation for transient heat conduction
In bodies where discontinuities, like cracks, emerge and interact, the classical equations for heat and mass transfer are not well suited. We propose a peridynamic model for transient heat (or mass) transfer which is valid when the body undergoes damage or evolving cracks. We use a constructive approach to find the peridynamic formulation for heat transfer and test the numerical convergence to the classical solutions in the limit of the horizon (the nonlocal parameter) going to zero for several one-dimensional problems with different types of boundary conditions. We observe an interesting property of the peridynamic solution: when two m-convergence curves, corresponding to two different horizons, for the solution at a point and an instant intersect, the intersection point is also the exact classical (local) solution. The present formulation can be easily extended to higher dimensions and be coupled with the mechanical peridynamic description for thermomechanical analyses of fracturing bodies, or for heat and mass transfer in bodies with evolving material discontinuities.
A slowly rotating coil system for AC field measurements of Fermilab Booster correctors
A method for measurement of rapidly changing magnetic fields has been developed and applied to the testing of new room temperature corrector packages designed for the Fermilab Booster Synchrotron. The method is based on fast digitization of a slowly rotating tangential coil probe, with analysis combining the measured coil voltages across a set of successive magnet current cycles. This paper presents results on the field quality measured for the normal and skew dipole, quadrupole, and sextupole elements in several of these corrector packages.