Thermal-Electric interaction (also known as Joule heating) allows coupled simulation between electrical current flow and local resistive heating. Current flow generates heating, heating changes resistivity, resitivity change alters current flow. This type of simulation is useful in sensitive electronics devices such as fuses, links, electrical traces, and lightbulb filaments.
The Thermal-Electric Multiphysics capability in Abaqus provides a complete fully-coupled capability including nonlinear effects in material properties in both the electrical and thermal physics components. This allows a full range of Joule heating capabilities to be simulated within the familiar Abaqus environment.
Hilali, S. Y., and B. -J. Wang, "ABAQUS Thermal Modeling for Electrical Assemblies," 1995 ABAQUS Users' Conference, Paris, May 1995, pp. 441-457.
Wang, B. -J., and S. Y. Hilali, "Electrical-Thermal Modeling Using ABAQUS," 1995 ABAQUS Users' Conference, Paris, May 1995, pp. 771-785.
Fuses are the primary circuit protection devices in automobiles. They are available in a range of different current ratings and are designed so that when the operating current exceeds the design current for a period of time, heating due to electrical conduction causes the metal conductor to melt, thus the circuit to disconnect. Since the electrical conductivity of the fuse depends on temperature which in turn depends on the heat generated due to current flow, it is necessary to consider fully coupled thermal-electrical effects in the dsign of the fuse.
Temperature-dependent electrical and thermal conductivity, and the Joule heat fraction (representing the fraction of electrical energy dissipated as heat) are specified. Appropriate boundary conditions are imposed and a fully coupled thermal-electrical transient analysis under constant electrical current flow of 30 A is conducted and allowed to reach steady state conditions.
Both the transient distribution of the current and temperature and the final steady state conditions determine the feasible range of operating conditions for the fuse. The thermal results may also be used to drive a subsequent structural analysis of the fuse so that thermal strains and phase changes can be studied.
Contours of electrical curent density in the fuse.
Contours of electrically-induced temperatures in the fuse.
Thermal design of electronic components and packages must include the effect of heating due to current flow.
The Mutiphysics solution from SIMULIA allows electronics manufacturers to analyze the coupled thermal-electrical fields and further to use the thermal solution to drive a coupled mechanical analysis. Tools are available to simply and efficiently build complex electronics assemblies from Electrical-CAD data
An example of an electrical heating problem taken from an automobile audio system.
Accurate simulation taking into account coupled-thermal, electrical, and mechanical fields is key to electronic component and package design. Virtual package design and qualification offers significant time savings over physical testing.
Analysis temperature predictions agree extremely well with physical test results. A design change introducing heat sinks on the diode legs was qualified virtually before being tested as the appropriate solution to this problem.