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Main >> Applications >> Sample problems >> Transmission line trap

air core coil, wave trap, transmission line filter, multiphysics analysis

An example of the calculation of the forces and mechanical stresses for the high-frequency line trap at the short circuit current.

**Problem Type:**

Axisymmetric multiphysics problem of AC magnetics coupled to Stress analysis.

**Geometry:**

**Given:**

Current (peak value) *I* = 12 kA, frequency *f* = 50 Hz.

Aluminum cable:

cross-section area *A* = 2 cm².

conductivity γ= 37 MS/m;

Young's modulus *E* = 70 GPa;

Poisson's ratio ν = 0.34;

Fiberglass case:

Young's modulus *E* = 20 GPa;

Poisson's ratio ν = 0.11;

**Task:**

Determine forces and mechanical stresses in the high-frequency line trap body.

**Solution:**

The actual spring-coil is modelled as a set of circular turns embedded in a fiberglass case. That facilitates 2D axisymmetric simulation.

The solution consists of two stages: the calculation of forces in a AC Magnetic problem, and then the calculation of mechanical stresses in a mechanical problem. The transfer of forces from AC Magnetic problem to mechanical one is automated using the coupling mechanism.

**Results:**

Current density distribution in the aluminum cable:

Mechanical stress in the aluminum cable, wave trap deformed shape (zoomed 1000:1) and Ampere force value acting on the ending turn:

*Reference: Line trap in Wikipedia.