'Cobham Technical Services has extended the multiphysics capabilities of the Opera-3D finite element software for electromagnetic design with a new solver that can be used to analyse natural vibration modes.

According to the company, the tool is expected to prove particularly useful for electrical machine developers, who can employ it to investigate and minimise forces that might cause oscillations close to the natural frequencies of the equipment and thereby avoid excessive vibration or collisions between rotating and stationary parts.

By capturing such mechanical vibration in conjunction with electromagnetic modelling, and thermal performance if required, the integrated 3D (three-dimensional) tool suite can greatly reduce the complexity and timescales of design projects. One of the key benefits of this capability is a further reduction in the need to create physical prototypes, explains the company.

“Finite element simulation is the most practical tool for exploring design concepts and validating device performance. Adoption from the outset of the design process can stimulate innovation and lead to designs which are right first time,” says Jeremy Howard-Knight of Cobham Technical Services. “With engineering skills at a premium, design automation using computer modelling is an extremely effective investment that companies can make to ensure successful products and a continuing flow of design ideas.”

Mechanical stress and vibration is an important consideration in the design of coils and windings in transformers, motors, generators, actuators, large electro-magnets, and superconducting magnets.

The new modal solver – known as STRESS/EV – finds a user-specified number of eigenvalues within a specified frequency range and calculates the eigenvectors of each mode. It works in conjunction with the static stress analysis capability of Opera which calculates the deformation, stresses and strains of a body which is subject to external and internal forces. The forces calculated from electromagnetic fields can be used as input to the stress analysis.
STRESS/EV accommodates isotropic, orthotropic and fully anisotropic materials, the properties of which can be specified as a constant or an expression.