Numerical determination of the mechanical stiffness of a force measurement device based on capacitive probes: Application to roller bearings

- The principle of capacitive measurement is explained.
- We model the upper half of the bearing placed in a housing in which grooves for the capacitive probes have been machined.
- Numerical results in terms of stress field due to probe housings presence and fillets on this housing are explained.
- FE simulations allow computation of local mechanical stiffness and transmitted radial forces.
- Very good agreement is obtained between recomputed roller-wise radial force and that directly extracted from the FE results.

Bearings allow external loadings to be transferred from one raceway to the other through rolling elements, which induces strains in the bearing constituents. In order to measure the radial component of these forces, the fixed ring is inserted within a housing equipped with capacitive probes able to measure displacements with very high sensitivity. This work mainly focuses on determining the optimal housing shape using FE simulations and their influence on the global stress state undergone by the structure. Finally, an averaged global stiffness is computed, allowing proper calculation of the contact forces involved in the bearing.