Demagnetization Effect in a Meander-Core Orthogonal Fluxgate Sensor

Demagnetization effect plays an important role in the magnetic core design of the orthogonal fluxgate sensor. In this paper, a meander-core orthogonal fluxgate sensor based on amorphous ribbon is described. The demagnetization model of meander-core structures is established, and the average demagnetization factor can be evaluated by finite element modeling. Simulation and experimental analyses were performed to study the effects of demagnetization on the sensitivity and linear range of orthogonal fluxgate sensors in the fundamental mode by varying the number of strips, the line width, and the spacing of the meander-cores. The results were compared and revealed a very close match. The results show that the demagnetization factor increases with an increase in the number of strips and the line width, which leads to an increase in the linear range of the sensors. The sensitivity can be improved by increasing the number of strips appropriately, however, it is reduced when the line width increases. Smaller spacing results in a larger demagnetization factor due to the magnetic interactions between adjacent strips, which reduces the sensitivity of the sensor. The results obtained here from simulations and experiments are useful for designing magnetic sensors with similar structures.

Piston Finite Element Modeling for the Estimation of Hydrodynamic and Contact Forces and Moments

Modeling the thermal and mechanical behavior of a piston is crucial, as it allows for the evaluation of piston performance including piston dynamics and friction. These characteristics directly affect the efficiency, reliability, and lifespan of an internal combustion engine. This work migrates from the conventional parameterized piston modeling approach and uses a full CAD finite element modeling simulation for the evaluation of the piston’s thermal and mechanical behavior as well as the resultant hydrodynamic and contact forces and moments experienced by it. The analysis is performed for two different piston to cylinder bore nominal clearances, and for one of them at two different engine speeds, while assuming the piston is moving at the center of the cylinder bore with no transverse or tilting motion.