Thermally optimized designs for electro-hydrostatic actuators using surrogate models and topology optimization

Electro-hydrostatic actuators (EHA) can help reduce the weight of future-generation aircraft. Due to their high power density and compact design, interactions between all involved subsystems must be considered during the design. Especially the structural design, distributing and dissipating the heat within and from the system, needs to be addressed during all design phases. While there exist different methods for the preliminary design of thermal systems, design methods for the detailed design are often not suitable for the design of an EHA. In this work, we propose a new design method for the detailed design of thermally optimized structural geometries, taking into account the heat distribution by the hydraulic fluid. The design method consists mainly of a steady-state surrogate model to replicate the transient heat transfer within the hydraulic fluid and a two-step topology optimization to generate optimized designs. The surrogate model greatly reduces the computational cost of the underlying thermal simulation model. This is necessary for the iterative topology optimization to be employed on the system level. By combining the steady-state surrogate model and the two-step topology optimization, we were able to optimize the structure of an EHA with respect to average surface temperature and temperature variations within the system.