An innovative design procedure has been formulated by developing a mathematical model for the pressure compensator of an axial piston pump. The compensator provides energy saving by making the pump variable displacement type depending on the system load, thereby providing energy saving by better resource management. The procedure involves simple static design steps to ensure a balanced swiveling torque on the swash plate for specified cut-in and cut-off pressure limits. Adopting the basic pump model from the earlier works, the dynamic model of the pump has been updated by including the compensator dynamics. A design sensitivity analysis through dynamic simulation has been performed that corroborates the need of the design through torque balancing. Also, through dynamic simulation, tolerances of some critical dimensions have been identified. The pressure compensator model has been validated against experimental result obtained from a reference pump.

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The study is focused on the design of a simplified spool valve to be incorporated in the pressure compensator of a variable displacement axial piston pump in order to perform a comparative study with a commercial pump having a two stage spool valve in its compensator. The design involves evaluation of the spool size and selection of spring from static equilibrium condition to satisfy cut-in and cut-off pressure. Following the development of dynamic model of the system, a design sensitivity analysis of the spool valve has been carried out through simulation to identify the critical sizes of the parameters, which affect the pump performance. By systematic design, it is possible to have a single stage spool valve controlled pressure compensator that can produce performance of the variable displacement axial piston pump at par with the similar commercially available pump.

A suitable scaffold architecture is always desirable to get a biomimetic scaffold for bone tissue engineering. In this regard, a fluid structure interaction analysis was carried out on different Micro-CTs (µCTs) and gyroids to observe the in vitro mechanical responses due to fluid flow. Computational fluid dynamics method was used to evaluate the permeability and wall shear stress (WSS), followed by a finite element method to obtain the mechanical stress within scaffolds. Different types of gyroids were designed based on the number of unit cells and porosity, where porosity of gyroids was kept same as µCTs. The main objective of the study is to examine the variations of permeability, WSS and mechanical stress with respect to the number of unit cells and porosity for different gyroids and µCTs. Mechanical responses were also compared between gyroids and µCTs. The results of this study highlighted that permeability and WSS of µCTs came close to the gyroids with 8 unit cells but had significant differences in mechanical stress. The permeability of gyroids increased with the increase of porosity but decreased with the increase in number of unit cells. The opposite trend was shown in case of WSS within gyroids. This study will guide us in predicting an ideal scaffold for trabecular bone replacement.

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