Investigation of dual varying area flapping actuator of a robotic fish with energy recovery

Autonomous under-water vehicles (AUV) performing a commanded task require to utilize on-board energy sources. At the time when on-board power source runs low during operation, the vehicle (AUV) is forced to abort the mission and to return to a charging station. The present work proposes the technique of an energy recovery from surrounding medium. This effect is studied for dual action actuator movement that obtains energy from fluid. It is realized that a flapping or vibrating actuator can be used for energy extraction phenomenon apart from the non-traditional propulsive technique. In the present work a simple dual flapping actuator that can switch between simple flat plate and perforated plate at extreme end positions (angles) by using an efficient mechatronic mechanism that would help in overcoming viscous forces of the operating medium is extensively studied. The main objective of the present article is to develop a new approach for energy gain and recharge power pack of on-board sources from the surrounding medium and to create a robotic fish that would work autonomously by using unconventional drive along with the possibility of energy restoration by using dual varying area type vibrating actuator. At the time of recharge, the robotic fish would project its tail (actuator) out of water and use surrounding medium (air) to scavenge the energy. All the equations describing the process are formed according to classical laws of mechanics. The mechatronic system is explained and the results obtained are discussed in detail for air as the operating fluid to scavenge energy

Analysis of non-stationary flow interaction with simple form objects

ArticleThe paper is devoted to the analysis of a non-stationary rigid body interaction in a fluid flow. Initially, an approximate method for determining the forces due to fluid interaction with the rigid body is offered. For this purpose, the plane movement of a mechanical system with an infinite DOF (degrees of freedom) is reduced to 5 DOF motion: 3 DOF for the body and 2 DOF for the areas of compression and vacuum in fluid flow. Differential equations of non-stationary motion are formed by the laws of classical mechanics. The use of an approximate method has been quantified by computer modelling. The average difference in results was found to be small (< 5%). The analysis of the fluid (air) interaction is carried out for a rigid body of two simple geometries - flat plate and diamond. The results obtained are used to refine the parameters of the proposed approximate method that is addressed in the present study for fluid interaction with the non-stationary rigid body. Theoretical results obtained in the final section are used in the analysis of the movement of prismatic bodies in order to obtain energy from the fluid flow

Microstructure analysis and Hardness of Al C355.0 with step varying weight of Hematite particulate reinforcement

Received: December 23rd, 2022 ; Accepted: July 17th, 2023 ; Published: October 16th, 2023 ; Correspondence: [email protected] detail study on the microstructure of engineered Al C355.0 metal matrix with step varying weight of hematite particulate reinforcement from 0–12% in the step of 3% by using stir casting method in the copper chills with and without water circulation is carried out in the present work. It was earlier realized that copper chills increase the hardness of metal matrix compared to its base alloy. The novelty lies in the circulation of water during solidification process so that a stronger matrix reinforcement bonding, low cluster regions, grain reinfinement with minimum porosity could be achieved. The maximum hematite particulate size was 150 μm. From the Scanning Electron microscope, it is clear that there was good distribution of reinforcement in the matrix but not exactly clear whether it is uniform or non-uniformly distributed. SEM and XRD analysis results show the presence of hematite in the matrix. With increase in reinforcement the hardness increased up to 9% of the reinforcement and then decreased. It is concluded that water circulation on casted composites have good effect in improving the hardness of the Al C355.0 at 9% of hematite resulting to BHN 128 and without water circulation it was found to be BHN 124. It is realized that water circulation improves the hardness of the composite for all the cases with hematite as particulate reinforcement for Al C355.0

Analysis of non-stationary flow interaction with simple form objects

ArticleThe paper is devoted to the analysis of a non-stationary rigid body interaction in a fluid flow. Initially, an approximate method for determining the forces due to fluid interaction with the rigid body is offered. For this purpose, the plane movement of a mechanical system with an infinite DOF (degrees of freedom) is reduced to 5 DOF motion: 3 DOF for the body and 2 DOF for the areas of compression and vacuum in fluid flow. Differential equations of non-stationary motion are formed by the laws of classical mechanics. The use of an approximate method has been quantified by computer modelling. The average difference in results was found to be small (< 5%). The analysis of the fluid (air) interaction is carried out for a rigid body of two simple geometries - flat plate and diamond. The results obtained are used to refine the parameters of the proposed approximate method that is addressed in the present study for fluid interaction with the non-stationary rigid body. Theoretical results obtained in the final section are used in the analysis of the movement of prismatic bodies in order to obtain energy from the fluid flow