Papers by Keyword: Moment of Inertia

Abstract: A technique for studying contact stresses in the connection of heat-exchange tubes with tube sheets using roller rolling is described. Formulas for the determination of contact stresses, taking into account the formation of local deformation of the tube due to force action of each roller and features of axial movement of the tool spindle are given. Calculation was based on the assumption of medium continuity, known relations between normal stresses and deformations, as well as experimental oscillograms of the process.

Abstract: In order to increase the measuring range of the moment of inertia, a new measurement equipment with triple torsion bars based on torsion pendulum was designed. The equipment could switch the number of torsion bars from single to double or triple by inserting or extracting two movable pins and implement the function of three different measurement devices. The detailed deducing process for the measuring range of the moment of inertia at various measurement states was given. The results show that the measuring range of the measurement equipment has been significantly improved compared with other equipment using single torsion bar or double torsion bars and verify the effectiveness and practicability of the measurement equipment.

Abstract: This paper focuses on making some review and observation on the performance of equipment named Mass Properties Measurement System (MPMS) which capable to calculate the center of gravity (CG), moment of inertia (MOI) and Product of Inertia (POI) of a satellite. Before approving to receive such a huge machine/equipment consist of mechanical and electronic structure, National Space Agency (ANGKASA) which acts as a Malaysian Government Agency has to go through an Acceptance Test Procedure (ATP) to compare with the factory acceptance result on its performance review. The Factory Acceptance Test (FAT) for this machine has been done earlier in United States (USA) as the equipment is manufactured in Connecticut, USA. This ATP is responsible on determining the requirements of a specification or contract are met or not by conducting test which is commonly applied for engineering and its various subdisciplines and the test have been witnessed by a Malaysian Research Institute; SIRIM Berhad, local and international contractors as well as the principal or manufacturer of the equipment itself and took place in ANGKASA, Banting, Selangor. It may involve chemical tests, physical tests, or performance tests by comparing the results with FAT [1].POI-1000M Rotary table, a rotor, deadweights, a compressor and a beam are the main components to be used for the acceptance performance test assisted by a control system for operators to calculate the desired measurements. Results confirmed that the ATP and FAT results are finally been compared and the equipment is successfully approved.

Abstract: The article presents the detection method of moment of inertia in frequency domain based on the torsion pendulum method. It analyzes the frequency spectrum distribution of pendulum motion under the condition of linear damping, establishes the relationship between peak frequency and moment of inertia; it proposes the detection method of moment of inertia based on FFT. The frequency spectrum analysis of multiple sets of simulation sequence shows that it has mapping relationship among un-damped natural vibration frequency, frequency bandwidth and damping ratio. The experiment results verify the correctness of detection method of moment of inertia based on FFT.

Abstract: This paper focuses on the capabilities of equipment known as Mass Properties Measurement (MPM) to calculate the center of gravity (CG) of a jig or an adaptor, which is used for mounting a structural model of Malaysian satellite, RazakSAT on POI-1000M Spin Balance Machine. The adaptor needs to be designed accurately to precisely accommodate the bolt sizes in both sides of the Device Under Test (DUT) side and the rotary plate side. In other words, the adaptor must be able to act as a good interface plate. A Malaysian research institute, SIRIM Berhad was chosen to undertake the design and manufacturing of the adaptor according to the specifications made by ANGKASA. The list of requirements of MPM should be considered during measurement to have optimum results, so that the satellite fixture onto the rotary table can be preceded for further calculations. Space Electronics (SE), the manufacturer for this MPM machine, has provided the control system for operators to calculate the required measurement such as CG, moment of inertia (MOI) and Product of Inertia (POI). Results confirmed that the simulation and experimental values are successfully obtained.

Abstract: In the paper, an approach for parameter identification during regular movements of servo axes is discussed. In contrast to the usual case, where test signals are applied to the process, there is no deterministic excitation present in this manner. Consequently, the accuracy of the identified parameter depends on the available excitation and needs to be assessed after the identification is completed. Considering that, several methods of error calculation and similarity measurement are presented in the paper and discussed for the specific use case of non-invasive parameter identification.

Abstract: This paper presents the experimental determination of the moment of inertia of USM e-UAV by using pendulum method. Compound pendulum experiment is used to determine the moment of inertia about x and y axes while the moment of inertia about z-axis is determined using bifilar torsion pendulum method. An experimental setup is developed with appropriate dimension to accommodate USM e-UAV. Experimental data are presented and discussed.

Abstract: Fluid-structure interaction (FSI), which solves the coupling between solid and fluid, has more and more been adopted by researchers to better study interaction between the hydrodynamic and structural flexibility. In this paper we adopt FSI and study a model simplified from the pectoral fin of Koi Carp. Flexibility is a comprehensive assessment of soft structures, it not only relates to the material constitutive parameter, but also relates to the apparent morphology parameter. The Young’s modulus and moment of inertia are two typical parameters. In this paper we first investigate the Young’s modulus’ effect on the propulsive performance, the fluid structures are analyzed and the motions are presented, then we discuss the moment of inertia, their thrust forces are compared. Results show that proper flexibility can greatly increase the thrust forces while too flexible fin’s behavior is worse. Moreover, the bending stiffness, a uniform parameter combines the material property and morphology parameter, is explored. It is found out that even for the same bending stiffness, different couples of Young’s modulus and moment of inertia will lead to different propulsive performance. These findings will provide a useful guidance for the design and manufacture of novel flexible underwater bio-mimetic vehicles.

Abstract: In this paper, a solution for the automatic control of the driving mechanisms that load/unload billets in/from a rotary hearth furnace is proposed. This problem is approached because in the actual stage the control of the loading/unloading machines is made manually. The treated solution is based on using, for each machine, a direct-current motor (d.c. motor) supplied through a direct-current converter (d.c. converter) for the forward-backward moving of the two machines to/from the furnace. In this context, the tuning of the controller implemented in the converter is made in order to assure the imposed speed of the motors and implicitly of the machines, respectively an appropriate speed evolution of the motors in the period of their acceleration and deceleration to assure the machines correct positioning.

Abstract: In this paper, a mathematical model of the loading system is established. The characteristics of the loading channel and disturbance channel are analyzed through this mathematical model. Analysis results show that the loading channel is unstable and disturbance torque leading the input command. It directly impact on the output torque, serious affect the systems loading precision. Characteristics of the loading system are analyzed, and the results show that stiffnesss effect on the loading system is twofold, should be considered at the same time. Reduce the system's moment of inertia is good for the characteristics of the loading system.