Papers by Keyword: Vibration

Abstract: This paper presents a novel single-point rolling bearing fault diagnosis mechanism through vibration signal analysis. It is highlighted that the rolling bearing operational state can be well estimated by the first small set of Intrinsic Mode Function (IMF) components of the original vibration measurements through Empirical Mode Decomposition (EMD). These IMF components can be further translated into envelope spectrum by using Hilbert Transform. As a result, the difference of fault characteristic frequencies (DFCF) is derived to properly characterize different fault patterns for fault diagnosis. The suggested method is implemented and evaluated in a rolling bearing test bed for a range of failure scenarios (e.g. inner and outer raceway fault, rolling elements fault) with extensive vibration measurements. The result demonstrates that the proposed solution is effective for characterizing and detecting arrange of rolling bearing faults.quality).

Abstract: The intention of this paper is to explore the dynamic behavior of three distinctive types of automobile .In this paper, the modal analysis of the vehicle frameworks simulated by ANSYS and the vibration and the resonance behavior of localizations are introduced .The results of this research could provide engineers with useful information to understand the dynamic vibration behavior and design the frame of vehicles.

Abstract: For a wind energy generator, the most significant factor which decreases the working life of it is the vibration from the rotating turbine blades under wind. In this paper, we do modeling and simulating in the constrained layer damping (CLD) approach, which is called passive control. Here, we use software PRO/ENGINEER to design and model a wind turbine blade before using COMSOL to simulate the dynamic motion of the wind turbine blade and its interaction with aerodynamic force of wind in finite element method. Some different models are built, the original turbine blade and the turbine blade with damping patches on different location and quantity. Then, according to the simulation results, we compare the effects of passive damping control in defferent patches locations and quantities under different wind speed. This research can provide us foundation and comparision with our future study which is related to the piezoelectric layer damping (PLD).

Abstract: On the basic of passive damping control, we do modeling and simulating in another approach to improve the vibration alleviating effect, the piezoelectric layer damping (PLD), which is called active control. The piezoelectric damping patches are under control of PID controller (matlab simulating) in voltage defference. Here, we use the software PRO/ENGINEER to design and model a wind turbine blade before using COMSOL to simulate the dynamic motion of the wind turbine blade and its interaction with aerodynamic force of wind in finite element method. Some different models are built-- the original turbine blade and the turbine blade with damping patches on different location and quantity. Then, according to the simulation results, we compare the effects of passive and active damping control, also the effect of patches locations and quantities under different wind speed. This research can provide a direction for future study about ways to decrease vibration of turbine blades.

Abstract: The purpose of this paper is to assess the material characteristic by using vibration signal analysis during drilling process. Generally, material with high mechanical properties exhibits low damping capacity and vice versa. The main objective of this paper is to develop a relationship between the signal parameters and the strengths of materials. Aluminum alloy 1100, stainless steel 304, and mild steel were selected as the specimens to be drilled using CNC machine. The vibration signal was captured using a transducer and recorded using a DAQ system. The signal parameters such as maximum amplitude, vibration energy, and the RMS value were extracted using MATLAB software. From the results obtained, the graphs of signal parameters versus strength of each specimen are plotted to show their relationship. It was found that the signal parameters increased exponentially as the strengths of materials increased. Besides that, the vibration signal of the specimens are analysed and compared based on their mechanical characteristics.

Abstract: The traditional hydraulic shock absorber suspension converts the vibration energy between the sprung mass and unsprung mass into heat energy. The realization of vibration energy recycling can reduce vehicle's energy consumption, developing ideals for the research of the active suspension/ semi-active suspension. Four kinds of energy reclaiming suspension's structure principle is introduced in detail and the development restricting factors of the suspension at present are worked out through the unified measure, indicating the technology breakthrough points.

Abstract: The movement characteristics of hydraulic exciting piston is a small displacement and high reversing frequency. The movement of the piston is to adapt to the requirement of quick reversing resistance. The mating surface seal uses to reduce the motion resistance to meet the requirements of the piston movement. Piston position should be in the oil chamber oil area to meet the requirements of the piston movement and oil circulation. Elastic beam with hydraulic cylinder is connected together . This structure is conducive to the piston and the connection of elastic beam and the installation of the oil cylinder. The causes of the different moving displacement of piston is leaking.

Abstract: Surface-wave dispersion analysis is widely used in civil engineering to infer a shear wave velocity model of the subsoil for a wide variety of applications. Combining with a example, multi-channel analysis of surface waves method (MASW) was discussed in this paper. The entire MASW's procedure of three steps: acquiring ground roll data in the field, processing the data to determine dispersion curve, and back calculation of the geologic parameters for different depths. Based upon all the research results by far, MASW method is an efficient methods because of its high accuracy that is achieved by both special field technique and data processing technique.

Abstract: Pressure of the liquid is used as power source of hydraulic vibration exciter. Rotary directional control valve is the realization of oiling-way veversing components . The piston is reciprocated under the influence of the change of the hydraulic. The reciprocating movement of the piston is a result of fluid pressure.Working area of the piston multiplied by the pressure of the liquid is equal to the thrust of the piston.Displacement response of the vibration exciter can be simplified to the second-order vibration systems.Elastic beam is used as limit components of piston of vibration exciter,the piston vibration waveform is a sine wave .The volume of elastic beam is smaller than the volume of fluid elastic element . The hydraulic circuit is a dual pump fuel supply circuits.Pumps are used to supply rotary valve and hydraulic cylinder .Dual pumps fuel supply system is conducive to control fluid pressure and flow of the rotary valve and vibration piston.

Abstract: This work addresses the effect of intermediate lamina orientation and chemical treatment of natural fiber reinforced hybrid composites on tensile and free vibration properties. Two different form of fibers such as Sansevieria cylindrica (SCF) in the form of loosely separated and coconut sheath (CS) in the form of naturally available woven mat have been chosen for hybrid reinforcement in polyester matrix resin. The compression molding technique was used to fabricate the composites with the help of specially designed mold for fiber orientation. By keeping the overall weight percentage of hybrid composites constant (40 wt %), the long fiber SCF was sandwiched between two CS. The hybrid composites were fabricated the with five different intermediate lamina orientation (i.e, 0°, 30°, 45°, 60° and 90°) using SCF. The tensile strength and free vibration properties were analyzed for all the fabricated composites according to the ASTM standard and impulse hammer technique.The change in orientation of intermediate lamina have shown significant effect on both tensile and vibration properties. The potassium permanganate (KMnO₄) chemical treatment was also carried out for the optimum oriented angle laminate. The chemical treatment shows the siginificant enhancement in both the properties compared to the untreated condition.