Acceleration Of Rod Research Articles

Analisis Kinematika pada Quick Return Mechanism dengan Menggunakan Metode Bilangan Kompleks

Kinematics analysis includes analysis of position, velocity and acceleration of the rods of a mechanism. The complex number method is a kinematic analytical way to express position, velocity and acceleration vectors in the form of complex numbers. The first step that needs to be done is to determine the position vector of the point to be analyzed, then determine the velocity and acceleration vectors by differentiating with time. After that is done, then the algorithm can be made. The mechanism used for this study is the quick return mechanism. The assumed data for this analysis is the angular velocity of rod 2 is 19.0986 rpm and the acceleration of rod 2 is 0 rad/s2. The results of the position analysis show that if rod 2 rotates one full rotation (360o), then rod 4 rotates about 1/6 circle (232.72o - 294.12o) and the slider moves along the X axis (406.939 - 504.111). The maximum speed behind the slider is 121.45 mm/s while the maximum speed forward for the slider is 101.09 mm/s. A large change in velocity (acceleration) is needed when bar 4 and the slider change direction (from CW to CCW or vice versa), this is indicated by a decrease and increase at the beginning and end of the graphic with significant acceleration

Evaluating the dynamic behaviour of bone anchored hearing aids using a finite element model and its applications to implant stability assessment.

The dynamic behavior of osseointegrated implants can be used for the non-invasive evaluation of thecondition of the bone-implant-interface (BII). The Advanced System for Implant Stability Testing (ASIST) is a vibration measurement system that relies on an impact technique and an analytical model to compute the interface stiffness and the ASIST stability coefficient ([Formula: see text]). The objective of this work is to develop a finite element (FE) model capable of capturing the dynamic behaviour of the bone-anchored hearing aid under the ASIST loading condition. The model was validated with previously collected in vitro and in vivo data which were compared to the model's acceleration responses and [Formula: see text] scores. Similar acceleration responses were obtained, and the maximum absolute differences in [Formula: see text] scores between the FE model and the in vitro and in vivo data were 1.15% and 5.48% respectively. The model was then used to show the existence of a relationship between the rod's acceleration response and the BII stress field. Finally, the model was used to interpret the factors that affect the stiffness parameters of the ASIST analytical model. The interface stiffness and the system's dynamic properties were more influenced ([Formula: see text]) by the BII material and friction coefficient compared to the implant geometry. In this work, a finite element model of the bone anchored hearing aid was used to simulate the dynamic behaviour of the bone-implant system under the ASIST's loading conditions. The model was first validated with previously collected experimental and clinical results. The validated model was then used to study the relationship between the impact rod's acceleration response and the response at the bone implant interface. Finally, the model was used to formulate a better understanding on the influencing factors on the interface stiffness.

Dynamic evaluation of a shock absorberwith the use of additional noncontact in-fluid laser measurementsof the intake base valve

Abstract The aim of this paper is to evaluate vibrations of a semi-active shock absorber take-apart unit assembled with a base valves replaced during conducted evaluation test with the same valve component. Intake valves significantly contribute to the overall vibration level of the shock absorber. The valves are further recalled in the paper as "OK" and "NOK" corresponding to audible noise perception criteria. These criteria are frequently subjective and difficult to be expressed by a technical specification. The take-a-part unit was evaluated by means of piston- rod acceleration in the time-frequency domain. The analysis was completed by other measurements (i.e. load, compression and rebound pressures, and intake valve opening displacement) in order to correlate their waveforms with spectrogram maps. The intake valve opening value (i.e. displacement of the shim supported by the coil spring) was measured using three laser sensors which were capable to conduct measurements directly in fluid. The wavelet time-frequency analysis based on the synchrosqueezing transform (SST) was applied in order to identify the fingerprint OK and NOK valve. A servo-hydraulic tester was used in order to apply a sine-wave excitation to the shock absorber. The experiments involved the soft and hard settings of the semi-active shock absorber corresponding to low (I=0.29 A) and high (I=1.6A) value of the current applied to the internal servo-valve.

Control-oriented friction modeling of hydraulic actuators based on hysteretic nonlinearity of lubricant film

Friction modeling of hydraulic actuators is essential to system control and the prediction accuracies of friction models (e.g., Stribeck, LuGre) need to be improved when they were applied to hydraulically actuated systems. The test platform for hydraulic cylinders was constructed and the friction forces of plunger type hydraulic actuators were measured under different operating conditions. The dynamic behaviors of film thickness of seal/rod interface were investigated based on elastic hydrodynamic lubrication (EHL) method. The effects of acceleration of rod on friction force were examined using coherence function estimation technique. The Stribeck and LuGre model were modified by incorporating physically based hysteretic film dynamics and Bouc–Wen model into Stribeck function, respectively. It is shown that the Stribeck and LuGre model cannot preferably describe the friction force-velocity behavior, especially for the fluid lubrication regime. The modified Stribeck and LuGre model can simulate the hysteretic behavior of friction force-velocity loop more effectively than unmodified ones and the friction estimation accuracies of Stribeck and LuGre model were improved remarkably.

Study of Flow-Induced Vibration Phenomena in Automotive Shock Absorbers

The purpose of this study was to develop a model of the dynamic behavior of a hydraulic vehicle double-tube shock absorber. The model accounts for the effects of compressibility, valve stiction, inertia, etc. and can be suitable for use in the analyses on flow-induced pressure fluctuations in the device. The author highlights all major variables to influence the output of the shock absorber, and then proceeds by performing a series of simulations using the developed model. The model is demonstrated to operate well in the large amplitude and low frequency range as well as the small amplitude and high frequency excitation operation regimes. The results are presented in the form of time histories of pressures in each fluid volume of the damper, flow rates through the valves, piston rod acceleration and force. Fast Fourier Transform (FFT) graphs are presented, too, in order to identify major components of the pressure fluctuation phenomena in frequency domain.

Pumping Unit Optimization Design Based on Virtual Prototype Technology

Using Solidworks establish the virtual prototype of the conventional beam pumping unit. After that, by using ADAMS moves on to the kinematics simulation of prototype, detailed the polished rod motion parameters curves are present. When compared the results with the calculation results of accurate analysis method, discovered that these two results of different methods coincide quite well, and the reliabilities of simulation results of using virtual prototype technology. are validated. The optimal design of pumping unit skeletal structure parameters is explored in this paper, taking the polished rod acceleration as objective functions. From the simulation solution, we get the optimal structure and size of pumping unit. Virtual prototype technology provides a kind of economical, fast and reliable way to design and optimize structure of the pumping unit.

STUDY OF FLOW-INDUCED VIBRATION PHENOMENA IN AUTOMOTIVE SHOCK ABSORBERS

The purpose of this study was to develop a model of the dynamic behavior of a hydraulic vehicle double-tube shock absorber. The model accounts for the effects of compressibility, valve stiction, inertia, etc. and can be suitable for use in the analyses on flow-induced pressure fluctuations in the device. The author highlights all major variables to influence the output of the shock absorber, and then proceeds by performing a series of simulations using the developed model. The model is demonstrated to operate well in the large amplitude and low frequency range as well as the small amplitude and high frequency excitation operation regimes. The results are presented in the form of time histories of pressures in each fluid volume of the damper, flow rates through the valves, piston rod acceleration and force. Fast Fourier Transform (FFT) graphs are presented, too, in order to identify major components of the pressure fluctuation phenomena in frequency domain.

Analysis on Kinematic of Rod on Rotor with Sine Curve Revolving Speed in Twin-Rotor Cylinder-Embedded Piston Engine

Twin-rotor cylinder-embedded piston engine are a high power density and no valve mechanism engine. Given the motion law of two rotors sine curve change, its kinematic model of rod can be established, and key parameters of rod related to engine performance, such as angular displacement, velocity and acceleration of rod are presented. And then the kinematic model of rod is imported into MATLAB, the moving law of angular displacement, velocity and acceleration of rod are analyzed by changing the value of swing amplitude k. It can be concluded that the changes of rods motion are periodic, relatively gentle, and the periodic of angular displacement, velocity and acceleration of rod are the same. For different value of k, the fluctuation of velocity and acceleration of rod are in direct proportion to k and angular displacement of rod is fixed.

Optimum Design of Double-Well Pumping Units Based on Calculation of MATLAB Optimization Toolboxes

Beam double-well pump unit as a new generation of pumping unit is currently used in mechanical oil production. However, due to a number of pumping system parameters, the conventional design can not achieve the optimal pumping system parameters Using MATLAB simulation optimization algorithms, simulates the structural parameters, rod speed, rod acceleration, rod load, crank torque factors and gear’s crank shaft net torque of the double horse head double-well pumping unit, achieving optimal design of double horse head double-well pumping system, with the existing conventional design of double horse head double-well pumping unit, double horse head double-well pumping unit has a great improving than conventional pumping unit in motion and power dynamic characteristics.

Simulation tool for shock absorber noise prediction in time and frequency domains

This paper investigates the validity of a hydraulic simulation model to calculate the piston rod acceleration for further frequency domain analysis. At the present time, simulation results analyses of shock absorber characteristics are mostly restricted to the low frequency range for the hydraulic behaviour and the high frequency range for Noise, Vibration and Harshness (NVH) studies. However increasing demand on vehicle noise reduction is focusing more attention on high frequency matters caused by shock absorbers hydraulic effects. The most important noise concern related to shock absorbers is knocking noise. This is a structural noise caused by the vibration of chassis components excited by the shock absorber's piston rod vibrations. These vibrations are caused mainly by valves opening-closing and friction during stroke changes. The validation process is based on quantitative and qualitative comparison results between test and simulation both in time and frequency domain.

Integrated Well Performance and Analysis

Summary Computer acquisition, processing, and analysis of acoustic, dynamometer, and related data at the wellsite offer new capabilities in analyzing a well's performance. A powerful lap-top computer is used in conjunction with a compact analog-to-digital (A/D) converter to acquire data from acoustic microphones, pressure transducers, load cells, accelerometers, motor current sensors, tachometers, and other transducers to analyze a pumping well's performance. The system is used in conjunction with a gas gun, microphone, and pressure transducer to measure the annular liquid-level depth in a well acoustically. This measurement is combined with the casing pressure and the casing-pressure buildup rate to determine the producing bottomhole pressure (BHP). This flowing BHP is analyzed in conjunction with the reservoir pressure and an inflow performance model to establish the producing rate efficiency of the well. The same equipment can be used with special software to acquire pressure-transient data. The computer is programmed to acquire data at a frequency specified by the operator. The computer automatically obtains the acoustic liquid-level depth measurement and the casing pressure. These data are processed to calculate the BHP as a function of test time. Conventional diagnostic plots [Horner, Miller-Dyes-Hutchinson (MDH), log-log, etc.] are presented at the wellsite to aid the operator in the analysis of the data and to determine appfopriate test completion time. In beam-pumped wells the system is also used to perform dynamometer analysis by the acquisition of polished rod load, polished rod acceleration, and motor-current data. Accelerometer data are integrated to calculate polished-rod velocity and position. Conventional surface and pump dynamometer calculations allow presentation of results for a complete dynamometer analysis in the field. All these data acquisition and analysis capabilities are available in one package. Software with operator prompts is used to aid in the proper acquisition and analysis of digital data. The acquired and processed digital field data are combined with a well database file and a pumping-unit library to assist the operator in obtaining a complete analysis of the well's performance.

Transient longitudinal vibrations of a finite cylindrical rod connected to an elastic half-space

An analysis is presented of the transient longitudinal vibrations of a cylindrical rod connected to an elastic half-space under the condition that an arbitrarily shaped free field vertical acceleration is given as an input. By applying Laplace transformations with respect to time and numerical inverse Laplace transformations, the time histories of the rod acceleration at the interface and at the free end are obtained. Generally, the maximum value of the rod acceleration decreases and the acceleration attenuates slowly as the foundation becomes soft compared with the rod and the contact area at the interface increases. When the foundation stiffness is not very small compared with that of the rod and the rod is slender, the rod acceleration at the interface is larger than the input free field acceleration in a certain frequency range of the input acceleration.

Predicted vs. Measured Loads in a Sucker Rod Pumping System

Abstract In order to apply an oilfield pumping unit on the most economical basis, itis often necessary to predict its torsional and structural loading in advanceof well completion. Frequently, a pumping unit is misapplied because thedetermination of these values by simple prediction formulae does not conform toeventually measured loads. An investigation of the simplified predictionformulae most commonly used in applying a sucker rod pumping unit illustrateswhy discrepancies between predicted and measured loads may exist. Introduction One of the numerous problems faced by the pumping unit manufacturer is topredict the torsional and structural loading that will be imposed on thesurface equipment for any given set of well conditions. As a precise determination of these loads involves, complex formulationemploying many variables (some of which are unknown prior to well completion), it becomes necessary to develop a set of prediction equations with solutionswhich are fast and simple and require knowledge of only a few known quantitiessuch as rod and fluid weight and polished rod acceleration. In most cases, these simple and convenient formulae, employing only a smallportion of the items which actually control torsional and structural loading, are entirely adequate to apply the surface pumping unit on a most economicalbasis – but the results obtained are admittedly only approximations and maydiffer considerably from measured loads. In a recent study of two different types of sucker rod pumping units over anumber of applications chosen at random, the predicted peak torque determined by these simplified methods was compared to the measured peak torque. The results showed that, in both types of units, approximately one-third of the applications measured greater than predicted, one-third measured less than predicted and one-third measured about the same as predicted. (See Table I).