Advanced Materials Research Vols. 308-310

Abstract: To those old ships, one of the frequent faults is that the exhaust temperature of marine diesel generator is too high. This fault may lead exhaust pipe to be burned red, outlet valve to be burned down, piston and piston ring to be melted, and many other troubles. In this paper, aiming at the reason of fault of NO.1 marine auxiliary diesel engine exhaust pipe burned red while running without load, the author analyzes the every possible causes of the malfunction, finds out the real causation of high exhaust temperature is steady ball bearing of timing gear partial wears seriously. Then, the writer expounds elimination process and solutions, and proposes some suggestions about operation and maintenance in the end.

Abstract: Based on elastic dynamic model, an elastic dynamic controllable model of the vehicle flexible robot system was established. Regarding the low-order modes as the control modes, setting the boundary coordinates in the locations of the hydraulic actuator, the controllable state-space equations of the system was formed. A precondition for realizing system’s precise control is that the system is controllable. According to system’s controllability discriminant qualification, the influence of physical parameters on the controllability of system got broad discussed, and some reference data was obtained, which would be helpful for the next step to control the vibration. Aiming at the interference of the state-space equations, disturb distributing matrix was merged with input matrix, disturb vectors was merged with input vectors, a new state-space equation was established. By dynamic simulation, vibration response of the vehicle flexible robot system was achieved, and the experimental results showed that the treatment about disturb distributing matrix is feasible.

Abstract: The purpose of this paper is to design a smooth and higher-degree polynomial curve for satisfying the need of dynamic features of high-speed cam. In this paper, the dynamic model of cam mechanism is simplified into a single-free-of-degree dynamic model. The dynamic equation in this model can be used to establish the design equation of the cam profile. Finally, a typical cam mechanism is used as a simulating example to validate this dynamic modeling method and the curve obtained from calculation is smooth and can satisfy the requirement of dynamics characteristics.

Abstract: In this paper, the authors conducted a modal analysis of a drilling machine for blades of wind turbines. A simplified model of the machine was established with a commercial FEM software package, Ansys. At a specific working position the first six order natural frequencies were calculated and the results obtained from two different contacting manners were compared. The influence of static structural stress induced by gravitational load on natural frequency was also evaluated. The variations of the natural frequencies of the machine with the position angle of the rotary box were subsequently obtained. This is helpful for the determination of range of the excitation frequencies.

Abstract: This paper mainly addressed the kinematics simulation of the Slider-Crank mechanism. After proposing a mathematical model for the forward displacement of the slider-crank mechanism, the mathematical models for the forward velocity and acceleration of the slider-crank mechanism are constructed, respectively and the simulation models for the forward kinematics of the slider-crank mechanism are constituted in the Matlab/Simulink simulation platform. Finally the forward kinematics simulation of the slider-crank mechanism was successfully accomplished based on Matlab/Simulink. Examples of the simulation for the forward kinematics of a slider-crank mechanism are given to demonstrate the above-mentioned theoretical results.

Abstract: In this paper, ADAMS multi-body dynamics simulation was introduced in order to solve the diesel engine piston pin dynamics. Take diesel engine piston for example, the model of piston system was established based on ADAMS/Engine module. According to rotational speed of crankshaft, piston pin dynamics simulation was analyzed. Through Fast Fourier Transformation, piston pin power spectral density was got for piston pin fault diagnosis. The results show that simulation results are consistent with theory, dynamics simulation applied in fault diagnosis is feasible.

Abstract: The rigid-flexible coupling dynamics of a hub-flexible beam system carrying a payload with rotary inertia is presented. Both the transversal deformation and the longitudinal deformation of the flexible beam are considered. And in the total longitudinal deformation the non-linear coupling term, also known as the longitudinal shortening caused by transversal deformation, is considered. The approach of assumed modes is used to describe the deformation of the beam. The rigid-flexible coupling dynamic equations of the system are established via employing the second kind of Lagrange’s equation. Solving for this mathematical model, we can obtain the dynamics of the system. Then the natural frequencies are studied though the transversal bending vibration analysis. The natural frequencies are shown to be proportional to the angular speed ratio and the hub radius ratio, inversely proportional to the payload mass ratio and the rotary inertia ratio. When the angular speed ratio increases up to a certain value, the longitudinal deformation will also have an obvious influence to the transversal bending vibration.

Abstract: According to structure feature and principle of relying on relative rotation among hubs to realize elastic deformation of elastic spoke and varying diameter of a novel variable diameter walking wheel, finite element model was created based on the theory of continuous collision and the nonlinear contact between the wheel’s caster and ground was defined through introducing mobile marker in SIMPACK software. Dynamics simulation analysis was carried out respectively under two varying diameter strategies of the wheel and get the dynamic response in the mode of changing the diameter in situ and the minimum size of torque needing for varying diameter. The suitable for working condition and varying mode was pointed out via comparative analysis of the simulation’s results, and can provide theoretical basis for further rational design and study.

Abstract: Through analyzing the specialty and limitation of the current driving simulators, the main factors affecting fidelity of driving simulators are summarized. Then, a new driving simulator of high fidelity based on the multi-body dynamics is proposed, with focus on the dynamics modeling and the road feel. Furthermore, a control algorithm of the road feel is designed and by the means of co-simulations in MATLAB/Simulink and ADAMS environment, the measuring steering wheel torque proves the control algorithm of road feel is reasonable. The control algorithm has been put into practice and got satisfactory results.

Abstract: In order to study characteristics of loads on a cutting drum of a continuous miner, a mathematic model of random loads on the drum is set up in the paper by means of defining probability distributions of three-direction loads, loads and their variations on a cutting drum are given by building a computer simulation program when it cuts pure coal, rock and hard parcel. Results show that swing resistance is the greatest, forward resistance is the second, axial resistance is the least; a cutting resistance torque increases with the increase of broken media strength; loads cut stone layer are much larger than pure coal; range of load change and load fluctuations are big as cutting hard parcel, these conclusions are correspond with the actual situation.