Advanced Materials Research Vols. 199-200

Abstract: The horizontally vibrating conveyor (HVC) is excited by a exciting implement with four shafts which have eccentric quality, and the materiel is transported by the friction between the materiel and conveying trough. The friction force varies continuously in the process of material transportion. To solve the problem, a dynamical model of HVC is set up, and an adaptive method based on the discreteness of time is presented. Then the transportation theory is discussed.

Abstract: To reduce the angular velocity fluctuation of the input shaft to a machine, we deduced that a machine under the combined action of the inertia and the load may keep running smoothly if the equivalent kinetic energy (EKE) of the machine is constant during its operation. Furthermore, we introduced a novel type of flywheels with variable equivalent mass moment of inertia (VEMMoI) and without fixed connection with the input shaft to the machine. The kinetic energy fluctuation of the flywheel is used to dynamically decrease the EKE fluctuation of the original machine, thereby realizing smooth machine operation. Three types of flywheels with VEMMoI driven by a two-link dyad, a pair of noncircular gears and a planet cam respectively were designed as examples. The velocity fluctuation of the machine is significantly reduced. In the second and the third examples, in particular, the input shaft may rotate at a constant rate, since its angular velocity fluctuation is eliminated completely in principle.

Abstract: The boom is one of main load bearing parts for the excavator operation; accordingly, it is very important to make the strength calculation. Considering the excavator boom is of complicated working condition and difficult stress analysis, based on the expression of parts of the excavator working device concerning length parameters of the cylinder, establish the full parameterization model in the MSC.adams, so as to make the secondary development process, automatically achieve the force analysis and calculation of all-poses, and process and save hinged forces under all-poses. In addition to the above, by establishing the finite element parameterization model, invoke the macro command to modify all hinged forces, so as to calculate the max. equivalent stress of the boom under all-poses. The calculation result shows that, the boom can meet the strength requirements under all-poses.

Abstract: Based on the heuristic nonlinear creep model, the nonlinear coupled differential equations of the motion of a 12 degree-of-freedom (12-DOF) bogie system which takes account of the lateral displacement, vertical displacement, the roll angle and the yaw angle of the each wheelset and the bogie frame, moving on curved tracks are derived. The nonlinear creep forces and moments are constructed via the saturation constant of the nonlinear creep model in completeness. The effect of the suspension parameters of a bogie system on the derailment quotient is investigated. Results obtained in this study show that the derailment quotient of a bogie system increases as the vehicle speed increases. In addition, the derailment quotient of a bogie system is generally decreased with the increasing values of suspension parameters.

Abstract: The rigid-flexible coupling dynamics of a radially rotating flexible beam with impact is investigated in this paper. The transversal deformation and nonlinear coupled deformation, which means the longitudinal shortening caused by transversal deformation, is considered here. The impact force is calculated based on Hertz contact theory and nonlinear damping theory. By introducing the concept of impact potential energy, the system’s rigid-flexible coupling dynamic equations with impact is obtained by using Lagrange equation. The dynamic simulation is given to validate the method presented here, and get some dynamic response, such as impact force and flexible deformation.

Abstract: Based on requirements of pipe transport systems on deepwater pipelaying vessel, a new pipe lifting mechanism was designed. It was composed of crank-rocker and rocker-slider mechanism with good lifting capacity and high efficiency. When the slider went to the upper limit position, the mechanism could approximatively dwell, meeting the requirement for transverse conveyor operation. According to the theory of dynamics, numerical analysis method was used to the dynamic analysis of the mechanism. The results showed the maximum counterforce was at the joint between the rocker and ground, and this calculation could be a guideline for the kinematic pair structure designing.

Abstract: This article describes the clutch release bearings research on the separation of research methods and characteristics of the bearings described in detail. the off-road vehicle Clutch release bearings often speed, strong vibration, high temperature, humid workability pollution conditions work require release bearings good strength and toughness, resistant to impact wear and excellent contact fatigue performance. Release bearing vibration characteristics and on life affect important theoretical significance and socioeconomic value.

Abstract: A mechanical litchi picking process using a cut-clamp combined picker was modeled. A minimum clamping velocity model is required to ensure such a picker working reliably as well as to limit consumed energy. The picking process was sub-divided into seven stages. Three variables, namely the width of fiction head (D), the press on the clamping head(N) and fiction index between fruit branch( μk (v)) were chosen as independent variables. The output of modeling is the minimum cutting (or clamping) velocity. The model was verified using the experimental results of cutting and clamping by a simulated cut-clamp combined picker. The experimental results also showed if setting safety factor k=1.5, calculated velocities can ensure fruit branch be clamped firmly by the cut-clamp combined picker.

Abstract: SKZT3500 NC rotary table adopts constant-current hydrostatic bearing and unloading guide two sets of hydraulic system. Aiming at the characteristics of two sets of hydraulic system, this paper deduces the constant-current hydrostatic bearing static stiffness formula. Then, the theory and algorithm of BP neural network were applied to predict the constant-current hydrostatic bearing static stiffness, based on experimental measurements in a physical prototype and neural network toolbox of MATLAB. Testing results show that BP neural network can accurately forecast the constant-current hydrostatic bearing of the static stiffness.

Abstract: On the basis of the CAD/CAM design system of parallel indexing cam mechanism which is developed successfully based on VC environment, use it to generate precise profile data, then create the three-dimensional model of the parallel indexing cam and assemble it with other parts under the Pro/E environment. At last, the model is transformed into ADAMS through interface Mechanism/Pro, then its virtual prototype is built and the dynamic simulation is conducted. Then makes an intensive analysis according to the result of simulation, collects accurate test data by simulating the physical prototype, so as to achieve the goal of improving the comprehensive properties of the parallel indexing cam mechanism.