An enhanced formulation to model spatial revolute joints with radial and axial clearances

Zhang

Wang

et al. 2019

Radial clearance, particularly the axial clearance in the 3D joint of a mechanism owing to the assemblage, manufacturing tolerances, wear, and other conditions, has become a research focus in the field of multibody dynamics in recent years. In this study, a hydraulic cylinder model with 3D clearance joints was constructed by combining various potential contact scenarios. The novelty of this study is that potential contact points between the bearing wall and journal were calculated when the bearing wall circle was projected to an ellipse owing to misalignment of axes. Moreover, the simulation model considered the effective bulk modulus of the hydraulic oil and applied the Lagrange multiplier method. Subsequently, an experiment was conducted to verify the simulation results. The simulation and experimental results indicated that the dynamic responses of the hydraulic cylinder with 3D clearance joints can be classified as free, rebound, slide, and contact. The effects of input force, frequency, and clearance size on the dynamic behavior of the hydraulic cylinder were also investigated. Increasing the input force and clearance size will degrade the hydraulic cylinder dynamic response; however, the input force frequency can reduce the deterioration of the dynamic response. This study aids in providing improved understanding of the hydraulic cylinder with 3D clearances in the theoretical field and for practical engineering applications.

Section: Model Of 3d Revolute Joints With Radial and Axialmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Numerical and Experimental Investigations on Dynamic Response of Hydraulic Cylinder with 3D Spatial Joints considering Radial and Axial Clearances

Zhang

Wang

et al. 2019

“…Erkaya et al [14] took a fully articulated 3D slider-crank mechanism as the research object, the effects of spherical joint clearance on partly compliant were studied by a numerical method, and the advantages and disadvantages of flexible connection are analyzed. Marques et al [15] presented a new formulation to model spatial revolute joints with radial and axial clearances, and the numerical calculation of the planar and spatial crank-slider mechanism is taken as an example. Tian et al [16] put forward a new approach to model and analyze flexible spatial multibody systems with cylindrical joint clearance that considered the dry friction and lubrication.…”

Section: Introductionmentioning

confidence: 99%

Dynamics Analysis of Spatial Parallel Mechanism with Irregular Spherical Joint Clearance

2019

Clearances caused by machining accuracy and assembly requirements are regular, but they will be irregular due to the wear of the kinematic pairs. At present, there are few studies on wear of space kinematic pairs. In order to grasp the effect of irregular spherical joint clearance after wear on the dynamic response, a method for solving irregular clearance problems based on the Newton–Euler method is proposed, and the dynamic response of 4-UPS-UPU spatial parallel mechanism with irregular spherical joint clearance is investigated. The kinematic model and contact force model of the clearance of the spherical joint are derived. The dynamic model of the mechanism with spherical joint clearance is established by the Newton–Euler method. Based on the Archard model, the three-dimensional dynamic wear model for spherical joint with clearances is developed. The wear depth and wear position of the spherical joint are obtained by the numerical solution. The method of reconstructing the geometric morphology after wear is proposed based on the finite element thought. The solution of the irregular clearance problem is put forward, and the dynamic response of the mechanism after wear is also analyzed. The results show that the dynamic response curves of the mechanism fluctuate around the ideal curves whether before wear or after wear. Compared with the regular clearance before wear, the results of the irregular clearance after wear have a greater impact on acceleration and contact force, and the vibration of the acceleration and contact force curve become more intense than before. Moreover, the displacement, velocity, and acceleration curves of the irregular clearance show some hysteresis than that before wear. Therefore, it can be inferred that the irregular clearance has more adverse effects on the mechanism and aggravates the wear between the elements of the kinematic joint; in addition, the stability and the reliability of the mechanism can be reduced.

“…Muvengei et al [10] explored the influences of differently located frictionless joints with clearance on overall dynamic behavior of the crank-slider mechanism. Marques et al [11] proposed a novel method to build spatial revolute joint containing the axial clearance and the radial clearance. e motion equation which governs dynamic response of multibody system has been established.…”

Section: Introductionmentioning

confidence: 99%

Nonlinear Dynamics and Analysis of a Planar Multilink Complex Mechanism with Clearance

Jiang

Deng

et al. 2018

In order to understand the nonlinear dynamic behavior of a planar mechanism with clearance, the nonlinear dynamic model of the 2-DOF nine-bar mechanism with a revolute clearance is proposed; the dynamic response, phase diagrams, Poincaré portraits, and largest Lyapunov exponents (LLEs) of mechanism are investigated. e nonlinear dynamic model of 2-DOF nine-bar mechanism containing a revolute clearance is established by using the Lagrange equation. Dynamic response of the slider's kinematics characteristic, contact force, driving torque, shaft center trajectory, and the penetration depth for 2-DOF nine-bar mechanism are all analyzed. Chaos phenomenon existed in the mechanism has been identified by using the phase diagrams, the Poincaré portraits, and LLEs. e effects of the different clearance sizes, different friction coefficients, and different driving speeds on dynamic behavior are studied. Bifurcation diagrams with changing clearance value, friction coefficient, and driving speed are drawn. e research could provide important technical support and theoretical basis for the further study of the nonlinear dynamics of planar mechanism.