Dynamic response and chaos analysis of a spatial multi-body system with multiple clearance joints and a flexible component

Abstract

The clearance joints and flexible components are crucial factors influencing the dynamic characteristics of mechanisms. Previous studies mainly focus on the dynamic response of simple mechanisms, with limited research on the dynamics analysis and chaotic behavior of complex spatial multi-body systems. To study the dynamic response of the Variable Stator Vane (VSV) mechanism, a nonlinear dynamic model considering clearance joints and a flexible component is established based on the Lagrange multiplier method and the Absolute Nodal Coordinate Formulation (ANCF) method. An adaptive step-size solution algorithm is proposed to address the low efficiency of dynamic calculation for multi-clearance mechanisms. The influences of different joint clearance positions, clearance quantities, and sizes, driving speeds and modes, as well as flexible components on the mechanism dynamic characteristics including motion response, driving force, and joint contact force, are investigated. Chaos phenomena are analyzed using phase diagrams, Poincaré maps, and bifurcation diagrams. The results indicate that the mechanism exhibits varying sensitivities to clearance positions. Increasing the number or size of clearances, or using higher driving speeds, all contribute to decreasing the precision and stability of the mechanism, leading it towards chaotic behavior. The flexible component can mitigate the influence of joint clearances, which is beneficial for enhancing the stability of the mechanism and reducing costs.