Overturning Stability Analysis Of Aerial Work Platform Based On Large Deflection

For its extensive applications in services, wind power, airport and fire, aerial work platform (AWP) has captured special attention of many researchers in recent years, working height over one hundred meters especially. Overturning stability analysis of working height over one hundred meters AWP is the key component of its safety requirements of basic performance. And the overturning stability characteristics of AWP affect directly the basic performance and overturning accidents occurred. However, overturning stability analysis of working height over one hundred meters AWP is still relatively rare, and there is not yet mature design and analysis theory. Therefore, the working height over one hundred meters AWP was taken as the research object, and the theory of the geometric nonlinearities 3D beam element and the algorithm of finite element method are applied in the research of the nonlinear large deflection of AWP boom, and the Zero Moment Point (ZMP) dynamic stability determination method was introduced, systemic research has done at the overturning stability analysis of AWP based on large deflection in this paper.The current deflection analysis of boom doesn't take into account of torsion of boom, coupling effect of range plane and revolution plane, and the nonlinear factor. Therefore, accuracy of analysis is not high. In this paper, the geometry of 3D beam element was assumed, then the 3D beam element mechanical model, which had the initial deflection, and the 3D beam element geometric nonlinear finite element method calculation process was discussed. The incremental Newton-Rapson method was adopted. The mechanical model includes element tangent stiffness matrix in elemental coordinate system, element coordinate transformation matrix, and the element rod end resistance. Finally, the 3D beam element geometric nonlinear finite element program was developed, which was structured based on MATLAB language, and which can analyzed the large deflection of AWP boom. Two numerical examples are analyzed. The numerical result illustrates the beam analytical model and analytical methods presented in this paper are accurate and effect.ZMP method was introduced to analyze the overturning stability of working height over one hundred meters AWP. First, the working height over one hundred meters AWP the overturning stability assumptions was introduced. Then, the expression of the ZMP point coordinate based on ZMP method was given. The value of the dynamic stability margin was derived. Finally, the method of overturning stability analysis of working height over one hundred meters AWP was discussed, which based on boom new pose by the results of boom large deflection. The ZMP dynamic stability determination method was adopted. The method and algorithm for solution the overturning stability problem of AWP based on large deflection is obtained.The results in this paper provide an important theoretical basis for optimization, analysis and the design of the overturning stability analysis and the boom of working height over one hundred meters AWP, and have been used in the product design and development of GHK111 meters large boom AWP, which was the actual project cooperation by our school construction machinery research centers and Zoomlion Ltd.