The invention relates to a multi-support shafting
finite element method with
bearing stiffness coupling nonlinearity considered. The method comprises the steps of (1) establishing a local coordinate
system of each bearing and obtaining a six-freedom-degree
bearing stiffness matrix of each bearing under the corresponding local coordinate systems through calculating by means of the difference method with a corresponding bearing load calculation formula; (2) dividing a shaft into different shaft sections according to the difference of diameters, establishing nodes at the positions of bearing section starting positions, the bearing installation position and load action positions, then establishing finite element models of the shaft between the nodes, and obtaining a
stiffness matrix of the whole shaft; (3) establishing a
global coordinate system of a shafting, establishing another node at the bearing installation position to be used for simulating a fixed end, integrating the
bearing stiffness matrix onto the installation node and the corresponding fixed end node on the shaft to obtain the overall
stiffness matrix of the shafting, and establishing the stiffness equation of the shafting; (4) restraining the freedom degrees in six directions of the fixed end node, restraining the freedom degree, of rotating around the axis, of the node at the position of origin of the
global coordinate system of the shafting, reducing the stiffness equation of the shafting according to restraining conditions, and solving the reduced stiffness equation of the shafting with the Newton-Raphson method in an iterative mode to obtain the displacement and load of each node.