| With the development of urbanization, high-rise buildings have been increasing in recent years, the height increase of the construction make higher requirement on the properties of tower crane. With the increase of tower height by independent state, the nonlinear performance is more obvious. To analyse the influence of nonlinearities on the structural performance of the tower crane, taking a certain tower crane as the research object, the element mode of tower crane was founded by the software of ANSYS, the influences of nonlinearities on strength, static stiffness, seismic response and stability of the tower-body were studied.The static strength and stiffness were analyzed by finite element software ANSYS, the result shows that the static strength and stiffness meet the design requirements. Based on those results, using nonlinear finite element technology, material nonlinearity and geometric nonlinearity were considered, the strength and static displacement were calculated with different parameters. The analysis shows that the nonlinearities has little effect on static strength, the calculation has little difference from the linear solution, the static stiffness calculation of tower crane is greatly influenced by the geometric nonlinearity. With the increase of free height of tower body, the influence of geometric nonlinearity for the static displacement of tower crane gradually increased. At maximum independent height, the calculated deviation between linear solution and nonlinear solution was close to 20%. At this time, it was difficult to ignore the impact of geometric nonlinearity on the static displacement of tower crane, therefore, it can be concluded that the calculation considering structure geometrical nonlinearity will more accurate when analyze tower crane’s static stiffness in actual engineering.The natural frequency at maximum independent height were calculated by ANSYS, the structure’s front eight modes and fundamental period were also calculated. El-Centro are used to analyze the dynamic response of tower crane under seventh intensity seismic load. Results showed that the maximum vertical displacement appears in the end node of the jib, the maximum stress of structure occurs in initial time of seismic response, the maximum stress of tower body has great fluctuation in the whole seismic response. Compared linear results with nonlinear results, conclusion that nonlinear factor has a great influence on structural dynamic response of tower crane. The nonlinear seismic response were calculated when the jib and seismic loads in different angles, the result shows the angles have certain influence on structural dynamic response of tower crane,it is beneficial to the safety of tower crane when the jib parallel to the horizontal seismic load. The analysis shows the seismic fortification intensity have a big impact on vertical displacement and stress, with the increase of the seismic fortification intensity, both maximum stress of tower body and maximum stress of structure showed a tendency to grow exponentially.Finally, the structural buckling of tower body was analyzed, comparing the results between eigenvalue solutions and nonlinear solutions, it can be concluded that the result of eigenvalue method was 10.46 times of the total wheel pressure produced by the rated lifting load, it was a unconservative solution. The nonlinear solution was 2.16 times of the total wheel pressure, the result was more consistent with the reality. The buckling analysis under different height and jib in different angles shows that the height has a great influence on the ultimate bearing capacity of tower body, with the increase of free height, the ultimate bearing capacity of tower body was gradually reduced, but the vertical displacement at the top of tower body was increased gradually, the position of the jib also has a certain influence on the ultimate bearing capacity of tower body. |
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