Research On Thrust Inversion System Of Mast Structure

Due to the large slenderness ratio of the mast structure,it is too sensitive to wind loads and is prone to instability and damage.If the thrust acting on the mast structure can be accurately known,the occurrence of damage accidents can be effectively reduced.Dalian Shipbuilding Industry Corporation is developing a sail system with independent intellectual property rights for VLCC.Relying on the sub-projects of this project,the thrust inversion system is researched based on the mast structure to realize the real-time inversion of the thrust applied to the mast structure.Based on the hypothesis of linear elastic small deformation,this paper proposes a high-precision thrust inversion algorithm based on the monitoring point data of the mast.This paper mainly studies the thrust inversion system of the mast structure from both numerical simulation and experiment.The main research contents and conclusions are as follows:（1）The ABAQUS finite element analysis software is used for calibration simulation,and the simulation relationship matrix B_simu between the unit load of the model and the strain response of the measuring point is obtained.Design the scale ratio model experiment,the data of the measuring points of the resistance strain gage and the FBG strain sensor are close to the simulation data under each working condition.Use B_simu to perform thrust inversion according to the algorithm The results of the two types of sensors are:The maximum error percentage of F_x is 20%,Because the experimental value itself is small,and the maximum absolute error is only 2k N.Considering the influence of the minimum resolution of the monitoring instrument,the inversion accuracy of the F_x component is good;the maximum error percentage of F_y is 5%,and the maximum difference of angle θ is only 3°.Comprehensive analysis of the errors of the three indicators,the inversion algorithm has certain validity and accuracy.（2）The inertial force of the mast structure caused the corresponding dynamic response of the monitoring point due to the rolling of the hull.A method based on the integration of Newton’s second law of physics F=m×a was proposed to derive the inertial force of the model.Design the impact hammer experiment,perform Hilbert-Huang transform processing on the monitored acceleration data,extract the main characteristic signals for analysis,and find that the acceleration extrapolation based on finite measuring points,the conic extrapolation model has the smallest error,only -3%,using the quadratic curve extrapolation model and the Hilbert-Huang transformation processing method can successfully derive the overall acceleration curve equation of the mast model.（3）It is difficult to capture the dynamic response of the strain measuring point under the excitation of the impact hammer.The ABAQUS numerical simulation is used instead,and the static load and dynamic excitation are applied to the model at the same time.After the dynamic excitation is completed,take the data of the stable and damped oscillation stage of the model after the end of the dynamic excitation for analysis,Reduced the dynamic load value by 83.6%,which improves the accuracy of the thrust inversion system of the mast structure.