Topology Optimization Of Derricks Basied On Finite Element Analysis

Derrick is an important part of the oil rig to place crown block,travel block and other lifting equipment to withstand the load of various operations.The carrying capacity of the derrick to some extent determines the ability of the drilling rig.The current design of multi-derrick to static strength as the main design criteria,in accordance with the conditions of use without damage as a design standard,through blindly adding materials to ensure the safety and reliability of the structure,cause material waste.Therefore,it is significant to find a suitable structural optimization method to reduce the amount of steel used in the derrick under the condition of ensuring the safety of the derrick.This article will consider the particularity of derrick optimization,such as the discrete variable and multi constraints,to improve traditional genetic algorithm.And the improved genetic algorithm is combined with static and dynamic analysis program of derrick,established the derrick static and dynamic discrete topology optimization program.The main research work of this paper is as follows:(1)According to the finite element theory,the element stiffness matrix of space beam element is derived by using the principle of minimum potential energy,and the direct stiffness method is assembled into the whole stiffness matrix,and the general finite element analysis program is compiled by MATLAB;The static load condition is analyzed,and the finite element analysis program is used to carry out the finite element analysis of various working conditions.Through the static analysis,the most dangerous conditions and the maximum force units of the derrick are obtained,which lays the foundation for the topology optimization of the derrick based on the static constraint.(2)Research on dynamic characteristics of derrick.By analyzing the natural vibration characteristics of the derrick,the natural frequencies and vibration modes are obtained,and coMPared with rotary resonance analysis to find the resonance frequency range;Derrick transient response analysis.Choosing appropriate parameters,the dynamic numerical integral method-Newmark method is used to respectively to solve the transient response of derrick under iMPact load,iMPact load and static wind load combination,and the corresponding program is compiled with MATLAB.Through the analysis,the maximum stress response and maximum displacement response of the derrick are obtained,which lays a foundation for the topology optimization of the derrick based on dynamic constraint.(3)According to Davenport spectrum theory,considering the influence of fluctuating wind speed on the derrick,the harmonic synthesis method is used to simulate the wind load,and the wind vibration response of the derrick is analyzed.the dynamic numerical integral method-Newmark method is used to respectively to solve the dynamic response of derrick under no hook load,full setback and the effect of wind vibration load combination,and the corresponding program is compiled with MATLAB.The analysis results show that the vibration of the derrick is more severe than that without considering the fluctuating wind,which provides a reference for the topology optimization of the derrick structure.(4)According to the characteristics of the structure of the derrick,and considering the convenience of processing and equipment,Size and topology synchronization optimization algorithm is proposed based on the genetic algorithm.For coupling relation between derrick size optimization and topology optimization,the genetic code of the combination of integer and logical values is proposed,and the global nature of genetic algorithm optimization is improved by adaptive crossover probability and mutation probability.The derrick dangerous conditions of static and dynamic finite element analysis program combined with genetic algorithm,using MATLAB software to compile derrick static and dynamic size and topology synchronous optimization program,and the optimization results are analyzed and optimized.Optimization results show that: the developed topology optimization program can achieve the goal of optimization;optimization results under dynamic constraints are more secure than the optimization results under static constraints;considering the influence of fluctuating wind on the derrick,closer to the actual structural design.