Dynamic CharacteristicAnalysis And Model Test Research Of Oil Derrick Based On The Similarity Theory

The oil rig derrick is one of the most important components of the eight lifting systemsin oil drilling, whose safety performance related to the normal operation of the entire rigsystem. The functions of oil rig derrick mainly include installing crown block, mounting crane,completing manipulations such as making a trip, and assisting another drilling equipments toinsure drilling working normally and smoothly. People can install Owing to it is made ofmany beams, and stands complex force, the finite element analysis is an important step inmast design.Currently, the oil derrick in use always appears the problems of steel bearingcapacity which caused by damage defect. These problems have been paid closed attention byconstruction site. Therefore, in order to consider installing and maintenance is in the rightplace or not, the condition of construction, whether the operation is standard and so on, weshould also need to take the dynamic characteristics of derrick steel structures, reliability andsafety problems into account.The oil derrick has a large steel structure, when it is carried on a simulation research andcalculation with finite element software, the calculation efficiency is always limited owing tomasses of structure node and unit. The following passage defines the similar proportion ofderrick overall structure considering the similar condition of oil derrick such as quality, size,load, critical, based on the approved structure experimental mechanics and similar theory. wemake a finite element similar model of oil rig derrick,set the parameter and restriction andmake static calculations in different situations with finite element analysis software (ANSYS).Taking account of the effect of vibration load, we conduct a modal analysis toward thestructure of derrick similar model to achieve its basic vibration mode and find the vibrationrule of the derrick structure. We can also get the derrick’s instability by conducting bucklinganalysis of the derrick model structure with load limit.By the survey of dynamic characteristics and test of derrick model, we obtain thecharacteristics and rules of the derrick structure in real. In this way, we can not only lower thecost of the survey and development, but also improve the accuracy of the result and enrich thesurvey method toward the similar theory of large steel structure. By the survey of modeltheory and testing, we infer the structure characteristics of derrick in real. The surveydevelops a new method toward design of oil derrick and system survey, which will be muchof value in the future.