Analysis Of Mechanical Characteristics And Study Of Fatigue Life For Rotary Drilling Rig

As a pile foundation engineering machinery, rotary drilling rig is widely used in all kinds of traffic engineering and civil construction areas by its more highly drilling efficiency, better hole quality, higher automatization, and convenient move. As for its numerous advantages, it has taken possession of a leading position of pile foundation engineering at home and overseas. Because of its complicated and changeable work objects, large load change scale and atrocious work environment, the cracking phenomenon easily occurs when it is in service, which brings large economy losses to the enterprises. What’ worse, if the fault couldn’t be solved in time, the enterprise reputation will be depressed seriously. Therefore, at the beginning of product design, it’s indispensible to analyze a product’s mechanical characteristics and research on its fatigue life. In this way, it can provide reference for structural optimization design and improve a product’s reliability on a large extent. The result of this paper has great practical significance.This paper primarily performs mechanical characteristics analysis and fatigue life research on a certain kind of rotary drilling rig. The main works are as follows:(1) Combing with work principles of rotary drilling rig, this paper confirms several typical operating conditions in which its structure static analysis is processed at extreme state to provide load basis for dynamics and finite element(FE) analysis.(2) Based on the theory of Lagrange, this paper makes use of ADAMS to obtain every component’s dynamics characteristics when the rotary drilling rig is in Mast Uprising condition, Lifting condition and Abnormal Mast Fall condition. At the same time confirming the most unfavorable posture under stress in the corresponding working conditions to provide the basis for subsequent finite element statics analysis.(3) Through the FE analysis at extreme state of Drilling-Bucket-Lifting condition, Drilling condition, horizontal upright condition and abnormal mast fall condition based on the Hyper Mesh and ABAQUS software, the stress distribution of weak structure position can be detected in relevant conditions. Simultaneously, mode analysis of upright drilling gesture is processed. So, we can see the rotary drilling rig’s inherent frequency and vibration type in order to avoid vibrating with excitation source. This chapter result can be reference as structure design and further optimization of rotary drilling rig.(4) Performing stress test experiment when the rotary drilling rig is at extreme state in relevant conditions. The result indicates the finite element mode is correct and the virtual analysis is accurate and reliable.(5) Based on linear fatigue cumulation damage theory, this paper uses nominal stress method to research on the fatigue life of main winch base weld metal and the intersectant weld metal of mast, orbit and inner clapboard. The analysis result can provide reference for practical engineering application.