煤层气车载钻机桅杆设计及分析

Analysis and design on CBM mobile drilling rig's mast

针对煤层气车载钻机桅杆在提高起拔能力时,存在桅杆强度降低和超重的问题,提出了分负载桁架式、分负载实腹式和全负载实腹式3种煤层气车载钻机桅杆的设计方案,并采用有限元数值分析和稳定性理论计算的方法,对钻机桅杆的强度、刚度、稳定性和模态进行了分析。结果表明,在极限载荷条件下3种方案的强度和稳定性均满足设计要求,但分负载桁架式和分负载实腹式的强度较高,分负载实腹式和全负载实腹式的静力整体稳定性较好,全负载实腹式的振动稳定性较好。但分负载式桅杆结构具有较好的综合机械性能,尤其是分负载实腹式桅杆的结构强度最好。在满足强度要求的前提下,考虑降低桅杆所受重力以符合车载钻机上路要求,最终选择分负载桁架式结构为最优方案,其他2种方案同样可为煤层气车载钻机桅杆的设计提供参考。

Three different CBM mobile rig' s masts,truss mast with fractional load,solid-web mast with fractional load,solid-web mast with whole load,were designed to resolve the problem of strength decrease and over-weight,while increasing the pull capability of CBM mobile drilling rig's mast.Then the three mast structures were analyzed for strength,stiffness,stability and vibration mode.The results show that the strength and stability of the three schemes meet the design requirement under the ultimate loads,yet the truss mast with fractional load and solid-web mast with fractional load have higher strength,and solid-web mast with fractional load and solid-web mast with whole load have better whole static stability,and solid-web mast with whole load have better vibration stability.However,mast structure with fractional load has better comprehensive mechanical properties,especially solid-web mast with fractional load,which has the highest strength.Eventually,truss mast with fractional load is selected as the optimal structure as considering weight decrease of mast to meet the request for driving on the road.Moreover,the other two schemes are able to provide references for design of CBM mobile drilling rig's mast.