Research On Out-of-lifting-plane Stability Of Complex Lattice Combination Boom

In order to meet the requirements of the overall lifting in wind power, nuclearpower industry, the combination jib crane with large lifting capacity and liftingheight has developed rapidly However, the trend of towering and lattice makes thestability problem more highlitghted. This paper considers the jib with two-lift pointsand combination jib as the research object, adopts the differential equation methodto deduce the critical buckling equation, and proposes specific measures to improvethe integrated stability and the stability of single-limb. The main research contentand research results are as follows:The critical buckling equation of twin-lift crane jib is studied. Because theeccentricity between lifting point and boom section centroid gives rise to additionalmoment, the influence on the stability of the jib caused by eccentricity is also fullytaken into account. Meanwhile, a simplified mechanical model is presented to helpthe desingers to calculate the rod force in the case of boom with additional moment.Through establishing the force balance equations of three ropes, thecoordinates of the intersection are obtained, and the forces of the rope on the boomare expressed as a function of the deflection at the hanging point.By means ofdeformation compatibility conditions, the out-of-plane characteristic equation isobtained for the crane jib with auxiliary bracing.The angle coordinate conditions are presented at the intersection of the mainarm and jib, meanwhile by considering the tow rope and strut rod as two-force barand by means of simultaneous force system equations and deformationcompatibility conditions, the out-of-plane buckling equation of combination boomwith tow rope is deduced.The method by which the external load exposed to jib is decomposed to theplane truss is discussed, and some specific measures aimed to improve theintegrated stability and single-limb stability of crane jib are presented. Additionally,in case of triangle abdominal truss boom, the force formulas of main chord andbrace are deduced in both of in-plane and out-of-plane cases, which providetheoretical supports for determining the location of single-limb instability andincreasing resistance to buckling.