Analysis Of Relationship Between Force And Vibration Frequency Of Short Boom

As the rapid development of national economy in recent years, more and morediversified and MeiGuanHua bridge design and construction, at the same time, thesafety problem has always been a top priority. In bridge construction and detection, thestress of the derrick and cable testing is important one job. Currently applied widely,effective and convenient method is frequency measurement, the method is through themeasured natural frequency of the derrick or lasso to estimate. Due to the naturalfrequency of the derrick and cable not only affected by the cable force, but also by thebending stiffness, boundary conditions, the cable sag, shock absorber, etc. The influenceof various factors, so the calculation formula need to be further validation.Based on the finite element analysis software ANSYS has carried on the boom ofparameterized modeling, mainly finished the following work:①The interaction force between the wire was calculated by ANSYS finite elementsimulation analysis of the bridge cable force between the two wires in contact stress，using plane element mesh model accuracy analysis.②By analysis of existing the short boom string vibration equations obtainedmultiple sets of cable force versus frequency equation, found the boom bendingstiffness and the boundary conditions has a great effect on the relationship between theshort boom force and the natural frequencies. through defining the boom bendingstiffness and the boundary conditions to solve the relationship between the short boomforce and frequency，so that the string vibration method can successfully be applied toshort boom.③To better understand the static and dynamic properties of the boom, the boom canbe seen as the contact relationship between the steel structure. Considering theinteraction between the inner wire boom, we can obtain correction calculationmodel ofshort boom through static analysis to calculate the nominal flexural stiffness andboundary conditions.④This paper use ANSYS to establish boom model, simulating the mutual contactstress among the boom of the inner wire bundles. At the same time, it also studysformula error analysis of natural frequencies and cable force relationship of boom,analysising the formulas practicality of short booms’ frequency method.