Abstract:The hinged boom structures of crawler cranes are typical slender frame structures, whose stability is an important basis for lifting performance. The boom structures are divided into several substructures by taking each section as an element, and an embedded coordinate system is defined. Internal displacements of each substructure are reduced to the displacements of its boundary ends through the condensation of degrees of freedom. Based on the co-rotational method, the generalized

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... internal forces for substructure elements are formulated. Considering the mechanism constraints for the boom structures and the load lifting ways, the additional nodal external forces and their derivatives on the structure and mechanism displacements are obtained. The equations by differentiating the equilibrium equations of generalized nodal forces for the boom structures of crawler cranes with respect to the load factor are obtained. The critical load can be obtained through solving the differential equations and considering the instability criterion. A numerical example of hinged boom structures for a kind of crawler crane is given, which proves the presented method to be quick and high accuracy. Key words: crawler crane; hinged boom structure; critical load; geometric nonlinearity; co-rotational method; mechanism constraint 0 前言 * * 国家自然科学基金资助项目(11372057)。20140216 收到初稿,20140902 收到修改稿 米,履带式起重机使用的臂架结构通常都是细长的 框架结构。因此,起重机的起重性能不仅需要考虑 结构的强度,同时还需要考虑整个系统的稳定性。 传统的起重机臂架结构稳定性分析,主要采用 压杆屈曲分析方法,将臂架等效为细长杆件,拉板 力和吊重向臂架结构的轴向进行等效,采用经验公 式计算臂架结构的屈曲载荷。这种方法对于主臂工 况的起重机得到了广泛的应用,但是对于副臂工况 的起重机折线式臂架的稳定性分析就显得无能为力 了。同时,这类传统方法没有完全考虑臂架结构的 机 械 工 程 学 报 第 51 卷第 3 期期 112