外伸悬挑组合式锅炉大板梁的静力试验及有限元模拟分析

为揭示外伸悬挑组合式锅炉大板梁的受力机理和破坏模式,并验证某工程大板梁的设计可靠性,通过对外伸悬挑组合式大板梁缩尺模型的静力试验和考虑各种非线性的ABAQUS有限元数值模拟分析,研究了大板梁简支段和悬挑段在各加载阶段的承载力、局部应力、整体变形和局部屈曲等关键响应,对试验中的破坏现象给出了合理解释,并重点研究了悬挑段与简支段拼接端板与拼接螺栓的受力和变形特点。试验与模拟结果均表明大板梁在设计荷载作用下处于线弹性阶段,并具有足够的安全储备;支座附近腹板局部屈曲和悬挑段端板拼接螺栓断裂是大板梁的主要破坏模式,决定了梁的整体承载力;按拼接螺栓群的受力模式,悬挑梁端的弯矩和剪力分别由翼缘附近螺栓的抗拉连接和腹板附近螺栓的摩擦连接来承担。各阶段试验现象和数值模拟结果吻合较好,也验证了数值模拟方法的可靠性。

STATIC TEST AND FINITE ELEMENT ANALYSIS ON SPLICED PLATE-GIRDER WITH CANTILEVER SEGMENT

To explore the mechanical behaviors and failure modes of a spliced plate-girder with cantilevered segments in a boiler steel structure, and to verify the design reliability of this type of girder in practical engineering, the static test for a reduced scale model and nonlinear finite element analysis by Abaqus Program are carried out. The loading capacity, local stress, flexural deformation, local buckling and other key performances at every loading stage, for both the simply supported segment and cantilevered segment, are analyzed with a reasonable explanation. The behaviors under bending moment and shear force are also studied for the bolted end plate splice, connecting the simply supported segment and cantilevered segment. Test and simulation results can both prove that the plate-girder is in a linear elastic stage under design loads, and has enough safety redundancy in subsequent loadings. The loading capacity of the spliced plate-girder depends on two major types of failure modes, i.e. the local buckling on webs near supports and fracture of splice bolts on the support plate. According to the internal force distribution in the splice, it can be assumed that the bending moment and shear force in the cantilevered segment are transferred separately to the bolts near the upper flange and the two webs. The accuracy and practicability of the simulation method are also verified by its well agreement with test results.