对于端部约束条件确定的简支梁、固定梁、悬臂梁,其稳定性分析已有不少文献作了比较全面的论述。然而,在工业与民用建筑、桥梁、水利等工程中,常遇到另一种由邻跨延伸出来的伸臂梁,论述其稳定性的文献则尚少见,由于它的根部无论是侧向还是横向屈曲都属弹性约束,而且影响其整体稳定性的因素较多,如相邻跨的长度、相邻跨是简支还是连续等。对于这种不确定条件复杂约束的梁,想推导出统一的精确临界荷载解析解确实是十分困难的。本文是运用势能驻值原理,通过求得双伸臂梁的临界荷载的 For the stability analysis of simply supported beam, fixed beam and cantilever beam determined by the end constraint conditions, many literatures have been discussed comprehensively. However, in industrial and civil buildings, bridges, water conservancy and other projects, there is often encountered another kind of extension beam extending from the adjacent span. The literature on its stability is still rare, because its roots are lateral or Lateral buckling is an elastic constraint, and there are many factors affecting its overall stability, such as the length of adjacent spans, whether the adjacent span is simply supported or continuous. It is very difficult to derive a unified analytical solution for accurate critical loads for a beam with this kind of uncertain condition and complex constraints. This paper uses the principle of potential energy resident to obtain the critical load of the double-arm beam.