非对称内外刚性法兰连接力学性能分析与优化设计

MECHANICAL ANALYSIS AND OPTIMAL DESIGN OF ASYMMETRIC INNER-AND-OUTER RIGID FLANGE CONNECTIONS

  • 摘要: 内外螺栓数相同的对称内外刚性法兰连接结构常被用于输电铁塔的设计与建设中。然而,由于内外法兰螺栓圆半径与周长的差异,这种对称结构在实际工程中容易产生加工与安装上的问题。为了方便加工以及现场安装,本文设计了一种内外螺栓数不同的非对称内外刚性法兰连接结构。通过商用有限元软件ABAQUS模拟分析了这种非对称刚性法兰连接结构在轴拉,弯曲以及复合加载下的受力情况,研究了螺栓分布配置与几何参数对法兰连接结构的影响。发现在非对称内外法兰中,可以使用内外螺栓的轴向拉力作为指标评估连接结构性能。结果表明:受拉时,内外螺栓受力比与内外螺栓距主管壁的距离比成线性关系,当距离比为0.925时,内外螺栓拉力相同;受弯矩时,内外圈上最大螺栓力之比与距离之比成线性关系,距离比为0.832时,内外圈的最大受力相同;受复合载荷时,螺栓力为一正弦分布和轴拉下螺栓力的叠加。此外,本文还研究了内外法兰盘交错角和螺栓预紧力对螺栓受力的影响,发现前者对螺栓受力的影响较小,在设计时可以忽略;而后者的影响随着外荷载的增加逐渐减小。因此,本文的研究可以为非对称内外法兰结构的优化设计提供理论指导。

     

    Abstract: The symmetric inner and outer rigid flange connection structure, with an equal number of bolts, is commonly employed in the design and construction of transmission towers. However, due to discrepancies in the circular radius and circumference of the inner and outer flange bolts, this symmetrical configuration often gives rise to processing and installation challenges in practical engineering applications. To address ease of manufacturing and on-site installation, this study introduces a design concept for an asymmetric inner and outer rigid flange connection structure with varying bolt quantities. Utilizing the commercial finite element software ABAQUS, the stress analysis of this asymmetric rigid flange connection structure is simulated under axial tension, bending, and combined loading conditions. The investigation explores the impact of bolt distribution and geometric parameters on the flange connection structure. In the context of this study's design, the axial tension of the inner and outer bolts serves as an indicator for evaluating the structural performance. The findings reveal that under tension loading, the ratio of forces on the inner and outer bolts correlates linearly with the distance ratio from the main pipe wall, achieving equal tension on both when the distance ratio is 0.925. Similarly, under bending moments, the ratio of maximum bolt forces on the inner and outer rings exhibits a linear relationship with the distance ratio, resulting in equal maximum forces on both rings at a distance ratio of 0.832. Under combined loading conditions, the bolt forces represent a superposition of those experienced under pure bending and pure tension. Furthermore, this study examines the influence of the stagger angle of inner and outer flanges and bolt pre-tension on bolt forces. The research indicates that while the former has a minor impact on bolt forces and can be disregarded in design considerations, the influence of the latter diminishes gradually with increasing external loads. Consequently, this study offers theoretical guidance for optimizing the design of asymmetric inner and outer flange structures.

     

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