新型波形钢腹板组合箱梁等效阻尼比计算方法

为确定新型波形钢腹板组合箱梁等效阻尼比的合理取值,基于阻尼等效前后复频率相等原则,利用复频率和组合结构材料阻尼比之间的关系,提出新型波形钢腹板组合箱梁各阶模态等效阻尼比计算方法。采用有限元软件建立3个新型波形钢腹板组合箱梁的动力分析模型,利用该方法计算得到该新型组合结构等效阻尼比并与实测结果进行对比。结果表明:采用该方法求得的新型波形钢腹板组合箱梁等效阻尼比与试验测试结果吻合较好,进一步可说明该方法物理意义清晰明确,能够较准确地反映新型波形钢腹板组合箱梁的阻尼耗能特性。建议在对新型波形钢腹板组合箱梁进行动力特性分析时,等效阻尼比取为0.03。

Calculation of Equivalent Damping Ratio of New-Type Composite Box Girder with Corrugated Steel Webs

To determine the rational equivalent damping ratios of a new-type composite box girder with corrugated steel webs(CSWs),a method to calculate equivalent damping ratios of different vibration modes is proposed,which is based on the principle of equal damping before and after the complex frequency and takes into account the relationship between complex frequency and material damping ratios of composite structure.Finite element models of three new-type composite box girders with CSWs were established to calculate the equivalent damping ratios of the composite structures,and the calculated values were compared with the measured ones.The results show that the equivalent damping ratios gained by the proposed method agree well with the test results,further proving that the physical meaning of the method is clear,and the method can reflect the energy dissipation property of the new-type composite box girder with CSWs with relatively higher accuracy.An equivalent damping ratio of 0.03 is suggested for the dynamic property analysis of the box girder of such type.