碳纤维斜拉索的动力参数特性分析

为探索碳纤维(CFRP carbon fiber reinforced polymer)索本身的动力学行为,寻求影响CFRP索自振频率的主要因素及影响量.采用悬链线索单元分析CFRP单索结构的自振频率与相应振型随单索的垂度及索结构参数的变化规律,在理论推导的基础上,通过具体算例将分析计算得到的结果与频率法测试索力的结果进行了对比。分析结果表明:CFRP斜拉索随着垂度的增大,一阶振型由单波正对称向反对称过渡;当斜拉索的垂跨比处在不同范围内时,CFRP索与钢索的自振频率差值也有所变化;因CFRP拉索垂度小,采用频率法计算索力产生的误差可以满足工程精度要求。因此,合理设置CFRP索身的垂度能有效地避免索身在外荷载作用下产生的一系列不利振动.

Analysis of dynamic properties for CFRP stayed cables

To search for some dynamic characteristics of CFRP(carbon fiber reinforced polymer) cables and some main factors with their corresponding proportions which may influence the natural frequency of vibration for CFRP cables,this paper uses catenary cable elements to analyze some changing laws of natural frequency of vibration and the corresponding vibration pattern for CFRP single-cable structure with the change of its sag and parameters.Based on the theoretical calculation,this paper employs idiographic cases to compare the results obtained by FEA method with those obtained by frequency testing method.The analytic results indicate that the first-order modal shape of CFRP stayed-cables changes from single-wave symmetry to dissymmetry with its increasing sag;when sag-to-spanratio of stayed-cables lies in different ranges,gaps of the natural frequency of vibration between CFRP cables and steel cables will change;the error of cable tension calculated by the frequency method is allowed in designing projects due to the small sag of CFRP cables.Therefore,the reasonable setting of the sag for CFRP cables will effectively avoid those bad librations happening on cables under outer loads,and making full use of these dynamic characteristics of CFRP cables will promote the development and application of its new structures.