【摘要】 针对基于环境激励的斜拉索实测信号由于环境干扰而呈现出非平稳性和非平滑性的问题,提出了利用五点三次平滑法对快速傅里叶变换(FFT)得到的频域数据进行平滑处理,即考虑多因素影响来提高斜拉索索力识别精度。以实际斜拉桥工程中的拉索实测信号为研究对象,应用五点三次平滑法对拉索信号进行平滑消噪处理,考虑采样时间和采样点数对拉索频率识别精度的影响,利用求极值方法确定拉索各阶频率值及其位置,比较了基频法、频差法和峰值法确定拉索索力的计算精度,进行了索力测试的误差分析。结果表明:五点三次平滑法结合极值处理可以很好地识别拉索各阶频率,各因素对拉索频率的识别精度影响也有所不同,为频率法更加准确识别斜拉索索力提供了方便;同时也为开发高精度的索力测试仪器提供了有效依据。更多还原

【Abstract】 Based on the measured signal of stay cable under ambient excitation,the method with five points and three times was put forward to smoothly process the frequency-domain data obtained from fast Fourier transform(FFT) because of the non-stability and non-smoothness resulting from ambient interference.This method was used to enhance the identification precision for stay cable tension by considering some influencing factors.Using the measured signal of stay cable in practical engineering,the method with five points and three times was used to process smooth denoise.By considering the effect of sampling time and sampling numbers on the identification precision for stay cable tension,the method to calculate extreme method was used to determine the frequency and its location of stay cable at various ranks.The precisions of basic frequency method,frequency difference method and peak value method were compared.The error analysis for cable tension measurement was also carried out.The results show that combining with extreme process,the method with five points and three times can well identify the frequency of stay cable at various ranks;different factors have different influences on the identification precision for stay cable frequency.It is possible to identify the stay cable tension more accurately by basic frequency method,and it also provides the efficient proof for the development of cable tension measurement instrument with high precision.更多还原