應用聲音訊號進行纜索張力值估算

Abstract

本文探討使用麥克風測量振動纜索之聲壓訊號並求取張力值的可行性。在張力計算方面，分別使用弦理論帶入兩端固定邊界條件以及梁理論帶入簡支梁邊界條件來推導出纜索自然頻率值與張力值之間的關係式，由聲壓訊號識別出自然頻率值後進行反算，實驗設置方面，將固定於結構物之受張力鐵線模擬為實際纜索進行聲壓訊號測量，並驗證在不同結構參數下此方法求得之張力值皆可靠，再進一步對鐵線做加速腐蝕處理以探討纜索受到腐蝕損害時可能反映之跡象。

This thesis explores the feasibility of using a microphone to measure the sound pressure signal of a vibrating cable and to obtain the tension value. In terms of tension calculation, the relationship between the natural frequency value and tension value of the cable is derived using string theory with fixed boundary conditions at both ends and beam theory with simple-supported beam boundary conditions. After identifying the natural frequency value from the sound pressure signal, the tension value is calculated. In terms of experimental setup, the tension iron wire fixed to the structure is simulated as an actual cable to measure the sound pressure signal, and the reliability of the tension values obtained under different structural parameters is verified. Further, the iron wire is subjected to accelerated corrosion treatment to explore the possible indications of cable damage due to corrosion.