纖維繞線複材圓管的導波波傳

Abstract

複合材料壓力容器的品質確認及使用期間的定期安全檢查，極需可靠、有效的非破壞檢測方式。本研究應用漢彌頓理論及有限元素法分析纖維繞線複材圓管導波波傳的相速度，並以雷射超章波技術量測導波暫態訊號與反算圓管的材料性質。實驗以Nd:YAG脈衝雷射產生點波源，使用錐形控頭測得複材圓管的暫態波傳訊號，由波傳訊號使用相位頻譜的差分計算導波波傳的相速度。複材圓管的各積層假設為橫向等向性材料，考慮纖維纏繞角度為±a，因此圓管的有效材料係數可視為五個獨立變數之系統。由管壁之壓力波與剪力波量測，可先求得圓管三個材料係數。再利用相速度、波傳頻率與材料係數間關係，建立一目標函數，以簡單體法反算其餘兩個材料係數。

Filament wound composite pressure vessels are being increasingly used in industry. This has resulted in a critical neeed for reliable and effective nondestructive testing methods for quality assurance and safety assessment. This study presents an analysis of guided wave propagation in laminated composite tubes by using finite element method based on Hamilton's principle. Each lamina of the composite tube is assumed to be transversely isotropic medium with five independent material stiffness components. The phase velocities were determined by numerical computation and compared with measurements. The transient guided waves were excited by a Q-switched Nd;YAG laser and were detected by a broadband conical transducer mounted on the surface of a composite tube. After transformation from local coordinates of eaxh lamina to the global coordinates of the tube, the number of independent material constants is still the same for the ones manufactured with symmetric filament winding at ±a angles .Three of the material constants are directly measured by pulse-echoes of pressure wave and shear wave and shear waves propagating along the thickness of the tube. The remaining two stiffness components are determined by inversion of simplex based on phase velocities of the guided waves.