复合材料叠层板之表面与基材裂缝检测.docVIP

複合材料疊層板之表面與基材裂縫檢測 The Detection of Surface Crack and Matrix Cracking in Composite Laminates 研究生：李政信 Lee, Chen-Hsin 指導教授：胡惠文 Hu, Hui-Wen 【摘要】 本文應用模態分析配合應變能法 SEM 針對複合材料疊層板之表面與基材裂縫進行非破壞檢測。複合材料採用碳纖維/聚二醚酮 AS4/PEEK 製造成、、與等疊層板。表面裂縫與基材裂縫分別以雷射切割與拉伸試驗產生。首先，應用有限元素分析軟體 ANSYS 建立疊層板破壞前後之有限元模型，進行模態分析以獲得破壞前後疊層板之自然頻率與模態振型。實驗模態分析則以衝擊鎚為驅動器、加速度計為感測器，針對疊層板破壞前後進行模態實驗，求取結構模態參數。經由比對分析與實驗之模態參數，確認有限元模型之等效性。最後，將破壞前後之模態振型以應變能法定義一破壞指標用來預測破壞的位置。其中，應變能之計算採用微分值積法 DQM 。結果顯示，分析與實驗之破壞指標均可成功地預測出複合材料疊層板之表面與基材裂縫位置。 關鍵字：模態分析、應變能法、複合材料疊層板、微分值積法 DQM 、表面裂縫、基材裂縫 【Abstract】 The work presents an approach to detect surface crack and matrix cracking in composite laminates by using modal analysis and strain energy method SEM . Carbon/epoxy composite AS4/PEEK was used to fabricate laminated plates, 、 、 and . Two types of damages, surface crack and matrix cracking, were investigated in this study. Surface crack damage was created on one side of the plate using a laser cutting machine. Matrix cracking in 90-degree lamina was created by subjecting to tensile test. A CAE software, ANSYS, was used to create finite element model for laminated plates. Normal mode analysis was performed to obtain the natural frequencies and the associated mode shapes. Experimental modal analysis EMA was also carried out using impact hammer and accelerometer to obtain modal parameters. Both FEA and EMA results were compared in order to validate FE model. The measured mode shapes were then used to compute the strain energy using differential quadrature method DQM . A damage index was defined using the change of strain energy of the laminated plates before and after damage. Consequently, the damage index successfully located the surface crack and matrix cracking in the laminated plates. A pre-study was performed to access this approach by using a 3-D finite element analysis FEA . Keywords：Modal Analysis, Strain Energy Method SEM , Composite Laminates, Differential Quadrature Method DQM , Surface Crack, Matrix Cracking