探討添加球狀補強材之奈米複合材料的阻尼響應及其三明治結構的阻尼響應

Abstract

本研究探討添加二氧化矽奈米顆粒與橡膠顆粒(CTBN, CSR)於環氧樹脂基材中之奈米複合材料的阻尼特性，並觀察當奈米複合材料作為三明治結構中核心部份材料時，三明治結構的阻尼響應。以上材料的阻尼特性則是透過振動試驗與半能量頻寬法所決定。接著，本研究利用傳統的微觀力學模型來預測奈米複合材料的阻尼特性，並與實驗結果作比較。此外，透過有限元素法的分析，可瞭解奈米複合材料與三明治結構於振動試驗時其主導的能量消散機制。 由實驗結果可發現，雙重顆粒的材料系統(10 wt%二氧化矽奈米顆粒與10 wt% CTBN橡膠顆粒)有優於其他材料系統的阻尼特性，而在它的三明治結構複合材料上也可觀察到較佳的阻尼特性。另外，在本研究中發現添加二氧化矽顆粒的奈米複合材料有比純樹脂材料還好的阻尼效果，這與微觀力學模型所預測的結果是相佐地。所以，若要以微觀力學模型來描述奈米複合材料的阻尼特性時，分子鏈段的型態學、奈米顆粒與基材介面的作用力等情況也需要一併加入計算考量中。最後，雖然主導的能量消散機制在懸臂梁試片與三明治結構並不相同，但實驗結果皆顯示在添加雙重顆粒的奈米複合材料擁有優於其他材料系統的阻尼響應。

The research aims to investigate the damping responses of the epoxy based nanocomposites as well as the composites sandwich structures with the nanocomposite as core materials. Both the silica nanoparticles and the rubber particles (CSR, CTBN) are introduced in the epoxy matrix. The damping performances of the material systems were basically determined from the vibration test together with the half power method. The damping properties of the nanocomposites were predicted using conventional micromechanical model. In addition, the dominant energy dissipation mechanisms during the vibration tests were characterized through the FEM analysis. Results indicate the hybrid material system (10wt% silica nanoparticles and 10wt% CTBN rubber particles) can have better damping properties than other cases. Moreover, this superior damping property can also be present in its composite sandwich structures. It is noted that the silica nanocomposites can have better damping behavior than the pure resin. This observation is different from the model prediction and thus, the micromechanical model including the morphology of molecular chains and the interfacial interaction is required to describe the damping properties of the nanocomposites. In addition, Although the dominant modes in cantilever-type sample and sandwich structures is different, experimental results demonstrate that the hybrid nanocomposites still exhibit superior damping responses than other cases.