- 學位論文
電磁場控制金屬纖維於環氧樹脂基材之配向與分佈研究
Investigation on Orientation and Distribution of Metal Fiber in Epoxy Substrate Controlled by Electromagnetic
摘要
科技發展日新月異，其中複合材料的應用範圍也越來越廣泛，在產品研發中控制複合材料之纖維配向與分佈是關鍵議題之一。本研究使用電磁場控制流體中纖維配向與分佈並探討對於纖維配向與穿透導電度之影響。研究中分為三個部分，首先評估電磁鐵設計找出最佳磁場分佈探討該區域對纖維配向的影響。其中對基材黏度、磁通密度及纖維長度探討對纖維轉向之影響並驗證纖維配向與穿透導電率的關係。最後經由可視化系統觀察實際纖維在流動中受磁場控制之轉向情形與流動形為。 電磁鐵設計實驗結果中，實驗與分析都顯示在電磁鐵中心區域其磁通密度較其他區域高。當電流增加，磁通密度則越高。在工作氣隙方面，當工作氣隙越小時，磁通密度越高，工作氣隙為3mm時其最高磁通密度為1132G。在線圈匝數方面，隨著匝數的增加其磁通密度也越高。 實驗結果發現，無磁控之纖維分佈角度主要集中於0o~30o和151 o ~180 o區間，有磁場控制之纖維角度集中於61 o ~120 o區間，纖維朝磁場方向排列，其中靜流磁控之纖維配向程度較動流磁控還高，靜流磁控相較於無磁控其穿透導電率增加12.2倍，而動流磁控增加了9.6倍。當黏度越小纖維受到的環境阻力越小，纖維較容易朝磁場方向排列。磁通密度越高，電磁場作用於纖維之磁扭力矩越大，使得纖維越容易朝磁場方向排列。纖維長度越長，纖維與纖維之間容易相互干擾，當纖長1 mm時纖維配向性最佳。 可視化系統實驗中觀察到未通磁前，纖維呈無定向之排列，而磁場開啟後，纖維會立刻朝磁場方向排列。另外，比較混摻鐵粉與不銹鋼纖維其流動行為時發現在充填過程中由於鐵粉導磁係數較高，使得鐵粉容易被磁場吸引及移動，進而改變流動波前的形貌。經由上述之結果，即可驗證感應電磁場對纖維配向影響之可行性。
並列摘要
Following by the advance of technology, application of high polymer composite components is more and more wide. In product development, controlling orientation and distribution of fiber composite materials is one of the key. This study using induction electromagnetic controlling fiber orientation and distribution in flow field to investigate effect of distribution of fiber orientation angle and penetrating conductivity. It has three parts. Initially, estimating the electromagnet design and finding the best magnetic field distribution investigate the impact of the fiber orientation on the best magnetic field distribution region. Then, it focuses on substrate viscosity, magnetic flux density and fiber length to study the effect of fiber steered, and verify the relationship between the fiber orientation and penetrating conductivity. Finally, using visual system observes fiber which is steered by the magnetic field controlling in the flow and flow behavior. In the result of the induction electromagnet design, both experience and analysis show that the region in the center of the electromagnet has higher flux density than other regions. The higher current, the higher magnetic flux density. In the working air gap, when it was smaller, the magnetic flux density was higher. 3mm working air gap has highest magnetic flux density which is 1132G. In the number of coil turns, when it increased, the magnetic flux density was higher. In the results, non-magnetic controlling the number of fiber angle is mainly in 0o~30o and 151o~180o. It means fiber arranges along the flow pattern. Magnetic controlling the number of fiber angle is mainly in 61o~120o and it means that fiber arranges along the magnetic direction. The fiber orientation level of static magnetic controlling is higher than dynamic magnetic controlling one. The penetrating conductivity of static magnetic controlling increases 12.2 times than non-magnetic controlling one. The penetrating conductivity of dynamic magnetic controlling increases 9.6 times. Lower viscosity has less environment resistance. It causes that fiber is arranged along magnetic direction easily by magnetic field. If magnetic flux density is higher, the magnetic torque in introduction magnetic is higher, too. Afterwards, fiber is more easily arranged along magnetic direction by magnetic field. Longer fiber interfere with each other easily. 1mm fiber has the best fiber orientation. Investigating fiber without magnetic field by visual system, fiber shows non-direction arrangement. After opening magnetic field, fiber arranges along magnetic direction immediately. On other hand, comparing flowing pattern of iron powder with epoxy and stainless steel fiber with epoxy, iron powder one is more easily attracted and moved after magnetized by magnetic field and changes front flow pattern because iron powder has higher permeability in flow state. Above of all, these can verify that the feasibility of induction electromagnetic impacts fiber orientation.