含中心孔添加奈米二氧化矽編織複合材料平板之破壞強度探討

A Study of the Strength of Nanosilica/Braided Composite Plates with a Central Hole

蔡昆恊(K. H. Tsai) ； 黃宗立(C. L. Hwang) ； 陳彥誠(Y. C. Chen)

《華岡紡織期刊》 23卷2期 (2016/03) Pp. 94-100

摘要

本研究探討添加不同重量百分比奈米二氧化矽對編織複合材料平板開孔強度的影響，並利用有限元素軟體ANSYS與點應力準則預測不同開孔半徑下編織複合材料平板之破壞強度。首先將碳纖維編織帶含浸改質後的環氧樹脂，以熱壓法製成編織複合材料平板，並計算纖維體積含有率，帶入Visual Basic程式計算編織複合材料之整體工程模數，將所得等效工程模數帶入有限元素軟體ANSYS中進行拉伸分析，得開孔平板的應力分布圖，配合點應力準則求出特徵長度，由特徵長度和孔洞半徑與材料板寬度比值(2R/W)呈現乘冪關係計算不同孔徑破壞強度之預測值，並與實驗值比較。結果顯示，與未添加奈米二氧化矽的試片相比，改質過後的試片其軸向楊氏模數與破壞強度皆有所提升，其中以3 wt%的提升效果最為顯著。未添加奈米二氧化矽試片的特徵長度會隨著孔洞半徑的增大而有減小的趨勢；添加3 wt%奈米二氧化矽試片的特徵長度則會隨著孔洞半徑的增大而有增加的趨勢。ANSYS分析結果顯示，本研究方法可以準確預測含中心孔編織複合材料平板之破壞強度，其誤差在3%以內。破壞強度皆隨著開孔半徑的增加而有下降的趨勢。

關鍵字

奈米二氧化矽 ； 編織複合材料 ； 點應力準則 ； 有限元素 ； 開孔強度

並列摘要

In this study, we observed the effects on different percentage nano-SiO_2 to braided composite plates, and then used ANSYS and Point Stress Criterion to calculate and predict differ hole radius the notched strength of braided. First carbon fiber braid was impregnated with the improved epoxy resin to make braided composite plates by Hot-press method. Calculate the fiber volume fractions of composites. Then Visual Basic was used to calculate module of the braided composite plates. The calculations were then input into ANSYS to analyze the stress distribution around each hole. Then, a Point Stress Criterion was used to calculate the characteristic length for each hole size. Through the characteristic length expressed with the ratio of the hole radius and the specimen width (2R/W) by a power-law was used to predict the strength of the plates for each hole size. The result showed that, compare with the sample of matrix without nano-SiO_2, the modified sample's Axial Young's modulus and the notched strength increase. The sample with 3 wt% upgrade the most. Besides, the sample of matrix without nano-SiO_2, its characteristic length decreases when the hole sizes increases. The sample with 3 wt%, its characteristic length the characteristic length increases when the hole sizes increases. ANSYS analyze results showed that our method accurately predicted the notched strength of braided composite with a Central Hole with a maximum error of only 3%. The notched strength decreased with increasing major hole diameter.

並列關鍵字

Nano-SiO_2 ； Braided Composite ； Point Stress Criterion ； Calculate Module ； Notched Strength