海水老化與外力頻率於玻璃纖維複合材料疲勞特性之探討

Frequency and water immersion aging effect in fatigue performance of fiber reinforced composites

劉百育(Pai-Yu Liu)

指導教授 ： 黃心豪

國立臺灣大學/工學院/工程科學及海洋工程學研究所/碩士(2018年)

https://doi.org/10.6342/NTU201800227

摘要

隨著海洋能源開發技術的發展，擁有黑潮資源的台灣也已開始著手於相關技術研發，然而，台灣海洋能源開發技術剛起步而尚未成熟，尤其目前仍未有深水環境下，漂浮式渦輪發電機組運作的實例，許多流場、結構相關之議題仍尚待釐清，因此，建立適當的模擬與實驗，預先掌握黑潮渦輪發電機組的狀況及疲勞年限，實有其必要性。
本文以實驗的方式，探討台灣大學團隊所設計的黑潮渦輪發電機組複合材料葉片的疲勞性質。首先，利用SCRIMP製程製作黑潮渦輪發電機葉片設計疊層之複合材料試片，並透過高溫水浴的方式，模擬黑潮渦輪機組葉片在海水下運作20年後的老化情況，再利用MTS 810材料試驗機進行三點彎曲的擬靜態試驗，得到此疊層下之複合材料所能承受之的極限應力，並根據極限應力百分比進行疲勞試驗。疲勞試驗中，探討老化、外力頻率與溫度對於複合材料疲勞壽命之影響，了解材料疲勞特性，根據本研究的結果顯示，老化後的試片破壞形式會有所改變，頻率的升高會使溫度上升，導致複合材料疲勞壽命下有顯著的下降，然而，在進行有效降溫後發現，若能夠排除高頻率外力對材料造成的溫度效應，則複合材料的疲勞壽命將隨著外力頻率增加而有增加的趨勢，本文亦比較了疲勞壽命曲線與剛性衰減曲線，兩者均能提供不錯的預測。

關鍵字

黑潮發電 ； 複合材料 ； 疲勞試驗 ； 海水老化 ； 疲勞壽命曲線

並列摘要

With the development of marine energy technology, Taiwan, with the Kuroshio resources, has also started in the related technology research and development. However, Taiwan's marine energy technology has just started and not fully developed. In particular, there are no precedent of operating floating turbine generators in deepwater environments. Issues related to flow fields and structures remain uncertain. Therefore, it is necessary to establish appropriate simulation and experiment, as well as to predict the status and fatigue life of the floating Kuroshio turbine generators.
In this research, fatigue characteristics of composite blades of the Kuroshio turbine generator designed by the Taiwan University team is discussed experimentally. First, we used Seemann Composite Resin Infused Molding Process(SCRIMP) to fabricated the designed composite coupon of the turbine blade, and simulated the aging conditions of the blades of the Kuroshio turbine under seawater operation for 20 years through hot water bath. Three-point bending quasi-static test, carried out by MTS 810, to obtain the ultimate stress that the composite under this laminate can withstand,then Fatigue tests were performed according to the percentage of ultimate stress. In the fatigue test, aging, external force frequency and temperature effects on the fatigue life of the composite material are discussed. According to the results of this study, the damage form of the test composite coupon after aging will be changed. The increase of the frequency will cause the temperature rise, then resulting in a significant decrease in the fatigue life. However, after effective cooling, excluding the temperature effect caused by the high frequency on the material, the fatigue life of the composite tends to increase with the increase of the external force frequency. This paper also compares S-N curve with stiffness loss model, both of them can provide good predictions.

並列關鍵字

Kuroshio turbine ； composite material ； fatigue test ； seawater aging ； S-N curve

參考文獻

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