Bending Fatigue Behavior Study on the Sandwich Panels with Glass-Fiber Reinforced Thermoplastic Resin Laminate Skins and Foamed Aluminum Cores

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Project title

Code/計畫編號

NSC100-2221-E019-027-MY3

Translated Name/計畫中文名

以發泡鋁/玻璃纖維強化熱塑性高分子積層板製作之三明治結構彎矩疲勞行為研究

Project Coordinator/計畫主持人

Yi-Ming Jen

Funding Organization/主管機關

National Science and Technology Council

Department/Unit

Department of Mechanical and Mechatronic Engineering

Website

https://www.grb.gov.tw/search/planDetail?id=2325631

Year

2011

Start date/計畫起

01-08-2011

Expected Completion/計畫迄

31-07-2012

Bugetid/研究經費

769千元

ResearchField/研究領域

機械工程
材料科技

風力機葉片(wind turbine blade)的外型及結構強度是影響葉片運轉效率的主要因素。三明治結構 (sandwich structure)由於具有高比勁度(stiffness-to-weight)及高比強度(strength-to-weight)的優點，因此常被使用為風力機葉片蒙皮(skin)的主要材料。由於風力機葉片材料所承受的負載均是變動的，因此掌握其材料的疲勞強度特性極為重要。本計畫將利用三年的時間針對一種用於風力機葉片的新式三明治結構進行一系列的彎矩疲勞基礎研究。此一新式的三明治結構是利用發泡鋁(foamed aluminum)為芯材 (core)；玻璃纖維強化熱塑性高分子複合材料積層板(glass-fiber reinforced thermoplastic resin laminates) 為面板(face sheet)。由於此類三明治結構是利用發泡鋁為芯材，因此預期較傳統以高分子發泡材 (foamed polymer)為芯材的三明治結構具有更好的機械強度。另外，發泡鋁高熔點的特性也使其易於與熱塑性高分子複材面板進行熱壓接合，其面板強度也將比傳統以熱固性(thermosetting)高分子複材為面板的三明治結構優良，且易於從事修補。在本計畫的第一年將研究各種試片製作變數對此類三明治結構疲勞強度及破壞機制的影響。這些考慮的製作變數包括了發泡鋁芯材的密度、高度以及複合材料面板的纖維積層方向。除了探討這些變數對其疲勞強度之影響外，計畫中也將利用有限元素法(finite element method)的模擬結果，配合觀察的疲勞破壞機制，發展出合理的疲勞壽命預測參數。第二年的計畫則是考慮風力機葉片所承受的動態負荷往往是變動振幅(variable amplitude)的，因此將針對此類三明治結構進行兩階段累積疲勞(cumulative fatigue)研究，以瞭解負荷順序的交互作用對其疲勞壽命的影響。研究中將分別利用線性損傷理論 (damage rule)及以勁度下降定義的非線性損傷理論來預測累積疲勞壽命，並與實驗結果相比對。另外，由於考量風力機葉片長期處在戶外的環境，因此在本計畫第三年中，將研究溫濕度效應對此類三明治結構疲勞強度的影響。研究中也將觀察疲勞破壞機制與溫濕度條件的關係；並利用考慮溫濕度相關材料性質的有限元素法分析結果，配合觀察到的破壞機制，提出合理的疲勞壽命預測參數。"The shape and structure design of blades is the main factor to affect the operation efficiency of the wind turbine. Due to the high stiffness- and strength-to-weight properties, sandwich structures are frequently employed as the skins of the blades. Because the blades are always subjected to the variable loading, to realize the fatigue characteristics of the employed sandwich structures is important for the development, design and application of such materials. Hence, the bending fatigue strength of a novel sandwich structure for the usage of wind turbine blades will be systematically studied in this three-year project. The proposed novel sandwich structure consists of a foamed aluminum core and glass-fiber reinforced thermoplastic laminate face-sheets. The sandwich panels with foamed aluminum cores are expected to have stronger mechanical properties than those with polymer cores. Moreover, the high melt temperature of the foamed metal makes the core easy to be mounted with the thermoplastic laminate face-sheets, which display higher strength and stiffness than the traditional thermosetting laminate face-sheets. In the first year, the basic fatigue strength will be experimentally analyzed for the sandwich beams with various core densities, core heights and angle-ply directions of the face sheets. The relationship between the considered variables and the fatigue behavior will be developed in details. Furthermore, the fatigue life prediction parameters will be proposed in the study based on the observed fatigue failure mechanism and the simulated results using the finite element method (FEM). Moreover, because the blades are always subjected to the variable-amplitude loading, the two-stage cumulative fatigue behavior of the studied sandwich structures will be investigated in the second year to realize the interaction effect of loading sequence on the fatigue strength and failure modes. The linear and the stiffness-drop-based non-linear damage rules will be used to predict the remaining fatigue life of the second stage. The predicted results will be compared with the experimental data. In the third year, the effect of temperature/humidity on the fatigue strength of the studied sandwich structures will be studied for the wind turbine blades usually locate and operate outdoors. The fatigue life prediction parameters will be proposed based on the observed fatigue failure mechanism and the results of FEM incorporated with the temperature-/humidity-dependent material properties."

Keyword(s)

三明治結構
發泡鋁
玻璃纖維強化高分子複材積層板
熱塑性
疲勞
破壞模式
sandwich structure
foamed aluminum
glass-fiber reinforced resin composite
thermoplastic
fatigue
failure mode

DSpace CRIS

Bending Fatigue Behavior Study on the Sandwich Panels with Glass-Fiber Reinforced Thermoplastic Resin Laminate Skins and Foamed Aluminum Cores

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