本篇論文探討竹纖維複合材料在彎曲負載下，不同折角勁度變化的行為與劣化程度。第一階段探討竹纖維複合材料之竹纖維體積比，研究結果表明，在竹纖維數量以及寬度、厚度相同的情況下，120° 試片的折角較小，導致樹脂填充較少，因此纖維體積相對150° 試片比較高。第二階段探討竹纖維複合材料折角處與平板處之厚度偏差率，研究結果表明，因模具為凸模，使材料更容易在真空壓力作用下，折角處樹脂流失更多，因此折角處厚度比平板處更減少，且角度越小，折角處與平板處之厚度偏差率會越大。第三階段探討竹纖維複合材料不同折角角度在彎曲試驗下，比較所得出的荷重與位移之關係，進一步評估材料之剛性、強度及變形行為，研究結果表明，120° 折角較為尖銳，在彎曲載荷下產生較大的局部應力集中，導致其承載能力與變形容許度相對較低。折角 150∘試片表現出較高的剛性與強度，受力分佈較均勻、抗破壞能力較強。第四階段將透過微觀及巨觀方式觀察彎曲試驗後材料折角處的裂紋情形，研究結果表明，折角 120∘試片裂紋擴展行為相較於150∘較為顯眼。第五階段則透過模擬試驗，使模擬與實驗結果達到最大程度一致性，最後針對折角處進行材料性質劣化分析，用數據化呈現折角處之局部材料勁度對整體彎曲剛性的影響。

This study investigates the behavior and degradation of bamboo fiber-reinforced composites under bending loads, focusing on variations in stiffness at different fold angles. First, we examine the fiber volume content of bamboo fiber composites to assess its impact on mechanical properties. The composites are fabricated using the vacuum preforming process and the vacuum-assisted resin transfer molding (VARTM) method. Thickness deviation rates between the fold areas and flat sections are calculated to ensure the accuracy of mechanical performance analysis. Subsequently, bending tests are conducted to compare the load-displacement relationships of specimens with different fold angles and to observe crack formation at the fold areas. Finally, simulations are performed using ANSYS Workbench to achieve the possible consistency between experimental and simulation results. The localized stiffness at the fold areas was quantified, and the results demonstrated that such localized degradation has a significant impact on the overall flexural stiffness of the composite structure.

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