Experimental and theoretical investigation of prestressed natural fiber-reinforced polylactic acid (PLA) composite materials
Experimental and theoretical investigation of prestressed natural fiber-reinforced polylactic acid (PLA) composite materials
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DOI：
10.1016/j.compositesb.2016.03.089
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发表时间：
2016-06-15
影响因子：
13.1
通讯作者：
Srubar, Wil V., III
中科院分区：
文献类型：
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作者：
Hinchcliffe, Sean A.;Hess, Kristen M.;Srubar, Wil V., III
在这项工作中，我们证明了聚乳酸（PLA）的特定（重量归一化）机械性能可以通过利用(a)增材制造（3D打印）和(b)连续天然纤维增强的初始后张力的组合来增强。在这项研究中，具有不同横截面几何形状的拉伸和弯曲PLA样品都是3d打印的，有和没有后张管。两种连续增强纤维股（即黄麻，亚麻）的机械性能在穿线之前进行了实验表征，后拉伸到规定的应力水平，并用3d打印锚固定。通过拉伸和弯曲力学测试，研究了纤维类型、基体横截面几何形状、增强股数和后拉伸程度对PLA的特定力学性能（即强度、刚度、重量比）的影响。实验结果证实，单独增材制造可以提高PLA的拉伸和弯曲力学性能，并且通过天然纤维增强的初始机械预应力进一步提高这些性能。数据表明，与固体、未增强的PLA相比，拉伸比强度和刚度分别增加了116%和62%，弯曲比强度和刚度分别增加了14%和10%。采用了预应力复合材料拉伸响应的理论模型，发现该模型可以准确地预测(
In this work we demonstrate that the specific (weight-normalized) mechanical properties of polylactic acid (PLA) can be enhanced by leveraging a combination of (a) additive manufacturing (3D printing) and (b) initial post-tensioning of continuous natural-fiber reinforcement. In this study both tensile and flexural PLA specimens with different cross-sectional geometries were 3D-printed with and without post-tensioning ducts. The mechanical properties of two continuous reinforcing fiber strands (i.e., jute, flax) were experimentally characterized prior to threading, post-tensioning to a prescribed level of stress, and securing in place with 3D-printed anchors. The effect of fiber type, matrix cross-sectional geometry, number of reinforcing strands, and degree of post-tensioning on the specific mechanical properties (i.e., strength-, stiffness-, rigidity-to-weight) of PLA were investigated using both tensile and flexural mechanical testing. Experimental results confirmed that additive manufacturing alone can improve the specific tensile and flexural mechanical properties of PLA and that these properties are further improved via initial mechanical prestressing of natural fiber reinforcement. Data indicate increases of 116% and 62% for tensile specific strength and stiffness and 14% and 10% for flexural specific strength and rigidity, respectively, compared to solid, unreinforced PLA. A theoretical model of the prestressed composite tensile response was employed and found to accurately predict (