Bolcu Dumitru, Stănescu Marius Marinel
Department of Mechanics, University of Craiova, 165 Calea Bucureşti, 200620 Craiova, Romania.
Department of Applied Mathematics, University of Craiova, 13 A.I. Cuza, 200396 Craiova, Romania.
Materials (Basel). 2019 Apr 15;12(8):1232. doi: 10.3390/ma12081232.
As a result of manufacture, composite materials can appear to have variations to their properties due to the existence of structural changes. In this paper, we studied the influence of material irregularity on the mechanical behavior of two categories of bars for which we have used hemp fabric as a reinforcing material. The common matrix is a hybrid resin based on Dammar and epoxy resin. We molded two types of bars within each of the previously mentioned categories. The first type, also called "ideal bar", was made of layers in which the volume proportion and the orientation of the reinforcing material was the same in each section. The ideal bar does not show variations of mechanical properties along it. The second type of bar was molded to have one or two layers where, between certain sections, the reinforcing material was interrupted in several segments. We have determined some mechanical properties, the characteristic curves (strain-stress), the tensile strength, and elongation at break for all the sample sets on trial. Moreover, we have studied the influence of the non-uniformities on the mechanical behavior of the composites by entering certain quality factors that have been calculated after experimental determinations.
由于制造过程的原因，复合材料可能会因结构变化的存在而在性能上出现差异。在本文中，我们研究了材料不规则性对两类棒材力学行为的影响，这两类棒材我们均使用麻织物作为增强材料。常见的基体是基于达玛树脂和环氧树脂的混合树脂。我们在上述每类棒材中模制了两种类型。第一种类型，也称为“理想棒材”，由各层组成，其中增强材料在每个截面中的体积比例和取向相同。理想棒材沿其长度方向不会表现出力学性能的变化。第二种类型的棒材模制为具有一层或两层，在某些截面之间，增强材料在几个部分中断。我们已经测定了所有试验样品组的一些力学性能、特征曲线（应变 - 应力）、拉伸强度和断裂伸长率。此外，通过输入在实验测定后计算出的某些质量因子，我们研究了不均匀性对复合材料力学行为的影响。
