The main objective of this research is to find experimentally the effect of impact damage on the flexural strength of glass fiber/epoxy laminated composite materials at two different test conditions. The other objective is to determine the critical buckling load of laminated composite material after impact loading. Thus, the loss of flexural and buckling performances of the damaged material has been established by comparison with the undamaged material. Initially, angle-ply laminated composite plates with rectangular shaped have been subjected to impact load at different energy levels by using a drop-weight testing machine and impact damage has been created. To find the residual flexural strength, four-point bending tests have been carried out. Four-point bending specimens have been cut from the damaged area of the middle of the laminated plates and have been positioned in two different ways according to the face subjected to the impact. For buckling tests, a unidirectional compression load has been applied to the impacted specimens with the size of 100 mm x150 mm. According to the four-point bending test results, the flexural strengths of the specimens subjected to impact at 10 J and 30 J have decreased approximately 25 and 42%, respectively. Similarly, the reductions in critical buckling loads of specimens subjected to impact at 10 J and 40 J are approximately 16 and 32%, respectively. Consequently, the impact load significantly reduces the flexural and buckling performances of laminated glass/epoxy composites. Furthermore, the positioning of the four-point bending test specimen affects the flexural strength.

中文翻译：

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实验确定冲击破坏的玻璃/环氧树脂层压板的残余弯曲强度和临界屈曲载荷

这项研究的主要目的是在两种不同的测试条件下，通过实验找到冲击损伤对玻璃纤维/环氧层压复合材料弯曲强度的影响。另一个目的是确定冲击载荷后层压复合材料的临界屈曲载荷。因此，与未损坏的材料相比，已经确定了损坏材料的弯曲和屈曲性能的损失。最初，通过使用落锤试验机，将矩形角叠层层压复合板在不同的能量水平下承受冲击载荷，并造成了冲击破坏。为了找到残余弯曲强度，已经进行了四点弯曲测试。从层压板中间的受损区域切出四点弯曲试样，并根据受到冲击的面以两种不同的方式进行定位。对于屈曲测试，已对大小为100 mm x150 mm的受冲击样品施加了单向压缩载荷。根据四点弯曲测试结果，在10 J和30 J冲击下的试样的抗弯强度分别降低了约25％和42％。同样，在10 J和40 J冲击下，试样的临界屈曲载荷的减小分别约为16％和32％。因此，冲击载荷显着降低了层压玻璃/环氧树脂复合材料的挠曲和屈曲性能。此外，