The composite materials exposed to dynamic loads may suffer damage at strength value, which is under own yield strengths. Also, improper environmental conditions accelerate the damage process. In this study, the effect of heavy chemical environments such as acid and alkaline and retaining time for these environments on flexural strength and fatigue behavior of E-glass/epoxy laminated composites was investigated. In this content, glass/epoxy (G8) having eight layers was produced by using the hand lay-up method. The produced composite materials were retained into acidic and alkali solution having 5%, 15%, and 25% concentration a period of 1, 2, 3, and 4 months. A computer-controlled fixed-end type fatigue test machine capable of tilting 10 test samples at the same time was designed and manufactured to determine the fatigue behavior of composite samples. Fatigue behavior of glass/epoxy was determined under dynamic flexural load which corresponds to 80%, 70%, 60%, 50%, and 40% of static three-point bending strength of the test sample. SEM image of damaged specimens was taken to describe the failure mechanism of damage which occurs after fatigue. Also, to better understand environmental condition on the fatigue life, results were compared with results of glass/epoxy laminated composites, which were not retained into any environments (0%).

中文翻译：

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不同环境条件对电子玻璃/环氧树脂复合材料弯曲强度和疲劳行为的影响

承受动态载荷的复合材料可能会在强度值下受到损坏，这是在自身屈服强度之下。此外，不适当的环境条件会加速损坏过程。在这项研究中，研究了酸和碱等重化学环境以及这些环境的保留时间对 E 玻璃/环氧树脂层压复合材料的弯曲强度和疲劳行为的影响。在该内容中，使用手糊法制造了具有八层的玻璃/环氧树脂(G8)。将制备的复合材料分别在5%、15%、25%浓度的酸碱溶液中保存1、2、3、4个月。设计并制造了一台可同时倾斜10个试样的计算机控制的固定端式疲劳试验机，用于测定复合材料试样的疲劳行为。玻璃/环氧树脂的疲劳行为是在动态弯曲载荷下测定的，该载荷对应于测试样品静态三点弯曲强度的 80%、70%、60%、50% 和 40%。通过对损伤试样的扫描电镜图像描述疲劳后发生损伤的失效机理。此外，为了更好地了解环境条件对疲劳寿命的影响，将结果与未保留在任何环境中 (0%) 的玻璃/环氧树脂层压复合材料的结果进行了比较。和试样静态三点弯曲强度的40%。通过对损伤试样的扫描电镜图像描述疲劳后发生损伤的失效机理。此外，为了更好地了解环境条件对疲劳寿命的影响，将结果与未保留在任何环境中 (0%) 的玻璃/环氧树脂层压复合材料的结果进行了比较。和试样静态三点弯曲强度的40%。通过对损伤试样的扫描电镜图像描述疲劳后发生损伤的失效机理。此外，为了更好地了解环境条件对疲劳寿命的影响，将结果与未保留在任何环境中 (0%) 的玻璃/环氧树脂层压复合材料的结果进行了比较。