Mertgenç Yoldaş Dudu
Department of Mechanical and Metal Technologies, Dokuz Eylul University Izmir Vocational School, Buca, 35360 Izmir, Turkey.
Polymers (Basel). 2025 Jun 17;17(12):1672. doi: 10.3390/polym17121672.
Composite materials have the advantages of high strength and low weight, and are therefore used in many areas. However, in humid and marine environments, mechanical properties may deteriorate due to moisture diffusion, especially in glass fiber reinforced polymers (GFRP) and carbon fiber reinforced polymers (CFRP). This study investigated the damage formation and changes in mechanical properties of single-layer adhesive-bonded GFRP and CFRP connections under the effect of sea water. In the experiment, 0/90 orientation, twill-woven GFRP (7 ply) and CFRP (8 ply) plates were produced as prepreg using the hand lay-up method in accordance with ASTM D5868-01 standard. CNC Router was used to cut 36 samples were cut from the plates produced for the experiments. The samples were kept in sea water taken from the Aegean Sea, at 3.3-3.7% salinity and 23.5 °C temperature, for 1, 2, 3, 6, and 15 months. Moisture absorption was monitored by periodic weighings; then, the connections were subjected to three-point bending tests according to the ASTM D790 standard. The damages were analyzed microscopically with SEM (ZEISS GEMINI SEM 560). As a result of 15 months of seawater storage, moisture absorption reached 4.83% in GFRP and 0.96% in CFRP. According to the three-point bending tests, the Young modulus of GFRP connections decreased by 25.23% compared to dry samples; this decrease was 11.13% in CFRP. Moisture diffusion and retention behavior were analyzed according to Fick's laws, and the moisture transfer mechanism of single-lap adhesively bonded composites under the effect of seawater was evaluated.
复合材料具有高强度和低重量的优点，因此被广泛应用于许多领域。然而，在潮湿和海洋环境中，由于水分扩散，其机械性能可能会恶化，尤其是在玻璃纤维增强聚合物（GFRP）和碳纤维增强聚合物（CFRP）中。本研究调查了海水作用下单层粘结GFRP和CFRP连接件的损伤形成及机械性能变化。在实验中，按照ASTM D5868-01标准，采用手糊法将0/90取向的斜纹编织GFRP（7层）和CFRP（8层）板制成预浸料。使用数控铣床从为实验生产的板材上切割出36个样品。将样品置于取自爱琴海、盐度为3.3-3.7%、温度为23.5℃的海水中1、2、3、6和15个月。通过定期称重监测吸湿情况；然后，根据ASTM D790标准对连接件进行三点弯曲试验。使用扫描电子显微镜（ZEISS GEMINI SEM 560）对损伤进行微观分析。经过15个月的海水浸泡，GFRP的吸湿率达到4.83%，CFRP的吸湿率达到0.96%。根据三点弯曲试验，GFRP连接件的杨氏模量相比干燥样品下降了25.23%；CFRP的下降率为11.13%。根据菲克定律分析了水分扩散和保留行为，并评估了海水作用下单搭接粘结复合材料的水分传输机制。
