Jalali Shahin, Carbas Ricardo J C, Marques Eduardo A S, da Silva Lucas F M
Institute of Science and Innovation in Mechanical and Industrial Engineering (INEGI), Rua Dr. Roberto Frias, 4200-465 Porto, Portugal.
Departamento de Engenharia Mecânica, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal.
Polymers (Basel). 2025 Feb 28;17(5):648. doi: 10.3390/polym17050648.
In modern engineering applications, the use of sustainable materials and eco-friendly methods has become increasingly important. Wood joints, especially those strengthened with bio-adhesive, have attracted considerable attention due to their inherent environmental benefits and desirable mechanical properties. Compared to traditional joining methods, adhesive joints offer unique advantages such as improved load distribution, reduced stress concentration, and enhanced aesthetic appeal. This study aims to enhance delamination resistance in wooden adhesive joints using a novel method involving reinforced high-toughness resin on surfaces. Additionally, a hybrid substrate approach applies a tough layer to outer plies and a densified wood core with greater fiber direction strength. Normal, toughened, and hybrid single-lap joint specimens were analyzed through both experimental and numerical methods under various loading conditions, including quasi-static and intermediate rates. The proposed method involved bio-adhesive penetration into the wood substrate, forming a reinforced surface zone. The experimentally validated results show a significant improvement in joint strength, exhibiting an approximate 2.8-fold increase for the toughened joints compared to the reference joints under intermediate-rate conditions. Furthermore, the absorbed energy of the toughened joints increased by a substantial factor of up to 4.5 times under the same conditions. The fracture surfaces analysis revealed that the toughening method changed the failure mechanism of the joints from delamination to fiber breakage, indicating that the strength of the substrate was lower than that of the joint under impact conditions. The viscoelastic behavior of the bio-adhesive also influenced the response of the joints to the changing displacement rate. The toughening method enhanced the resilience and load-bearing capacity of the wood joints, making them more suitable for dynamic applications.
在现代工程应用中，使用可持续材料和环保方法变得越来越重要。木质接头，尤其是那些用生物胶粘剂加固的接头，因其固有的环境效益和理想的机械性能而备受关注。与传统连接方法相比，胶粘剂接头具有独特的优势，如改善载荷分布、降低应力集中和增强美观性。本研究旨在采用一种在表面使用增强高韧性树脂的新方法来提高木质胶粘剂接头的抗分层性能。此外，一种混合基材方法是在外层应用一层坚韧层，并使用具有更大纤维方向强度的致密木芯。通过实验和数值方法，在包括准静态和中等速率在内的各种加载条件下，对普通、增韧和混合单搭接接头试件进行了分析。所提出的方法包括生物胶粘剂渗透到木材基材中，形成一个增强表面区域。实验验证结果表明，接头强度有显著提高，在中等速率条件下，增韧接头与参考接头相比，强度提高了约2.8倍。此外，在相同条件下，增韧接头的吸收能量大幅增加，最高可达4.5倍。断口分析表明，增韧方法改变了接头的失效机制，从分层变为纤维断裂，这表明在冲击条件下，基材的强度低于接头。生物胶粘剂的粘弹性行为也影响了接头对变化位移速率的响应。增韧方法提高了木质接头的弹性和承载能力，使其更适合动态应用。
