Interpretable Symbolic Regression Modelling of Stacking Sequence Effects in Jute/Ramie and Jute/Flax Hybrid Composites

Öz

In this study, a symbolic regression-based framework was developed to investigate the tensile and flexural behavior of natural fiber-reinforced hybrid composites with different stacking sequences. Experimental data from eleven six-layer laminates, including jute, ramie, flax, jute/ramie, and jute/flax configurations, were reanalyzed. Due to the limited dataset size, the proposed approach was considered an exploratory and interpretable modelling framework rather than a universal predictive model. Fifteen descriptors related to fiber position, interlayer contacts, fiber weight fractions, and density were defined to analytically represent laminate architectures. Pearson and Spearman correlation analyses were first performed, followed by symbolic regression modelling using HeuristicLab to derive interpretable expressions for tensile and flexural strength. The results indicated that ramie-related parameters generally showed positive relationships with mechanical performance, while the symbolic regression models highlighted the potential importance of flax fibers in the outer layers, jute fibers in the core region, and ramie–ramie contact density. The obtained models showed satisfactory agreement with the available experimental data; however, their interpretation should be limited to the investigated laminate configurations. Therefore, the obtained expressions are not intended as universal predictive equations, but as data-driven analytical representations that may help interpret the influence of stacking sequence on the mechanical behavior of hybrid composite laminates. The proposed framework may serve as an example for future studies aiming to establish interpretable relationships between laminate architecture and mechanical performance using larger and more diverse datasets.

Anahtar Kelimeler

• Natural fiber composites
• hybrid laminates
• mechanical properties
• stacking sequence
• symbolic regression.

Etik Beyan

I declare that this study is original; that I have adhered to scientific ethical principles and rules in all stages of the study, including preparation, data collection, analysis, and presentation of information; that I have cited all sources for data and information not obtained within the scope of this study and included these sources in the bibliography; that I have not made any changes to the data used; and that I have complied with all ethical duties and responsibilities by accepting all the terms and conditions of the Committee on Publication Ethics (COPE). I also declare that I am willing to accept all moral and legal consequences should any situation contrary to this declaration I have made regarding the study be detected at any time.

Jüt/Rami ve Jüt/Keten Hibrit Kompozitlerde İstif Dizilimi Etkilerinin Yorumlanabilir Sembolik Regresyon Tabanlı Modellenmesi

Öz

Bu çalışmada, farklı katman dizilimlerine sahip doğal fiber takviyeli hibrit kompozitlerin çekme ve eğilme davranışlarını incelemek amacıyla sembolik regresyon tabanlı bir yaklaşım geliştirilmiştir. Jüt, rami, keten, jüt/rami ve jüt/keten konfigürasyonlarını içeren on bir adet altı katmanlı laminattan elde edilen deneysel veriler yeniden analiz edilmiştir. Laminat mimarilerinin analitik olarak temsil edilebilmesi amacıyla fiber konumu, katmanlar arası temaslar, fiber ağırlık oranları ve yoğunluk ile ilişkili toplam on beş tanımlayıcı parametre oluşturulmuştur. İlk olarak tanımlanan parametreler ile mekanik özellikler arasındaki ilişkileri belirlemek amacıyla Pearson ve Spearman korelasyon analizleri gerçekleştirilmiştir. Daha sonra, çekme ve eğilme mukavemetleri için yorumlanabilir analitik ifadeler elde etmek amacıyla HeuristicLab yazılımı kullanılarak sembolik regresyon modelleri geliştirilmiştir. Korelasyon analizleri, rami fiberi ile ilişkili parametrelerin hem çekme hem de eğilme performansı ile genel olarak en güçlü pozitif ilişkilere sahip olduğunu göstermiştir. Sembolik regresyon modelleri ise dış tabakalarda keten fiberlerin, çekirdek bölgede jüt fiberlerin ve rami–rami temas yoğunluğunun önemini tutarlı bir şekilde ortaya koymuştur. Geliştirilen modeller, nispeten basit matematiksel yapıları korurken 0.99'a kadar belirleme katsayısı (R²) değerlerine ulaşmıştır. Elde edilen sonuçlar, laminat mimarilerinin fiziksel olarak anlamlı ve sınırlı sayıda parametre ile temsil edilebileceğini ve sembolik regresyonun katman diziliminin hibrit kompozit laminatların mekanik davranışı üzerindeki etkisini yorumlamak için etkili bir yaklaşım sunduğunu göstermiştir. Önerilen yaklaşım, laminat mimarisi ile mekanik performans arasında yorumlanabilir analitik ilişkiler kurmayı amaçlayan gelecekteki çalışmalar için örnek bir çerçeve sunabilir.

Anahtar Kelimeler

• Doğal elyaf kompozitler
• hibrit laminatlar
• mekanik özellikler
• katman dizilimi
• sembolik regresyon.

Etik Beyan

Bu çalışmanın, özgün bir çalışma olduğunu; çalışmanın hazırlık, veri toplama, analiz ve bilgilerin sunumu olmak üzere tüm aşamalarından bilimsel etik ilke ve kurallarına uygun davrandığımı; bu çalışma kapsamında elde edilmeyen tüm veri ve bilgiler için kaynak gösterdiğimi ve bu kaynaklara kaynakçada yer verdiğimi; kullanılan verilerde herhangi bir değişiklik yapmadığımı, çalışmanın Committee on Publication Ethics (COPE)' in tüm şartlarını ve koşullarını kabul ederek etik görev ve sorumluluklara riayet ettiğimi beyan ederim. Herhangi bir zamanda, çalışmayla ilgili yaptığım bu beyana aykırı bir durumun saptanması durumunda, ortaya çıkacak tüm ahlaki ve hukuki sonuçlara razı olduğumu bildiririm.

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