The 12th Global Conference on Polymer and Composite Materials (PCM 2025)

Abstract: Cracked orthotropic dissimilar plate specimens are often used to evaluate the strength of fiber-reinforced composites. For isotropic dissimilar plates, the stress state is determined by so-called Dundurs parameters α^iso, β^iso. Similar composite parameters are proposed for orthotropic dissimilar plates as α, β, Γ_A, Γ_B, ρ_A, ρ_B. Compared to two parameters in isotropic cases, orthotropic cases have such six independent parameters, making it much more difficult to use previous analysis results and requiring a new analysis each time. In this study, by applying the mesh-independent proportional method the interface edge crack in orthotropic dissimilar materials is widely analyzed considering previous studies. Then, the singular stress field in orthotropic materials is compared with that in the isotropic dissimilar material under the condition α=α^iso, β=β^iso. The results show that the singular stress field in orthotropic dissimilar material can be evaluated within a few percent error in most cases from that in isotropic dissimilar material when α=α^iso, β=β^iso. In this isotropic replacement by applying α=α^iso, β=β^iso, the singular interface stress distributions in orthotropic dissimilar plates can be estimated within the 8% error even in the worst case where the material anisotropy changes significantly.
Keywords : Fracture mechanics, Stress intensity factor, Interface crack, Orthotropic dissimilar materials, Material composite parameters, Dundurs parameters

Biography: Professor Kazuhiro Oda is a faculty member in the Mechanical Engineering Program, Faculty of Science and Technology, Oita University. He received his Ph.D. in Engineering from Kyushu Institute of Technology in 1995. His research interests include strength of materials, elasticity, and fracture mechanics, with a particular focus on stress analysis and singular stress fields at dissimilar material interfaces and strength design of adhesive structures. After completing his doctoral studies in 1995, he served as a Research Fellow of the Japan Society for the Promotion of Science (JSPS) and later joined Tokuyama College of Technology, where he held positions as Associate Professor and Professor. In 2012, he moved to Oita University as Professor in the Faculty of Engineering (now the Faculty of Science and Technology). He is currently engaged in research on advanced strength evaluation methods for adhesive joints and stress intensity factor analysis for orthotropic dissimilar materials. Professor Oda also serves as Special Assistant to the President for Industry–Academia Collaboration, promoting partnerships between the university and industry. He was a Board Member of the Society of Materials Science, Japan (2020–2024). With numerous publications and contributions, he is recognized as one of the leading researchers in fracture mechanics–based design of dissimilar material joints. In 2025, he received the Society of Automotive Engineers of Japan’s Technical Paper Award.