Co-authors​ :

 Doyoung KIM (KOREA, REPUBLIC OF), Hyun Joon YANG (KOREA, REPUBLIC OF), Kyeong Mo KANG , Woong-Ryeol YU (KOREA, REPUBLIC OF) 

Compared to 2D composites, 3D composites offer superior properties in the thickness direction, expanding their potential application in various fields. However, characterizing their full 3D behavior poses unique challenges. First, Understanding the properties of composite materials involved presenting two-dimensional properties, which was deemed sufficient. The lack of standardized testing methods for through-thickness properties hinders comprehensive evaluation. Secondly, the intrinsic complexity of weaving patterns, exemplified by our new mechanism's fixed and wrapping warp bundles, demands tailored property assessment approaches. In our specific example, fixed warp bundles, aligned along the x-axis, primarily reinforce the composite in that direction. During weaving, they establish layer boundaries on the z-axis, guiding the y-axis arrangement of weft bundles. Wrapping warp bundles, on the other hand, collaborate with wefts to form a 2D or 3D woven structure, reinforcing the z-axis. Lastly, it is very difficult to fabricate specimens to standard specifications for actual data analysis tests, and it is also challenging to produce a sufficient number of specimens for data analysis. Accurately characterizing the 3D properties of such intricate structures necessitates finite element analysis methods that acknowledge their unique complexities.
To predict the mechanical behavior of 3D woven composites, many researchers employ finite element analysis methods with shell elements. However, this approach makes it challenging to analyze the properties of thick 3D composites. We developed a detailed mechanical model employing fiber-based continuum analysis. This approach defines the 3D woven structure at each material point within the composite and assigns material properties through a constitutive law. Using this model, we successfully calculated the tensile modulus and strength of the material in all three directions, alongside other key properties like shear and delamination strength. Furthermore, we established a dedicated measurement method, specifically for accurately determining the tensile modulus and strength in the critical thickness direction. This research is expected to contribute substantially to the comprehension and engineering design of material properties. And its potential for significant applications in the fields of aerospace, automotive, and construction industries, offering substantial engineering advantages. We will present a comprehensive explanation of these advancements at the forthcoming conference.