Analysis of the strength of joints in fabric/ unsaturated polyester composites

Fabric/unsaturated polyester composites have garnered significant attention due to their lightweight properties and superior mechanical characteristics. Despite these advantages, the strength of joints within these composites remains a crucial aspect requiring thorough investigation. This paper presents a study focused on comprehending the factors that influence joint strength in fabric/polymer composites, emphasizing the importance of effective load transfer and robust adhesion within the fabric/polymer matrix. The objective is to minimize stress concentration and enhance load distribution within the joint. The failure mechanism involves a combination of Bearing Failure and shear-out failure, particularly in single-fabric layer composites. The study establishes a linear relationship between composite bending stiffness and the enforcement fabric’s flexural rigidity. A comparison of tensile properties across various joining methods, such as bolts, adhesive bonding, and tongue grooves, reveals that bolt joints exhibit the highest strength and elongation, followed by tongue groove joints. Notably, bolt joints demonstrate elevated toughness, efficiency, and stiffness in samples of two-layer twill fabric when the twill lines are oriented perpendicular to each other. Under these conditions, joint properties are measured at 0.89%, 14804.65 Nm, and 20.46 J, respectively. Increased fabric flexural rigidity yields advantages in terms of load distribution, load transfer efficiency, and dimensional stability. This study deepens the understanding of factors influencing joint strength, contributing valuable insights for the development of optimized joint designs and manufacturing processes. These advancements aim to enhance the performance and reliability of fabric/unsaturated polyester composites in applications requiring high strength and structural integrity.