4-Point Bending of Composite Laminates for FEM/FEA Validation

Abstract: When designing structures and vehicles using composite materials, engineers need access to critical information regarding the composite materials in question. This information describes the strength, stiffness, failure mode, and other variables that can be used to properly determine how a structure will perform while undergoing various loads and effects. Within boat building industries, several ISO standards are leveraged to allow for easier and faster design of new craft. One suite of ISO standards that provide this information is the ISO 12215 group. Within this group, ISO 12215-5:2019 provides calculation methods for designing boats using fiberglass and carbon fiber composites as well as the values required to do so. Diab, a manufacturer of composite materials that are often used by boat building companies, provides guidance and its expertise when designing and building with the materials they fabricate and sell. Being familiar with the ISO 12215 standards, Diab has helped multiple customers better understand the process of designing small boats with composite materials. To ensure that it provides accurate information, Diab has validated many of the values outlined in ISO 12215-5:2019. One set of values still need to be validated, the compression strength and stiffness of an E type fiberglass. To do so, Diab engineers would like to fabricate and test coupons in a 4-point bending test then compare the results to the values outlined within ISO 12215-5:2019. This thesis outlines the theory, method, tests, and results found while validating this information. The project found that the fiberglass likely has a higher failure strength and a lower stiffness than outlined in the ISO standard. The team members in this project had hypothesized that the strength in the standard would be lower for safety reasons.