Stability Analysis of Slender Plates Stiffened with Topologically Optimized WAAM Stiffeners: Experimental and Numerical Investigation

Abstract

This thesis explores how slender plates can be reinforced with stiffeners to improve their stability, and how new manufacturing methods can lead to more efficient designs. Traditional stiffeners are often simple in geometry, which limits their structural efficiency. With Wire Arc Additive Manufacturing (WAAM), however, it becomes possible to produce complex shapes that may perform better. The research combines experiments, numerical simulations, and optimization studies. Plates with WAAM stiffeners were manufactured and tested alongside plates with conventional rectangular stiffeners. Numerical models were developed and validated against the experimental results, including the influence of imperfections and residual stresses. Different initial stiffener shape models were then used in a topology optimization process to design further improved stiffener geometries. The results indicate that the numerical models of the WAAM stiffeners can replicate the experimental performance, considering the restricted number of specimens utilized in the tests. However, the models of the plates employing prismatic rectangular stiffeners demonstrated reduced compliance with the experimental results. New initial stiffener geometries underwent topological optimization and showed performance comparable to that of conventional prismatic stiffeners of equivalent volume, thus lacking any advantages. The study highlights both the opportunities and challenges of using WAAM in structural applications and provides recommendations for future research.