Strengthening metallic shells with FRP against buckling

Thin metallic shell structures such as silos and tanks are susceptible to bucklingfailure which is usually very sensitive to local imperfections. The strengthening of such thinshells has previously been rather difficult if not impossible. Welding additional metal plates tothe existing structure is not easy, and can be prohibitive for health and safety reasons if thestructure contains materials like harmful chemicals, flammables, explosive liquids or gases.Welding also introduces imperfections and residual stresses which may reduce the bucklingstrength of the structure. The authors have recently proposed to strengthen such structures usingexternally bonded FRP. This paper presents a numerical study of the buckling behaviour of cylindricalmetal shells with a dent and strengthened with FRP. The results show that the schemeis very effective and economical.