Collapse Characteristics Of Composite Reinforced Metal Hemispherical Shells

Spherical shells are widely applied as energy-absorbing structures to improve crashworthiness of space vehicles,submarines,buildings and storage tanks.Compared with conventional metallic shells,composite reinforced metal shells and those with aluminum foam-filler have attained wide acceptance for higher specific energy absorption capacity.Based on previous researches,the analytical method and finite element method are applied to investigate the energy absorption behavior of composite reinforced metal hemispherical shells,rotational hemi-ellipsoidal shells and combined geometry(dome-cone)shells undergoing axial compression,as well as those with aluminum foam-filler.To begin with,the analytical models of foam-filled composite reinforced metal hemispherical shells,rotational hemi-ellipsoidal shells and combined geometry shells undergoing axial compression are established,to predict the mean collapse load,representing energy absorbed during a unit axial compression distance.All of the analytical models can be degraded to those of composite reinforced metal shells,foam-filled metal shells and metal shells correspondingly.Next,the corresponding finite element models are established.To supplement the lacking test data,numerical simulations are implemented.The reasonableness of FE models and computation is verified indirectly through extant test data and previous numerical simulation results.Comparing the theoretical results derived from the analytical models with the numerical simulation results,the feasibility of the analytical models is verified.Finally,employing analytical models,the effects of composite layer(viz.fiber layer thickness proportions and fiber reinforced orientation),loading velocity,geometric parameter of hemispherical shells R/t,rotational hemi-ellipsoidal shells a/t and b/a,combined geometry shells thickness and half cone apex angle on the mean collapse loads of composite reinforced shells are described and investigated in examples respectively.In addition,the effects of foam-filler density and Poisson's ratio on the mean collapse loads of composite reinforced shells with foam-filler are investigated,utilizing numerical calculation.Some relevant suggestions of optimum proposals are made to reduce devices' weight with the achievement of expected energy absorption capability by comparing enhancing shells energy absorption undergoing axial collapse when laying fiber reinforced composite outside and filling aluminum foam inside shells.