Part II: Structural response and tank contact assessment of hydrogen tank trailer protective housing under AI-augmented probabilistic multi-directional collision loading

Abstract

High-pressure hydrogen tank trailers are entering road transport in growing numbers, but the structural conditions under which a vehicular collision reaches the cylinder assembly have not been characterised. UN GTR No. 13 and FMVSS No. 307/308 govern post-crash containment and do not address intrusion. This study quantifies how far collision intrusion penetrates the protective housing of a hydrogen tank trailer, and whether it reaches the cylinder, across thirty multi-directional collision scenarios. Furthermore, it demonstrates that the clearance available to protect the cylinder varies strongly with impact direction. The scenarios were drawn by Latin Hypercube Sampling from 60,501 NHTSA FARS vehicle records and simulated in LS-DYNA with rate-dependent material properties measured by quasi-static and high-strain-rate tensile testing; energy balance was checked for all thirty simulations, of which twenty-nine met the criterion. Structural clearance to the housing was measured from the model geometry for all twelve clock directions, from 350 mm laterally to 3180 mm frontally, and intrusion was normalised by that clearance to give a penetration ratio. Intrusion reached the housing envelope in sixteen scenarios but reached the cylinder in only seven. In seven cases the intruding structure passed beneath the cylinder, with vertical clearances of 143–552 mm, although its penetration had exceeded the depth at which the cylinder could have been reached. Conversely, one scenario reached the cylinder without attaining that depth, through inward deformation of the cylinder support. Two scenarios whose penetration depths differ by 0.66 mm classify differently. This underride-induced severity inversion means that no scalar measure of intrusion depth reproduces the outcome: a three-dimensional alignment test is required alongside any normalised depth criterion. The analysis is bounded at the point where collision load reaches the cylinder and does not extend to rupture or release.