Axial Load‐Bearing Enhancement of Thin‐Walled Metal Tubes via Internal Pressurization

Abstract

As a lightweight load‐bearing member for aerospace truss structures, thin‐walled metal tubes require improved buckling resistance without additional mass. To this end, this paper innovatively designs a thin‐walled metal inflatable tube structure. The axial compressive behavior of the proposed tube and the influence of internal pressure are preliminarily investigated through experiments and numerical simulations. Axial compression buckling tests were conducted on two sets of specimens under 0 and 2 bar to evaluate the pressure‐induced changes in axial stiffness, critical buckling load, and buckling mode. Concurrently, a finite element model was established using material parameters obtained from independent tensile tests. The model was validated against the experimental results at 0 and 2 bar and was subsequently employed to numerically investigate the axial compressive response over a wider pressure range. In addition, initial local dimple imperfections were introduced into the finite element model to examine the imperfection sensitivity of pressurized thin‐walled tubes. Combining experimental and numerical simulation results reveals that pressurization significantly increases the buckling critical load of thin‐walled tubes and improves buckling morphology, thereby suppressing the occurrence of abnormal deformation. The numerical results also indicate that internal pressure can reduce the sensitivity of thin‐walled tubes to local dimple imperfections.