International audienceAnalytical models with geometric nonlinearities accounting for interactions between local and global instability modes leading to localized buckling in sandwich struts are formulated. For the core material response, two increasingly sophisticated bending models are compared against each other: Timoshenko beam theory (TBT) and Reddy-Bickford beam theory (RBT). Numerical solutions of the analytical models are validated with the commercial finite element code Abaqus. It is found that there is a small but significant difference in the critical load between the two models and that the previously obtained solution slightly underestimates the linear buckling strength. More importantly, it is found that the RBT model predicts the onset of interactive buckling before the TBT model and, according to the results from the finite element study, matches the actual behaviour of a strut in both its initial and advanced post-buckling states with excellent correlation

Due to their mechanical properties, metal foams are used in various fields. The aim of the present research is to collect different studies about the important mechanical properties of metal foams, such as Young’s modulus, tensile and shear strength, relative density, etc. under tensile and shear loading. Gaps were identified in the methodological embodiments of the experiments due to the use of different standards, as well as in the calculation of mechanical properties through mathematical relations in tensile and shear, which led to deviations between the experimental results and these. Furthermore, this work records sequences and connections between experimental results of different tasks as well as solutions to the aforementioned issues.

An analytical model founded on geometric and potential energy principles for kink band deformation in laminated composite struts is presented. It is adapted from an earlier successful study on confined layered structures that was formulated to model kink band formation in the folding of geological layers. This study's principal aim was to explore the underlying mechanisms governing the kinking response of flat, laminated components comprising unidirectional composite laminae. A pilot parametric study indicates that the key features of the mechanical response are captured well and that quantitative comparisons with experiments presented in the literature are highly encouraging.

Recent work on localized buckling with different core bending theories in sandwich struts is adapted for a sandwich beam-column that combines the effects of bending and compression. The two distinct bifurcations present in the pure compression case are replaced by a single pitchfork bifurcation point that combines local and global buckling behaviour. Several models with a various number of degrees of freedom (DOFs) are developed to account for the explicit effect of end moments. All models are formulated using total potential energy and variational principles, which are used to derive the governing equations that are solved using the numerical continuation package Auto97. Results are validated with a finite element model formulated in the commercial package Abaqus. Comparisons with the interactive buckling profiles and the mechanical response in the nonlinear range are very favourable and the models with more DOFs are determined to be superior.