Design space for bifurcation buckling of laser-welded web-core sandwich plates as predicted by classical and micropolar plate theories

Abstract

The strength of laser-welded web-core sandwich plates is often limited by buckling. In design of complex thin-walled structures the combination of possible structural and material combinations is basically infinite. The feasibility of these combinations can be assessed by using analytical, numerical and experimental methods. At the early design stages such as concept design stage, the role of analytical methods is significant due to their capability for parametric description and extremely low computational efforts once the solutions have been established for prevailing differential equations. Over the recent years significant advances have been made on analytical strength prediction of web-core sandwich panels. Therefore, aim of the present paper is to show impact of this development to the design space of web-core sandwich panels in buckling. The paper reviews first, briefly the differential equations of a 2-D micropolar plate theory for web-core sandwich panels and the Navier buckling solution for biaxial compression recently derived by Karttunen et al. (Int J Solids Struct 170(1):82–94, 2019) by exploiting energy methods. By comparing the micropolar and widely-used classical first-order shear deformation plate theory (FSDT) solutions, it is shown that the different equivalent single layer (ESL) formulations and plate aspect ratios have a significant impact on the practical outcomes of the feasible design space and this way motivating further developments for micropolar formulations from practical structural engineering viewpoint.

Fractional-Order Shell Theory: Formulation and Application to the Analysis of Nonlocal Cylindrical Panels

“…For example, size-effects within lowdimensional (micro-and nano-scale) structures, such as carbon nanotubes, emerge due to the long-range forces that become more prevalent at these scales [5,6]. Several studies have also demonstrated the presence of nonlocal interactions at the macro-scale in complex structures like porous solids [7][8][9], periodic structures [10,11], intentionally engineered nonlocal structures [12], and sandwiched structures [13]. The inability of the classical (local) continuum theory to capture the nonlocal effects has been one of the main drivers fostering the development of nonlocal continuum theories.…”

Coarse mesh finite element model for cruise ship global and local vibration analysis

“…For stiffened panel only, such modes can be calculated using e.g., Brubak et al [26] presented semi-analytical approach. Similar local effects also occur in buckling modes, and for web-core sandwich panels they were captured using correction for ESL-FSDT in [27] or more advanced micropolar ESL-FSDT plate model [28], [29], which is based on non-classical continuum mechanics where microrotations and -inertia are included. In [30], natural frequencies of stiffened panel were obtained by combining ESL-model frequencies with the local plate between stiffener frequencies, using the assumption that stiffeners with plate between them act as springs and masses in series.…”