Under torsion and beyond the buckling point, multi-walled carbon nanotubes MWCNTs develop a periodic wave-like rippling morphology. Here, we show that torsional rippling deformations can be accurately described by a simple sinusoidal shape function. Combining this observation with the geometry optimization, we develop an effective coarse-grained model that reproduces the complex nonlinear mecha...

PANDA2, a computer program for the minimum-weight design of elastic perfect and imperfect stiffened cylindrical panels and shells under multiple sets of combined loads, is used to obtain optimum designs of uniformly axially compressed elastic internal T-ring and external T-stringer stiffened cylindrical shells with initial imperfections in the form of the general buckling mode. The optimum desi...

The nonlinear dynamic analysis of imperfect hemispherical shell under pressure was executed. finite element model hemisphere in the software NASTRAN built. wall form three-cornered and four-cornered net presented. Shape imperfection as a lower buckling (Buckling) perfect action static modelled. Value amplitude set proportionally to thickness. Two boundary conditions rigid hinged supports on nod...

In this paper, static response and buckling analysis of functionally graded saturated porous beam resting on Winkler elastic foundation is investigated. The beam is modeled using higher-order shear deformation theory in conjunction with Biot constitutive law which has not been surveyed so far. Three different patterns are considered for porosity distribution along the thickness of the beam: 1) ...

Failure in cold-formed steel beams is generally initiated by one of three instabilities: local, distortional, or lateral-torsional buckling. For cold-formed steel joists, purlins, or girts, when the compression flange is not restrained by attachment to sheathing or paneling, distortional buckling may be the predominant failure mode. Experimental results on cold-formed steel beams with unrestrai...

Abstract Topology optimization has been identified as a powerful tool to improve aircraft structures for many years. Yet, innovative layouts have not successfully implemented in commercial several reasons. One reason by our research group is the lack of design constraints during topology optimization, such buckling stability, which yields complex solutions that are easily manufacturable. Second...