The critical points of the generalized complementary energy variational principles are clariied. An open problem left by Hellinger and Reissner is solved completely. A pure complementary energy (involving the Kirchhoo type stress only) is constructed. We prove that the well-known generalized Hellinger-Reissner's energy L(u; s) is a saddle point functional if and only is the Gao-Strang gap funct...

This paper investigates the relationship between mechanical behaviors and shape of corrugated fiberboard by means of buckling analysis, which is done by FEM (Finite Element Method). Firstly, after analyzing the structure of corrugated fiberboard a single-wall corrugated fiberboard model was built. The buckling load was measured in the ideal condition by linear buckling analysis (eigenvalue buck...

Steel plates are used in various structures, such as the structures of the deck and body of ships, bridges, and aerospace industry. In this study, we investigate the buckling and post-buckling behavior of rectangular steel plates having circular cutouts with two boundary conditions: first, clamped supports at upper and lower ends and free supports at other edges; second, clamped supports at upp...

Bending manipulation and direct force measurements of ultrathin boron nitride nanotubes (BNNTs) were performed inside a transmission electron microscope. Our results demonstrate an obvious transition in mechanics of BNNTs when the external diameters of nanotubes are in the range of 10 nm or less. During in situ transmission electron microscopy bending tests, characteristic "hollow" ripple-like ...

the purpose of this study was to compare the anatomic and visual outcome of primary vitrectomy with scleral buckling in patients with retinal detachment following cataract surgery. fifty-six consecutive patients with retinal detachment after cataract surgery were randomly assigned to two treatment groups: standard scleral buckling and standard three-port deep vitrectomy. successful treatment wa...

ABSTRACT: In this study, large-deformation and small-strain elasto-plastic analysis of space frames with symmetric cross sections and semi-rigid connections are presented. The effect of axial forces on the bending moment and lateral buckling are included. However, axial-torsional and warping effects are omitted. The Eulerian equations for a beam-column with finite rotation taking into account b...

Piezoelectric nanobeams having circular, rectangular and hexagonal cross-sections are synthesized and used in various Nano structures; however, piezoelectric nanobeams with hexagonal cross-sections have not been studied in detail. In particular, the physical mechanisms of the surface effect and the role of surface stress, surface elasticity and surface piezoelectricity have not been discussed t...

Thin solid shell contrast agents bubbles are expected to undergo different volume oscillating behaviors when the acoustic power is increased: small oscillations when the shell remains spherical, and large oscillations when the shell buckles. Contrary to bubbles covered with thin lipidic monolayers that buckle as soon as compressed: the solid shell bubbles resist compression, making the buckling...