Seeing auxetic materials from the mechanics point of view: A structural review on the negative Poisson’s ratio

Models in Ecology

http://spiral.imperial.ac.uk/bitstream/10044/1/66422/2/Metal%203D%20printing%20in%20construction%20-%20LG.pdf

Metal 3D printing in construction: A review of methods, research, applications, opportunities and challenges

Stress-strain curves for hot-rolled steels

A long structural system with an unstable (subcritical)post-buckling response that subsequently restabilizes typically deformsin a cellular manner, with localized buckles first forming and thenlocking up in sequence. As buckling continues over a growing number ofcells, the response can be described by a set of lengthening homoclinicconnections from the fundamental equilibrium state to itself. In thelimit, this leads to a heteroclinic connection from the fundamentalunbuckled state to a post-buckled state that is periodic. Under suchprogressive displacement the load tends to oscillate between twodistinct values. The paper is both a review and a pointer tofuture research. The response is described via a typical system, asimple but ubiquitous model of a strut on a foundation which includesinitially-destabilizing and finally-restabilizing nonlinear terms. Anumber of different structural forms, including the axially-compressedcylindrical shell, a typical sandwich structure, a model of geologicalfolding and a simple link model are shown to display such behaviour. Amathematical variational argument is outlined for determining the globalminimum postbuckling state under controlled end displacement (rigidloading). Finally, the paper stresses the practical significance of aMaxwell-load instability criterion for such systems. This criterion,defined under dead loading to be where the pre-buckled and post-buckledstate have the same energy, is shown to have significance in the presentsetting under rigid loading also. Specifically, the Maxwell load isargued to be the limit of minimum energy localized solutions asend-shortening tends to infinity.

/pdf/cellular-buckling-in-long-structures-53jot1yv4d.pdf

Cellular Buckling in Long Structures

A recent two-dimensional prototype model for the initiation of kink banding in compressed layered structures is extended to embrace the two propagation mechanisms of band broadening and band progression. As well as interlayer friction, overburden pressure and layer bending energy, the characteristics of transverse layer compressibility and foundation stiffness are now included. Experiments on constrained layers of paper show good agreement with the predictions of angle of orientation, kink band width and post-kink load–deflection response obtained from the model.

M. Ahmer Wadee

Papers

Kink Band Instability in Layered Structures

Effects of periodic and localized imperfections on struts on nonlinear foundations and compression sandwich panels

Mechanical and microstructural testing of wire and arc additively manufactured sheet material

Post-buckling behaviour of prestressed steel stayed columns

Numerical studies of interactive buckling in prestressed steel stayed columns