research

In all textbooks, when iteration methods are introduced, the iterative formula is always H(x)x+f=0, where f is the external force applied on the system. All methods are stated when f is fixed.

Recently, I find that definitions of secant stiffness and tangent stiffness in many books seem pretty confused.Therefore, here I am giving the definitions I think correct, then give my questions on them.

Consider the equation

H(x)x+f=0

(1) Definition of tangent stiffness. As for the above equation, what is the tangent stiffness for some particular value x₀?

Let's give the definition according basic knowledge of advanced mathematics. Let's consider the curve H(x)x~x. For this curve, y=H(x)x, so the tangent at x₀ is

I am working with shape memory alloys (nitinol), and am in that respect investigating fracture behaviour of NiTi, using, among other things, simulations in ABAQUS. ABAQUS doesn't have a material model that include plasticity unless you pay for it. I am wondering if anyone have implemented either of the following models as a UMAT, and if you are willing to share the code with me.

The models I am interested in are:

Phys. Rev. E 80, 046601 (2009) [5 pages]

Power loss and electromagnetic energy density in a dispersive metamaterial medium

The effects of boron doping and boron grafts on the mechanical behaviour of armchair (6, 6)

and zigzag (10, 0) single-walled carbon nanotubes (SWCNTs) under axial loading are

investigated using the molecular dynamics (MD) simulation method. The results show that

Young’s moduli, the tension strength, the buckling loads and the buckling strains of SWCNTs

decrease after functionalization. The influences of the distribution density of functionalization

on Young’s moduli of SWCNTs are also systematically studied. The results show that Young’s

We recently find that embryonic stem cells are very sensitive to a local cyclic stress applied to the focal adhesion.  They spread and differentiate (Oct3/4 downregulation) in response to this local force.

Hi all,