Hi all,
Just thought that the following paper archived at the arXiv yesterday could be of general interest to any mechanician:
Xingyu Zhang, Matthew Tomes, Tal Carmon (2011) "Precession optomechanics," arXiv:1104.4839 [^]
The fig. 1 in it makes the matter conceptually so simple that the paper can be recommended to any mechanician for his general reading, and not only to a specialist in the field.
--Ajit
[E&OE]
Last day, I took my class of Nonlinear Analysis of solids and structures.
And I learned about the strong form & weak form in the prilciple of Virtual work.
I can find the origin of those two form that is from Piola-Kirchhoff stress tensor.
but why Integral form is called "weak form"? why Differential form is called "strong form"? why?
I was just wondering.
Hi, I’m trying to implement a mixed hardening J2 plasticity model. The idea is to use the Ludwik law to represent the isotropic hardening and the Amstrong-Frederick law for the kinematic hardening, both combine in a J2 classic von Mises model.
I need some advice for the return mapping algorithm.
Once that I have check that the elastic trial state is not plastically admissible I have to solve a three equation system, where the first two are a tensor equations and the third one is the J2 yield function equation.
The 48th Annual Technical Meeting of Society of Engineering Sciences will be held October 12-14, 2011 at Northwestern University Evanston, Illinois 60208, USA. The meeting will have 43 symposia covering a wide range of topics in engineering sciences. To learn more about the conference and submit an abstract, please check the conference webpage www.ses2011.org.
An analytical model is developed to study the coupling effects in
cord-rubber composite materials. The analytical model takes into account
the mismatch of stiffness between the cords and the rubber matrix
material, and the twist-extension coupling. The transverse deformation,
i.e., normal to the cords direction is based on the normal modes of a
special system which describes the orthotropic and the coupling
behaviour of cord-rubber composites. The equations of motion for the
cord-composite plates are derived using the principle of virtual work.
Results of deformation and stresses are obtained for some typical
cord-rubber composite plates and are compared to the existing solutions.
The results presented illustrate that the coupling effects are
The main purpose of this paper is to complete the works presented by
Andrieux and Varé (2002) and El Arem et al. (2003) by taking into
account the effects of shearing in the constitutive equations of a beam
cracked section in bi-axial flexure. The paper describes the derivation
of a lumped cracked beam model from the three-dimensional formulation of
the general problem of elasticity with unilateral contact conditions on
the crack lips. Properties of the potential energy and convex analysis
are used to reduce the three-dimensional computations needed for the
model identification, and to derive the final form of the elastic energy
that determines the nonlinear constitutive equations of the cracked
In countries with a moderate seismic hazard, the classical methods
developed for strong motion prone countries to estimate the seismic
behaviour and subsequent vulnerability of existing buildings are often
inadequate and not financially realistic. The main goals of this paper
are to show how the modal analysis can contribute to the understanding
of the seismic building response and the good relevancy of a modal model
based on ambient vibrations for estimating the structural deformation
under weak earthquakes. We describe the application of an enhanced modal
analysis technique (frequency domain decomposition) to process ambient
vibration recordings taken at the Grenoble City Hall building (France).
We have recently published a paper on measurements of the density of geometrically necessary dislocations (GND) associated with wedge indentation of a single face-centered cubic crystal. The deformation field is two-dimensional and there are three effective in-plane slip systems that contribute to the plastic slip. We determine the lower bound on the total GND density with a three micrometer spatial resolution. We also show that in certain regions of the domain, the lower bound on total GND density corresponds to the exact total GND density.
