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Can a beam act like a spring in relation to other spring?

Submitted by tarekaly on
a simply supported beam (length= L) is subjected to an upward force= F at the middle , at the same time there is a spring above the top of the beam at the middle too and the spring is subjected to a downward force = - F .

the spring stiffness is k1, beam stiffness k2 (which equal to the force which produce 1mm deflection at the middle of the beam i.e = 48EI/L^3 ).
the beam can be steel beam UPN 80 , considering weak axis Y (19.4 cm4)

An interesting arXiv paper: "Precession optomechanics"

Submitted by Ajit R. Jadhav on

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]

I was wondering what is origin of weak form in continuum mechanics.

Submitted by roger84 on
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 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.

 

Mixed hardening Amstrong-Frederick and Ludwik J2 plasticity model VUMAT implementation

Submitted by bitamendi on

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

Submitted by jqu on

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.

MODELING COUPLING EFFECTS IN CORD-RUBBER COMPOSITE STRUCTURES

Submitted by saberelarem on

 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

Shearing effects on the breathing mechanism of a cracked beam section in bi-axial flexure

Submitted by saberelarem on

 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