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Beam Theory for larger cross section

Submitted by ravitejk4u on

hi,

i want the mid point deflection in case of "four point bend test" on a specimen of length 140mm, width of 40mm and thickness of 10mm.

Problem is that, beam theory is valid if the cross-sectional dimensions are less than axial dimensions. Here this condition is violated. i had modeled the specimen in Abaqus and the diffection at mid point is almost double that of the actual diffection calculated from beam theory. 

how can i find the theoritical difflection at mid point in this case?

Two Doctoral Research Positions Available in the Cornell Fracture Group

Submitted by Anthony R. Ingraffea on
job
PhD studies in computational fracture mechanics

The Cornell Fracture Group (CFG) has 2 new PhD student positions open on NASA-sponsored projects.

NASA Constellation University Institutes Project:  Develop a hierarchical, multi-scale simulator for damage tolerance and durability of advanced composite structures.

NASA Integrated Resilient Aircraft Control Project:  Develop a simulation capability to determine residual strength of damaged aircraft structure.

Cell mechanics workshop

Submitted by Taher A Saif on
research

The Center for Cellular Mechanics at U of Illinois has recently hosted a week long summer workshop on Cell Mechano Sensitivity (July 30-Aug 3, 2007. The workshop had lectures in the morning an hands on-labs in the aternoons. All the lectures are on the web (with slides and video). They include a large collection of references. The web also has the laboratory protocols for cell culture, cell fixing and staining, single molecule detection, florescence microscopy, and much more. Visit the website:

www.ccm.uiuc.edu  

Special Journal Issue on Bridging of Material Length Scales

Submitted by Rashid K. Abu Al-Rub on
research
size effect; gradient plasticity; gradient damage; nonlocal; micro systems; nano systems; length scale

Dear Esteemed Researcher,

 

It is my pleasure to invite you to submit your recent work as a contribution to the special issue on “Bridging of Material Length Scales” for the journal “International Journal of Materials and Structural Integrity” [http://www.inderscience.com/browse/index.php?journalID=162].

 

Resonance frequency of cantilever

Submitted by Somashekara Bhat on
research
Microcantilever

Resonance frequency of a cantilever beam is given by

f=(kn/2pi)*sqrt(EI/mL4)

where, kn=3.52 for cantilever, E is Young's Modulus, I is moment of Inertia, m is mass, L is beam length.

The equation is available in Raymond J. Roark and Warren C. Young, “Formulas for Stress and Strain”, McGraw-Hill, Kogakusha, 5th Edition, (1976).

Can any one help me in deriving this. Or any books or websites which deal with this equation.

Large elastic strain - limits of Green strain

Submitted by Peter Hartley on
research

I am looking at problems of large deformation and large elastic strain in biological materials, using an analytical model that determines the current deformed state in a single step from the original undeformed state. The approach is to propose a strain energy function to allow the calculation of Piola-Kirchhoff 2 stresses which may then be converted to true Cauchy stresses via the usual mapping. Since I initially calculate PK2 stresses, the strain energy function must be a function of Green strain.

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