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An effective bead-spring model for polymer simulation

Submitted by Bin Liu on

An effective bead-spring model combining the advantages of large time steps of traditional bead-rod models and computational rigor of traditional bead-spring models is proposed to simulate the dynamic behaviors of flexible polymer chains with arbitrary longitudinal stiffness. The proposed model can be used to simulate many types of polymer chains or networks with different chain elasticity via a unified integration scheme with reasonably large time steps. The paper can be found at http://dx.doi.org/10.1016/j.jcp.2007.11.012

Variational Theory: Variable-independence and Consistency

Submitted by Jian-zhong Zhao on

Variational theory of elasticity is surveyed in the context of mathematical logic in the present paper titled "Variational Theory: Variable-independence and Consistency" . The problem of variable-independence of variational principles raised by Professor Chien Wei-zang is discussed.

HELICOPTERS: CALCULATION AND DESIGN. VIBRATIONS AND DYNAMIC STABILITY

Submitted by DJackson on

 Hi Everybody, Im new to iMechanica. I must admit If I knew of it earlier it could have changed so many things in my life :). Im really glad to be here now. For a start I would like to ask if anyone has any links /sources to this book. I simply cant find it. Ive checked Amazon etc etc. Please help me find this book

"HELICOPTERS: CALCULATION AND DESIGN. VIBRATIONS AND DYNAMIC STABILITY "(Mil, M. L. ; Nekrasov, A. V. ; Braveman, A. S. ; Grodko, L. N. ; Leikand, M.) 1968.

Rgds.

Dominic.

Traction separation laws in Cohesive zone models - Some Questions

Submitted by yoursdhruly on

Hello! 

As a student who has spent a lot of time studying cohesive zone models in fracture mechanics, I have several questions that have bothered me over the past year or so, and I have not been able to find suitable answers to them. I am limiting myself here to questions related to the traction-separation law, which invariably forms the basis of CZM as it is implemented today. I am raising these questions in the hope that I can receive some response here, even if it means my question is invalid (as I suspect a few may be).  So here is my list:

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Drying-induced bifurcation in a hydrogel-actuated nanostructure

Submitted by Taher A Saif on

Fascinating paper. Congrats to Wei, Xuanhe, and Zhigang. Nice to see a simple and an elegant model together with an intuitively appealing physical interpretation of the bifurcation phenomenon in gels. It woud be interesting to see the time evolution of the drying process and the orientation (theta) of the nano wires.  

Nikolaos I.Ioakimidis _introduce hypersingular integral equations into 3D fracture mechanics

Submitted by BoJing Zhu on

N.I.Ioakimidis.1982.Application of finite-part integrals to the singular integral equations of crack problems in plane and three-dimensional elasticity. Acta Mechanica.45. 31-47.

N.I.Ioakimidis.1983. A new singular integral equation for the classical crack problem in plane and antiplane elasticity. Int J fracture. 21. 115-122

Boundary conditions given by functions

Submitted by mpatrici on

Hi,

 I am using Abaqus/CAE to model the elastic behaviour of a plate. I would like to give/define a function to prescribe the displacement along one boundary, but Abaqus does not seem to accept this the way I'm doing it*. Can anyone help me out?

 

* on the Load module, I choose create boundary condition > displacement, then I select a boundary, select distribution user defined, and on u1 i type "x". I then get a message saying this is not accepted.