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Hi.

I want to model creep of concrete beam in ABAQUS. I will be appreciated if anybody send me a sample of UMAT subroutine.

Thanks a lot.

Mohsen

Fracture Toughness of Graphene

P. Zhang, L. Ma, F. Fan, C. Peng, P.E. Loya, Z. Liu, Y. Gong, J. Zhang, X. Zhang, P.M. Ajayan, T. Zhu, and J. Lou
Nature Communications, Vol. 5, article number 3782, 2014. DOI: 10.1038/ncomms4782

http://www.nature.com/ncomms/2014/140429/ncomms4782/full/ncomms4782.html

I'm doing an research about a cantilever which can undergoes large rotations along two directions. At the head of the cantilever there is a magnetic particle. When I establish the dynamic model for this cantilever, I just consider the mass of the particle(since the mass of the beam is small). However after I obtian the mass matrix (6 by 6, six DOFs), i found it is not symmetric. I don't know the reason. Can anyone help me? By the way, if the beam undergoes large rotation, will the stiffness matrix(tangent matrix) at each state keep symmetric ? Thank you