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why the mass matrix of my structure is unsymmetric?

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   

Modeling of Particulate Composites

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I am trying to model particulate composites and simulate their stress-strain response. The problem that I am facing is that the inclusions (stiffer than the matrix) are only acting as points of stress concentration. Consequently their is no strengthening and hence no apparent increase in load carrying capacity of the composite. Any help/suggestioin in this regard would be higly appreciated.





Hello, Please Do you have this full book:


Gautam Puri

Force-driven evolution of mesoscale structure in engineered 3D microtissues and the modulation of tissue stiffening

Force-driven evolution of mesoscale structure in engineered 3D microtissues and the modulation of tissue stiffening

Ruogang Zhao, Christopher S. Chen, Daniel H. Reich, Biomaterials, Vol. 35, Issue 19, June 2014, Pg 5056–5064


High order isogeometric cohesive elements for delamination analysis

Please find attached two recent papers on the use of high order B-splines/NURBS cohesive interface elements for an efficient modeling of delamination of composite laminates.  

Mecahnics on the behaviour of Horizontal/laterally loaded thin hollow tubes

Dear all,

Please give some reading material on the horizontal/laterally loaded thin hollow tube, which explains with suitable formulas to calculate circumferential/hoop stresses in the thin tube subjected to lateral/horizontal loaḍ


Urgent help - Contact modelling in Abaqus

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Dear all
I urgently need the answer to my question. I am modelling a clapping or contact between two surfaces similar to a crack.
I have used abaqus : 1-tangential : frictionless  2-Hard contact
I wanna know what moelling approach does abaqus use for above situation ?
Does abaqsu use hertzian contac ? bilinear stiffness or what ?
Thank you

Postdoc Position Available in Theoretical & Applied Mechanics Group at Drexel University (Dept. of Mechanical Eng. & Mechanics)

A postdoc position is available in the Theoretical & Applied Mechanics Group ( Of particular interest are expertise in subcontinuum and continuum computational mechanics methods. Available researh projects include both alloy and composite material systems. 

Applicants should submit a full CV, a statement of research and their earliest employment availability to



Yonggang Huang's picture

Journal of Applied Mechanics (ASME Transactions) now publishes very fast.

Journal of Applied Mechanics (JAM) received 526 submitted manuscripts in 2013.  Among them 4 are still in review.  

The average time for the 1st round of review, with the decision to accept, or reject, or revise, is 18 days.  After the 1st round of review, the average time to make the final decision is 34 days, which include both the authors' revision time and 2nd (and more) round(s) of review.

After acceptane the uneditted manuscript appears online with the assigned DOI within 48 hours.

Postdoctoral researcher position opening at Pohang University of Science and Technology (POSTECH), Korea

We are seeking a highly qualified candidate for a full-time postdoctoral researcher position in the area of Computational Mechanics at the Graduate Institute of Ferrous Technology (GIFT), Pohang University of Science and Technology (POSTECH), Korea. Candidates with a strong background in continuum/dislocation-based plasticity theory, computational mechanics of sheet metals, FE modelling of sheet metal forming processes… are highly encouraged to apply.

mohsenzaeem's picture

An elastic phase field model for thermal oxidation of metals: Application to zirconia

Abstacrt: A multi-phase field model was developed for non-selective oxidation of metals which captures both the oxidation kinetics and stress generation. Phase field formulation involved a non-conserved phase field variable as the marker for the metallic substrate, oxide scale, and a fluid phase containing oxygen, and a conserved phase field variable representing the concentration of oxygen.

Curve Fitting for Viscoplastic (Anand) Model in ANSYS

Hello everyone, 

            I would like to know if it is possible to use TBFT option in ANSYS to curve-fit Anand's model parameters using experimental force-displacement data.

     I am aware that the ANSYS manual  has description for hyperelastic and even chaboche model, but is there an established procedure to obtain Anand model parameters using experimental curve fitting ? 


Thank you. 


 Hi my friends!

I hope everythin's ok! 

As I previously said I'm doing some researches about fully developed turbulent flow inside an annuli.Now I've faced some problems. Does anyone know how can I calculate Darcy friction factor for a fully developed turbulent regime inside an annuli not using colebrook equations and moody diagram? is there any other way?

I'd be really thankful if anyone could help me .

PhD Scholarship in Geotechnical Engineering Postgraduate Research of the University of Adelaide

One research scholarship is immediately available to support a PhD
student to work on a project in Geotechnical Engineering area.  The project is funded by the Australian
Research Council (ARC) and lasts 3 years. 
The scholarship will provide a stipend of A$ 25,392 per annum (in
2014).  Tuition waiver will be
nominated.  Exceptional candidate is
eligible to be awarded an extra amount of allowance in appreciation of his (or
her) possible high quality research outcomes. 

New view of DNA

Recently, the classical view of DNA as an isotropic elastic rod has been questioned. Here we model DNA as an elastic rod inlaid with fibrils, based on which we have made prediction that is in consistency with experiments. Our analysis suggests that the bending of short DNAs can be facilitated if there exists a specific structural heterogeneity.

Journal Club Theme of April 2014: Challenges and Opportunities in 3D Printing: A Mini Introduction

3D printing, or Additive Manufacturing (AM), has drawn significant attention from both general public and research community in recent years.  Although the first prototype of 3D printing (called rapid prototyping) emerged about three decades ago and has gone through significant development, the recent explosion in its popularity appears to be mainly due to intensive media reports.

Is anyone familiar with deriving shape functions for different beam end conditions?

I am doing my research in nonlinear vibration of beams. In that research, I have to derive the shape function for different end conditions of the beam. Regarding this,I need some ideas. Are there books I can reference?

Thank you for your help.

ABAQUS fatigue and fracture

I am trying to find the rate of crack growth in steel beam under fatigue loading using ABAQUS... i am having trouble with the loading part.... How to provide cyclic loads in ABAQUS...and obtain the increment in crack length with time??? Please help


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