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ravimech04333's picture

Fracture Mechanics

Hello...

Can any one help me in how to solve J INTEGRAL for simple 2D geometries.Atleast can anyone help me where can i get PDF files on J integral... Plz its urgent its a part of Thesis...   Plz post your conmments at ravikumar_04333@yahoo.com

low velocity impact on composite plate

HI,

     I m working on low velocity impact on composite plate. Can anybody tell me after modeling plate in matlab how can i analysis it in  Ansys software?

Geometric factor for mode II stress intensity factor for a finite strip under under pure shear loading

The geometric factor for mode I stress intensity factor for a finite strip under pure tensile loading is reported in Tada handbook as F(a/h) = 1.122 - 0.231(a/h) + 10.55*(a/h)^2 - 21.71*(a/h)^3 + 30.382*(a/h)^4 , but in the existing literature, I could not find such geometric factor for mode II stress intensity factor for a finite strip under under pure shear loading. Does anyone know such geometric factor for mode II stress intensity factor for a finite strip under under pure shear loading, if it is reported in the existing literature? or, if it is available in any unpublished sources?

Help with ABAQUS SIGINI subroutine

Choose a channel featured in the header of iMechanica: 

Dear ABAQUS Users,

I am trying to assign the initial stresses for a region in my model using the SIGINI subroutine. I learned some fortran programming skills the last week and I managed to open the file where the stresses that I retrieve from an Abaqus analysis and assign these stresses in Array using fortran commands.

Now I am stuck with the writing of the SIGINI subroutine where I have the corresponding stresses that I store in my Array to the corresponding NOEL and NPT.

Cai Shengqiang's picture

A theory of constrained swelling of a pH-sensitive hydrogel

Many engineering devices and natural phenomena involve gels that swell under the constraint of hard materials. The constraint causes a field of stress in a gel, and often makes the swelling inhomogeneous even when the gel reaches a state of equilibrium. To analyze inhomogeneous swelling of a pH-sensitive gel, we implement a finite element method in the commercial software ABAQUS.  The program is attached here.  Contact Shenqiang Cai (shqcai@gmail.com) for a description of the program.

Dear Omid and Sepehr

I think a non-zero entry in the stiffness matrix doesn't necessarily imply dependence of ith DOF on the jth DOF. This is the case also for standard FEM (without any enrichments). For example for a quadrilateral 2D element the x component of displacement has interaction with y component at each node, but as we know, two independent values of translation in x and y directions can

Parabolic distribution of shear stress

Hi all

According to Timoshenko beam theory shear stress is distributed uniformly across the cross-section depth which is contrary to real distribution of shear stress i.e parabolic distribution. I know there is a shear adjusment factor (5/6 for rectangular cross-section) can solve this problem. But I don't know how can I utilize this adjustment factor in the beam formulation to get parabolic distribution.

Could anybody please help me?

 

Regards

Huma

m_meisam's picture

Modeling concrete wall covered by FRP under blast load

Dear Guys

Is there any one that can help me for below questions?

1- Modeling FRP in abaqus CAE

2- Define interaction between FRP layer and concrete wall

Regards

M.Mojtahedpour

LG's picture

Some questions about wave propagation

Dear Sir

As we know, periodic signals are best analysed in the frequency domain while stochastic signals are usually more profitably analysed in the time domain. The analysis in the frequency domain usually concern only one signal while in the time domain often involves the comparison of several different signals.

A Problem in Nature Of XFEM Approximation


There is a basic problem in NATURE of approximation of discontinuity in element using XFEM.I tried to illustrate that below:
for example, If you consider an element with strong discontinuity( like fracture or contact) which usually we use heaviside function as enrichment function. we expect two parts of element deform independently because of nature of problem.

Mechanics connection to memory

Taxonomy upgrade extras: 

Mechanics connection to memory

Mechanical tension contributes to clustering of neurotransmitter vesicles at presynaptic terminals. 

Scott SiechenShengyuan YangAkira Chiba and Taher Saif

vikas sharma's picture

Damage Investigation In Drilling of Polymer Matrix Composites

hii friends

              I am doing project on damage investigation  in drilling of polymer matrix composite and using FEM approach ABAQUS 6.8. so i want to damage compare between trepanning tool & twist drill. i have problem in simulation and  plotting(graph). so plz solved this problem

Question in sequentially coupled thermal stress analysis using ABAQUS

I was wondering if anyone has solved a “sequentially coupled thermal stress analysis” problem using ABAQUS?

If so, here is what I am looking to solve.

Let’s assume we solved for the temperature (T) as a function of time and space using the transient heat transfer analysis given certain BCs.

Clarifications o Stroh formalism

sir,

I am solving some problomes for Stresses around holes for Anisotropic cases. In this connection most of authors have solved the stresses in cartesian co-ordinates only. Can I have any papers which are solved in polar co-ordinates by Stroh formalism for Stresses around holes in Composite laminates.So kindly help me

thanking you

 M.Ramesh Babu 

how to start a research

hi all,

 I am a mechanical engineer currently pursuing Master degree (Post graduation). Ultimately i also want to pursue a research leading to PhD after my master's. Its my burning desire to do some significant research in the field of Fatigue analysis using Fracture mechanics approach preferably for aerospace domain using advanced CAE softwares like Nasgrow, Afgrow, Abaqus, FE-safe, MSC Fatigue, etc,..

zishun liu's picture

International Journal of Applied Mechanics (IJAM) Vol.1 No.4

Forthcoming papers of International Journal of Applied Mechanics (IJAM) Vol.1 No.4 

1. “Strain Deconcentration In Thin Films Patterned With Circular Holes”, Matthew B. Tucker and Teng Li, (University of Maryland, USA). 

I'm looking for a new vibration exciter

I'm looking for a new vibration exciter which exciting frequency can reach 300hz .I'll use it to load the cantilever beam specimen , compare the  fatigue life of the specimen under different loading frequency. the electric exciter can not  generate the same amplitude under difference exciting frequency.

who can tell me that how can I found or design a mechine to finish the expriment.thank you

vh's picture

Compositional patterning in coherent and dislocated alloy nanocrystals

Variations in the distribution of the alloy components can significantly influence the electronic properties

of self-organized alloy nanocrystals. Using a combination of finite element and quadratic programming

optimization methods, we have developed an efficient numerical technique to compute the equilibrium

composition profiles in coherent and dislocated nanocrystals. We show that the variations in composition

profiles arise due to the competition between chemical mixing effects and the relaxation of composition-

dependent mismatch strain as well as strain due to dislocations. We find that the composition profiles

BoJing Zhu's picture

Comparison of intrapore velocities measured and simulated in the highly macro-porous biscayne aquifer

Using the data from 3D hybrid lattice boltzmann code under parallel environments, some interesting simulated results are obtained by using Tecplot.

Tips:

After download the attached files, please change files name from *.ppt to *.wmv, then they  can be display normally by media player  

Li Han's picture

Water diffusion and fracture behavior in nano-porous low-k dielectric film stacks

Among various low-dielectric constant low-k materials under development, organosilicate glassesOSGs containing nanometer-size pores are leading candidates for use as intrametal dielectrics infuture microelectronics technologies. In this paper, we investigate the direct impact of waterdiffusion on the fracture behavior of film stacks that contain porous OSG coatings.

kaushik das's picture

Symmetry breaking, snap-through, and pull-in instabilities under dynamic loading of microelectromechanical shallow arches

Arch-shaped microelectromechanical systems (MEMS) have been used as mechanical memories, micro-relays, micro-valves, optical switches, and digital micro-mirrors. A bi-stable structure, such as an arch, is characterized by a multivalued load deflection curve.

Light Activated Polymers

Soft active materials have received increasing interests recently. Here, soft materials can broadly refer to polymers, elastomers, hydrogel gels. Active materials mean that these materials can respond to external stimuli. Examples of soft active materials include shape memory polymers, environmentally responsive hydrogels, liquid crystal elastomers, etc.

Rui Huang's picture

Effect of constraint on swelling of hydrogels and formation of surface creases

Inspired by recent works by Wei Hong , Xuanhe Zhao, Zhigang Suo, and their coworkers, we started a project on hydrogels, with particular interest in various instability patterns observed in experiments. The attachment is our first manuscript on this subject. Through this work we hope to achieve the following:

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