# research

## Positive definite stress-strain matrix in Ansys

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Dear friends,

I'm an MSc. student at Bogazici University, Turkiye and I'm working on a thesis project about the failure behaviour of fiber reinforced laminated composite plates under different loading types. The material which we use are AS4 fiber reinforced  prepregs and their mechanical properties are the following:

E11 =134,000 MPa

E22 = E33= 9480 MPa

G12 = G13= 5490 MPa

## Micro Modelling of Masonry Wall Panel in ABAQUS

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Hi All,

I am doing research of micro modelling of masonry panel using ABAQUS. I try to model the interface using cohesive element in ABAQUS. I want to compare the result with the experimental research available.

Is there anyone here have done that or doing it right now. I have some difficulties to define the interaction between cohesive element and bricks. It is really difficult since I use abaqus standard, to define the surface one by one. Until today I also can not make my cohesive element geometry thickness to be zero.

## How to view random material properties in ABAQUS

In ABAQUS, I have 100*100 elements and the material properties of each element (say elasticity, angle of friction) varies. How can I view (plot) the mesh as per material properties value (say elasticity) (like colorbar)

## Fliiping nodes normal directions for a solid section

Does Anyhone have any idea about fliping the normal directions for a solid sections to be pointed in not out, because am having an error: nodes have incorrect normal definitions.

## Delamination and Cohesive zone model

I want to work on delamination and cohesive zone model. I would also like to model this in Abaqus. I’ve read the material available there but it’s not adequate. I would like to know the concepts and fundamentals of the cohesive zone model and its implementation. Can anyone explain this? Please suggest some good literature/books on this for beginners.

Praveen.

## ABAQUS Fully-coupled Thermal Analysis / ABAQUS Explicit

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Hi everyone,

I am new to ABAQUS. I am working on a research topic where I need to study the temperature increase arised due to strains applied to a body. From the user's manual I understood that I need to use "Sequentially Coupled Thermal-Stress Analysis" for my model.

## Crack Initiation with UMAT

Dear all,

I want to model crack initiation and propagation for a user defined material, using Abaqus. When I try to model , I get the following error:

A MATERIAL PROPERTY THAT IS NOT ALLOWED WITH A USER MATERIAL HAS BEEN SPECIFIED

when I take out critical damage initiation, the model works fine; which means that it doesnt allow me to couple UMAT with crack initiation. Does anyone know how to handle this problem?

All the best,

Panos

## how to apply a torsional moment to shell made up of composite in ANSYS

HI,
I am performing a non linear buckling analysis in ansys using shell 181 element. My geometry is made up of composite material and has a shell structure. The shell is subjected to torsion at one end so as to buckle throughout it length. the other end is fully constraint.
My problem is how to apply this torsional moment at the free end.

## Stress Field near a crack tip with different crack fibre orientations of an orthotropic lamina

I was going through these papers:

1.P.K. Sarkar and S.K. Maiti, 'Prediction of mode-1 fracture toughness of unidirectional fibre composites with arbitrary crack fibre orientation from its lowest or matrix fracture toughness'. int. J. Fracture, vol. 40. pp. R91-R96, (1989).

2.S.K. Maiti and P.K. Sarkar, 'A method of calculation of total strain energy release rate and its layer-wise distribution for an arbitrary through the thickness crack extension in a composite laminate', Engg. Fracture Mechanics, vol. 36, pp. 639-646,(1990).

## Fatigue Analysis on ANSYS 11.0

I am currently having difficulty modelling fatigue analysis on a wheelchair frame with hollow circular sections (pipe 16). When assigning the stress locations it says that the stress is not available for that node.

Any help would be appreciated!