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Beam on elastic foundation

Dear All,

I am wondering that is there any closed form solution for beam on elastic foundation in case which we have got two stiffness for the springs namely (axial and shear stiffness). The axial force are born because of the some loading conditions in the support.Would you please help me about this?

Thank you,

Parisa

Fracure mechanics

Hi Every body,

I know that the crack propagation energy release rate G is by defination the release of elastic energy and potential energy of loads per unit area of crack extension and for a linear body loaded by a single load P is given by :

G=P^2/(2b)*dc/da

Any body know if instead of load P, moment M is being used what would be formulation?

I really need this one

Thank you,

Parisa

Cohesive elements parameters

Dear All,

I modelled a beam with a hole and used cohesive elements on the possible crack plane.

When I run the model in 2D, it works very well and I can get the results pretty good.

Why running the same model in 3D (making 3D model and running it) has caused me a headach for a long time and I can not

get the results?

Any idea highly appreciated,

Thanks,

Parisa

Tension in screw because of moment in section

Hi,

In a section of a beam with a rectangular hole which has got crack (see attached picture); Moment and shear are specefied. I can undrestand why we have tension in the screw because of the shear but why do we have tension because of moment in the screw? Can anybody explanin me why moment in the section can cause tension in the screw which should be accounted for in the screw design.

 

Thank you,

Parisa

Finite element modelling

Hi,

I am modellling a beam with a  hole in ABAQUS and runs pretty well. Now I would like to model a small area of the beam.

For an example the rectangular area which has been shown in the attachment file. When I model it What should I put as a boundry

conditions ?. I know that you may say that reactions of the beam (namely, Moment, shear, axial force) but I would like to just

investigate this part under pure bending and shear. What should I do? 

A model without  support is unstable ????

Modelling 2D instead of 3D in ABAQUS

Hi,

I modeled a beam with a hole in ABAQUS in 2D and now I would like to stick one plate to the beam surface.

I can do it easily in 3D but actually I do not like to jump 3D because It will make analyses very hard to follow.

My question is that, Is there anyway to stick a the plate to beam in 2D in ABAQUS and avoid 3D?

Thank you,

Parisa

Cohesive elements parameters

Hi,

I am working a long time on using cohesive elements in ABAQUS but up to now my efforts have be unsucessful.

I want to use of cohesive elements with the following paramters:

Damage initiation: Normal stres= 1.9 MPa, shear stress= 6.2 MPa 

Damage evolution:  Mode I fracture energy= 0.5307, Mode II farcture energy= 0.6623

Could any body kindly let me know that what would be my model E/Knn, E/Kss parameters?

Thank you,

Parisa

 

Stiffness of a beam

Hi,

As a part of my research, I would like to break down a simply supported beam to two beams shown in the attachement.  I expect to remove the bond and use of springs for transforming deformation of upper beam to lower beam. What could be the stiffness of springs which could be used in new model?

Thank you for your comment,

Parisa

 

Solution for beam on elastic beam

Hi,

I am looking at some deformations in beams.  I have an elastic beam sleeping on another elastic beam and connected via springs that have two dimensional stiffness. Anybody knows how should I go for closed form solution of this beam and obtain deformations in springs??? I can model it in sap2000 or ABAQUS and solve it at there but I am now looking for only closed form solution... Besides, I am looking for deformations in spring caused by applied load. I have attached a sketch of my model. Any idea or comment will be highly appreciated.

Thank you for your comment, 

Stress intensity factors at crack tip for beam with a hole

Hi everybody,

I am dealing with a beam with a hole containing a crack loaded at the mid-span. I am wondering if the stress intensity factors

(KI, KII) closed form solution have been expanded for this case or not? I would appreciate if anybody could hlep me about this

case.

Thank you,

Parisa

Fracture toughness of wood in mode II

Hi everybody,

I have done some experiments on the fracture toughness in mode II of wood specimens using attached geometry;so using

formula KIIc= 5.11P(3.1415*a)^0.5 /(2BW) I was able to calculate the frcature toughness of wood, but I am quite suprised

why this equation does not iclude depth of the specimens and moreover, I think that I have obtained higher values for the

fracture toughnes values. Is there any other formulation for obtaining the fracture toughness in mode II for this specimen?

P.s. dimension of my specimens is 100*100*63mm

Analysis of beams with hole

Hi everybody,

Is there any limits for using of LEFM?  I have modelled a beam with a penetration.I have moved the holes vertically in the beam and obtained the stress intensities for each movements at the corners of the hole. Now the hole is closing the edge, stress intensities in mode I and II, suddenly change values (positive to negative and vice versa)  what does this mean ?... Does it mean that I should limit my movements?,,,,

Thank you,

Parisa, 

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