research

Dear Friends,

     I have developed a ser of 2-D finite elements for the problems of structural mechanics. These two dimensional elements are capable of accurately predicting three dimensional stress states using three diemnsional constitutive law. My doubt is: can these elements be used for the analysis of 3-D crack propagation using XFEM?.  The displacements chosen for these elements are simple.

Subramanian

I am using Deform 3D for my analysis but wats the problem in this software. Can anyone help in designing rectangular die with a ram to press a rod of dia15 mm and length 120mm in DEFORM 3D?As I am not getting way to design die     

Lately I began to wonder why I hadn't learned how to calculate the beam shear stiffness in college. I vaguely recalled that the teacher told us the shear stiffness could be omitted in the beam calculation compared to the bending stiffness.

Can anybody show me how to calculate the shear stiffness if it is large enough and cannot be ignored?  Like the example shown in the picture below

Hey to imechaica, i am doing my M.E Project in composites.i have done finite element analysis of composite plate with different boundary conditions and  different orientation angle with antisymmetric stacking sequence. i absorve  tip center displacement of cantilever plate is increasing with orientation angle increment and for simple supported plate it decreases.

stacking sequence is [0/-θ/θ/-θ/θ/0] 

please help me to understand this. 

Looking through books and papers I see an often quoted equation to show that the contact radius (a) of spherical indenter of radius (R) is related to the indentation depth (h):

a= √(R.h)

However, using simple trigonometry of a spherical cap it can be shown that:

a=√(2Rh-h2)

Contact area is very important for use in nanoindentation - however, if it is based on the wrong contact area calculation, then more errors become apparent.

Hi all,
I 'd like to ask whether anyone has applied XFEM for a user-material (UMAT). What is the process to do that? Could anyone provide some advice, documentation or guidelines?

All the best,
            
Panos

p.s. I 've heard that a UEL code is needed to couple XFEM with UMAT.

Dear friend:

            As known to all, the magnitude of the stress/strain at the crack tip is  mathematically infinite,while it is physically finite. So,what i am concerned is how to caculate the value of the stress/strain at the tip.What's more, i doubt that  whether the CTOD is constant during the propogation process.if yes.so can i take a constant range of the limited stress/strain near the crack tip? If there is any reply ,i will be appreciated!

The response of structural materials to external mechanical load may strongly depend on the rate at which the load is imposed. For example, a specimen may exhibit ductile fracture if loaded at quasi-static rate (strain rate below 1.0/s), but may show brittle fracture under impact (high-rate) loading. According to the classic monograph of Professor Marc Meyers, if the strain rate is above 100/s, it can be put into the high-strain rate regime. The mechanical behavior of structural materials under such loading conditions is dubbed dynamic.