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mjalilych1's blog

2D corotational beam

Submitted by mjalilych1 on

hello Dear friends

I am phd student in mechanical engineering. I want to compare field consistent total lagrangian 

and corotational formulation for geometrically nonlinear 2D beam analysis. I wrote

a code for total lagrangian approach and my results are exct but in corotational

I have some difficulties in coding. if someone has a sample corotational code please

contact with me.

 

 

 

ill condition tangent stiffness matrix

Submitted by mjalilych1 on

hello Dear friends

I study large displacement analysis of euler-bernoulli beam. the beam is under pure bending moment.

wtangent stiffness matrix is dependent to tanget of rotation. so when rotation of nodes approches 90 this matrix become ill condition. I use of matlab for coding. I was wondering if some one give me a solution.

best wishes.

how to convert total lagrangian tangent stiffness to corotational

Submitted by mjalilych1 on

hello Dear friends

I am working on large displacement of euler beam. I used total lagrangian approach. because of field consistency between degrees of freedom(displacement and theta) tangent stiffness matrix depends on tangant theta and consequently becomes singular for theta=90. so I am seeking for a method to overcome this problem. I believe that the solution is to remove rigid body rotation from analysis. please correct me. is this reasonable. if yes how should I remove rigid bodu rotation

best regards.

feasibilty of corotational formulation

Submitted by mjalilych1 on

hello Dear friends

I am working on geometrically nonlinear behavior of 2D beam.

I used field consistent approach using total lagrangian. because of field consistency, satisfication tangent stiffness matrix is dependent to tangant of node angles. this means that when beam is subjected to pure bending when angle of rotation approches to 90 degree, tangent stiffness matrice become singular. can any one give solution to this problem. how about corotational formulation.

thanks a lot.

best regards.

cantilever with end moment

Submitted by mjalilych1 on

hello Dear friends

I am working on large deflection of cantilevers with total lagrangian approach. my code is converged very well in cantilever with end point load but when I apply end moment the problem does not converged and tangent stiffness matrix became singular. if there is any special note that I ignored. please help me.

convert load control to displacement control

Submitted by mjalilych1 on

Hello Dr. scientists

I want to study nonlinear behavior of williams toggle frame by finite element method.

I use of load control method and my results is a little different. is it reasonable that I change to displacement control. if ok please help me on useful literature in this topic. 

thanks in advance.