Hi,
I am trying to model a composite tube with bilinear isotropic material property in ANSYS WB which gets crushed under impact using. After I run the simulation the material tends to act as a spring. Wanted to know if this is the way it is supposed to behave? and how can I make the tube...
Hi Doug,
I used the same method you mentioned here but am having a lot of convergence issues. This is the command being inserted under the spring,
et,_sid,COMBIN39,0,0,1,0,,1
r,_sid,0.0, 0.0, 0.001016, 2224, 0.002032, 4448,
rmore, 0.003048, 6672, 0.004064, 8896, 0.00508, 11120...
Hi,
Sorry for the late reply. I forgot to mention that I got the same results from ANSYS for this simulation. So Pete's approach and code is right!
Thanks,
David
Hi All,
I am working on a simulation where I am using a spring in ANSYS Workbench 11.0, and would like to change the slope of the spring when the force in the spring exceeds a certain value. I do not know how to extract the force in the spring. Is there any way I can do this in ANSYS WB 11.0...
Hey guys I am currently working on a impact simulation problem in ANSYS WB. The problem is that I am using an educational version which does not have the LS DYNA solver, so I wanted to ask if you guys using a LS DYNA solver? If not where did you learn to carry out drop tests in ANSYS WB...
Yes you are right but I want the stress strain curve for the geometry only and don't want to characterize the material.
The load-deflection curve was obtained from a reference standard handbook so even though there must have been some bowing, I do not know the values of the out of...
Thanks for the reply & sorry for not providing details. This is a composite tube with a quasi-static compressive force applied to it, so I guess it would be the parts overall length that is used for calculating strain. The load-deflection curve is highly non-linear so no constant Young's...
Hi,
I have the load-deflection data for a composite tube and would like to find the stress-strain curve. I know the dimensions of the tube.
Is it just calculating stress=force/area & strain = change in length/original length at each point from the load-deflection curve or do I have to take...
Hi,
Like the subject line says, I am looking for a pro/engineer cad model of a 5/16" grade 18 bolt which is 1 1/4" long.
Anyone know of any resources or have the model themselves?
Thanks,
David
Hi,
I am trying to model a Carbon/Epoxy structure in a finite element software but the software does not have the capability to analyze composite materials at this point. So, I wanted to find the equivalent Young's modulus and Poissons ratio so that it can be treated as an isotropic material...
hmmmm that is what i am trying to figure out....i.e. if I can pre-program an acceleration, disp, vel profile in ANSYS. will let you know as soon i figure it out.
Thanks,
David
I have attached the reference used to get the acceleration crash pulse and time period data. Fig. 1 (a) on page 3 shows the crash pulse and also the change in velocity to be 42...
I just noticed a change in velocity, deltaV = 42 ft/sec....which is equal to ((48G's*32.2*0.054sec)/2) corresponding to the triangular acceleration crash pulse also given in the specifications, but will this change in velocity be the same as initial velocity?
I am trying to verify my answer...
Ok I take that back.........applying an initial velocity will also require a transient analysis since the spring is nonlinear........but will applying an intial velocity to the mass be same as applying the acceleration crash pulse to the fixed support?
David
Hi everyone, I seem to be having a little conceptual problem. The spring-mass model here was for a helicopter seat (where mass represents the mass of man and seat) and the acceleration pulse was taken from a military standard for dynamic testing of a helicopter seat.
Now, I cant understand if...
Pete thank you again for your valuable help!! the matlab code runs fine and the next step for me would be to add some damping to the system to represent the crash of the aircraft floor.
The force on the man will depend on the spring force which is an independent function of time. So even...
Hello,
I want to find the load-deflection characteristics of a composite crash tube used in aircraft seats for impact energy absorption. Can anyone tell me if it is possible to model this in ANSYS using a quasi-static analysis without the LS-DYNA solver? I tried to do this in ansys with...
wow thank you so much!! I really appreciate your help! Your logic seems to be right and excel calculations also look good. I will go through it again and try to validate it........
Thanks,
David
My system is similar to the one shown on page 5 of the paper attached except that it does not contain a damper, the spring is non-linear and the G forces are higher.
Greg what are you referring to when you say it is contradictory...
