Menu

Discussion Forum

New Discussion
Filter

Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.

laser material removal simulation

Posted Jan 24, 2012, 12:14 p.m. EST Heat Transfer & Phase Change, Materials Version 4.2, Version 5.2 4 Replies

Hirendra Choudhary
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

hi , i am trying to simulate material removal (steel) by a laser by changing the density and other properties of steel to that of air once the temperature goes above the vaporization temperature but the problem is that as soon as the material cools, the density goes back to that of steel . i want to make a permanent change in the material property .
the expression which i am using is
rho = rho_steel*(T<T_vap) + rho_air*(T>=T_vap)
here T_vap is the vaporization temp.
Can anyone help me with this ?
Thanks
Hirendra
4 Replies Last Post Mar 7, 2012, 5:50 a.m. EST
Huang simom
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago Feb 9, 2012, 1:04 a.m. EST
Hi, just build a function() under the material node.

by the way, Do you think this kind of method to model the material removal is ok? because during the laser-material interaction, the laser-material interface change with time(due to the accumulated temperature of the absorbed laser energy). this kind of method do not change the so-called interface, so the temperature at the original boundary(initial laser-material interface) will increase with time, but in fact, at the case of evaporation cutting or something similar, the part of material whose temperature arrive the evaporation temperature. this part of material should be remove.

best wishes to you and your family.
Hi, just build a function() under the material node. by the way, Do you think this kind of method to model the material removal is ok? because during the laser-material interaction, the laser-material interface change with time(due to the accumulated temperature of the absorbed laser energy). this kind of method do not change the so-called interface, so the temperature at the original boundary(initial laser-material interface) will increase with time, but in fact, at the case of evaporation cutting or something similar, the part of material whose temperature arrive the evaporation temperature. this part of material should be remove. best wishes to you and your family.
Hirendra Choudhary
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago Feb 13, 2012, 1:34 a.m. EST
hi ,
first of all thank you for replying :) actually my problem is how to make a permanent change in the properties as in once there is a switch in the property , it should remain so even if the material has cooled down.Material properties are a function of temperature so as soon as the temperature falls they switch back again to that of the previous material and i want to avoid this.

i think it is quite a good way to simulate material removal as it is not possible to actually remove elements in COMSOL , by the way do you know any other way to do it ? i am open to suggestions .
hi , first of all thank you for replying :) actually my problem is how to make a permanent change in the properties as in once there is a switch in the property , it should remain so even if the material has cooled down.Material properties are a function of temperature so as soon as the temperature falls they switch back again to that of the previous material and i want to avoid this. i think it is quite a good way to simulate material removal as it is not possible to actually remove elements in COMSOL , by the way do you know any other way to do it ? i am open to suggestions .
Huang simom
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago Mar 1, 2012, 9:29 p.m. EST

hi ,
first of all thank you for replying :) actually my problem is how to make a permanent change in the properties as in once there is a switch in the property , it should remain so even if the material has cooled down.Material properties are a function of temperature so as soon as the temperature falls they switch back again to that of the previous material and i want to avoid this.

i think it is quite a good way to simulate material removal as it is not possible to actually remove elements in COMSOL , by the way do you know any other way to do it ? i am open to suggestions .


firstly, sorry to the later response.
if I have made all clear, you just change the material density into the air density when the temperature pass the evaporation temperature, and while when the temperature cool down (i.e. the laser is turn off), this port of material (whose temperature have passed over than the evaporation temperature once) never turn back into the material density according to the temperature-dependent properties (the general setting is bidirectional instead of one-way). the material properties change way to simulate the material removal, I have tried a few months ago.
let us think if we only consider the temperature or material removal in the pulse width, i.e. the laser is on all the time, and there is no such question you encountered. there material density is set the density properties (this is simple ). but the temperature of the laser-material interaction boundary do not change. theoretically, if this method is right, this temperature is fixed at the evaporation temperature. Is there anything wrong with my model or somethings i miss?
if you are convenient, we can exchange our other IM (instant message) to have a more instant communication so that we can cooperate to work all out. look forward to you reply sincerely.
[QUOTE] hi , first of all thank you for replying :) actually my problem is how to make a permanent change in the properties as in once there is a switch in the property , it should remain so even if the material has cooled down.Material properties are a function of temperature so as soon as the temperature falls they switch back again to that of the previous material and i want to avoid this. i think it is quite a good way to simulate material removal as it is not possible to actually remove elements in COMSOL , by the way do you know any other way to do it ? i am open to suggestions . [/QUOTE] firstly, sorry to the later response. if I have made all clear, you just change the material density into the air density when the temperature pass the evaporation temperature, and while when the temperature cool down (i.e. the laser is turn off), this port of material (whose temperature have passed over than the evaporation temperature once) never turn back into the material density according to the temperature-dependent properties (the general setting is bidirectional instead of one-way). the material properties change way to simulate the material removal, I have tried a few months ago. let us think if we only consider the temperature or material removal in the pulse width, i.e. the laser is on all the time, and there is no such question you encountered. there material density is set the density properties (this is simple ). but the temperature of the laser-material interaction boundary do not change. theoretically, if this method is right, this temperature is fixed at the evaporation temperature. Is there anything wrong with my model or somethings i miss? if you are convenient, we can exchange our other IM (instant message) to have a more instant communication so that we can cooperate to work all out. look forward to you reply sincerely.
Hirendra Choudhary
Send Private Message Flag post as spam

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago Mar 7, 2012, 5:50 a.m. EST
hi , i have sent you a private message , take a look at that .
Hirendra
hi , i have sent you a private message , take a look at that . Hirendra

Note that while COMSOL employees may participate in the discussion forum, COMSOL® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team.

Suggested Content