thermal stress on Truss
thermal stress on Truss
(OP)
Hi,
I used Ansys Workbench to analyze the truss structure. The structure basically looks like the figure in following link.
http://img585.imageshack.us/img585/512/solidstruct...
The thermal strain is about 650 microstrain applying 50 degrees Fahrenheit change.
But for fatigue, I need the stress. Ansys doesn't show high stress based on the thermal load.
The questions:
1. Will termal strain generate certain thermal stress?
2. Can thermal stress calculated as strain times elastic modulus?
3. If there is thermal stress, can I add up this with equivalent stress for overall stress?
Thanks.
I used Ansys Workbench to analyze the truss structure. The structure basically looks like the figure in following link.
http://img585.imageshack.us/img585/512/solidstruct...
The thermal strain is about 650 microstrain applying 50 degrees Fahrenheit change.
But for fatigue, I need the stress. Ansys doesn't show high stress based on the thermal load.
The questions:
1. Will termal strain generate certain thermal stress?
2. Can thermal stress calculated as strain times elastic modulus?
3. If there is thermal stress, can I add up this with equivalent stress for overall stress?
Thanks.






RE: thermal stress on Truss
Not always, but in your case, it will. A beam with a hinge and roller can strain without creating stress. In your case, strain in the horizontal truss will lead to bending in the columns.
2. Can thermal stress be calculated as strain times elastic modulus?
No. Strain in the columns does not lead to any stresses at all. You must consider the change in length of the truss and determine how that affects the various members.
3. If there is thermal stress, can I add up this with equivalent stress for overall stress?
Yes. You can combine thermal stress with other stresses using the principle of superposition.
BA
RE: thermal stress on Truss
RE: thermal stress on Truss
Is thermal stress already considered in Ansys equivalent stress?
I checked the experimental results and Ansys results. The strain values are close. But for stress, I am not sure if it is included.
RE: thermal stress on Truss
RE: thermal stress on Truss
Alternatively, you could visit the ANSYS forum on Eng-Tips.
BA
RE: thermal stress on Truss
RE: thermal stress on Truss
Excessive repetitive strain can create a fatigue condition; however, thermal stresses are usually not high enough to induce this, unless restraint creates a true stress condition.
If thermal stresses are induced, they are additive to other stresses.