How to vary thermal exposure time(Steady state thermal)

Is it possible to vary thermal exposure time in Ansys? like for an hour or certain minutes?@peteroznewman

Answers

  • peteroznewmanpeteroznewman Member Posts: 11,071

    @PEP_ELZA

    If you selected Steady State Thermal, that means you don't care how long it takes to get to that distribution of temperature.

    If you care about how long it takes to get to Steady State, then you use a Transient Thermal analysis.

    Why do you care how long the materials are exposed to the temperature?

    One reason people care about time is if the structure is under load and the material will creep. Creep is solved in a Static Structural model if the temperature is at Steady State, but you have to add a Creep model to the material in Engineering Data.

  • PEP_ELZAPEP_ELZA Member Posts: 20
    edited January 20

    Hi sir,

    I am doing a validation study on thermal analysis on 'I section' steel beam(both steady state and transient). I just wanted to know how long the member can withstand fire. In the reference paper it was given as 28 minutes and 17 minutes respectively in each case . Is it possible to get that result in Ansys? or just the temperature response is available?

  • peteroznewmanpeteroznewman Member Posts: 11,071

    @PEP_ELZA

    How does the paper define "withstand fire"?

    If the I-beam is under an axial or bending load, and the material model includes temperature dependent modulus and plasticity data, it is possible to predict in ANSYS how many minutes before the beam fails to support the load from a transient structural simulation where the temperature is increasing with time. If the material model includes a creep model, it is possible for ANSYS to compute the time to failure to support the load from a steady state thermal solution.

    Or do you mean how long before the material melts? Ansys can do that too!

  • PEP_ELZAPEP_ELZA Member Posts: 20

    The peak temperature at the flange just before lateral torsional buckling failure.

    The beam is under 2 point loads equally spaced from center. The material model includes temperature dependent modulus and plasticity data.

    The time data available will be based on certain time period right? say if I've applied the loads in a single step the time period will be 1s right? How to interpret that in minutes?

    Is it possible to simulate 1 hr. time exposure to the beam in ANSYS?

    Thanks in advance

  • peteroznewmanpeteroznewman Member Posts: 11,071

    @PEP_ELZA

    In a transient structural simulation, time is measured in seconds so divide the seconds in the simulation by 60 to get minutes. The end time to simulate 1 hour is 3600 seconds.

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