The following commands set up the transient analysis: ! Convection loads with independently varyingīLOCK,0,5,0,1,0,1 ! Block 5x1x1 inches in sizeĪ simple block of SOLID70 thermal elements is formed:Ī thermal transient analysis is planned for the above model. Note required material values Density, Thermal Conductivity, and Specific Heat: The following APDL commands build the model. The only load on this model will be a time-varying convection load on one end. Thermal Model ExampleĪ simple Ansys thermal model is built with 8-node brick SOLID70 thermal elements. The purpose of this document is to illustrate the time-dependent Table Array technique for describing time-dependent loading when using the Ansys Mechanical APDL finite element analysis program, with a blend of rapidly-changing loads and slowly-changing loads in the model, as often seen in thermal transient work. This technique can be seen inside Workbench Mechanical models that have time-varying loads. Solutions are formed at all times entered in the time-dependent Table Arrays, and at other substeps.
![toy story 2 plot toy story 2 plot](https://www.simuleon.com/wp-content/uploads/2015/04/Structural-Analysis-Multiphysics-Thermal-Structural.png)
There are two commonly used ways in Ansys in which a blend of suddenly changed loads can be mixed with loads that ramp up and down gradually. As mentioned above, a convective heat transfer coefficient may have a nearly instantaneous step change, while a bulk temperature may change with a much slower ramped value. The KBC,1 setting will cause loads to instantly change value to the final setting for the load step, from the first substep onward. The default KBC,0 setting causes loads during the substeps to ramp up or down in value from one load step to another. It is common to guide the number of substeps with a DELTIM command in transient analysis, or a NSUBST command in static nonlinear analysis. In transient or nonlinear analysis, it is usually important to form intermediate time solutions inside load steps, at several substeps. The default KBC,0 setting ramps loads from one load step to another. Loads can be step-changed from one load step to another if the command KBC,1 is executed prior to SOLVE. Major load changes can be formed at the ends of individual load steps, with a SOLVE command executed for each load step. This “tips & tricks” article presents a simple example of such a procedure.Īnsys can form solutions at a variety of times during a transient analysis. In the Ansys finite element analysis program, Table Arrays are often employed to describe these time-dependent functions. In thermal transient analysis, time-dependent values of the bulk temperature and convection coefficients must be described as functions of time.
![toy story 2 plot toy story 2 plot](https://i.pinimg.com/originals/7e/0f/f2/7e0ff2c4c73716a4d6de3b6c9cf088e9.jpg)
![toy story 2 plot toy story 2 plot](https://www.simscale.com/wp-content/uploads/2017/01/convergence-FEA-featured.jpg)
Bulk temperature may ramp up and down slowly, whereas water flow rates may change quickly as pumps go on or off, or as valve positions change. The bulk temperature of the water may change at times that differ from times at which the flow rate changes. Consider the example of both water temperature and flow rate in a pressure vessel changing over time. When performing a time-transient thermal analysis in FEA, it is common to have bulk temperature loads and convective heat transfer coefficients that change values during the transient.