Temperature Gradient

 

 

 

Enter the temperature differences between the tops and bottoms of beam or plate elements for thermal stress analysis. Modify or delete previously entered temperature differences.

The temperature gradient analysis is applicable for elements with bending stiffness such as beam and plate elements. In the case of a beam element, enter the temperature difference and the corresponding distance between the extremities of the element with respect to the local y and z-axes. In the case of a plate element, the temperature gradient can be represented by the temperature difference between the upper and lower faces of the plate and the plate thickness. The gradient temperature produces the following equivalent moments:

    • In the case of a beam element

 

    • In the case of a plate element

 

Where, is the linear thermal expansion coefficient, E is the modulus of elasticity, I is the moment of inertia about the relevant axis of the beam element, is the temperature difference between the two extremities (outermost faces) of the element, h is the distance between the two extremities of the beam section, t is the thickness of the plate and is the Poisson's Ratio.

 

 

 

From the Main Menu select Load >  Temp/Prestress > Temp. Gradient.

 

 

Load Case Name

Assign the load case name. Click to the right to enter additional load cases and modify or delete existing load cases.

 

Load Group Name

Select the desired Load Group Name. Click to the right to enter additional load group names and modify or delete existing load group names.

 

Options

Add: To enter new or additional temperature gradients

Replace: To replace previously entered temperature gradients

Delete: To delete previously entered temperature gradients

 

Types, Gradient

Select the element type for which Temperature Gradient is to be specified. Refer to the figure to enter the required data.

Beam

T2z - T1z: Temperature difference between the two outermost faces in the element local z-direction

Use Section Hz: Use the section dimension information as is.

Hz: Distance between the two faces in the element local z-direction

T2y - T1y: Temperature difference between the two outermost faces in the element local y-direction

Use Section Hy: Use the section dimension information as is.

Hy: Distance between the two faces in the element local y-direction
 

Plate

T2z - T1z: Temperature difference between the two faces in the element local z-direction

Use Section Hz: Use the section dimension information as is.

Hz: Thickness of the plate element

 

Revision of Civil 2015 (v1.1)

Q1. I applied the Temperature Gradient load of 50 °C (25 °C at the top and -25 °C at the bottom, linear variation in between) to the horizontal member and got the deformed shape of horizontal member in hogging (upwards). I would like to know why the bending moment diagram is sagging (downwards), while the member is deflected in hogging (upwards).