Multilayer Thermal Conductive Sheetsexamples|products|Murata Software Co., Ltd.

Example23 Multilayer Thermal Conductive Sheets

General

  • An analysis model is an alumina substrate, on which copper, nickel, and gold are plated. A thermal analysis is performed.
     

  • The temperature distribution, the thermal resistance between the temperature boundaries, and the heat flux distribution are solved.
     

  • Unless specified in the list below, the default conditions will be applied.

Analysis Condition

Item

Setting

Solver

Thermal analysis [Watt]

Analysis Space

3D

Analysis Type

Steady-State Analysis

Unit

mm

Options

None

Model

An alumina substrate is created by a box. A sheet body is created on the upper face of the box. Copy the sheet twice making it three.

Each sheet is given copper, nickel, and gold as material property. They are also given thickness as body attribute.

The sample project contains a model whose electrodes are made of solid bodies in addition to the one with electrodes of sheet bodies for comparison purpose.

The temperature boundary condition for the two models is 0 deg and 100 deg at the ends of the substrate.

 

Body Attributes and Materials

Multilayer Sheet Model

Body Number/Type

Body Attribute Name

Thickness of Sheet Body

Material Name

0/Solid

Substrate

 

001_Alumina *

4/Sheet

Electrode1

20×10-3[mm]

008_Cu (*)

5/Sheet

Electrode2

5×10-3[mm]

010_Ni *

6/Sheet

Electrode2

5×10-3[mm]

002_Au *

* Available from the material DB

 

Multilayer Solid Model (Thickness is same as that of sheet body)

Body Number/Type

Body Attribute Name

Material Name

0/Solid

Substrate

001_Alumina *

4/Solid

Electrode1

008_Cu (*)

5/Solid

Electrode2

010_Ni *

6/Solid

Electrode2

002_Au *

* Available from the material DB

Boundary Condition

Boundary Condition Name/Topology

Tab

Boundary Condition Type

Setting

100degree/Face

Thermal

Temperature

100[deg]

0degree/Face

Thermal

Temperature

0[deg]

 

Results

The temperature distribution and the thermal resistance across the two temperature boundaries are shown below. The unit of the color scale is [deg].

 

 

 

For both multilayer sheet model and multilayer solid model, the thermal conductivity of the electrodes is higher than the substrate. Their thermal resistance is lower than that of the substrate-only model.

The temperature gradient is low because the thermal conductivity is especially high on the wider areas at the ends of the electrode.

 

The number of element divisions is 24640 for the sheet body, and 54576 for the solid body.

The sheet model gives the results comparable to that of the solid model at the smaller calculation load.

 

The contour diagram of the heat flux is shown below. The unit of the color scale is [MW/m2].

The results of the multilayer sheet model is as follows.

 

 

The results of the multilayer solid model is as follows.

 

 

The multilayer sheet model and the multilayer solid model show almost the same heat flux density.

 

The thermal conductivity of Cu (Electrode1) and Au (Electrode2) is high and their heat flux is higher than Ni (Electrode2).

 

As the sheet bodies of the model are overlapping, the contour display of each sheet will overlap if they are output at the same time.

Select the body only of your interest on the body tree to see the results.

 

(Note)

If multiple sheet bodies are created on the surface of a solid body, they will work as multilayer thermal conductive sheets.

The heat conductivity in the face direction can be analyzed with the multilayer sheet model the same way as the multilayer solid model.

For the heat conductivity in the thickness direction, however, the multilayer structure is not considered and the thermal resistance is assumed to be zero. The sheet body, therefore, is not suitable if prominent temperature gradient occurs due to the heat conductivity in the thickness direction.

To take the temperature gradient of the heat conductivity in the multilayer direction, use the solid body.

To use Mesher G1, the multilayer sheet body must be the same form. (The body form is irrelevant in the case of Mesher G2.)