Validation Case: Bimetallic Strip Under Thermal Load

This article is part of the series of FEA validation cases performed using OnScale Solve.

The FEA model bimetallic strip under thermal load. Bimetallic strips are subject to bending due to heat – and can be used to convert change in temperature to mechanical displacement.

The resulting comparison of the simulation results against the analytical calculations validates the use of following conditions for thermomechanical static analysis in Solve:

• Thermomechanical Solver
• Temperature Load
• Restraints

Geometry:

Download the geometry here used for this analysis:

Geometry Dimensions

• Part 1: 20cm x 0.3cm x 0.1cm
• Part 2: 20cm x 0.3cm x 0.1cm

Material:

These materials are taken directly from the OnScale library of materials.

Part 1:

• Iron
  • Young’s Modulus (Ea) = 200 GPa
  • Density (ρb) = 7870 kg/m³
  • Thermal Expansion (γb) = 2e-5 1/K
  • Specific Heat (Cpb) = 480 J/(kgK)
  • Thermal Conductivity (κb)= 60 W/(mK)

Part 2:

• Cast Iron
  • Young’s Modulus (Eb) = 200 GPa
  • Density (ρb) = 7870 kg/m³
  • Thermal Expansion (γb) = 1e-5 1/K
  • Specific Heat (Cpb) = 480 J/(kgK)
  • Thermal Conductivity (κb)= 60 W/(mK)

Note: All other material properties can be left as their default values.

Physics:

Mechanical Physics:

• Restraints (Fixture) – Part 1

• Restraints (Slider Z) – Part 1

• Restraints (Restraint Y) – Part 2

Thermal Physics:

• Temperature – 100°C

Meshing:

OnScale Solve automatically generates a 3D second-order tetrahedral mesh. The meshing statistics are:

Mesh Quality: Very Fine

Analytical Solution:

The values for d_x and d_z are taken from the center middle of the max X extent. The contact point between the top and bottom plate.

d_x:

The equations were taken from Roark’s Formulas for Stress and Strain, Eighth Edition

Results:

 

Output Variables	Analytical Method	Onscale Solve
dx (m)	30um	30um
dz (m)	1.5mm	1.497mm
σxx (MPa)	50MPa	50MPa

References:

[1] (2011)”Roark’s Formulas For Stress And Strain, Eighth Edition”, W. C. Young, R. G. Budynas, A. M. Sadegh