Feasibility of Measuring Stress in Glass with a SCALP



Photo of Nabhajit Goswami

Nabhajit Goswami


Michigan Tech University


Photo of Stephen M Morse, P.E., Ph.D.

Stephen M Morse, P.E., Ph.D.

Assistant Professor, Civil and Environmental Engineering Assistant Professor, Mechanical Engineering-Engineering Mechanics

Michigan Tech University




The SCALP device is designed to measure the residual compressive surface stress of glass. As the SCALP does not rely on the birefringence properties of the Tin present on the glass surface the device should be able to measure the stress in a glass sample regardless of whether it is due to the residual compressive surface stress or mechanically imposed due to an applied load. The feasibility and accuracy of using a SCALP to measure imposed stress due to an applied load are explored for heat-treated and annealed glass. Multiple specimen sizes and heat-treatment are used in a 4-point bending test with varying applied loads. The ability to quickly and easily measure the stress in a glass component provides valuable insight into the loading (state of stress) before and after installation and while the component is under load.


Glass is a construction material that is constantly evolving with the passage of time. With new architectures, the shape and use of glass from rectangular window pane have evolved to

Members Only


Optical anisotropic materials which can resolve light into two orthogonal components and transmit the components with different velocities are known as birefringent or birefractive or doubly refracting materials. Since the

Members Only

Test method for determining the feasibility of measuring stress in glass

A 4-point bending rig was built for this experiment and the stresses measured with the SCALP and the GASP were compared to the stress calculated analytically at the extreme most

Members Only

Results and Discussion

Tables 1 through table 3 are the SCALP reading of the fully tempered glass with the difference in stress between analytical and measured and the percentage difference tabulated. The SCALP

Members Only


This paper looked into the method to measure the installation stresses using instruments used in the glass industry – the SCALP and the GASP. The experiments were repeated to see

Members Only

Rights and Permissions

  • Aben, H., Anton, J., Errapart, A., Hödemann, S., Kikas, J., Klaassen, H., & Lamp, M. (2010). On non-destructive residual stress measurement in glass panels. Estonian journal of engineering, 16(2), 150.
  • Äppelqvist, M. (2015). Curved glass: an obstacle or opportunity in glass architecture.
  • Belis, J., Inghelbrecht, B., Van Impe, R., & Callewaert, D. (2007). Cold bending of laminated glass panels. Heron, 52(1-2), 123-146.
  • Trate, D. J., Griffin, J. A., & Zickel, M. (1999). Windshield Investigation-Manufacturing & Installation Stresses (No. 1999-01-3160). SAE Technical Paper.