Salim outlines new way to predict laminated glass failure

January 29, 2024

Hani Salim

A Mizzou Engineer has outlined an innovative new way to simulate and predict how laminated glass windows might fail during an explosion.

Hani Salim, a professor of civil and environmental engineering, and his team have created a simulation approach that integrates detailed modeling with a relation considering both elasticity and damage.

Laminated glass windows, commonly used in vehicle windshields and structural facades, offer the advantage of keeping glass fragments together after cracking. This characteristic makes them the preferred choice for structures susceptible to explosions or blasts.

But it’s tricky to predict at exactly what point that glass will fail under pressure. There are existing software tools, such as Abaqus and ANSYS, that allow engineers to simulate the behavior of materials in certain conditions, but they’re not perfect.

“We need to understand how glass breaks, how fragments propagate cracks, and how it responds all the way to failure,” Salim  said. “Our goal is to enhance predictive tools for better designs. The idea is to improve upon existing codes and refine predictions by utilizing a different type of damage model.”

Salim’s simulation method is unique because it veers away from criteria typically used to predict material failure. Rather than the conventional approach of predicting failure in material exhibiting ductile behavior, such as plastic. For laminated glass, the research team used what’s known as the Rankine Failure Criterion for Damage Evolution, which predicts failure in material exhibiting brittle behavior.

Salim’s team was able to validate the accuracy of their model by conducting simulations and comparing the results with actual tests using a shock tube.

“This paper reveals the limitations of existing codes, such as Abaqus or ANSYS where the failure criterion is typically formulated using the von Mises criterion in modeling glass failure,” Salim said. “We developed an elasto-damage glass model subroutine based on the Rankine failure criterion for predicting brittle failure in the glass layers of laminated glass panels. This approach offers a robust tool to accurately evaluate and enhance the safety of blast-resistant laminated glass windows.”

Salim and collaborations’ methods were selected for the cover story of the December issue of the journal Buildings. Co-authors were Ahmed Elbelbisi, Alaa Elsisi, Mohammed H. Saffarini and Zhen Chen.  Salim is also a James C. Dowell Fellow in the College of Engineering and chair of the Department of Engineering and Information Technology.

Learn more about civil and environmental engineering at Mizzou.